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Introducing a New Horse to the Stable



 
 
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  #1  
Old September 3rd 19, 09:11 PM posted to rec.audio.high-end
Peter Wieck[_2_]
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Posts: 96
Default Introducing a New Horse to the Stable

Howard Stone's experience with the Radford amp brought this on, so please f=
orgive the rant-like process here.=20

Guys and Gals:=20

When introducing a new piece of equipment to the system, please take NOTHIN=
G for granted, not even it it is brand-new, fresh from the box. And if it i=
s used, or, much worse, vintage-used please be exceedingly cautious. Equipm=
ent failure can be anything from minimally annoying to spectacularly annoyi=
ng to genuinely dangerous to life and property.=20

I have no problems running my 56 year old tube system in my office, and lea=
ving it unattended for hours at a time. It has been through my bench, sat f=
or hours on a metered variac, and I created a temperature-table using a hea=
t-gun such that if I see changes over time, I have a pretty good idea wher=
e to look for trouble. But when it came to me, I had no such faith.=20

In all seriousness, if one is going to pursue this hobby at more than an oc=
casional level, one should obtain the basic tools necessary to do so safely=
both for the equipment and the real-estate. This is not to suggest that su=
ch would have prevented Howard's experience - but he very probably would ha=
ve seen it coming in time to prevent the special effects.=20

If there is a consensus, I would be glad to take a picture of my (very basi=
c) bench, and (very basic) tooling, with an explanation for each item and t=
he purpose(s) it services.

Thoughts?

Peter Wieck
Melrose Park, PA
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  #2  
Old September 6th 19, 10:53 AM posted to rec.audio.high-end
Trevor Wilson[_3_]
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Posts: 106
Default Introducing a New Horse to the Stable

On 4/09/2019 6:11 am, Peter Wieck wrote:
> Howard Stone's experience with the Radford amp brought this on, so please forgive the rant-like process here.
>
> Guys and Gals:
>
> When introducing a new piece of equipment to the system, please take NOTHING for granted, not even it it is brand-new, fresh from the box. And if it is used, or, much worse, vintage-used please be exceedingly cautious. Equipment failure can be anything from minimally annoying to spectacularly annoying to genuinely dangerous to life and property.
>
> I have no problems running my 56 year old tube system in my office, and leaving it unattended for hours at a time. It has been through my bench, sat for hours on a metered variac, and I created a temperature-table using a heat-gun such that if I see changes over time, I have a pretty good idea where to look for trouble. But when it came to me, I had no such faith.
>
> In all seriousness, if one is going to pursue this hobby at more than an occasional level, one should obtain the basic tools necessary to do so safely both for the equipment and the real-estate. This is not to suggest that such would have prevented Howard's experience - but he very probably would have seen it coming in time to prevent the special effects.
>
> If there is a consensus, I would be glad to take a picture of my (very basic) bench, and (very basic) tooling, with an explanation for each item and the purpose(s) it services.
>
> Thoughts?


**Yeah, one. I don't get the attraction to valve (tube) equipment.
Anything that is done with valves, can be done, better, cheaper and with
more consistency with solid state.

I mean to say: I get why hipsters embrace the stuff. Hell, my business
has undergone a renaissance thanks to hipster. Old Marantz, Yamaha,
Sansui, Accuphase and the others are suddenly desirable and, therefore
valuable and worth repairing. And for an old fart like me, well, I cut
my teeth fixing that stuff. No surface mount, or microprocessors in
sight. Well, not if you exclude cassette decks.

But, Hell, valves start wearing out the minute they're first switched on!

And, before you get started, I've done a few blind tests with valves,
vs. solid state. The very best valve gear is VERY hard to pick from
decent SS gear. It just costs a whole lot more (check out the cost of a
decent, multi-interleaved output tranny sometime - YIKES!). And then, of
course, there's those pesky valve replacements at regular intervals.
I've replaced a full set of valves in a big power amp more than once and
seen the cost run to a couple of grand.

And yes, I've owned and built valve stuff too. Not anymore though. I
have better things to do with my life. Noisy and microphonic valves. No
thanks. You can stick 'em where the Sun don't shine.


