Hi,
Actually, this is the beauty of the circuit, the LTPC does all the gain AND phasesplitting in one go.
Just imagine two twin triodes in a cascode circuit where the bottom triode is configured as LTP.
The cascode has the high gain of a penthode and the LTP does the phase splitting.
From the two top triodes' anodes you have the two out of phase signals to drive the output PP.
The only remaining question is whether or not this stage alone can drive a PP triode. A penthode being much easier to drive.
This is why I suggested the ECC99 as it should be able to provide ample current and voltage swing, considerably more so than a pair of 6DJ8s anyway.
Cheers,
Actually, this is the beauty of the circuit, the LTPC does all the gain AND phasesplitting in one go.
Just imagine two twin triodes in a cascode circuit where the bottom triode is configured as LTP.
The cascode has the high gain of a penthode and the LTP does the phase splitting.
From the two top triodes' anodes you have the two out of phase signals to drive the output PP.
The only remaining question is whether or not this stage alone can drive a PP triode. A penthode being much easier to drive.
This is why I suggested the ECC99 as it should be able to provide ample current and voltage swing, considerably more so than a pair of 6DJ8s anyway.
Cheers,
Frank; OK!!! I see it now, found an example in the Tube Cad circuit guide. I believe that I now have enough info to make the circuit will probably use the ECC99 and will skip the interstage iron, after all, $208 for iron vs a few dollars for a tube and some resistors and caps is appealing to one on a budget, many thanks to you and all who helped!
Regards,
Pete
Regards,
Pete
OT, sorry
Just back. I missed Germany this time, but did manage a nice visit to Austria. And in France, I had a marvelous Sunday strolling around Lyon, my favorite city on Earth. There was a wonderfully fun, enthusiastic, and out-of-tune brass band playing on one of the pedestrian bridges across the Rhone. I sat and listened for a while for a while and contemplated about how microphones, recording engineers, and loudspeakers manage to lose the sense of dynamics that clue our ears/brains about the difference between live and canned.
We have a long way to go.
Just back. I missed Germany this time, but did manage a nice visit to Austria. And in France, I had a marvelous Sunday strolling around Lyon, my favorite city on Earth. There was a wonderfully fun, enthusiastic, and out-of-tune brass band playing on one of the pedestrian bridges across the Rhone. I sat and listened for a while for a while and contemplated about how microphones, recording engineers, and loudspeakers manage to lose the sense of dynamics that clue our ears/brains about the difference between live and canned.
We have a long way to go.
Could someone please scratch up a schematic for Sy's idea?
I have a pair of 6k Vintage Sansui 1000A OPTs sitting that I bought for a version of Ralph Power's PP 6B4G that I never built.
Although, I never lost a hankering for PP 6B4G
But, I just can't seem to picture what everyone's talking about.
I have a pair of 6k Vintage Sansui 1000A OPTs sitting that I bought for a version of Ralph Power's PP 6B4G that I never built.
Although, I never lost a hankering for PP 6B4G
But, I just can't seem to picture what everyone's talking about.
Have not had a chance to work out all the details but it will go something like this; A cascoded differential stage (2-6922's) into an ECC99 into a PP6B4G stage. My output trans, are Magnequest units from a Dyna 70 clone (4300 ohm).
Still working out details of the main scematic as well as the negative voltage for the power supply. Will keep advised as I go.
Regards
Pete
Still working out details of the main scematic as well as the negative voltage for the power supply. Will keep advised as I go.
Regards
Pete
Thanks Peter...
What is the advantage of trading out one stage(if we can count the IT in Power's as a stage) for another?
Anyway, I look forward to hearing about your results. I'm finishing up a Gainclone solid state amp and need a good tube one to compliment it. My speakers are 97dB efficient and a fairly stable 8 ohm load, so I don't need much more power than PP 6B4G's deliver.
BTW, the new issue of ValveDIY has a SRPP 6N1P/IT/ PP6B46 article .
But, back to your original question about using a ECC99 driver, here's a version of Ralph Power's amp using one for a driver that a local around here, Stigla, did two years back. The original thread can be found here. It documents the entire evolution of the amp.
