Ronald wrote:

Hi John ,

I think your problem is the Newsreader/mail program you are using.

Might be , but I don't care to much knowing a simple way around .

Best regards ,

Ronald .

The instability with email and getting RAT ok was due to the ISP I have, and the
next
upstream ISP in Sydney.
My ISP checked it out, and the faults are not with my newsreader program.

Patrick Turner.



"John Byrns" schreef in bericht
...

Hi Ronald,

I think your problem is the Newsreader/mail program you are using.


Regards,

John Byrns


In article , "Ronald"
wrote:

Hi Pat ,

I also have troubles if I want to send a post to NG's and E-mail
in the same move ...... Might be my ISP , but ......
Anyway I always send the mail first and then "copy / paste" from
the "send-E-mail" folder to post on a NG .
You just might have the same problems and if you wanna test you're
free to use my E-adress also .
(read backwards and skip the spamblock if you lost my adress) .

Ronald .


"Patrick Turner" schreef in bericht
...


Ronald wrote:

Hi Pat ,

I can see this (same) post 3 x !!
So your server might still be a little wacky.....

Ronald .

Ah, behold the wonders of dumb PCs.
Don't let 3 x the "old PITA" get you down.

I sent this message to RAT, and to Tim privately, in case it never
showed
up at
RAT.

But after clicking the send button, it went to RAT ok,
but I got a message the ISP was down, & an access bad/try again later/
please check settings, triggered by the failure of the private part of
the
email.
So I tried again later 3 times, same "no can do" message.
So it seems I am able to post to RAT, but not to private emails.
3 other private emails were stopped,
so I have problems to solve tomorrow.

Wouldn't it be nice to have a PC which told you the exact reason
why something you tried to do didn't work out.

I'll have to complain to Bill when he visits for dinner next week to
check up on the Oz users of his funny systems.
I think he only deserves an old mouldy meat pie and a hot flat coke.

Patrick Turner.



"Patrick Turner" schreef in bericht
...


Tim Williams wrote:

1. How much voltage gain do you need?
2. Inputs? Straight through or multi? Switched or mixed?
Stereo?
3. Any options such as tone controls, headphones output, etc.?

Tim

Just little long list to consider eh!

BTW Tim, does this post and the other two I just sent appear on
RAT?

Patrick Turner.



--
"I have misplaced my pants." - Homer Simpson | Electronics,
- - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting
and Games: http://webpages.charter.net/dawill/tmoranwms

"Spade" wrote in message
om...
Hello,

I planning to build tube line and phono pre amplifiers for my
hi-fi
systems. Can you recommend me some good and simple schematics
that
are
proven to work fine. I like to use tubes that can take 12,6 on
heaters, like ECC81-83, since I have couple of transformers
that
give
230VAC + 12VAC, but sure I can regulate heater supply to
6,3VDC...

Any ideas?

Than you!

Best regards,
Spade




Surf my web pages at, http://users.rcn.com/jbyrns/

John Byrns wrote:

Hi Ronald,

I think your problem is the Newsreader/mail program you are using.

Regards,

John Byrns

All last night I couldn'r send private emails.
Today I can; the system has come good.
So sometime systems do that; they get clogged, and a dose of castor oil
is needed from a puter nerd someplace.

Patrick Turner.





In article , "Ronald"
wrote:

Hi Pat ,

I also have troubles if I want to send a post to NG's and E-mail
in the same move ...... Might be my ISP , but ......
Anyway I always send the mail first and then "copy / paste" from
the "send-E-mail" folder to post on a NG .
You just might have the same problems and if you wanna test you're
free to use my E-adress also .
(read backwards and skip the spamblock if you lost my adress) .

Ronald .


"Patrick Turner" schreef in bericht
...


Ronald wrote:

Hi Pat ,

I can see this (same) post 3 x !!
So your server might still be a little wacky.....

Ronald .

Ah, behold the wonders of dumb PCs.
Don't let 3 x the "old PITA" get you down.

I sent this message to RAT, and to Tim privately, in case it never showed
up at
RAT.