--
Trevor Wilson
www.rageaudio.com.au

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  #3  
Old September 6th 19, 06:50 PM posted to rec.audio.high-end
Peter Wieck[_2_]
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Posts: 96
Default Introducing a New Horse to the Stable

Almost the entire reason for a hobby is to be able to indulge in pointless behavior without consequence.

Peter Wieck
Melrose Park, PA
  #4  
Old September 7th 19, 12:39 AM posted to rec.audio.high-end
Trevor Wilson[_3_]
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Posts: 106
Default Introducing a New Horse to the Stable

On 7/09/2019 3:50 am, Peter Wieck wrote:
> Almost the entire reason for a hobby is to be able to indulge in pointless behavior without consequence.
>


**I have a different aim: That is to attempt to provide for myself and
my clients, a musical experience that is as close to the original event
that is possible to obtain, given the usual room and budgetary
constraints. OH, and the partner, if one is in the picture.

[ASIDE] Many years ago, I was asked to supply and set-up a very nice
system for a local, well-heeled politician. The man was cultured and had
put in place an endowment for budding pianists. When I saw the room the
system was to be installed, my first words we "Well, the Steinway has
to go." Went down like a lead balloon. We compromised. The Steinway
remained. The sound system woulda sounded better without it.


--
Trevor Wilson
www.rageaudio.com.au

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  #5  
Old September 10th 19, 11:08 AM posted to rec.audio.high-end
Howard Stone
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Posts: 44
Default Introducing a New Horse to the Stable

I don’t think Trevor, that the problem was caused by the fact that it’s a tube amp. I mean, in principle valve amps are as robust as SS aren’t they - apart from the fact that the tubes wear out,

My aim was to find an amp which I liked, regardless of whether or was valve or SS - the fact that the Radford has valves seemed an implementation detail which I would learn with,

Anyway, I’d like to hear a list of your favourite amps Trevor. Since I still don’t have my Radford!
  #6  
Old September 10th 19, 11:37 AM posted to rec.audio.high-end
Trevor Wilson[_3_]
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Posts: 106
Default Introducing a New Horse to the Stable

On 10/09/2019 8:08 pm, Howard Stone wrote:
> I don’t think Trevor, that the problem was caused by the fact that it’s a tube amp. I mean, in principle valve amps are as robust as SS aren’t they - apart from the fact that the tubes wear out,


**Not even remotely close. Assuming good design and build quality, a
valve amp will always be a less reliable product. If only due to the
necessarily higher Voltages involved and consequent extra stress on
insulation and other things. Then there's the output transformers. Two,
large, heavy and expensive components, which, whilst reasonably
reliable, are less reliable than a typical power transformer, thus
adding an extra layer of unreliability. And of course, whilst valve
failures are part of the game with valve products, the failure of a
valve can also result in the failure of some surrounding components. And
over the years I've seen some (ahem) 'interesting' valve amp failures.

>
> My aim was to find an amp which I liked, regardless of whether or was valve or SS - the fact that the Radford has valves seemed an implementation detail which I would learn with,
>
> Anyway, I’d like to hear a list of your favourite amps Trevor. Since I still don’t have my Radford!


**Oh, there's only one. Locally built (Australia) and has been out of
production for a number of years, but sonically stunning. Solid state
(BJT), of course. Many listeners say that it has some of the
characteristics of the finest valve amps (triode, of course), but with
none of the drawbacks. The key? Zero global NFB, critically matched
components (better than 1% for transistors) and over-sized power
supplies, employing multiple, small value capacitors. I have not had
another amp (permanently) in my system since 1980. I have, however, had
a great many in the system for short periods. Some costing a great deal
of money.


--
Trevor Wilson
www.rageaudio.com.au

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  #7  
Old September 10th 19, 12:54 PM posted to rec.audio.high-end
Peter Wieck[_2_]
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Posts: 96
Default Introducing a New Horse to the Stable

OK, OK, I will bite! Minor rant to follow:=20

Tube vs. Solid State on reliability:

There are not so very many 60-year old components in operation these days u=
nmodified since-new. My oldest tube item turned 100 this year and likely wo=
rks better than when it was new based on a better understanding of antenna =
systems, optimum tube voltages and so forth. Other than moving parts (CD pl=
ayer), the newest component in my office system was made in 1963. The syste=
m runs 9 hours per day, 5 days per week. Oh, and the tubes are original as =
well.=20

