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John Byrns John Byrns is offline
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Default Which tube expert can do custom works?

In article ,
Patrick Turner wrote:

John Byrns wrote:

In article ,
Patrick Turner wrote:

Using tubes only is all you need, and its not a very complicated
matter for design unless you want lots of bells and whistles such as
tube based
12 band graphic eq to each input channel, and all floating balanced
inputs and balanced outputs.


Tubes easily did the floating balanced inputs and outputs thing by
making use of transformers. 12 band graphic equalizers are child's play
with tubes. A much more serious challenge would be to design a tube
based parametric equalizer. If anyone has a reasonable idea for how to
approach the latter please let me know as I would like to pursue it.


Gee, if what you say is just so easy and simple, I'd hate to see your
idea of complexity.


I meant conceptually simple, that the design is straight forward, I
didn't mean that you could build a 12 band graphic equalizer using only
half a dozen parts.

But yes, floating outs and ins is very well done with transformers,
that's for sure.

But using output and input trannies IS complex compared to using none at
all.


But assuming you are buying the transformer ready made, it is no more
complex than a good solid state op amp approach as is used today, and
arguably it is less complex than today approach.

And for each band is not one triode needed? 12 bands for each input
channels adds up
to a huge box of tubes....


I haven't looked at 12 band graphic equalizer designs in many years, but
IIRC going back 35 years or so the typical 12 band graphic equalizer
used 12 gyrators and an op-amp with differential inputs. Each of the 12
gyrators used an op-amp, so yes at least 12 triodes would be required,
not including those used in the main op-amp, and several triodes might
even be required per band to get adequate performance from the gyrators.
The point is that the design is simple, straight forward, and relatively
obvious, even for those among us not well schooled in math, unlike the
design of parametric equalizers. If you don't like all the triodes,
simply replace the gyrators with 12 inductors, perhaps a more
appropriate solution for a tube design anyway.

I have no idea where a tubed parametric schematic can be located.


I doubt such a thing even exists.


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/
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RickH RickH is offline
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Default Which tube expert can do custom works?

On Jan 5, 1:24*am, "Tynan AgviŠr" wrote:
I am a recording engineer, and I would like to check with some persons who
are working with tube audio equipment(making it) about manufacturing for me
a custom 8 in, 2 out tube based mixer. I record all acoustic music, chamber
music, folk, bluegrass, celtic, world music, choir, acapella, etc. there a
lot of mass produced choices, but I would like something very special. I
have spoken to MOSCODE months ago, and he said he would do it, but then
never answered my last emails. If anyone can help me, I would much
appreciate it, and will send you all the first recordings of my label
(audiophile type label beginning late this year).

Tackar så mycket,

-Tynan


I would suggest you start out by having someone make you just a single
channel tube pre-amp using a top of the line mic transformer and a
minimalist tone stack and a meter (externally powered). If you like
it, then just clone that as your channel strips in a more modular
fashion, if that just means bolting together mini boxes and just pay
by the channel construction after the initial one is perfected. The
summing buffer is less of an issue than getting the channel strips
right. The backplane could be on a separate back panel chassis
containing the summing buss(es) output buffering, monitor, headphone
amp, main meter, etc. With a modular approach if you dont like the
single channel prototype preamp then you dont have to fund the
backplane, more channels or even continue with the project. I seem
to remember someone here doing mic preamps, and thats where you need
to start IMHO. Modularity can also make it a group project, but then
again I've never seen a documented modular "group project" attempted
on this group with photos, etc.

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Ian Iveson Ian Iveson is offline
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Ian asked:

What are the 'SQ' tubes mentioned on this site?


Special Quality. I guess an example would be E88CC rather
than ECC88. I could be wrong though.

Ian


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Eeyore Eeyore is offline
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Ian Thompson-Bell wrote:

Eeyore wrote:
Ian Thompson-Bell wrote:

Eeyore wrote:
Oh right. You'd dismiss the only pro-audio design engineer posting here.
And who would that be, then?


Are you claiming to be active in this field still ? Did you do design ? I
honestly don't know. You're not a regular enough poster for me to know that
much about you.


I was simply asking who *is* the only pro-audio designer posting here?


That's me then. I've been designing pro-audio for the last 36 years.

Graham

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John Byrns wrote

Eeyore wrote:
Ian Iveson wrote:
Eeyore continued:

It seems that Tynan AgviŠr isn't fooled by your
posturing.

Why should I care, why should I posture, and quite what
posture do you believe I have adopted?

Submit a sample schematic of a valve circuit of your design.
Let's see what you can really do.


A typical triode stage requires a grid, anode load and cathode resistor
(possibly 'bypassed'). What is there to 'design' ? Choosing a resistor
value ?


That's a lot more complex than designing with op=amps today where there
is nothing to choose, where you don't even need to pick values for the
"anode load and cathode resistor (possibly 'bypassed')."


Complete nonsense.

An op-amp circuit is so much more versatile and adaptable that suitable
resistor values may vary over several orders of magnitude according to the
application. Easily by 1000:1 for example.

In the triode circuit you can be fairly sure that the grid resistor will be in
the region of 100k - 1M, the anode load R maybe 47k - 270k and the cathode R
perhaps from several hundred ohms to a few k.

'Designing' with valves is more of a 'cookbook' experience. Op-amps you can
configure to much much more than just some simple amplification stage.

Graham





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John Byrns wrote:

designing with op-amps is considerably more formulaic even than designing
with tubes.


You've clearly never DESIGNED with them then.

I confess to being slightly astonished at your poor level of understanding of
op-amp circuitry.

I may post an example and see if you don't think it's way beyond what you can
do with a tube.

Graham

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John Byrns wrote:

Graham, you claim to have been a "pro audio designer", why don't give
all of us who haven't worked as "pro audio designers" a tutorial on
designing mixing networks? By mixing networks I mean the part of a
"mixer" that does the actual mixing of the multiple inputs.


That's fairly trivial actually.

There are 2 main methods of mixing. 'Voltage mixing' and 'current mixing'.

In both cases, the inputs drive the mix bus using some fixed value resistor
usually following the pan-pot or pan-pot buffer.

