I made an MC phono recently with 6SN7 in the second stage focused to sound good by comparison to NJFET phono stages that I already had developed that people liked and had built. It may interest somebody. I call it the Valve Itch. 
If SRPP has a defined load that is tuned to, it may blend its push pull nature successfully with successive stages that lend enough complimentary distortion profile. Its a system thing. Such artisan amps like Kondo work as a sum of carefully tuned stages and custom components by ear. Its difficult to draw any conclusions from such stuff.
Just trying to join the discussion: the RPA (have you checked it, phrarod?) is CCDGC, or constant current draw grounded cathode.
Basically, CCDGC is the (correct) evolution of the usual concept first tube gain, second tube cathode follower. Correct in letting both tubes draw the same amount of current, in counterphase to each other, thus drawing constant current from the power supply.
It goes without saying that in practice your tubes will not draw exactly the same, unless they are perfectly paired... nevertheless, it will sound, well, great.
No pun intended, CCDGC well executed generally beats SRPP (and when you say SRPP there are several "totem pole" configurations, some quite simple, other quite elaborate...) at least in my experiences and the common experiences of most people who tried the variations of the RPA: they were all entusiastic about it because it improved greatly over their previous preamps that were mostly SRPP...
For WOT, well, no pun intended again, to me it is an added complication of the (high quality) output transformer. Whenever a tube can do without a transformer, it does its best. The same is basically a true illustration of OTLs, but in the contrary sense -- great and venerable beasts with a tendency towards overcomplication and extreme parts count, clearly over the point of diminishing returns.
Output tubes generally require transformers to drive low impedance (i.e. normal) real world drivers. Low power tubes generally do not require transformers to drive high impedance (i.e. normal) real world preamplifiers, gain stages, output stages... at least in my book.
That said, special salutes go to a man formerly known as Choky
who likes WOT preamps and hybrid power amps.
Basically, CCDGC is the (correct) evolution of the usual concept first tube gain, second tube cathode follower. Correct in letting both tubes draw the same amount of current, in counterphase to each other, thus drawing constant current from the power supply.
It goes without saying that in practice your tubes will not draw exactly the same, unless they are perfectly paired... nevertheless, it will sound, well, great.
No pun intended, CCDGC well executed generally beats SRPP (and when you say SRPP there are several "totem pole" configurations, some quite simple, other quite elaborate...) at least in my experiences and the common experiences of most people who tried the variations of the RPA: they were all entusiastic about it because it improved greatly over their previous preamps that were mostly SRPP...
For WOT, well, no pun intended again, to me it is an added complication of the (high quality) output transformer. Whenever a tube can do without a transformer, it does its best. The same is basically a true illustration of OTLs, but in the contrary sense -- great and venerable beasts with a tendency towards overcomplication and extreme parts count, clearly over the point of diminishing returns.
Output tubes generally require transformers to drive low impedance (i.e. normal) real world drivers. Low power tubes generally do not require transformers to drive high impedance (i.e. normal) real world preamplifiers, gain stages, output stages... at least in my book.
That said, special salutes go to a man formerly known as Choky
who likes WOT preamps and hybrid power amps.
well ......
I really felt cozy in this thread , so I posted these pages from great SP mag ...
without any intention to mix ( or match ) apples and oranges , I have no intention to place any sort of gain stage in competition with another one ........
same as my funny countryman ( funny , because we have same first name
) , I prefer some simpler stages to SRPP ......
lately I like cascoded and CCS-ed triodes ..... I must confess that A. Wright wasn't naive at all , using old Tectronix stage ( called by him SLCF) , and deriving it in new ways ........
pure and honest engineering .....
regarding WOT - it's certainly temple of dynamics , comparing it to almost every other gain stage ....
it has own limitations ( cost is one ) ....... but - I have strong impression that most important factor in choosing one between few adequate stages is nothing else than - taste .......
so - shall we enjoy further in nice chat about nice stages .... ?
I really felt cozy in this thread , so I posted these pages from great SP mag ...
without any intention to mix ( or match
) apples and oranges , I have no intention to place any sort of gain stage in competition with another one ........ same as my funny countryman ( funny , because we have same first name
) , I prefer some simpler stages to SRPP ......lately I like cascoded and CCS-ed triodes ..... I must confess that A. Wright wasn't naive at all , using old Tectronix stage ( called by him SLCF) , and deriving it in new ways ........
pure and honest engineering .....
regarding WOT - it's certainly temple of dynamics , comparing it to almost every other gain stage ....
it has own limitations ( cost is one ) ....... but - I have strong impression that most important factor in choosing one between few adequate stages is nothing else than - taste .......
so - shall we enjoy further in nice chat about nice stages .... ?
A MATTER OF TASTE
Yes, countryman, I agree that the choice between the various preamps is a matter of taste... just as the choice of power amps.
But I always like to point out that simple is better. Therefore, WOT must be the best, because simpler than that... BUT for the cost and availability of high quality output transformers.
Every time I tried, it was not the right thing for me. I keep hoping the reason is the lack of proper output transformer... because otherwise I would feel very bad not to be able to better myself
BTW, nice turntables
A friend of mine is a serious fan of german engineering, and I would like to join the club, but am limited in the money to spend / time to spend department.
We should meet some time.
Serbia rules in audio as well (just like basketball, and other sports)...
Yes, countryman, I agree that the choice between the various preamps is a matter of taste... just as the choice of power amps.
But I always like to point out that simple is better. Therefore, WOT must be the best, because simpler than that... BUT for the cost and availability of high quality output transformers.