On the other hand, and given my hobby, I see a large number of SS component=
s that have blown transistors, exploded capacitors and much worse, irrespec=
tive of age and source. The well made, well designed stuff is serviceable, =
distinguishing it from the rest of the garbage out there.=20

I would make a fairly apt comparison: A tube amplifier is much like a mid-l=
ast-century Mercedes or VW - few things were self-adjusting, and they requi=
red regular and attentive care-and-feeding. With such, they were good for s=
everal hundred thousand miles of reliable service. A contemporary Ford, Cad=
illac, Plymouth would be considered remarkable were it to survive 100,000 m=
iles without heroic measures. Might run very nicely when running, but that =
would be your basic solid-state device in comparison.=20

Put simply, they are different beasts designed with different things in min=
d, but for the same basic purpose. That one is or is not "BETTER" than the =
other is not relevant to the purpose in either case.=20

Now, when I here things like "Zero global NFB" and "Critically matched comp=
onents", I can smell the snake-oil from a great distance, even the 10,000 m=
iles from here to Australia. I am sure that process also contains descripti=
ves of "interconnects" rolled on the thighs of virgins on Walpurgis Night..=
..=20

Note that even "critically matched" solid-state components drift after a ve=
ry short period of time in-service. All of them, such that that "less than =
1%" is meaningful for perhaps 12 hours or so.=20

Being as this is a hobby for me, I get to try things that are otherwise unp=
roductive, unprofitable or impractical. Such as shotgunning a device with s=
ingle-value capacitors and then comparing it to the same device with carefu=
lly screened and matched caps. Or matching driver and output transistors an=
d comparing to a similar device with disparate values. Guys and gals - you =
would be seriously shocked to discover how little difference some things ma=
ke that the ALL-SEEING, ALL-KNOWING gurus will tell you are critical. Often=
no difference at all.=20

Peter Wieck
Melrose Park, PA
  #8  
Old September 11th 19, 12:29 PM posted to rec.audio.high-end
Trevor Wilson[_3_]
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Posts: 106
Default Introducing a New Horse to the Stable

On 10/09/2019 9:54 pm, Peter Wieck wrote:
> OK, OK, I will bite! Minor rant to follow:
>
> Tube vs. Solid State on reliability:
>
> There are not so very many 60-year old components in operation these days unmodified since-new. My oldest tube item turned 100 this year and likely works better than when it was new based on a better understanding of antenna systems, optimum tube voltages and so forth. Other than moving parts (CD player), the newest component in my office system was made in 1963. The system runs 9 hours per day, 5 days per week. Oh, and the tubes are original as well.
>
> On the other hand, and given my hobby, I see a large number of SS components that have blown transistors, exploded capacitors and much worse, irrespective of age and source. The well made, well designed stuff is serviceable, distinguishing it from the rest of the garbage out there.


**Sure. That has been my observation. I see a lot of junk across my
bench, though I tend to reject many products nowadays. Not worth my
time. FWIW: I have 70 year old radio coming in next week. Obviously,
it's not really worthwhile, but it is a family heirloom, so the client
will spend whatever is necessary. I expect it will be an electrolytic
cap swap. Maybe a valve. We'll see.

>
> I would make a fairly apt comparison: A tube amplifier is much like a mid-last-century Mercedes or VW - few things were self-adjusting, and they required regular and attentive care-and-feeding. With such, they were good for several hundred thousand miles of reliable service. A contemporary Ford, Cadillac, Plymouth would be considered remarkable were it to survive 100,000 miles without heroic measures. Might run very nicely when running, but that would be your basic solid-state device in comparison.


**That would be a poor comparison. Having owned a number of vehicles
over the past 50 years, I can assure you that, in general, modern cars
are VASTLY superior in most areas. Ignition systems and fuel handling
systems are the big ones. Before modern EFI, I grappled with
carburettors, that required constant adjustment and let's not even get
into the standard Kettering ignition systems. Such systems require
constant and careful adjustments. As for the body of the vehicle, shall
we discuss the impact of rust? Most (all?) modern cars utilise some kind
of rust prevention at manufacture. Older cars rely on paint. My two
present cars are thoroughly modern vehicles (one is 2 years old and one
is almost 20). Both are perfectly reliable and offer excellent levels of
safety, fuel economy and performance. Both demonstrate the kind of
performance which would be associated with race cars from the 1960s
(though both could manage a tight, twisty race track more quickly, due
to their all wheel drive ability). Without the unreliability.

