Low output impedance, 100W per channel, anti-clipping compressor-limiter that starts on 80W. Also, damper diodes to protect output transformers from blown in Magnepans fuses.
-80 dB of 2'Nd order error on 40W, goes even down with lower power. Higher order errors are below noise level. However, above 40W the tail slowly starts growing. I.e. a 100W per channel push-pull amp that beats SE amps by quality, to beat solid state amps on their territory. If needed, power output can be increased twice by using paralleled GU-50 tubes and 4K output transformers. However, for 200W per channel there will be full power from 40 Hz, to avoid unbearable weight, while the prototype easy delivers 80W per channel from 20 Hz to 20 KHz.
All voltages except +800V and 12.6V for output tubes are stabilized.
It drives well 3-4 way speakers with complex crossovers. During BAF few years ago one of previous prototypes was used to audit nice speakers.
All ideas were discussed on this forum multiple times. I even published here schematic diagram of the driver and phase splitter of this amp (one of previous versions), despite it is a commercial project. I don't hesitate to share my knowledge and experience with people on the forum, but I would not present the complete design for commercial copycats.
Thanks, you have me intrigued. I don't need details, I was just wondering about the kinds of things you designed into this amp. Nicely done!
Hi,
this is a stereo push-pull amplifier built in a cheese box.
The top plate was made by Schaeffer in Germany.
Tubes are 4 x EL84 and 2 x 6AN8.
The main goal of this exercise was the use of 100V transformers as output transformers.
Despite the small 100V output transformers, the amp is powerfull and the sound is not bad at all.
I was inspired by an old posting on the internet:
http://home.alphalink.com.au/~cambie/6AN8amp/6an8amp.htm
Best regards, Frans.
I like how you left the handles on the cheesebox.
Hi,
this is a stereo push-pull amplifier built in a cheese box.
The top plate was made by Schaeffer in Germany.
Tubes are 4 x EL84 and 2 x 6AN8.
The main goal of this exercise was the use of 100V transformers as output transformers.
Despite the small 100V output transformers, the amp is powerfull and the sound is not bad at all.
I was inspired by an old posting on the internet:
http://home.alphalink.com.au/~cambie/6AN8amp/6an8amp.htm
Best regards, Frans.
Very cheesy - But in a good way!
My recently completed TubeLab SSE and Aikido Pre-Amplifier:
Thanks,
Bibin
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Thanks,
Bibin
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Lots of nice stuff out there. Nice thread to browse through.
Here are some pictures of the SET amp that I built from a basic kit offered by a diyaudio forum member several years ago.
http://www.diyaudio.com/forums/vendors-bazaar/180897-kt88-se-basic-master-kit.html#post2428752
I like the natural beauty of wood, so I built my own case from oak and cherry, with an aluminum top plate.
KT88, 6550, or EL34 can be used. My preference is 6550 Winged C. Output transformers have 4-ohm, 8-ohm, and 16-ohm taps (not from original kit). Output is around 6-8W in triode mode, and probably 11-13W in ultra-linear.
I've replaced the ALPS pot with a Khozmo 48-step attenuator. The shrouds around the hand holds were made from a PA speaker handle recess.
I've really enjoyed it over the years.
Here are some pictures of the SET amp that I built from a basic kit offered by a diyaudio forum member several years ago.
http://www.diyaudio.com/forums/vendors-bazaar/180897-kt88-se-basic-master-kit.html#post2428752
I like the natural beauty of wood, so I built my own case from oak and cherry, with an aluminum top plate.
KT88, 6550, or EL34 can be used. My preference is 6550 Winged C. Output transformers have 4-ohm, 8-ohm, and 16-ohm taps (not from original kit). Output is around 6-8W in triode mode, and probably 11-13W in ultra-linear.
I've replaced the ALPS pot with a Khozmo 48-step attenuator. The shrouds around the hand holds were made from a PA speaker handle recess.
I've really enjoyed it over the years.
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My recently completed TubeLab SSE and Aikido Pre-Amplifier:Bibin
Wow! Simply Wow!
I would love to see it on in the dark.My recently completed TubeLab SSE and Aikido Pre-Amplifier:
An externally hosted image should be here but it was not working when we last tested it.
Nice work Bibin!
Thank you Zman
Yes, a nice clean rendition of both proven designs. Please do let us know what you think of how they work in your system!
Thank you. It sounds really awesome especially the mids. There is no hum or noise.
Wow! Simply Wow!
Thank you Navin
Bibin, very nice, sleek finish. well done.
