Thanks a lot DaMuffinMan.
The upgrade to MV rectifiers will not be the end. I intend to replace the signal transformers with amorphous core wound ones, because I was convinced a few weeks ago for their sonic superiority.
This is an "always changing" amplifier. One day it has different transformers, another day it might have another tubes. This is the one where I'm gathering all my tube SET knowledge.
I can even take it apart and rebuild another one, using the same parts but another enclosure.
The upgrade to MV rectifiers will not be the end. I intend to replace the signal transformers with amorphous core wound ones, because I was convinced a few weeks ago for their sonic superiority.
This is an "always changing" amplifier. One day it has different transformers, another day it might have another tubes. This is the one where I'm gathering all my tube SET knowledge.
I can even take it apart and rebuild another one, using the same parts but another enclosure.
Very impressive stuff. Can you share with us a bit the specs of the core in terms of material, size etcetc ? Would be great to see as well how much overspeced you got...and where to get this kind of quality...
I am currently using stuff like these...Valab 12H 200ma Filter Choke - Amorphous Metglass Double C-core UTC Transformer | #365570865
...not sure where they stand compared to yours or other, just got them from ebay, plugged them in and they do their job...
I am currently using stuff like these...Valab 12H 200ma Filter Choke - Amorphous Metglass Double C-core UTC Transformer | #365570865
...not sure where they stand compared to yours or other, just got them from ebay, plugged them in and they do their job...
Thank you Blitz, I'm glad you're interested at the subject.
The signal transformers are wound on TC-80 for the interstage and TC-270 output transformers. These are C cores taken from Russian power transformers. They have a reasonable quality, but after comparing them to a signal transformer wound on amorphous core, I don't want these anymore. Now I'm saving money for amorphous transformers.
The chokes are wound on better quality cores. The small one feeding the driver has a Mecagis brand core, salvaged from a power supply transformer.
The big choke feeding the output stage is on an unknown Japanese core picked from a power transformer again. Honestly, I didn't expect 27H at 120mA. Both cores have extremely good specs. I went to the flea market guy and bought some more of these same transformers to get their cores out.
I have a personal obligation in mind to wind chokes with same specs on different C cores - amorphous vs high quality silicon steel ; and compare these on a listening test with a small public. To compare and conclude if it is worth to wind chokes on an amorphous core.
The signal transformers are wound by a very talented engineer who currently is a colleague of mine. He gave me much of his "know-how" to wind the chokes. The later are divided into 6 vertical sections each, in order to minimize to stray capacitance, increasing bandwidth further, making the choke to act as a filter even outside the audio frequency band. Imagine one with a Fres of 50kHz. Winding such a choke is not a simple task and it is very laborious, this is why no manufacturer bothers of making these.
Recently, our company has purchased a CNC winding machine and we are winding many sorts of signal transformers, power transformers and chokes, using my colleague's know-how. For example, this is a prototype of an interstage transformer wound on AMCC160. Nomex insulation, non-magnetic (brass and fiberglass fasteners), direct lead outs to avoid additional soldering.
Best regards,
Alexander.
The signal transformers are wound on TC-80 for the interstage and TC-270 output transformers. These are C cores taken from Russian power transformers. They have a reasonable quality, but after comparing them to a signal transformer wound on amorphous core, I don't want these anymore.
Now I'm saving money for amorphous transformers.The chokes are wound on better quality cores. The small one feeding the driver has a Mecagis brand core, salvaged from a power supply transformer.
The big choke feeding the output stage is on an unknown Japanese core picked from a power transformer again. Honestly, I didn't expect 27H at 120mA. Both cores have extremely good specs. I went to the flea market guy and bought some more of these same transformers to get their cores out.
I have a personal obligation in mind to wind chokes with same specs on different C cores - amorphous vs high quality silicon steel ; and compare these on a listening test with a small public. To compare and conclude if it is worth to wind chokes on an amorphous core.
The signal transformers are wound by a very talented engineer who currently is a colleague of mine. He gave me much of his "know-how" to wind the chokes. The later are divided into 6 vertical sections each, in order to minimize to stray capacitance, increasing bandwidth further, making the choke to act as a filter even outside the audio frequency band. Imagine one with a Fres of 50kHz. Winding such a choke is not a simple task and it is very laborious, this is why no manufacturer bothers of making these.
Recently, our company has purchased a CNC winding machine and we are winding many sorts of signal transformers, power transformers and chokes, using my colleague's know-how. For example, this is a prototype of an interstage transformer wound on AMCC160. Nomex insulation, non-magnetic (brass and fiberglass fasteners), direct lead outs to avoid additional soldering.
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.
Best regards,
Alexander.
Hi folks,
This project is long disassembled, and all the transformers sold. The enclosures are stored, gathering dust.
Due to my startup attempt of audio transformer winding business, I really don't have leftover time to play with huge amplifiers.
This OPT was of very old design and I don't keep data of it. At the moment I'm winding a similar one (2.8k primary) on a huge nanocrystalline core with CFB windings and UL tap.
This project is long disassembled, and all the transformers sold. The enclosures are stored, gathering dust.
Due to my startup attempt of audio transformer winding business, I really don't have leftover time to play with huge amplifiers.
This OPT was of very old design and I don't keep data of it. At the moment I'm winding a similar one (2.8k primary) on a huge nanocrystalline core with CFB windings and UL tap.
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