He said the resulting amp sounded great. But, I wonder if a little filtering on the filament supplies might quiet things down a bit and clean up the resolution.
It may be a little hard to read, but that's 297V/60mA on the 6B4G's , 206V/20mA on the plate of the ECC99, 200mA off the choke in the PS, and 20 mA going to the VR tubes.
What is the advantage of trading out one stage(if we can count the IT in Power's as a stage) for another?
Anyway, I look forward to hearing about your results. I'm finishing up a Gainclone solid state amp and need a good tube one to compliment it. My speakers are 97dB efficient and a fairly stable 8 ohm load, so I don't need much more power than PP 6B4G's deliver.
BTW, the new issue of ValveDIY has a SRPP 6N1P/IT/ PP6B46 article .
But, back to your original question about using a ECC99 driver, here's a version of Ralph Power's amp using one for a driver that a local around here, Stigla, did two years back. The original thread can be found here. It documents the entire evolution of the amp.
He said the resulting amp sounded great. But, I wonder if a little filtering on the filament supplies might quiet things down a bit and clean up the resolution.
It may be a little hard to read, but that's 297V/60mA on the 6B4G's , 206V/20mA on the plate of the ECC99, 200mA off the choke in the PS, and 20 mA going to the VR tubes.
An externally hosted image should be here but it was not working when we last tested it.
Thanks for all the good info!
No particular reason for swapping out the IT stage except the fun of trying a new circuit config and the high prices for Lundhall IT"s.
Read the thread on Stigla's amp some time ago but could not get the schematic to show. Made two attempts to to E mail with no response and gave it up. Also looked at the Amity amp but the price just got higher.
The article from valve is very interesting because I currently have a Dyna clone with a trioded EF86 front end and the EL34's also wired as triodes and the sound is quite good. Might try a quick conversion to the 6N1P front end and the Hammond trans. just to hear how it sounds, but I will continue to pursue the cascode unit probably as monoblocks.
Just having way too much fun with this!
Regards
Pete
No particular reason for swapping out the IT stage except the fun of trying a new circuit config and the high prices for Lundhall IT"s.
Read the thread on Stigla's amp some time ago but could not get the schematic to show. Made two attempts to to E mail with no response and gave it up. Also looked at the Amity amp but the price just got higher.
The article from valve is very interesting because I currently have a Dyna clone with a trioded EF86 front end and the EL34's also wired as triodes and the sound is quite good. Might try a quick conversion to the 6N1P front end and the Hammond trans. just to hear how it sounds, but I will continue to pursue the cascode unit probably as monoblocks.
Just having way too much fun with this!
Regards
Pete
Hey Pete found a couple PP-PP6B4G amps...
You guys got me thinking about how to do it without the interstage tranni, so I decided to search the web.
Well, you know how that goes....
Maybe there's some good ideas in these two for you.
Check out the pictures of the Kairo differential PP6B4G, although unfiltered regulators directly into the filaments has got to be a little noisy, eh?
There's a pretty good discription of the circuit in Japanese (Babelfish seems to translate this page best).
Bilbao PP6B4G
You guys got me thinking about how to do it without the interstage tranni, so I decided to search the web.
Well, you know how that goes....
Maybe there's some good ideas in these two for you.
Check out the pictures of the Kairo differential PP6B4G, although unfiltered regulators directly into the filaments has got to be a little noisy, eh?
There's a pretty good discription of the circuit in Japanese (Babelfish seems to translate this page best).
An externally hosted image should be here but it was not working when we last tested it.
Bilbao PP6B4G
Whoops, here's that latest of that diffferential...
For some reason, they guy went with all solid state rectification.
It's late and Babelfish gets pretty dodgy on technical translations.
For some reason, they guy went with all solid state rectification.
It's late and Babelfish gets pretty dodgy on technical translations.
An externally hosted image should be here but it was not working when we last tested it.
There is a dual-differential 15 watt amp here; http://tinpan.fortunecity.com/saints/668/primer
Regards;
Pete
Regards;
Pete
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