But after clicking the send button, it went to RAT ok,
but I got a message the ISP was down, & an access bad/try again later/
please check settings, triggered by the failure of the private part of the
email.
So I tried again later 3 times, same "no can do" message.
So it seems I am able to post to RAT, but not to private emails.
3 other private emails were stopped,
so I have problems to solve tomorrow.

Wouldn't it be nice to have a PC which told you the exact reason
why something you tried to do didn't work out.

I'll have to complain to Bill when he visits for dinner next week to
check up on the Oz users of his funny systems.
I think he only deserves an old mouldy meat pie and a hot flat coke.

Patrick Turner.



"Patrick Turner" schreef in bericht
...


Tim Williams wrote:

1. How much voltage gain do you need?
2. Inputs? Straight through or multi? Switched or mixed? Stereo?
3. Any options such as tone controls, headphones output, etc.?

Tim

Just little long list to consider eh!

BTW Tim, does this post and the other two I just sent appear on RAT?

Patrick Turner.



--
"I have misplaced my pants." - Homer Simpson | Electronics,
- - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting
and Games: http://webpages.charter.net/dawill/tmoranwms

"Spade" wrote in message
om...
Hello,

I planning to build tube line and phono pre amplifiers for my
hi-fi
systems. Can you recommend me some good and simple schematics that
are
proven to work fine. I like to use tubes that can take 12,6 on
heaters, like ECC81-83, since I have couple of transformers that
give
230VAC + 12VAC, but sure I can regulate heater supply to 6,3VDC...

Any ideas?

Than you!

Best regards,
Spade



Surf my web pages at, http://users.rcn.com/jbyrns/

Hi Patrick

Thank you for the detailed description
Your design is certainly sophiscated.

Actually I am looking at simple circuit like Marantz M7 and Audio Note M7
and to improve the power supply like regulation and adding ripple removal
etc. I believe you use tube rectification. What about SS

Thank you

Goh A S


"Patrick Turner" wrote in message
...


A S Goh wrote:

Hi Patrick Turner

Where is the schematic of the regulated PS

I have never posted the schematic of the PS.

I did have a solid state regulator to produce +320v at 50mA,
and very low ripple, and this was further filtered by the RC infront of
each pair of L&R stages.

There was also a regulated 12.6 v DC supply for the heaters.

Since April 2,000, that amp has been reborn again without regulation.
There is really no need for it inh the B+ supply.
Now I have 470uF, 20H, 470 uF, then ecah channel has 470 ohms, 470 uF,
then another RC before each stage in each channel.
The phono stage has an extra RC with 470 uF as the final B+ C.
With all that RC, the hum is unmeasurable.
This proved to be more reliable and quieter than active regulation.
The regulator was series element LM350, but now it's a shunt type, using
"amplified" zener diode, ie, a zd to the base of a power transistor,
as well as lots of C.
The phono input stage has chokes to the heaters, and bypassed to 0V with
0.1
uF caps.

I hope to post the whole schematic when I upgrade the website soon.

But its not rocket science to make a good line stage.

I made mine on a chassis big enough to keep the PS away from the phono
input
stage.
The chassis is 500 mm long. The HT transformer is potted, ex navy, and
also
the heater trans, Both of these are inside sheet steel case, and the hum
from
the magnetic fields
is just low enough to not affect the fet input stage for MC which I now
have
instead
of the MM 12AX7 stage I have on the 2000 preamp.
That phono stage is hard to beat, but with MC at 20 dB lower output,
I needed something a little quieter.

With a line stage, you don't need to be so darn perfect, because the noise
of
a PS
won't affect the higher signal level so badly as it does with a phono
stage.
Nevertheless, don't be bashful or shy, build a good PS and you won't
regret
it.
Regulation isn't needed for the B+ for a class A amp.
The only supply variations seen are the very tiny slow moving variations
of
the B+
voltage due to mains levels variations.
But with my amp, you can turn it off, then back on after 5 seconds, and
hear
no sign of the B+ sliding down, then back up.