Thank you Dave
Regards,
Bibin
Lots of nice stuff out there. Nice thread to browse through.
Here are some pictures of the SET amp that I built from a basic kit offered by a diyaudio forum member several years ago.
http://www.diyaudio.com/forums/vendors-bazaar/180897-kt88-se-basic-master-kit.html#post2428752
I like the natural beauty of wood, so I built my own case from oak and cherry, with an aluminum top plate.
KT88, 6550, or EL34 can be used. My preference is 6550 Winged C. Output transformers have 4-ohm, 8-ohm, and 16-ohm taps (not from original kit). Output is around 6-8W in triode mode, and probably 11-13W in ultra-linear.
I've replaced the ALPS pot with a Khozmo 48-step attenuator. The shrouds around the hand holds were made from a PA speaker handle recess.
I've really enjoyed it over the years.
Hi Dave,
Nice Work, I am also in the process of build another TubeLab SSE in a wooden enclosure. Will share the images here.
Regards,
Bibin
Dave R,
Nice build. I see the volume and power button have swapped places in your amp?
Thanks. Actually, the volume and power buttons are still in the same place. The wiring pictures were taken from opposite sides of the chassis.
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Toccata 417a/6GK5/5842 Phono Stage
This is a well known design originally by Arthur Loesch and updated by Thorsten Loesch. Details of Thorsten’s version and build here.
I have more or less followed the design but decided it would be interesting to give each stage its own diecast box to improve screening and reduce potential interactions between the different amplifier stages. I used matched 2SK170s rather than the 2SK147 in the schematic due to availability.
Sounds really good so-far with my Linn Krystal. Very quiet, good at resolving fine detail and able to carry a tune. I had none of the reported oscillation issues with the 417a so cutting off spare grid connections on the valve socket and using ferrite beads seems to have worked.
This is a well known design originally by Arthur Loesch and updated by Thorsten Loesch. Details of Thorsten’s version and build here.
I have more or less followed the design but decided it would be interesting to give each stage its own diecast box to improve screening and reduce potential interactions between the different amplifier stages. I used matched 2SK170s rather than the 2SK147 in the schematic due to availability.
Sounds really good so-far with my Linn Krystal. Very quiet, good at resolving fine detail and able to carry a tune. I had none of the reported oscillation issues with the 417a so cutting off spare grid connections on the valve socket and using ferrite beads seems to have worked.
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I posted my latest valve circuit here:
http://www.diyaudio.com/forums/digital-line-level/166807-dac-gallery-24.html#post5065812
because it is not an amplifier.
http://www.diyaudio.com/forums/digital-line-level/166807-dac-gallery-24.html#post5065812
because it is not an amplifier.
Futterman OTL
I have just completed a new Futterman build. I more of less stuck to the schematic attached, but replaced the cold cathode voltage reference tubes with 5w Zenerdiodes. They start regulating at around the same current flow as the reference tubes and they are much easier to fit.
It uses 4 6gy5 tubes pr. channel - and delivers around 20 W into 8 ohms. I have experimented a little with the bias setting. Originally Futterman ran his output tubes up to something like 70-80% of their capability, which is very hard on the tubes. I run them at around 50mA pr. tube - and can't detect any downsides to this. The THD is still around 0.1% and sonically I can't detect differences either.
I mostly used off the shelf toroidal transformers, but added an extra 150Vac winding for the screen grid voltage and a 30Vac winding for the bias (I use a voltage doppler). The heather transformer in below deck - the B+ on top.
The amplifier is built on the remains of a Technics integrated amplifier I butchered some time ago.
In the bottom there is a slow moving fan which keeps the whole thing quite cool.
I have just completed a new Futterman build. I more of less stuck to the schematic attached, but replaced the cold cathode voltage reference tubes with 5w Zenerdiodes. They start regulating at around the same current flow as the reference tubes and they are much easier to fit.
It uses 4 6gy5 tubes pr. channel - and delivers around 20 W into 8 ohms. I have experimented a little with the bias setting. Originally Futterman ran his output tubes up to something like 70-80% of their capability, which is very hard on the tubes. I run them at around 50mA pr. tube - and can't detect any downsides to this. The THD is still around 0.1% and sonically I can't detect differences either.
I mostly used off the shelf toroidal transformers, but added an extra 150Vac winding for the screen grid voltage and a 30Vac winding for the bias (I use a voltage doppler). The heather transformer in below deck - the B+ on top.
The amplifier is built on the remains of a Technics integrated amplifier I butchered some time ago.
In the bottom there is a slow moving fan which keeps the whole thing quite cool.
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