Bas Horneman said:
Hi Bas
Try this link, it should answer it adequately:
http://members.ozemail.com.au/~lisaras/design.htm
Also find the thread Tube with Power IC Output Stage - JLTi where these are covered in detail.
You are right, with non-inverted implementation a buffer is not strictly a requirement.
Joe R.
Thanks Joe...
I guess bottom line is... if I understand correctly ....the Inverted gainclone practically NEEDS a buffer because of the way the feeback is applied.
But there is no harm in trying to play a little with a tube buffer to maybe voice a non-inverting gainclone is there?
The reason I ask is that I am thinking of building a 6c19p cathode follower preamp for the gainclones kits I got from BrianGT.
Cheers,
Bas
I guess bottom line is... if I understand correctly ....the Inverted gainclone practically NEEDS a buffer because of the way the feeback is applied.
But there is no harm in trying to play a little with a tube buffer to maybe voice a non-inverting gainclone is there?
The reason I ask is that I am thinking of building a 6c19p cathode follower preamp for the gainclones kits I got from BrianGT.
Cheers,
Bas
I find the influence of the buffer even more rewarding with NI GC. The only buffer I'm using is S&B TVC stage and the improvement in sound was as big with NI amp as it was with Inverting (or maybe even more). It seems like this stage was made for GC
.
This is not saying that the amp alone doesn't sound good. It's just that adding TVC takes it one step further (sonically).
.This is not saying that the amp alone doesn't sound good. It's just that adding TVC takes it one step further (sonically).
Hi Peter,
Unfortunately 6 * S&B TVC stage is out of my price range ;-)
But I have a transformer coupled preamp...www.raleighaudio.com
....loverley...am very curious how it will sound with gainclones.
Cheers,
Bas
I cannot comment on tube buffers, but I've been using my GC with an old Nac 32-5 for about two weeks now. I am really pleased with the results. The NAC is quite smooth for a Naim amp, and the forward prasentation/fine dynamics is quite similar with both. The NAC adds some punch and sense of space.
As a side effect, it solved my phono pre problem as well.
Probably still too harsh and "sand"-sounding for you.
As a side effect, it solved my phono pre problem as well.
Probably still too harsh and "sand"-sounding for you.
Peter Daniel said:I find the influence of the buffer even more rewarding with NI GC. The only buffer I'm using is S&B TVC stage and the improvement in sound was as big with NI amp as it was with Inverting (or maybe even more). It seems like this stage was made for GC
This is not saying that the amp alone doesn't sound good. It's just that adding TVC takes it one step further (sonically).
Hi Peter
Thanks for confirming that as I have no way currently to check it out. I suspect that like you I'm not stuck on either IGC or NIGC, except IGC has a more rational reason for a buffer, but that is all. The end results matters more.
Joe R.
Hi Sheldon,
Here is a description for a cathode follower.
http://www.tubecad.com/october99/
Copyright Tubecad
I don't know the best operating points for a 6c19 ...You could use one half of a 6080 or 6AS7 as well..(These tubes are more commonly available...especially in the USA)
I reckon low voltage around 200v on the plate and around 40mA would be a ballpark figure.
Here is a description for a cathode follower.
http://www.tubecad.com/october99/
Copyright Tubecad
I don't know the best operating points for a 6c19 ...You could use one half of a 6080 or 6AS7 as well..(These tubes are more commonly available...especially in the USA)
I reckon low voltage around 200v on the plate and around 40mA would be a ballpark figure.
Attachments
Hi Bas,
I see...
Well, if you want to build a great little 6C19-P SE amp I have something really nice in mind for doing just that.
After all, the CF in the GC doesn't have to work hard and the 6C19-P is just begging to be put to service in something like a SET or linestage IMHO.
Just a thought,
I see...
Well, if you want to build a great little 6C19-P SE amp I have something really nice in mind for doing just that.
After all, the CF in the GC doesn't have to work hard and the 6C19-P is just begging to be put to service in something like a SET or linestage IMHO.