Anyway, that's all a bit off-topic.

I service equipment from all generations. Older equipment almost always
require replacement of electrolytic caps and carbon composition
resistors (where used). That may be valve or SS.

>
> Put simply, they are different beasts designed with different things in mind, but for the same basic purpose. That one is or is not "BETTER" than the other is not relevant to the purpose in either case.
>
> Now, when I here things like "Zero global NFB" and "Critically matched components", I can smell the snake-oil from a great distance, even the 10,000 miles from here to Australia. I am sure that process also contains descriptives of "interconnects" rolled on the thighs of virgins on Walpurgis Night...


**I did not mention "interconnects". However, you may care to
investigate the possible reasons why many listeners prefer the sound of
valve amps. Consider the amount of global NFB used in typical valve
products. Compared to SS gear, that NFB is either very low, or
non-existent. Consider the action of valve amps under the conditions of
Voltage limiting (clipping) and current limiting. Most SS amps do not
cope with such conditions well, whereas most valve amps clip and current
limit in a benign fashion. SS camps can be designed to act similarly,
but few are. As for the matched components, it's a necessity in the
design I cited. Without matched components, it is impossible to achieve
high reliability, low distortion and zero global NFB. Cumbersome? Sure.

Further and for the record: I have subjected myself to many double blind
tests over the years to verify my preference is uncoloured by vision.


>
> Note that even "critically matched" solid-state components drift after a very short period of time in-service. All of them, such that that "less than 1%" is meaningful for perhaps 12 hours or so.


**The solid state devices are matched at the operational temperature of
the amplifier (60 degrees C) of course. The amplifiers use a demand
responsive fan (infinitely variable speed), which maintains the heat
sink temperatures at 60 degrees C (+/- 3 degrees) at all times. A short
(20 mins) warm-up time is necessary for optimal performance.


>
> Being as this is a hobby for me, I get to try things that are otherwise unproductive, unprofitable or impractical. Such as shotgunning a device with single-value capacitors and then comparing it to the same device with carefully screened and matched caps. Or matching driver and output transistors and comparing to a similar device with disparate values. Guys and gals - you would be seriously shocked to discover how little difference some things make that the ALL-SEEING, ALL-KNOWING gurus will tell you are critical. Often no difference at all.


**Well, that has not been my experience. It depends on the design. A
standard, high global NFB amp, which has been designed to cope with off
the shelf devices will likely show zero difference when fitted with
critically matched devices. HOWEVER, in a past life, I was service
manager for Marantz Australia for several years. During the late 1960s
and 1970s I noted that most Marantz models (even some of the Japanese
built stuff) was specified to use closely matched output and driver
devices (roughly 30% HFE match). I vividly recall the time when, for a
short time, stocks of output devices for the Model 240 (250, 250M, 1200,
1200B) were depleted. I decided to try using unmatched devices in one
repair. Distortion approached 0.5% (rated distortion was 0.1%, but I
would typically measure 0.01%). Clearly a most unacceptable result. I
explained to the customer that they would need to wait for Marantz to
supply the correct devices.

So, matched devices are not as uncommon as you might imagine.


--
Trevor Wilson
www.rageaudio.com.au

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  #9  
Old September 11th 19, 03:17 PM posted to rec.audio.high-end
~misfit~[_3_]
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Posts: 78
Default Introducing a New Horse to the Stable