In the case of the voltage mix method, the signal is attenuated by a figure
related to the number of channels due to mutual loading from all the mix Rs
and the level is then restored using a high(ish) impedance buffer stage (the
mix amp).

In the case of the current mix (or virtual earth) method, there are the same
mix resistors but this time the buffer amplifier is an inverting configuration
with feedback, the input node of this stage being the mix bus itself. This
makes the mix bus look like a 'virtual earth' by feedback action and has the
advantage that loading is constant and not affected by the number of channels
routed to the bus and the gain is set simply by Rfeedback/Rmix. This is a far
more practical arrangement and is effectively universally used today and has
been almost since I first took an interest in audio. The virtual earth method
also has lower crossstalk susceptibility if you care to run some models of it.

For best noise performance, the mix (and feedback) resistor values should be
as low as practical. A typical value might be 4k7.

Of course great care is needed with routeing a sensitive signal path like the
mix bus in audio mixers. You can also make a balanced mix bus if you like with
all the classic attendant advantages that balanced working has.

Graham

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"Eeyore" wrote in
message
robert casey wrote:

If you want a clinically accurate circuit, solid state
is the way to go. National Semiconductor for one are
making op-amps now with THD well over 100dB below
signal level.


Though I'm not enough of a mathematician to rigously
express it,
my gut feeling is that op-amps with the tons of negative
feedback is not a great device for audio work.


Let me recommend that you *enhance* that gut feeling with a good laxitive.
Your gut feel is due to gas.

Your 'gut feeling' is clearly defective. You're probably
stuck with a 60s / 70s idea of semicondcutor circuitry.


Good semiconductor op amps were better than that even in the 60s.

Non-linearities will create harmonics and
intermodulation products.


Yes, but do you really want to go here with tubes?

130dB down with, for exampe, the LME49710.


Good modern op amp. The scary part is that they have ADCs and DACs that are
as good.

Are you SERIOUSLY saying that you can hear THD that's
-130dB ?


Fact of the matter is that it is very difficult to have THD that has lots of
high harmonics, be audibly distorted at the -60 dB level.

Now, valve / tube circuitry regularly has THD figures
that are ~ -60dB.


Please see http://www.pcavtech.com/sig_proc/PV-2/index.htm for an example.

You would appear to be saying that THD
@ -60dB that's 'good tube distortion' is inaudible (or
'transparent' / other value judgement etc) yet THD @
-130dB that's 'bad solid-state distortion' is clearly
audible.


Note that the legacy (highly regarded in its day) tubed preamp that I tested
had more odd then even harmonic distortion, and more high order distortion
than 2HD?



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And I will die 1,000 death's defending your right to free speach,
but if I disagree with you its not a big deal, eh?

Of course not, Mr. Turner. I do want you to see where I am coming from,
though.




xists!

Something like what you want is much more complex than a normal
preamp, and its a one-off, so expect the price to be several times
whatever range of
preamp prices you see, so maybe between $1,000 and $5,000.

Yes, sir. I realize that. I knew it wouldnt be for peanuts. Nothing I
have that is any good was not created cheap.


..

But what if you end up having a lot of us argue about the best way to
do it
for a month and you have only $500 to spend?



Sir, I guess there have been a lot of people that have taken advantage of
certain people's kindness here, and I realize that this tendency to be
guarded/defensive is not without reason... Let me state this, I dont want
anything done for cheap, and I certainly didnt want anyone to argue. I
had hoped that someone would mention a name of a contact with whom I
could work. That is how I normally get steered to service type people..I
guess not here. This trolling nonsense..I dont understand. What am I
stealing by asking for names? I dont want schematics. I dont want build
advice, I know exactly what I want(well I guess Graham and Rudy helped me
clear up a couple of issues with terminology, etc). I wanted a referral
name or perhaps someone from these ranks to say they could work with me
(for payment).
What's in it for any of us?


Well, money is the most obvious answer. But satisfaction of helping
another human being is a collateral benefit. I realize in these trying
times that simply helping others doesnt account for dick. How many folks
get a buzz out of extending a helping hand/no strings attached? I know I
do, but perhaps that is a subconscious need for me to somehow make up for
the lives I ruined in the mideast/southeast asia/africa..and not any
indicator of the type of person I am..anyway.

Ive never done business that way, and
dont intend on ever doing it that way.


I think everyone here would realise that you would negotiate privately
about the actual agreed sum if you wanted to.


(Yes, I would..I still hope to work with someone here)

I had hoped someone would contact
me(and they have) , do a little brain storming with those expert
brains of theirs, get back to me with a figure and some scenario of
what they could do, yadda yadda. And lets work it out.. as for the
things you said.. *ive* never known any expert do do business in
that manner.


To prepare a prospective schematic neatly drawn up in MS paint is a
full day or two's work,
but I ain't got time now.


Sir, I dont expect a schematic. I dont want one. I just wanted a name of
someone who does this sort of thing so that I could make a phone call. If
such a person is here, that would be nice too. I do enjoy all the
discussion here though(infighting aside)




Maybe someone else has the time and will go all public about the
design to give the
whole world something, not just have you being the sole beneficiary of
the work.

You may not actually end up buying anything. Many people are saying
thay want this or that
and want to pay for it but after lots of discussion they get nothin.
Shop assistants call them tyre kickers.


I understand that skepticism..but I certainly will buy something.if I
dont find someone here or out and about I will have to buy used or mass
produced(which I dont want, but a man has to have tools to work with). I
have been multi-tracking for years, but I want to go back to how I worked
when I first began, ie mixing down to 2 in real time. Sounds better that
way in my opinion.



Well let's see if you get your design fully fleshed out for nothing.


I dont want to ****ing flesh a design out. I want to tell someone what I
want and have them build it!
What is this "nothing" bull****?? I will pay for ****s sake. So lets stop
talking about getting work for nothing, eh? Ive said over and over and
over and over what I want, why are some not hearing??

I want someone to work with me. I want to pay them....Is that clear
enough?


Tell me, Mr. Turner. What is the correct way to approach this? I am
anxious to know.



Meanwhile I have real work to perform or I starve.



as do I. Ive got a toddler , a wife, a mortgage, a farm, and my own grad
degree to cover.
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"robert casey" wrote in message


Then you try to cancel that all out with the feedback


That's NOT how feedback works (in some sequential
manner). You should learn something about proper
feedback theory.


