thanks Rajkom
i made a 6C4C PP driven by LL1660PP, E80CC and LL1540 input stage
this combination for 8W a 0,1% THD was excellent
PP 6B4G interstage DHT
i made a 6C4C PP driven by LL1660PP, E80CC and LL1540 input stage
this combination for 8W a 0,1% THD was excellent
PP 6B4G interstage DHT
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Just saying if looking for alternative to AN, J&K Audio Design makes a tailor made OT Double-C for 880USD pair.
for output transformer i do not like coreC high impedance high voltage
but EI transformers. if standard OPT give - 2db 18/20 Khz
a perfect linear transformer price X3
so we are very happy with standard canadian OPT 1629SEA
if i find a flycase plenty of dollars i will buy better OPT
thanks anyway
I looked your website and you build impressive audiophile amplifiers.
I liked the PPP kt88 and GM70 PP, very special.
I read your modification of the music angel 845, you did a very great work especially replacing the OT with Hammond! 3.5% thd to 0.5 is incredible!
P.s. I too have a stock of 5691 RCA NOS NIB , they are exceptional tubes! same with the 6sn7 too, very good section balance and a transparent sound the new tube completely lack off.
I liked the PPP kt88 and GM70 PP, very special.
I read your modification of the music angel 845, you did a very great work especially replacing the OT with Hammond! 3.5% thd to 0.5 is incredible!
P.s. I too have a stock of 5691 RCA NOS NIB , they are exceptional tubes! same with the 6sn7 too, very good section balance and a transparent sound the new tube completely lack off.
I have experimented with, listened to, and measured various IT designs/topologies. Once I managed to find a design that allows bifilar winding design with appropriate DC interwinding voltages, I will never go back. I was never able to even remotely approach the bifilar performance with split bobbin or layered/sectionalized windings.
That being said, I also subscribe to the philosophy that IT topology is best implemented between driver and output stage, where impedances are optimized. Between input and driver stage, not so much; you are better off with cap coupled. Blocking distortion should be an output stage challenge; so fix it optimally with an IT. Only poor designs will suffer with blocking distortion between input and driver stage; therefore cap coupled is a very reasonable (and low distortion) solution.
Optimal device for the optimal stage, IMO.
That being said, I also subscribe to the philosophy that IT topology is best implemented between driver and output stage, where impedances are optimized. Between input and driver stage, not so much; you are better off with cap coupled. Blocking distortion should be an output stage challenge; so fix it optimally with an IT. Only poor designs will suffer with blocking distortion between input and driver stage; therefore cap coupled is a very reasonable (and low distortion) solution.
Optimal device for the optimal stage, IMO.
Claudiomas,
I may have given you the wrong impression, I am sorry.
I have used interstage transformers in single ended amplifiers, and they sounded great.
Some were c core, some EI.
One interstage was EI and bifilar, and I used it with 4-65 Tetrode.
I used a push pull interstage with a current source and a cathode coupled phase splitter.
I also used an SE to PP interstage transformer as the phase invertor in a push pull amp, that had good performance too.
Like you, I only used EI output transformers.
Keep listening.
Keep building.
I may have given you the wrong impression, I am sorry.
I have used interstage transformers in single ended amplifiers, and they sounded great.
Some were c core, some EI.
One interstage was EI and bifilar, and I used it with 4-65 Tetrode.
I used a push pull interstage with a current source and a cathode coupled phase splitter.
I also used an SE to PP interstage transformer as the phase invertor in a push pull amp, that had good performance too.
Like you, I only used EI output transformers.
Keep listening.
Keep building.
They are a beautiful build but feel the need to comment that more recent technology using class A transistors such as the JLH or HIRAGA amplifiers will sound better, have a much better transient response, higher s/n ratio, and cost much less. Having started off with a SET nearly 60 years ago, my comment is not without some personal experience. Those thinking about valves in any configuration should read Self.
yes, of course Sakuma its the continuation of the old golden era
just have a look how things was going on before capacitors and penthodes take over the DHT sound
http://www.bunkerofdoom.com/xfm/UTC_1936/UTC1936.pdf
That is a sweet manual! Just read it cover to cover. Makes me want to run out and build some transformer-coupled SETs!
nice Kris
you can find old style input transformer and low level IT by Hammond 800/850 series, i use 850QA its really fantastic
you need alsop UTC transformers data, here linked:
http://www.dhtechservices.com/documents/SpecSheet/CAT_UTC_Transformer_Catalog_1963.pdf
or
http://www.bunkerofdoom.com/xfm/UTC_1951/UTC51PART.pdfhttp://
you can find old style input transformer and low level IT by Hammond 800/850 series, i use 850QA its really fantastic
you need alsop UTC transformers data, here linked:
http://www.dhtechservices.com/documents/SpecSheet/CAT_UTC_Transformer_Catalog_1963.pdf
or
http://www.bunkerofdoom.com/xfm/UTC_1951/UTC51PART.pdfhttp://
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testing PP input stage by input splitter transformer to 6N6P to no gap IT
PP to paralleled secondary for 2A3 driver for IT to 845.
like this:
next amp?
edit:
124F only 5W so 20mA but this only for preliminary test with E80CC??
PP to paralleled secondary for 2A3 driver for IT to 845.
like this:
next amp?
edit:
124F only 5W so 20mA but this only for preliminary test with E80CC??
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Last edited:
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