The April 2000 preamp uses shunt FB to control gain of the 12AT7.
The tone control uses 12AX7, but its gain is reduced to only 1 with the
tone
control
networks included in what's called a Baxandall network.
I don't mind some FB.

But for those who don't like shunt FB, or other loop FB, read on,
although with a cathode follower, you cannot escape the FB, since
all the output voltage is in series with the input; its a case of lotsa
FB.
But its very local, and somewhat the most blame free form of FB I know.

One line stage integrated amp I supplied a customer a couple of years back
uses two chassis about 220mm square each, one for PS, and one for the two
amp
channels.
The PS has an EL84 used as a shunt ripple reducer, about as effective as
a 30H choke.

The line stage uses 1 x 6CG7 per channel.
NOS Telefunken give the best sound.

The input comes via a 5 way source select twin wafer switch from DACT.
I have one triode loaded with 47k, cap coupled to a DACT switched
attenuator,
then this has a cathode follower output loaded with 47k; 2 uF to the
output.
Beyshlag resistors and Wima polypropylene caps are used.
6SN7 is the king of the signal triodes,
and is electonically identical to the 6CG7.
For a slightly warmer sound, use 12AU7.

The signal should come straight to the first tube and its level raised
from the maximum standard 0.2v line level to 2v.
Using 1/2 a 6SN7 with no cathode bypass cap give a gain of 10, (20 dB,).
12AU7 give a gain of around 7, with unbypassed Rk.
The 2v is then fed to a pot of attenuator, where the 12 o'clock
position reduces the level back down to 0.2v, and that is fed to a cathode
follower
output stage the same as shown at my site, and you get a nominal 0.18 vrms
output.
This is plenty for normal listening, and in fact if you measured the
input levels used for comfy listening, its usually around 20 mV.

If the power amp needs the standard 1v to make full power,
then the preamp with a gain of 7 can provide enough gain.
Even a gain of 4 is plenty, so balance controls can be also fitted.
If I am asked to fit them, I now place them on the input side of the gain
tube,
with volume after.
Its then I'd use 6CG7, gain = 10, or 15 with bypassed Rk
to compensate the drop with a balance control inserted.
Good systems don't need balance controls.


This is a very simple form of SET preamp, and despite trying lots of SRPP
and bootsrapped follower ideas, the simple thing sounds very accurate.
You have freedom to try ideas and build various things, and listen.
thd will be below 0.1%.

I have used CCS instead of the 47 k loads for the triodes.
I liked the sound of that.

I think its tube choice which governs the sound heard the most.
So if you make a circuit with ninepin sockets, different tubes can be
tried,
providing the heater voltage can be altered for either 6CG7 and 12AU7.

The use of good quality R&C also minimise likelyhood
of any cloudiness otherwise heard.

Patrick Turner.








Thanks
"Patrick Turner" wrote in message
...


Spade wrote:

Hello,

I planning to build tube line and phono pre amplifiers for my hi-fi
systems. Can you recommend me some good and simple schematics that
are
proven to work fine. I like to use tubes that can take 12,6 on
heaters, like ECC81-83, since I have couple of transformers that
give
230VAC + 12VAC, but sure I can regulate heater supply to 6,3VDC...

Any ideas?

Than you!

Best regards,
Spade

You could look at the complete preamp at
http://www.turneraudio.com.au/htmlwe...tubepreamp.htm

Then see the 12AT7 line stage which has a gain of 8, toprhs of the
schematic.

There is a volume control pot, log, with added balance pot, series,
after a tone control stage which can be deleted altogether.
My pre has two pair of LR outputs to suit trialing
different amps, but you could have just one cathode follower
output stage per channel.

Patrick Turner.

A S Goh wrote:

Hi Patrick

Thank you for the detailed description
Your design is certainly sophiscated.

Actually I am looking at simple circuit like Marantz M7 and Audio Note M7
and to improve the power supply like regulation and adding ripple removal
etc. I believe you use tube rectification. What about SS

Thank you

Goh A S

I use SS rectification almost always, and I see no need for
regulation and I now prefer a CLCRCRC type of filter.