That takes a little background in math. Count the typical
audiophool/basement constructor out! :-(

Well, there is some propagation delay of the signal as it
works its way thru a real op-amp.


That differs from any other electronic circuit in what way?

A bit of history - op amps have been around for a lot longer time than SS
audio gear has. The first op amps were, you guessed it now that you actually
thought about it, tubed! Google on "Philbrick amplifier" if you think I'm
kidding.

The common figure of merit for what you might call amplifier speed is
gain-bandwidth product. The last generation tubed op amps had
gain-bandwidth products of about 800 KHz or less. This less than the
gain-bandwidth of the earliest monolythic op amps from the late 60s and
early 1970s. A modern audio op amp of the lowest quality commonly used for
econo-audio might beat that by a factor of 10-15. The best ones beat it by a
factor of 100 or more.

Music signals are full
of transient spikes and such, not just continuous sine
waves.


This turns out to be false. All acoustical instruments, even percussion
instruments, are highly resonant. That means that when activated by being
blown on or by percussion, they produce a damped tone. The big difference
between a horn and a wood block is that the horn tends to be driven
continuously while the wood block is struck. They both ring pretty strongly.
When you strike many percussion instruments, they even take a while to build
up a tone.

About the only place one sees transient spikes in audio is in the lab or the
digital domain.

This propagation delay doesn't seem to be
specified or even presented in most datasheets.


That's because propagation delay is not how we engineer this kind of
circuit. Audio circuits are designed based on the accurate real-world idea
that they process damped bursts of complex waves which can be accurately
broken down into many sine waves with different frequencies and envelopes.

Since you brought up inverse feedback, that is also designed based on the
idea that real world signals are composed of collections of enveloped sine
waves. The relevant measure of how an operational amplifier works is its
Bode plot, which is usually given briefly as the op amp's gain bandwidth
product.

But looking at a somewhat randomly chosen op-amp
http://focus.ti.com/lit/ds/symlink/opa244.pdf on page 9 there's an
oscilloscope "picture" of the "small
signal step response". The op-amp is set to unity gain,
the output has an overshoot of about 2uSec duration.


Like you said, randomly chosen. This is an op amp that nobody in their right
mind would choose for a high performance audio application. Key
specification: the gain bandwidth product is a measely 430 KHz. It might be
found in a digital weather thermometer.

If you're going to talk about op amps for audio, try starting he

http://focus.ti.com/lit/ml/slyy013a/slyy013a.pdf

If you want to pick a crappy op amp that people might actually use for
cheap-ass audio, pick this one which everybody loves to hate, but lots of
people use anyway:

http://www.hoohahrecords.com/resfreq...ts/njm4558.pdf






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"Eeyore" wrote in
message
robert casey wrote:

Sure, that's not much time, about a half
cycle of 250KHz, and okay, that's probably fast enough
of a response for audio work.


Where are the 250 kHz signals in audio ?


This is an issue that no knowlegeable tubophile would bring up, because 250
KHz coming out of tubed audio gear, particularly tubed power amps, is not
often a pretty sight.


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"robert casey" wrote in message

Eeyore wrote:


robert casey wrote:


But there's a time delay in getting that feedback
signal to the input



WRONG again.

Oh, maybe 20uSec, but maybe not worth worrying about?


LOL!

If ignorance is bliss, you must be one very happy dude.

Take a butt-cheap audio op amp with a gain-bandwidth of as little as 10 MHz.
This puppy can pass a 10 MHz signal with just a little loss. A 10 MHz signal
repeats itself every 0.1 uSec or 100 nanoseconds.

If you hit this op amp with a 10 Mhz MHz tone burst, a signal appears at its
output terminals within the same nanosecond that the signal was applied.


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"John Byrns" wrote in message


Graham, you claim to have been a "pro audio designer",
why don't give all of us who haven't worked as "pro audio
designers" a tutorial on designing mixing networks? By
mixing networks I mean the part of a "mixer" that does
the actual mixing of the multiple inputs.


The short answer is that for low noise, you want the mix bus to run at a
very low impedance. But, you still need to drive it with a signal that is
capable of good dynamic range. People end up designing mixing bus drivers
like they were small power amps.

Hopefully, DSPs will be the end of analog mixing buses.


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Ian Thompson-Bell Ian Thompson-Bell is offline
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Eeyore wrote:

John Byrns wrote:

Graham, you claim to have been a "pro audio designer", why don't give
all of us who haven't worked as "pro audio designers" a tutorial on
designing mixing networks? By mixing networks I mean the part of a
"mixer" that does the actual mixing of the multiple inputs.


That's fairly trivial actually.

There are 2 main methods of mixing. 'Voltage mixing' and 'current mixing'.

In both cases, the inputs drive the mix bus using some fixed value resistor
usually following the pan-pot or pan-pot buffer.

In the case of the voltage mix method, the signal is attenuated by a figure
related to the number of channels due to mutual loading from all the mix Rs
and the level is then restored using a high(ish) impedance buffer stage (the
mix amp).


Just a couple of additional notes on this method since we both worked at
Neve and this (when I was there at least) was the way mixing was done.

First you need to add the source impedance of each of each channel to
the series mix resistor when working out the attenuation. Second the
source impedance directly affects the crosstalk achieved as the mix bus
signal is effectively fed back to the output of each channel which, via
channel routing may be fed to other mix busses. A channel cut or mute
switch is often included in mixers which, as well as disconnecting the
channel, also grounds its mix bus resistor thus giving a near zero
output impedance and improved cross talk. In a typical stereo desk the
channel fader is typically followed a pan pot which selects the
proportion of signal fed to each mix bus. In the worst case the source
impedance can then be half the value of the pan pot which is far too
high if a good crosstalk figure is required. In Neve desks of the 70s a
simple emitter follower buffer was often used after the pan pot to lower
the source impedance before the signal was fed to channel routing buttons.

Lastly the bus resistor values are often chosen such that the resultant
parallel combination is not far from the typical source seen by a mic
preamplier - why, because basically a mic pre, complete with input
transformer, was used in Neve desks as the mix amp. Typical bus resistor
values of 6K8 were used in the 70s so for an 8 channel desk with CF
source impedance of 500R the bus impedance is (6800 + 500)/8 = 912 ohms.
Neve mic pres had a typical Zin of 1K2 and you would need just over 18dB
of gain to restore the signal level.