Just a thought,
Hi,
Like something you could put in your pocket...kidding.
Remember you enquired about the 6AS7G/6080?
That got me thinking...I once heard a SET 6080 on a Lowther system and that actually sounded better to me than most of the other DHT SET amps I'd heard on that system...and elsewhere.
So I thought why not make a pair of these? They only use 1/2 of the 6080 anyway, so why not use a 6C19-P instead, right?
Naturally you can just as well stick to a regular stereo amp if you like.
The voltage amp uses 1/2 of 12AX7A followed by a cascoded 6DJ8 driving the 6C19-P.
A global FB loop is used but employs only a few dB of feedback.
I found a design by Tim de Paravicini that does just that.
No surprise there as it is his usual recipe.
I had no idea he ever designed a SET amp using a 6080 though.
Actually, I'm tempted to make me one provided I can squeeze it into the timeschedule.
Cheers,
Like something you could put in your pocket...kidding.
Remember you enquired about the 6AS7G/6080?
That got me thinking...I once heard a SET 6080 on a Lowther system and that actually sounded better to me than most of the other DHT SET amps I'd heard on that system...and elsewhere.
So I thought why not make a pair of these? They only use 1/2 of the 6080 anyway, so why not use a 6C19-P instead, right?
Naturally you can just as well stick to a regular stereo amp if you like.
The voltage amp uses 1/2 of 12AX7A followed by a cascoded 6DJ8 driving the 6C19-P.
A global FB loop is used but employs only a few dB of feedback.
I found a design by Tim de Paravicini that does just that.
No surprise there as it is his usual recipe.
I had no idea he ever designed a SET amp using a 6080 though.
Actually, I'm tempted to make me one provided I can squeeze it into the timeschedule.
Cheers,
Hi Frank,
I quite like it as well...although I have never used a 12ax7...and most current diy'ers have banned the 12ax7 from the popularity list ;-)...I must try it for myself oneday...
Tim just loves feedback though...Must also try that for myself oneday...so I will be sure to build a switch in the feedback loop..
Cheers,
Bas
I quite like it as well...although I have never used a 12ax7...and most current diy'ers have banned the 12ax7 from the popularity list ;-)...I must try it for myself oneday...
Tim just loves feedback though...Must also try that for myself oneday...so I will be sure to build a switch in the feedback loop..
Cheers,
Bas
Hi,
I'm not much of a follower of audio fashion myself...
Rather than making blanket statements it would be much better to know what valve suits what application best, wouldn't you say?
To my mind, there are at least two places where a 12AX7A can be put to good use: a phono stage and as input for an amp with a global NFB loop.
Note on the schematic you posted how cleverly the FB loop takes to cathode of the cascode with it. Just like the Futterman OTLs do.
Sure, he's also one of the few people who seem to know how to put it to good use though.
I heard almost all his amps and I never had the impression of listening to a design that had the hallmark of a badly applied FB loop unlike a few others I can think of.
BTW, the German fellow who built it with the 6C19-P iso the 6080 used (or rather his GF) it on a Fostex 103 Sigma and claims it actually betters his own amp using the original TdP design.
Not bad, huh?
Cheers,
I'm not much of a follower of audio fashion myself...
Rather than making blanket statements it would be much better to know what valve suits what application best, wouldn't you say?
To my mind, there are at least two places where a 12AX7A can be put to good use: a phono stage and as input for an amp with a global NFB loop.
Note on the schematic you posted how cleverly the FB loop takes to cathode of the cascode with it. Just like the Futterman OTLs do.
Sure, he's also one of the few people who seem to know how to put it to good use though.
I heard almost all his amps and I never had the impression of listening to a design that had the hallmark of a badly applied FB loop unlike a few others I can think of.
BTW, the German fellow who built it with the 6C19-P iso the 6080 used (or rather his GF) it on a Fostex 103 Sigma and claims it actually betters his own amp using the original TdP design.
Not bad, huh?
Cheers,
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