Every time I tried, it was not the right thing for me. I keep hoping the reason is the lack of proper output transformer... because otherwise I would feel very bad not to be able to better myself
BTW, nice turntables
A friend of mine is a serious fan of german engineering, and I would like to join the club, but am limited in the money to spend / time to spend department.
We should meet some time.
Serbia rules in audio as well (just like basketball, and other sports)...
I have a choke loaded circuit at the moment. Quite dynamic and clean. Just not WOT.
What I was taught about OT is that one trans doesn't fit all. The trans has to be wound to the tube/circuit you're using. Have low DCR and impedance. A proper OT shouldn't be that costly (don't need a AN crazy priced one). Just one that's designed with the proper tube curve in mind.
What I was taught about OT is that one trans doesn't fit all. The trans has to be wound to the tube/circuit you're using. Have low DCR and impedance. A proper OT shouldn't be that costly (don't need a AN crazy priced one). Just one that's designed with the proper tube curve in mind.
I am about to test a cascoded Mosfet electronic choke (gyrator) constant voltage, as anode load. One discussed with Wavebourn. CCS as anode load, even Mosfet cascoded, I did not like in all departments in the end. So if I like the electronic choke and keep it, I can finally be called e-choky.
P.S. Belgrade guys: How is that Korato tube gear company doing these days? I remember they had a rather big commercial store being also dealers of well known brands at the left side to a theater (or a theatrical school) at a square. I know that Serbia has excellent DIY, but does commercial Hi-End circulate more now? Is Audiophilia catching up?
P.S. Belgrade guys: How is that Korato tube gear company doing these days? I remember they had a rather big commercial store being also dealers of well known brands at the left side to a theater (or a theatrical school) at a square. I know that Serbia has excellent DIY, but does commercial Hi-End circulate more now? Is Audiophilia catching up?
salas said:I am about to test a cascoded Mosfet electronic choke (gyrator) constant voltage, as anode load. One discussed with Wavebourn. CCS as anode load, even Mosfet cascoded, I did not like in all departments in the end. So if I like the electronic choke and keep it, I can finally be called e-choky.
P.S. Belgrade guys: How is that Korato tube gear company doing these days? I remember they had a rather big commercial store being also dealers of well known brands at the left side to a theater (or a theatrical school) at a square. I know that Serbia has excellent DIY, but does commercial Hi-End circulate more now? Is Audiophilia catching up?
even if not complete catalogue about Serbian Audio production , it's certainly easiest - just google for 6moon and serbia
naah - here it is : http://tiny.pl/bnph
for Korato - CLICK
regarding constant voltage ..... yup , nice trick ...........
almost any tube is completely relaxed when cascoded ( with mosfet , what else ?) ........ loaded with CCS .......
what's in cathode - that's maybe matter of greatest compromise - LEDs , full degeneration , partial degeneration .... etc ......
great hobby ....... indeed
edit :
proper 6moon link placed
Aha! They look like they have made it in the end. I remember Kosta, the first part of Ko-ra-to first names acronym. He had managed to send me an amp I bought from them during the 1999 NATO raid, hidden in a fruit loaded track. They appreciated the purchase and trust I have shown during those hard days and they sent me an Easter card signed by all. I still got the card. War tube audio. Those tubes still glow weird (I hope not bcs of isotopes), maybe that is why I became insomniac?
NOT A FAN
I am not exactly a fan of Ko-Ra-To, maybe because I am as well an "old audiophile" from the old Yugoslav capital. Commercial, commercial, and yet again commercial.
Regarding war time tubes, I have a better story: approximately 10 year ago when Serbia was bombed by the NATO states, the building of the RTS (Serbian State TV) was bombed as well. Quite a disaster, and quite a few casualties: their relatives will never feel sympathy to westerners. Nevertheless, months later, the cellar of the bombed building was cleared and several NOS articles from yesteryear saw the light of day again. Among those were several boxes of tubes, and some of those tubes I got as a present from friends.
I am proud to have a 5U4 RCA on my amp -- a tube that survived the bombing.
I am not exactly a fan of Ko-Ra-To, maybe because I am as well an "old audiophile" from the old Yugoslav capital. Commercial, commercial, and yet again commercial.
Regarding war time tubes, I have a better story: approximately 10 year ago when Serbia was bombed by the NATO states, the building of the RTS (Serbian State TV) was bombed as well. Quite a disaster, and quite a few casualties: their relatives will never feel sympathy to westerners. Nevertheless, months later, the cellar of the bombed building was cleared and several NOS articles from yesteryear saw the light of day again. Among those were several boxes of tubes, and some of those tubes I got as a present from friends.
I am proud to have a 5U4 RCA on my amp -- a tube that survived the bombing.
No, the tower across the river was the old Central Committee (of the Communist party) building. They bombed that one on several occasions, but were unable to tear it down -- and is now rebuilt as one of the most modern and fancy office buildings in Belgrade (refurbished interior and new fasade).
The RTS building was a normal building in the center of the city, near the church of St. Marko and the Assembly building. Additional casualties (collateral damage) were risked in that attempt (who cares when it's not your folks). Anyway, the building was repaired and is in function today. The RTS has always had some strange idea about TV, that TV is not the equipment, or the people who make the shows... but the buildings they have
The RTS building was a normal building in the center of the city, near the church of St. Marko and the Assembly building. Additional casualties (collateral damage) were risked in that attempt (who cares when it's not your folks). Anyway, the building was repaired and is in function today. The RTS has always had some strange idea about TV, that TV is not the equipment, or the people who make the shows... but the buildings they have
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.