In the case of the current mix (or virtual earth) method, there are the same
mix resistors but this time the buffer amplifier is an inverting configuration
with feedback, the input node of this stage being the mix bus itself. This
makes the mix bus look like a 'virtual earth' by feedback action and has the
advantage that loading is constant and not affected by the number of channels
routed to the bus


Not quite sure what you mean by 'the loading is constant' as in the Neve
mix bus the loading was constant too.

and the gain is set simply by Rfeedback/Rmix.

The impedance of the 'virtual earth' is simply Rfeedback/open_loop_gain
which with op amps can be very small indeed (although it varies with
frequency) but rather harder to achieve with valves. The very low
virtual earth impedance improves crosstalk figures no end.

This is a far
more practical arrangement and is effectively universally used today and has
been almost since I first took an interest in audio.


Virtual earth mixing has been around a long time and is certainly very
commonly used in semiconductor based mixers, especially small ones.
However, it is not without its problems, particularly in physically
large mixers (many custom Neve mixers had mix busses over 10 feet long).
I have a copy of a Neve Technical report from 1976 which compared the
'traditional' Neve mix method with virtual earth mixing from a purely
technical standpoint. It concluded that the two were very similar and
the virtual earth mixing just had a slight advantage in noise
performance. I don't know if Neve ever adopted virtual earth mixing.

The virtual earth method
also has lower crossstalk susceptibility if you care to run some models of it.


It does. It is fairly easy to achieve a virtual earth about 10 times
smaller than with voltage mixing.

For best noise performance, the mix (and feedback) resistor values should be
as low as practical. A typical value might be 4k7.


The limit depends on the equivalent noise resistance of the summing amp
and the number of channels. For 30 inputs and 10K mix resistors the
virtual earth method is only 1dB quieter than the voltage method. For
smaller numbers of inputs a lower value mix resistor would be needed to
achieve the same noise level so 4K7 would be a reasonable value. Note
that the Neve mix amps had a noise resistance of 300R (this is with 70s
semiconductor technology) and modern op amps would undoubtedly improve
on this. For valves the equivalent noise resistance would probably be
somewhat higher..

Of course great care is needed with routeing a sensitive signal path like the
mix bus in audio mixers. You can also make a balanced mix bus if you like with
all the classic attendant advantages that balanced working has.


Too true.

Cheers

Ian

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Phil Allison wrote:
"robert casey masturbating audiophool TROLL "

But it felt good.... ;-)


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"robert casey masturbating audiophool TROLL "


Though I'm not enough of a mathematician to rigously express it,

my gut feeling



** Not really any way to do science or engineering.

Gut feelings are what primitive man used instead of "science", as did the
Alchemists, all manner of fakers and charlatans - and now that the human
race knows better - complete * ****wits * like you come along and want
to drag us all back to the pig ignorance of the Dark Ages.


is that op-amps with the tons of negative feedback
is not a great device for audio work. Non-linearities will create
harmonics and intermodulation products. Then you try to cancel that all
out with the feedback, but as you may cancel most of the lower order crud,
you then create even more higher order harmonics and intermodulation
products. And that loops back yet again.



** Total and ABSOLUTE ******** !!!!!!!!!!!!!!!!!

You criminal ass.



....... Phil







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"John Byrns Congenital TROLL "


Graham, you claim to have been a "pro audio designer", why don't give
all of us who haven't worked as "pro audio designers" a tutorial on
designing mixing networks? By mixing networks I mean the part of a
"mixer" that does the actual mixing of the multiple inputs. The design
of the various amplifiers that are required in a project like this is
not beyond the capability of many in this group, but the actual "mixing"
network and its requirements is a different matter. As a "pro audio
designer" please enlighten us about this aspect of "mixer" design.



** Yawn - another of Byrns ASININE brain dead trolls.


See under "Summing Technology":

http://www.dself.dsl.pipex.com/ampin...mixerdes.htm#6


Also for the basic idea:

http://hyperphysics.phy-astr.gsu.edu...opampvar5.html

http://www.all-electric.com/schematic/simp_mix.htm

http://www.ecircuitcenter.com/Circuits/opsum/opsum.htm

http://en.wikipedia.org/wiki/Operati...ng_amplifi er



**** off TROLL !!!



........ Phil


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..

Your rampant amateurism knows no bounds.



Indeed not. I'm proud to be an amateur, and happy to know no
bounds.


I'm an amateur too, and my callsign is WA2ISE. :-)
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flipper wrote:

1000 to 1 is not a 'more complex' ratio than 10 to 1. It is, however,
often simpler to design with a wide ratio device because it reduces
the number of devices/stages the designer has to do himself, which is
one reason why opamps are so convenient... and simple (to use).


Meaningless babble.

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Eeyore wrote:


robert casey wrote:


Eeyore wrote:

robert casey wrote:


But there's a time delay in getting that feedback signal to the input


WRONG again.


Oh, maybe 20uSec, but maybe not worth worrying about?



You think that the open-loop bandwidth of a typical op-amp is only 50kHz ?
LMAO !

Try 55MHz for the LME49710 and around 10 MHz for more pedestrian offerings.

It's NOT a *time* delay either.



Never said that it was. Open loop bandwidth doesn't care about propagation

delay, sometimes called phase shift at some specific frequency,

thru that op-amp. Suppose you had an op-amp with open loop

bandwidth of 60dB at 100MHz,
but had an internal propagation delay of 1msec. You'd have a hard time
doing a negative feedback circuit and be able to get closed loop gain
being the same from DC to 20KHz. 1msec delay on a sine wave at 500Hz
will make a phase shift of 180 degrees, which makes the negative
feedback loop look rather positive. And thus unstable. Of course such
an op-amp would not be used here! If such an op-amp even existed. Now
lets say the propagation delay is such that it makes a phase shift of 90
degrees at 10KHz. Now lets say that the op-amp has something inside
that creates some crossover distortion. Say at its output stage inside.
Lets further say that it doesn't become a total flatline to zero,
but the slope gets a kink that has a short segment of half gain at the
signal zero crossing. No big deal for an op-amp with no significant
propagation delay (like a fraction of a degree of phase shift at the
frequency of the sine wave signal getting amplified). But if the phase
shift is 45 degrees thru the op-amp, the feedback signal arrives 45
degrees too late to correct the crossover distortion to correct it in
time. So you end up with an output signal with a crossover glitch at
zero crossing, and another glitch 45 degrees later. Won't sound too good.