On 10/09/2019 11:54 PM, Peter Wieck wrote:
> OK, OK, I will bite! Minor rant to follow:
>
> Tube vs. Solid State on reliability:
>
> There are not so very many 60-year old components in operation these days unmodified since-new. My oldest tube item turned 100 this year and likely works better than when it was new based on a better understanding of antenna systems, optimum tube voltages and so forth. Other than moving parts (CD player), the newest component in my office system was made in 1963. The system runs 9 hours per day, 5 days per week. Oh, and the tubes are original as well.
>
> On the other hand, and given my hobby, I see a large number of SS components that have blown transistors, exploded capacitors and much worse, irrespective of age and source. The well made, well designed stuff is serviceable, distinguishing it from the rest of the garbage out there.
>
> I would make a fairly apt comparison: A tube amplifier is much like a mid-last-century Mercedes or VW - few things were self-adjusting, and they required regular and attentive care-and-feeding. With such, they were good for several hundred thousand miles of reliable service. A contemporary Ford, Cadillac, Plymouth would be considered remarkable were it to survive 100,000 miles without heroic measures. Might run very nicely when running, but that would be your basic solid-state device in comparison.
>
> Put simply, they are different beasts designed with different things in mind, but for the same basic purpose. That one is or is not "BETTER" than the other is not relevant to the purpose in either case.
>
> Now, when I here things like "Zero global NFB" and "Critically matched components", I can smell the snake-oil from a great distance, even the 10,000 miles from here to Australia. I am sure that process also contains descriptives of "interconnects" rolled on the thighs of virgins on Walpurgis Night...
>
> Note that even "critically matched" solid-state components drift after a very short period of time in-service. All of them, such that that "less than 1%" is meaningful for perhaps 12 hours or so.
>
> Being as this is a hobby for me, I get to try things that are otherwise unproductive, unprofitable or impractical. Such as shotgunning a device with single-value capacitors and then comparing it to the same device with carefully screened and matched caps. Or matching driver and output transistors and comparing to a similar device with disparate values. Guys and gals - you would be seriously shocked to discover how little difference some things make that the ALL-SEEING, ALL-KNOWING gurus will tell you are critical. Often no difference at all.


Thanks for your input Peter. If I may ask, do you have an opinion on 'storage capacitors' on an
amplifier power supply? What in your opinion is 'better', a single (or few) very large caps or
multiple smaller caps to the same / similar capacitance?

I have a long term project building my own amp based on PCBs taken from 100w MOSFET (two pairs of
J50 / K135 devices per amp) PA amps made by a New Zealand company in the 1980s. (Craft, Gary
Morrison's company before he went on to become head designer at Plinius until 2005 when he left to
set up Pure Audio). I got my hands on a rack of four of these mono amps and preliminary testing
using a clean source and good speakers suggest they will make a great stereo amp.

I need to put together a power supply to feed two of these and have some new 10,000uF caps but was
wondering if multiple smaller caps would be better. (In the PA amps they only had 2,200uF but
obviously weren't called on to reproduce much bass.)

As it is I'll be using fly leads from the rectifier PCB to the caps, then to the amps and I'm
building my own case. I was thinking of maybe using my 10,000uF caps as well as maybe some smaller
ones, perhaps 1,000 in a bank, the best of both worlds. (There are also 100uF electros across the
rails on the amp PCBs that I'll be replacing.) That said I could also just go to multiple

Cheers,
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy little classification
in the DSM"
David Melville

This is not an email and hasn't been checked for viruses by any half-arsed self-promoting software.

  #10  
Old September 11th 19, 03:45 PM posted to rec.audio.high-end
Peter Wieck[_2_]
external usenet poster
 
Posts: 96
Default Introducing a New Horse to the Stable

OK... getting down to basics:

Electrolytic capacitors are essentially chemical engines. The materials dev=
eloped over the last 20 years have greatly improved along with longevity an=
d reliability, but they remain chemical engines. A single very large capaci=
tor will, therefore, necessarily be slower than multiple smaller capacitors=
in parallel, all other things being equal. The limiting factor being real-=
estate in most cases.=20

Generally, I try to run multiple caps in parallel where real-estate permits=
, with a small-value, high-voltage film cap across each as a snubber. This =
is a preference, not a requirement.=20

For something as brute-force as a power-supply for audio purposes, the diff=
erence(s) will be manifest only at or near clipping, or when the amps are f=
ed signal with extreme Peak-to-Average content. A cap bank will be able to =
deliver a *marginally* faster transient than a single very large cap. NOTE:=
If you are going to have the capacity (pun intended) to overdrive your out=
put devices for these transients, you might need to install some sort of sp=
eaker protection. Solid-state devices often do not clip nicely.=20

Peter Wieck
Melrose Park, PA
 




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