This is a very interesting amp, as I've said before. The big issue with hybrids is the B+, the warmup from cold, and organising the very different voltages and impedances of tubes and SS.
I have done a number of hybrids over the last twenty years, one which used a 6SL7 in SRPP with a 340V B+ and a SE 3A 50V Class A mosfet output stage which sound wonderful but dissipated 150W EACH channel. I gave this up in 1995 and started work on the Class AB concepts. So when I see a tube used in an AB SS of relatively simple design I'm very interested........
A recent idea I'm working on is a very good quality AB SS amp, something like my commercial NAKSA, set at a gain of 17dB and global feedback. We then drive the input with a 12AU7/6SN7/6CG7 twin triode in SRPP, delivering a gain of around 15dB. No fb between tube and SS amp, but careful matching with Zin of the SS, as SRPPs are very sensitive to loading. As the tube warms up the voltages slowly rise and adjust so the SS is not discomforted.
With this arrangement you have the grace of tube, and the muscle and slam of SS. This is, of course, the goal of all hybrids and very few of them achieve it.
Hugh
I have done a number of hybrids over the last twenty years, one which used a 6SL7 in SRPP with a 340V B+ and a SE 3A 50V Class A mosfet output stage which sound wonderful but dissipated 150W EACH channel. I gave this up in 1995 and started work on the Class AB concepts. So when I see a tube used in an AB SS of relatively simple design I'm very interested........
A recent idea I'm working on is a very good quality AB SS amp, something like my commercial NAKSA, set at a gain of 17dB and global feedback. We then drive the input with a 12AU7/6SN7/6CG7 twin triode in SRPP, delivering a gain of around 15dB. No fb between tube and SS amp, but careful matching with Zin of the SS, as SRPPs are very sensitive to loading. As the tube warms up the voltages slowly rise and adjust so the SS is not discomforted.
With this arrangement you have the grace of tube, and the muscle and slam of SS. This is, of course, the goal of all hybrids and very few of them achieve it.
Hugh
Peter. Your long narrow board may sit an application. Can you point to the schematic?
Matthew
Sent from my SM-N9005 using Tapatalk
Hi Peter,
Did you ever post the layout for the ECC88 version. I would like to try your layout and see if it performs better than the one I built. If you can please post the foil and silk.
Thanks, Terry
Did you ever post the layout for the ECC88 version. I would like to try your layout and see if it performs better than the one I built. If you can please post the foil and silk.
Thanks, Terry
Terry, is it here PCB layout for this OPS in PDF format? I can't find it...
Thanks..
Regards,
Marcel
Today I have hooked up ECC88 IPS stereo, plays really awesome, the tubes I have are siemens one.
The bass is really powerfull, very good bottom end, plenty micro details in the middle and top octave. For me i is the best amp I have ever had.
Monday or Tuesday I will stick in the ECC82 IPS to compare them.
The bass is really powerfull, very good bottom end, plenty micro details in the middle and top octave. For me i is the best amp I have ever had.
Monday or Tuesday I will stick in the ECC82 IPS to compare them.
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Impressive........
Great that the bass is good. Often an issue with tube amps.
Congratulations, Peter!
Hugh
Great that the bass is good. Often an issue with tube amps.
Congratulations, Peter!
Hugh
AKSA,I've never listen this IPS with ecc88 but with 12Ua7 ONLY.I can say that is the only IPS with so deap bass even when listen this at very low volume levels!
Hi
Peter so these amplifier is a improvement over any of the FET-hex explendit amplifier
I write any of those because you built several version including the Toshiba mosfet
If you say yes I will go after these amplifier (just wanted to etch the PC boards for the FET-hex explendit amplifier. I will hold my horses with that until you confirm it.
Also when you have time I will need a favour from you to take a look my Toshiba mosfet OPS circuit (based on Cordell idea) If hope you remember you made some promise ....................
Of course not now.
Thank you
Greetings gabor
Marc
Files sended.
AKSA
Thanks.
Next step Ill try to do some tube VAS but this would have to wait few weeks.
I am done with amps for a while anyway. Very happy with resault.
Gabor
Yes there is big improvement vs FET-hex imho. I like it a lot because it match my ''amp taste'' perfectly (you may like something differend, who knows). But You will be happy for sure with hybrid amp. Post yours toshiba mosfet ops schematic please.