But modern op-amps have propagation delays so short that this becomes a
non-issue.








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robert casey wrote:

Open loop bandwidth doesn't care about propagation

delay, sometimes called phase shift at some specific frequency,


Propagation delay and phase shift are not even remotely the same thing. The
former applies to non-linear (typically saturated) switching circuits and the
latter applies to linear amplifiers.

Will you please STOP spouting this idiotic audiophool CRAP.

Graham

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robert casey wrote:

Suppose you had an op-amp with open loop bandwidth of 60dB at 100MHz,
but had an internal propagation delay of 1msec.


Just how ****ING STUPID are you ? Your suggested spec is nonsense and
self-contradictory. It's clear you haven't a clue about how to use GBP (gain
bandwidth product) either.

Ever heard of slew rate ? With modern op-amps they'll swing around a Volt (all
that's required for a typical audio signal) in around 100 NANO seconds ! NO
DELAYS !

However the input signal doesn't move that fast. A full power 1 V rms 20kHz
signal is only 0.18 V / usec maximum ( 18 mV in 100 ns). Result, the op-amp never
gets driven into uncontrolled slewing and stays in linear operation under any
audio signal condition.

All your ideas are plain barking mad.

Graham

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robert casey wrote:

If such an op-amp even existed. Now
lets say the propagation delay


It's NOT a propagation delay.


is such that it makes a phase shift of 90 degrees at 10KHz.


If an op-amp had a phase shift of 90 degrees at 10kHz it's simply not possible
for it to have a GBP of much greater than about 100k. It would be totally
unusable for audio.

Typical modern op-amps have 90 degree phase shifts somewhere in the 500kHz - 1
MHz region.

Graham

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robert casey wrote:

But if the phase
shift is 45 degrees thru the op-amp, the feedback signal arrives 45
degrees too late to correct the crossover distortion to correct it in
time. So you end up with an output signal with a crossover glitch at
zero crossing, and another glitch 45 degrees later. Won't sound too good.


Do you get a kick out of talking **** ?

Feedback in analogue circuits is instantaneous. It doesn't 'arrive later'.

You're barking mad.

Graham

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"Eeysore"


Typical modern op-amps have 90 degree phase shifts somewhere in the
500kHz - 1
MHz region.



** The humble LM741 ( dates from 1968) has such performance.

An LM301A ( dates from 1969) makes 10MHz with low phase shift, with
feed-forward compensation.

Most Bi-FET types ( TL071 etc) make 10MHz, as does the NE5532 et alia.



........ Phil




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"Eeysore"
robert casey wrote some ABSOLUTE CRAP


Do you get a kick out of talking **** ?

Feedback in analogue circuits is instantaneous. It doesn't 'arrive later'.

You're barking mad.



** Casey is another " Louie the Fly " type of usenet troll.

Like a disease carrying fly, the brain dead puke frequents places on the net
that reek with malodorous mis-information -he must like the smell of such
excreta.

Then, with the evil smelling stuff stuck all over him, he transfers it to
RAT on his next visit.

This video shows who " Louie the Fly" is.

Australian adults are all probably very familiar with the character and the
song.

" Straight from rubbish tip to YOU !!! "




......... Phil




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"Phil Allison"


** This video shows who " Louie the Fly" is.

http://video.google.com/videoplay?do...93673820188113




....... Phil


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So does anyone have any last words for the deceased?

My thread is long gone. Long damn gone.

Graham, Arny(Hey Arny!), and other instructive posters, thanks for your
insight. It is appreciated.

If anyone is out there that is capable and willing to build for me(for good
pay of course) shoot me an email. Maybe Jon Atkinson will help me out. Har
fecking har



Tynan


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"Tynan AgviŠr"

So does anyone have any last words for the deceased?



** You planning to top yourself ?

" Go ahead - make my day ........ "



My thread is long gone. Long damn gone.



** Shame YOU are not - you ****ing nut case.


If anyone is out there that is capable and willing to build for me(for
good
pay of course) shoot me an email.



** Only a charlatan would reply to a raving nut case like you.

I bet one does and rips you off blind by demanding a large down payment.





......... Phil








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"Tynan AgviŠr" wrote:

So does anyone have any last words for the deceased?

My thread is long gone. Long damn gone.

Graham, Arny(Hey Arny!), and other instructive posters, thanks for your
insight. It is appreciated.


I think we need to start a new thread and hope that the clowns don't hijack it
again so quickly.

Graham



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Phil, this has been a fun flame war, but your posts are getting boring...
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"robert casey"

Phil, this has been a fun flame war,



** This is no flame war - you despicable pile of sub human puss.

Casey is another " Louie the Fly " type of usenet troll.

Like a disease carrying fly, the brain dead puke frequents places on the net
that reek with malodorous mis-information - he must like the smell of such
excreta.

Then, with the evil smelling stuff stuck all over him, he transfers it to
RAT on his next visit.

This video shows who " Louie the Fly" is.

Australian adults are all probably very familiar with the character and the
song.

" Straight from rubbish tip to YOU !!! "

http://video.google.com/videoplay?do...93673820188113




......... Phil





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Propagation delay and phase shift are not even remotely the same thing. The
former applies to non-linear (typically saturated) switching circuits and the
latter applies to linear amplifiers.


Well, not all phase shifts are caused by propagation delays, but
propagation delays do create phase shifts.

And although "propagation delay" is usually used on digital devices, all
it is is the time difference from when a transient spike's rise time
gets from the input to output. You don't have to have saturation. And
"speed of light" is an upper limit on how fast a signal can go. Usually
of no significance in audio, but it does exist. Though it's like
peeing into the ocean. Or in this ****ing contest... :-)
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"robert casey"


** This is no flame war - you despicable pile of sub human puss.

Casey is another " Louie the Fly " type of usenet troll.