There are always simpler circuits than mine; feel free to try them.

But I think the boostrapped follower where the R between triodes is
increased to say 8k instead of the same value as Rk in a SRPP
means that the Ro of the cathode of the top tube is very low, almost
as low as a CF.
The gain of the bottom triode is very near the U of the triode, and its current
change is very low because its load is a very high, many times Ra and
approaching CCS conditions.
Therefore the thd of the bottom gain tube is very low.
I like to supply a fixed bias to the top "follower" triode, via a 1.5M resistor,

which gives better LF stability.
The bottom tube is cap coupled to the top tube, and if C = 0.47 uF,
the pole from the CR is at 0.22 Hz.

What you have with the bootstrapped follower is a stage
where very little degradation of the signal occurs because signal power is not
being wasted in resistors feeding DC to the anodes, or from the cathodes.
Instead of 1% thd at 10v rms output, it might be as low as 0.1%.
If you were to draw the load lines seen by each top and bottom tubes
then they are nearly horizontal lines
intersecting the anode resistance lines at even intervals, and so
thd is very low.

So where many other folk will use 1/2 a twin triode for a gain stage, I like to
use both halves for the same job, but Ro is far lower, and so is THD.
Noise is no worse.
Instead of resistor loads, an active load, a triode is used.
I like to have both halves of a single glass envelope used for the
same stage in the one channel.
Instead of having unecessary HF losses between one stage and the next because of
the miller
effect, the bootstrapped follower avoids the losses because its Ro is low.

The phono input stage of the April 2000 preamp sure
acts nice and quiet, and compared to many other MM inputs
it is good sounding.
The gain is around 88 to 95, depending on what 12AX7 is picked for the job.

For a line stage, the bootstrapped follower gets a gain of over 15 with 12AU7.
If the cathode of the bottom tube is left unbypassed, there is very little
current feedback,
since there is very little current change in the triode with such an effectively
high value load,
and you get very little gain reduction. It really doesn't matter whether you
bypass the Rk or not.
If 15 is too much gain, then a shunt FB loop has to be used, since there is no
other way to reduce the gain of the tube in this application.
A shunt FB reduction of gain to say 5 might be fine because line levels are
0.2v and the power amp needs only 1v for full po.

In my latest line level stage, I use 12AU7 bootstrapped follower,
with some shunt FB with the input resistor half of the FB network
including the balance control pot.
So when the gain block is switched in, the balance control is also included,
but for minimalist use, when no gain stage is switched in, there is no balance
control.
The loop of shunt FB is only about 10 dB of NFB.
It reduces the already low Ro of the BSF stage to very low levels.
and the use of a 50k volume pot cap coupled to the cathode output
is fine.

Patrick Turner.








"Patrick Turner" wrote in message
...


A S Goh wrote:

Hi Patrick Turner

Where is the schematic of the regulated PS

I have never posted the schematic of the PS.

I did have a solid state regulator to produce +320v at 50mA,
and very low ripple, and this was further filtered by the RC infront of
each pair of L&R stages.

There was also a regulated 12.6 v DC supply for the heaters.

Since April 2,000, that amp has been reborn again without regulation.
There is really no need for it inh the B+ supply.
Now I have 470uF, 20H, 470 uF, then ecah channel has 470 ohms, 470 uF,
then another RC before each stage in each channel.
The phono stage has an extra RC with 470 uF as the final B+ C.
With all that RC, the hum is unmeasurable.
This proved to be more reliable and quieter than active regulation.
The regulator was series element LM350, but now it's a shunt type, using
"amplified" zener diode, ie, a zd to the base of a power transistor,
as well as lots of C.
The phono input stage has chokes to the heaters, and bypassed to 0V with
0.1
uF caps.

I hope to post the whole schematic when I upgrade the website soon.

But its not rocket science to make a good line stage.