Next month I will be extremly busy but after that Ill make a prototype OPS with toshiba mosfets, they are great transistors.
thimios
Monday I will stick the other IPS to compare the Ecc82 Ecc88 one, just for fun.
Regards
Peter
Files sended.
AKSA
Thanks.
Next step Ill try to do some tube VAS but this would have to wait few weeks.
I am done with amps for a while anyway. Very happy with resault.
Gabor
Yes there is big improvement vs FET-hex imho. I like it a lot because it match my ''amp taste'' perfectly (you may like something differend, who knows). But You will be happy for sure with hybrid amp. Post yours toshiba mosfet ops schematic please.
Next month I will be extremly busy but after that Ill make a prototype OPS with toshiba mosfets, they are great transistors.
thimios
Monday I will stick the other IPS to compare the Ecc82 Ecc88 one, just for fun.
Regards
Peter
Hi Peter,
Can you share the layout for your ECC88 IPS? I want to try yours.
Thanks, Terry
Bellow files for home made boards.
Both LEDs on the board can be bypassed with a jumper, they only inform that the current is flowing form the ccs to LTP stage.
Both LEDs on the board can be bypassed with a jumper, they only inform that the current is flowing form the ccs to LTP stage.
Hi Peter, if it's not too much trouble could you give me a mirror of the silk screen? Not a huge deal but I like to add them to the top of the board when I can. A png file would be great.
Thanks, Terry
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Bellow top silk mirrored.
Please do some scope tests before You plug it in to some speaker, I have some phillips ecc88 tube and is working very badly but others I have are working perfect.
Regards
Peter
Please do some scope tests before You plug it in to some speaker, I have some phillips ecc88 tube and is working very badly but others I have are working perfect.
Regards
Peter
Hi Peter
Thank you for the green light to post my Toshiba OPS circuit.
These Toshiba OPS based on Cordell circuit with HEC correction.
It was not simulated..
Not sure these would work how it is or need more tweak (modification) .😀
I already made the layout for these but I decided to wait than to each a useless PC boards or even worst blow up the Toshiba devices.😱
Greetings
Thank you for the green light to post my Toshiba OPS circuit.
These Toshiba OPS based on Cordell circuit with HEC correction.
It was not simulated..
Not sure these would work how it is or need more tweak (modification) .😀
I already made the layout for these but I decided to wait than to each a useless PC boards or even worst blow up the Toshiba devices.😱
Greetings
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Gabor
I really have no experience with HEC circuit at all. Bellow is OPS from well known amp with toshiba mosfets, the drivers (I have them in stock anyway) can be IMHO substituted with BJT ones + small change ind Vbe circuit. I think you can try them out in the OS new V2 uni-OPS.
I do not know if HEC will bring any sonic improvement, the ''sound'' comes from the input stage mostly. If I were You I would wait for the V2 slevmaster which can take the mosfet transistors. I have too little knowledge for aplication of HEC circuit.
The OPS can be made with simple circuit and with well designed board the performace should be superb.
I really have no experience with HEC circuit at all. Bellow is OPS from well known amp with toshiba mosfets, the drivers (I have them in stock anyway) can be IMHO substituted with BJT ones + small change ind Vbe circuit. I think you can try them out in the OS new V2 uni-OPS.
I do not know if HEC will bring any sonic improvement, the ''sound'' comes from the input stage mostly. If I were You I would wait for the V2 slevmaster which can take the mosfet transistors. I have too little knowledge for aplication of HEC circuit.
The OPS can be made with simple circuit and with well designed board the performace should be superb.
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Thanks,
I'll get it populated tomorrow. Father's Day today so all family time.
Blessings, Terry
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Hi Borys,
i don't remember if you allready done, but could you describe the R9 bias setting for ECC88 and for 12AU7 even i will use 6SN7? R10 if i am rigth is for offset balancing.
Marc
i don't remember if you allready done, but could you describe the R9 bias setting for ECC88 and for 12AU7 even i will use 6SN7? R10 if i am rigth is for offset balancing.
Marc
Terry, seeing all your home etching job regive taste to the job, i have to build new UV exposure box mine is out, this time it will be with 1W UV star led.
Marc