Like a disease carrying fly, the brain dead puke frequents places on the net
that reek with malodorous mis-information - he must like the smell of such
excreta.

Then, with the evil smelling stuff stuck all over him, he transfers it to
RAT on his next visit.

This video shows who " Louie the Fly" is.

Australian adults are all probably very familiar with the character and the
song.

" Straight from rubbish tip to YOU !!! "

http://video.google.com/videoplay?do...93673820188113




......... Phil






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John Byrns wrote:

In article ,
Patrick Turner wrote:

John Byrns wrote:

In article ,
Patrick Turner wrote:

Using tubes only is all you need, and its not a very complicated
matter for design unless you want lots of bells and whistles such as
tube based
12 band graphic eq to each input channel, and all floating balanced
inputs and balanced outputs.

Tubes easily did the floating balanced inputs and outputs thing by
making use of transformers. 12 band graphic equalizers are child's play
with tubes. A much more serious challenge would be to design a tube
based parametric equalizer. If anyone has a reasonable idea for how to
approach the latter please let me know as I would like to pursue it.


Gee, if what you say is just so easy and simple, I'd hate to see your
idea of complexity.


I meant conceptually simple, that the design is straight forward, I
didn't mean that you could build a 12 band graphic equalizer using only
half a dozen parts.

But yes, floating outs and ins is very well done with transformers,
that's for sure.

But using output and input trannies IS complex compared to using none at
all.


But assuming you are buying the transformer ready made, it is no more
complex than a good solid state op amp approach as is used today, and
arguably it is less complex than today approach.


But ppl who use only opamps to do evrything with line level signals will
see the use of transformers
and tubes as more complex because its more difficult to build
physically.

They are right in thier view as much as you are right about the
transformer approach being
conceptually no more circuitarilly more complex.



And for each band is not one triode needed? 12 bands for each input
channels adds up
to a huge box of tubes....


I haven't looked at 12 band graphic equalizer designs in many years, but
IIRC going back 35 years or so the typical 12 band graphic equalizer
used 12 gyrators and an op-amp with differential inputs. Each of the 12
gyrators used an op-amp, so yes at least 12 triodes would be required,
not including those used in the main op-amp, and several triodes might
even be required per band to get adequate performance from the gyrators.


A tubed graphic eq would nearly always use tuned series or parallel
resonant LC circuits for the
bands to eliminate the cost and unreliability of 12 triodes just for
gyrators.


The point is that the design is simple, straight forward, and relatively
obvious, even for those among us not well schooled in math, unlike the
design of parametric equalizers. If you don't like all the triodes,
simply replace the gyrators with 12 inductors, perhaps a more
appropriate solution for a tube design anyway.


Exactly.

But without any eq, the mixer proposed is fairly simple.

I have no idea where a tubed parametric schematic can be located.


I doubt such a thing even exists.


If its doable with opamps, its doable with tubes.

Patrick Turner.

Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/



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Eeyore wrote:

John Byrns wrote:

designing with op-amps is considerably more formulaic even than designing
with tubes.


You've clearly never DESIGNED with them then.

I confess to being slightly astonished at your poor level of understanding of
op-amp circuitry.

I may post an example and see if you don't think it's way beyond what you can
do with a tube.

Graham


I have used 3 cascaded opamps with incomprehensibly derived positive and
negative
feedback loops overlapping each other to make a tunable audio bandbass
filter with Q = 50
between 1kHz and 10kHz, so its good for checking thd and IMD products
falling inside this band.

Its doable with tubes but what a waste of effort!

I got the schematic from somewhere in a book 30 years old at least.

And when I made it, the darn thing worked first go,
and was far easier to get running than a bunch of tubes.
Not bad for a circuit out of a book!
Some don't work because errors are in the schematic...

But such hi-Q tunable filters WERE used in film sound tracks to manually
remove the unwanted tones appearing in recordings. A film about
Robin Hood would sound silly if you heard a Cessna flying past over the
set
as some outragious proposal was being made to Maid Marian.

if I was starting out again I'd just devote an old PC to the job of
spectrum analyzer,
and all would be digitally analyzed....

Opamps have their place alright, and some oscillators and meters I
designed and built
have opamps, maybe one or two discrete j-fets or BJTs as well.

I like what tubes do with music.

Patrick Turner.
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In article ,
Eeyore wrote:

Propagation delay and phase shift are not even remotely the same thing. The
former applies to non-linear (typically saturated) switching circuits and the
latter applies to linear amplifiers.


OK, but I am curious what you call the effect of a thousand foot section
of coaxial cable, or telephone line, on an audio signal? An analog
signal injected in one end of the line does not come out the other end
immediately, the signal appears at the output at a later time, is this
propagation delay or phase shift?


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/
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"Tynan AgviŠr" wrote:

And I will die 1,000 death's defending your right to free speach,
but if I disagree with you its not a big deal, eh?

Of course not, Mr. Turner. I do want you to see where I am coming from,
though.

xists!

Something like what you want is much more complex than a normal
preamp, and its a one-off, so expect the price to be several times
whatever range of
preamp prices you see, so maybe between $1,000 and $5,000.

Yes, sir. I realize that. I knew it wouldnt be for peanuts. Nothing I
have that is any good was not created cheap.


.

But what if you end up having a lot of us argue about the best way to
do it
for a month and you have only $500 to spend?


Sir, I guess there have been a lot of people that have taken advantage of
certain people's kindness here, and I realize that this tendency to be
guarded/defensive is not without reason... Let me state this, I dont want
anything done for cheap, and I certainly didnt want anyone to argue.


I have never been knighted by the Queen, even though she's the official
head of state
for the Commonwealth of Australia.

So there's no need to call me "Sir", although I don't mind.

I am just a bloke, right?

I
had hoped that someone would mention a name of a contact with whom I
could work. That is how I normally get steered to service type people..I
guess not here. This trolling nonsense..I dont understand.


Trolling and time wasting and off topic bickering bitching occupies 95%
of the content
of most public non moderated news groups. For an extreme example of
crapological communications,
subscribe to soc.men, or soc.women.

All the axes used by nearly all posters have blood dripping off them.

This place is good compared to curmudgeon dominated other groups where
mainly grumpy old fartarses obscure meaning to life.