I made mine on a chassis big enough to keep the PS away from the phono
input
stage.
The chassis is 500 mm long. The HT transformer is potted, ex navy, and
also
the heater trans, Both of these are inside sheet steel case, and the hum
from
the magnetic fields
is just low enough to not affect the fet input stage for MC which I now
have
instead
of the MM 12AX7 stage I have on the 2000 preamp.
That phono stage is hard to beat, but with MC at 20 dB lower output,
I needed something a little quieter.

With a line stage, you don't need to be so darn perfect, because the noise
of
a PS
won't affect the higher signal level so badly as it does with a phono
stage.
Nevertheless, don't be bashful or shy, build a good PS and you won't
regret
it.
Regulation isn't needed for the B+ for a class A amp.
The only supply variations seen are the very tiny slow moving variations
of
the B+
voltage due to mains levels variations.
But with my amp, you can turn it off, then back on after 5 seconds, and
hear
no sign of the B+ sliding down, then back up.

The April 2000 preamp uses shunt FB to control gain of the 12AT7.
The tone control uses 12AX7, but its gain is reduced to only 1 with the
tone
control
networks included in what's called a Baxandall network.
I don't mind some FB.

But for those who don't like shunt FB, or other loop FB, read on,
although with a cathode follower, you cannot escape the FB, since
all the output voltage is in series with the input; its a case of lotsa
FB.
But its very local, and somewhat the most blame free form of FB I know.

One line stage integrated amp I supplied a customer a couple of years back
uses two chassis about 220mm square each, one for PS, and one for the two
amp
channels.
The PS has an EL84 used as a shunt ripple reducer, about as effective as
a 30H choke.

The line stage uses 1 x 6CG7 per channel.
NOS Telefunken give the best sound.

The input comes via a 5 way source select twin wafer switch from DACT.
I have one triode loaded with 47k, cap coupled to a DACT switched
attenuator,
then this has a cathode follower output loaded with 47k; 2 uF to the
output.
Beyshlag resistors and Wima polypropylene caps are used.
6SN7 is the king of the signal triodes,
and is electonically identical to the 6CG7.
For a slightly warmer sound, use 12AU7.

The signal should come straight to the first tube and its level raised
from the maximum standard 0.2v line level to 2v.
Using 1/2 a 6SN7 with no cathode bypass cap give a gain of 10, (20 dB,).
12AU7 give a gain of around 7, with unbypassed Rk.
The 2v is then fed to a pot of attenuator, where the 12 o'clock
position reduces the level back down to 0.2v, and that is fed to a cathode
follower
output stage the same as shown at my site, and you get a nominal 0.18 vrms
output.
This is plenty for normal listening, and in fact if you measured the
input levels used for comfy listening, its usually around 20 mV.

If the power amp needs the standard 1v to make full power,
then the preamp with a gain of 7 can provide enough gain.
Even a gain of 4 is plenty, so balance controls can be also fitted.
If I am asked to fit them, I now place them on the input side of the gain
tube,
with volume after.
Its then I'd use 6CG7, gain = 10, or 15 with bypassed Rk
to compensate the drop with a balance control inserted.
Good systems don't need balance controls.


This is a very simple form of SET preamp, and despite trying lots of SRPP
and bootsrapped follower ideas, the simple thing sounds very accurate.
You have freedom to try ideas and build various things, and listen.
thd will be below 0.1%.

I have used CCS instead of the 47 k loads for the triodes.
I liked the sound of that.

I think its tube choice which governs the sound heard the most.
So if you make a circuit with ninepin sockets, different tubes can be
tried,
providing the heater voltage can be altered for either 6CG7 and 12AU7.

The use of good quality R&C also minimise likelyhood
of any cloudiness otherwise heard.

Patrick Turner.








Thanks
"Patrick Turner" wrote in message
...


Spade wrote:

Hello,

I planning to build tube line and phono pre amplifiers for my hi-fi
systems. Can you recommend me some good and simple schematics that
are
proven to work fine. I like to use tubes that can take 12,6 on
heaters, like ECC81-83, since I have couple of transformers that
give
230VAC + 12VAC, but sure I can regulate heater supply to 6,3VDC...

Any ideas?

Than you!