What am I
stealing by asking for names? I dont want schematics. I dont want build
advice, I know exactly what I want(well I guess Graham and Rudy helped me
clear up a couple of issues with terminology, etc). I wanted a referral
name or perhaps someone from these ranks to say they could work with me
(for payment).
What's in it for any of us?


Well, money is the most obvious answer. But satisfaction of helping
another human being is a collateral benefit. I realize in these trying
times that simply helping others doesnt account for dick. How many folks
get a buzz out of extending a helping hand/no strings attached? I know I
do, but perhaps that is a subconscious need for me to somehow make up for
the lives I ruined in the mideast/southeast asia/africa..and not any
indicator of the type of person I am..anyway.


I don't know anyone who could help you other than Tim DeParavicini, Andy
Grove,
and other well know designers. Give these guys an email and ask who else
would do it if you think Tim's or Andy's hourly rate a bit too high...
!

Ive never done business that way, and
dont intend on ever doing it that way.


I think everyone here would realise that you would negotiate privately
about the actual agreed sum if you wanted to.


(Yes, I would..I still hope to work with someone here)

I had hoped someone would contact
me(and they have) , do a little brain storming with those expert
brains of theirs, get back to me with a figure and some scenario of
what they could do, yadda yadda. And lets work it out.. as for the
things you said.. *ive* never known any expert do do business in
that manner.


To prepare a prospective schematic neatly drawn up in MS paint is a
full day or two's work,
but I ain't got time now.


Sir, I dont expect a schematic. I dont want one. I just wanted a name of
someone who does this sort of thing so that I could make a phone call. If
such a person is here, that would be nice too. I do enjoy all the
discussion here though(infighting aside)

Maybe someone else has the time and will go all public about the
design to give the
whole world something, not just have you being the sole beneficiary of
the work.

You may not actually end up buying anything. Many people are saying
thay want this or that
and want to pay for it but after lots of discussion they get nothin.
Shop assistants call them tyre kickers.


I understand that skepticism..but I certainly will buy something.if I
dont find someone here or out and about I will have to buy used or mass
produced(which I dont want, but a man has to have tools to work with). I
have been multi-tracking for years, but I want to go back to how I worked
when I first began, ie mixing down to 2 in real time. Sounds better that
way in my opinion.


You have an admirable ambition, to be sure.

But I though Manley Labs would about make what you want.

Who cares if you ain't their only customer and they mass produce?

Just imagine what a Mercedes Benz would cost if only one a year was
made!



Well let's see if you get your design fully fleshed out for nothing.


I dont want to ****ing flesh a design out. I want to tell someone what I
want and have them build it!


But unless a design is thought about, proposed, schematicked up, then
argued about for awhile
until all get sick of it, then it hasn't been designed here, because
here
is where a lot of brainy ppl hang out along with the usual crop of
trolls, nit pickers and BS artists.


What is this "nothing" bull****?? I will pay for ****s sake. So lets stop
talking about getting work for nothing, eh? Ive said over and over and
over and over what I want, why are some not hearing??


Because its mainly a diy group whose existance is sustained by technical
talk about tube operated sound equipment.

I am not a true diyer because I sell what I make after doing much as
possible myself,
and I share that experience as I go along.

Very Very FEW other tradesmen like myself have enough facility with
english to
explain all as they proceed, and even fewer actuually want to talk about
their work
or anything complex at all to anyone.

I could say i was a professional, but a true pro has letters after his
name from doing a uni course,
and operates a proper established business with employees and makes both
a wage and profit.
They often like to charge what a tradesman will charge, then add an
extra nought to the fee.
Dentists for example dig holes and fill them in again but charge a pile
more than I do.

Anyway, I have chosen to convert a hobby and interest and passion into
what I consider a trade.
Winding OPT is a trade, not a profession, ditto chassis metalwork and
finishing.
However, when I design something, out comes the calculator, and on goes
the
engineer's hat, and I become the brains person; maybe that makes me a
pro by de-facto means...



I want someone to work with me. I want to pay them....Is that clear
enough?

Tell me, Mr. Turner. What is the correct way to approach this? I am
anxious to know.


You have asked who could design AND build something, and drawn a blank.

The few ppl out of many who stay here solely for the sake of tube craft
are not prolific makers of gear; its mainly a hobby for most of them.
Pros or tradesmen tend to stay well clear of the likelyhood of
being roundly attacked by trolls or charlatans were they to turn up here
to take part, hence her is where you will never see the boss of ARC,
Conrad Johnson, Manely Labs,
Quad, VAC, McIntosh, and many othes.

Email these companies and outline your design aims.
Ask them under what conditions and price would they make something for
you.

They design and manufacture tubed audio gear, and although I said I
didn't know anyone,
I meant that I didn't know anyone personally.
Well, maybe there's one exceptio; I have had pleasant email exchanges
with Eve-Anna Manley, the boss
os Manley Labs who helped me service some of her designs purchased by
locals here in Canberra.


Meanwhile I have real work to perform or I starve.


as do I. Ive got a toddler , a wife, a mortgage, a farm, and my own grad
degree to cover.


If I had a young family, a wife to keep and a loan to repay after
getting a degree,
and mortgage on a property, there is NO WAY I could be doodling along
like I am in my
late middle age designing and building custom masterpiece amplifiers and
repairing every man's broken tube gear.

I am getting by on less than USD $6,000 taxable per annum.
I'm not married, the house is all paid for, and have no loans to repay.
People like what I make a lot, but they want to pay less than half the
price
for the equivalent item they see in the shops or on the Net.
Because what I make is one-of-a-kind and special, I should get at least
twice the
ARC or Conrad Johnson price, or about 4 times what I get now.
But if I charged a higher price there'd be even fewer customers.
Most customers i do have come to me out of desperation because there is
nowhere else to go
for a decent repair by someone who is a real guru.
Then they realize what i can do when they hear music through their
re-engineered amp
or the repaired amp, and they wonder what else I could sew together for
them...
Some abuse the personal trust/friendship they try to establish by
expecting me to
work for almost nothing.
Last year a guy I'd known for 7 years and who i did regard as a friend
told me to get lost when I sounded him out about a 1958 all tubed Harmon
Kardon
receiver he left here for repair and rebuilding. Its a major amount of
work to
re-engineer something like this and a minimum is usually $500, and I
might take a fortnight
to do the work, including re-design of crummy circuit techniques that
were routinely used by most famous ****makers of 1958.
I said he only wanted to pay $200, and then he said the friendship was
over.
It is unbecoming of a bloke when he acts like a bitch, but its the real
world!
Good riddance to him because I have other many friends who can mix
friendship
and business without expecting to rip me off.
The HK receiver gathers dust in my shed and I don't care a hoot about
it.
I have to shop for the best payers or I starve.