Best regards,
Spade

You could look at the complete preamp at
http://www.turneraudio.com.au/htmlwe...tubepreamp.htm

Then see the 12AT7 line stage which has a gain of 8, toprhs of the
schematic.

There is a volume control pot, log, with added balance pot, series,
after a tone control stage which can be deleted altogether.
My pre has two pair of LR outputs to suit trialing
different amps, but you could have just one cathode follower
output stage per channel.

Patrick Turner.

Thank you very much for help!

Since this is my first Hi-fi project I´m looking for quite simple
solution. Also I have tranformers that could give 900mA 6,3V so that
limits number of tubes to 3.

I thought that I try RIAA amp:
http://www.turneraudio.com.au/htmlwe...ermedphono.htm

And add volume control in the front of the cathode follower. Also Add
CD input to that point. So connection would be like in "10 tube
Preamp, April 2000":
http://www.turneraudio.com.au/htmlwe...tubepreamp.htm

My power amp, Russian made Priboi, has quite sensitive input so I
think this pre could drive it easily.

Is there reason why adding vol pot and CD in would not work?

Thanks again!

Best regards,
Spade

Spade wrote:

Thank you very much for help!

Since this is my first Hi-fi project I´m looking for quite simple
solution. Also I have tranformers that could give 900mA 6,3V so that
limits number of tubes to 3.

I thought that I try RIAA amp:
http://www.turneraudio.com.au/htmlwe...ermedphono.htm

And add volume control in the front of the cathode follower. Also Add
CD input to that point. So connection would be like in "10 tube
Preamp, April 2000":

The 12AX7 in the above circuit has a high Ra.

What you would have to do is have the top of the volume pot taken to a
pole of a source switch, and thus phono, CD, tuner, etc, can be selected.

The pot would want to be about 250k so that when phono is selected,
the load on the anode is the 150k in parallel with 250k = 94k.
That is a minimum load which ought to be used with 12AX7.

Then the wiper of the pot is cap coupled to a CF as in my preamp,
which is very standard circuitry.
Alternatively, the phono input stage1 is 1/2 a 12AX7 and stage 2 is 1/2 a
12AT7,
and the Ra of the AT7 is a lot lower, so you might get away with a 100k
pot.
The gain of the AT7 is a lot lower than AX7, but maybe still OK.
12AT7 also makes a nice cathode follower.
You should use 4.7 k in series with the CF grid if using 12AT7,
and a 0.1 uF cap from the anode to 0V close to the tube,
since 12AT7 can sometimes be unstable at RF.



http://www.turneraudio.com.au/htmlwe...tubepreamp.htm

My power amp, Russian made Priboi, has quite sensitive input so I
think this pre could drive it easily.

Is there reason why adding vol pot and CD in would not work?

If you only need 0.5 v to drive the power amp to deafening levels, then
you won't need
a gain stage, and the CD can be fed into the pot from the source switch,
which ideally should be a nice wafer switch. Farnells have nice silver
plated wafer switches.
two pole 4 position is OK.

Good quality log volume pots of 250k are hard to find now.

Make the chassis nice and big, 500 mm long, 200 mm wide, 50mm high,
and you will have enough room for any additions in the future,
plus you will have the PS well away from the phono front end.
Alternatively, make the chassis 350 long, and have a remote
power supply with a 2 metre long cable.
It can be any sort of chassis/box, and kept well away from the TT and
preamp.

Patrick Turner.



Thanks again!

Best regards,
Spade

I just finished the pre amp. Did not add line in yet, since I do not
have any other player than record player at the moment, but added
volume pot.

Power supply is still under construcion, I had only 47uF/350V caps so
I wired 4 to get 200uf, then 5K and then 100uF. I think I might try
some active regulator since there is not so much space left in
chassis.

Anyhow... Phono pre amp sounds great to my ears!! I did not expect
much improve comparing to my old simple IC pre amp that I made years
ago but there really is difference. There is some noise, but not too
much to do some listening for a while.

After finished this have to star looking for power amp project.-)

Thank you very much for circuit and info!

Best regards,
Spade