So during the last 14 years of survival without much income
I concluded that the guy who told me I'd really do well commercially
with a website
was a complete BS artist, and that building a business on a niche market
product everyone loves but hates to pay for
meant financial suicide, and so I have stayed single, and so frugal of
habit it'd be impossible
to expect anyone to share a life with me. But I actually like frugality,
and transport for fun by bicycle, and don't want or need most of the
junk forsale in the shops....

I also concluded that if I couldn't be rich, I'd be be the one to know
more about most
tube audio related matters and so I gradually put together my website
for the betterment of
anyone wanting to visit the site.
I removed product prices I initially had, thus forcing anyone to talk to
me if they wanted prices.
I don't like dealing with anyone with whom I cannot get on with
personally
or financially.
There are fuctards who expect I work for lower prices than what are the
lowest priced Chinese crap...

So you see where I come from, not from Planet X, but from
Mother Earth, whose sons and daughters are a vexatious ****in lot to be
sure.

Patrick Turner.
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Phil Allison wrote:

"Tynan AgviŠr"

So does anyone have any last words for the deceased?


** You planning to top yourself ?

" Go ahead - make my day ........ "

My thread is long gone. Long damn gone.


** Shame YOU are not - you ****ing nut case.

If anyone is out there that is capable and willing to build for me(for
good
pay of course) shoot me an email.


** Only a charlatan would reply to a raving nut case like you.

I bet one does and rips you off blind by demanding a large down payment.


I don't know how many people you have built audio gear for Phil.

But I have worked for quite a number over the last 14 years.

Some said they were prepared to pay far more than the total expense
ended up being,
and then when presented with a bill after zero deposit, they failed to
ever pay or talk to me again.
After years waiting I have been forced to sell their gear to recover
part of the
payment owed to me.

I have done repairs of less glamourous SS gear worth less than $25 at a
garage sale
and because the repair cost came to $100, the customer never shows up to
pick up the item.
I've got 3 or 4 of those hanging around like boat anchors.

Let me just say that any tradesman or professional is the one to usually
get bad press
when a dealing goes sour, and its NEVER EVER the customer who is wrong
or
is strung up by the press for not paying. Business is expected to bear
the costs
of customer dysfunction, because if a business makes a public complaint
about Customer Z,
then it only gives the business a bad name, unless the customer tries to
burn down
a house, or smash things up, and even then business doesn't like any
story which could be
negative publicity.

And I can tell you all that 5% of customers are ones I happily wave
farewell to forever
after an initial little deal, and when they want more, I just say I am
far too busy.

For anything custom item such as a house extension or a tailor made
suit, a hefty
up-front fee is usually normal. It should be paid on both parties
agreeing to the condition that if the
maker fails to perform, its FULLY REFUNDABLE.
If the buyer fails to complete the deal then its parley time for both
parties,
and if a buyers has changed his mind or has changed circumstances then
the maker is entitled to
sell the gear for whatever he can get and refund what is fair thing if
any at all.

I have experienced customer failure to complete a deal on a couple of
occassions
with amps costing up to $8,000.
In one case I very unusually found another man who was very interested
in "taking over a contract"
after an initial customer pulled out due to circumstances. I paid the
deposit back to the customer fully and arranged
the new buyer to purchase the special parts previously paid for by the
initial customer. Everyone ended up happy, no sour grapes, and I
continue to offer full
after sales service. I've never been taken to court for ill-dealing, and
solved all contractual problems outside a court with a few phone calls
and emails.

So I have nobody out wanting to lynch me.

I always expect a deposit of 33% of the final expected price or initial
estimate without extras.

And before the item leaves my premises, payment must be IN FULL, and
after the amount registers in my bank account.

I give 90 days warranty on tubes, and 2 year warranty on anything else.
Usually nothing ever goes wrong with amps I build BECAUSE of the active
protection schemes I put in place, so when a customer gets flumoxed by
a wayward tube causing the amp to shut down several years after
purchase,
I will normally replace a tube
and do a service and test/observation of all things for no labour cost.

Patrick Turner.






........ Phil

  #120   Report Post  
Posted to rec.audio.tubes
RickH RickH is offline
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Posts: 67
Default Which tube expert can do custom works?

On Jan 9, 4:57*pm, "Tynan AgviŠr" wrote:
So does anyone have any last words for the deceased?

My thread is long gone. Long damn gone.

Graham, Arny(Hey Arny!), and other instructive posters, thanks for your
insight. It is appreciated.

If anyone is out there that is capable and willing to build for me(for good
pay of course) shoot me an email. Maybe Jon Atkinson will help me out. Har
fecking har



Tynan


If I could I would, but I'm a lowly hobbyist. But I think my earlier
post about just getting a modular one channel strip developed as a
preamp to your liking, then use that design to clone the other
channels. The buss and output buffer stages can be done second to
getting one good preamp design, the summing buss is really not very
complicated and can be built as a backplane to holding your channel
strip modules. Almost all mixers are developed this way, very few are
non modular. I was insulted similarly by Phil Allison last month when
I had the audacity to ask how transformers can be made lighter
possibly by using aluminum wire. I tend to not lurk here much anymore
after that, there is a lot of talent here but collaborative efforts
that produce tangible devices alas cannot happen in amp building, like
it happens regularly in software development when programmers
collaborate in open source projects. Software work can be mailed and
people can work together on the same project. A group like this would
have no hope I think of collaborating on any project, mostly because
of a few egos. Hopefully one of them will contact you offline and
give it a shot though. If not you might want to contact some students
at a local university, or someone on the antique radio repair/
restoration group, they are a pretty friendly bunch of geezers over
there.



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