Yes, and it outperforms any other part. Now I'll have to write an
article...
Indeed!
OK - I'm very interested in this. Thanks Nelson and Jan!
I never built the Nemesis but spent a good deal of quality time with Hiraga's build of the amp at the shop in Paris. Heavy booger! And it sounded very nice. Mono blocks, IIRC.
Now that we have a new article and new transistor, let's return to the transformer. What can be done about it? Bud P's remarks are discouraging, as he certainly knows his transformers. But transformers for this DID exist - I saw and heard them, Jan bought them and used them.
Could we approach Edcor for a design? They would charge $40 for the custom design, then transformer costs. If they are similar to the GXSE series then they'd be about $40 a piece for a 15W transformer.
Edcor asks for:
We should be able to supply those, right?
I never built the Nemesis but spent a good deal of quality time with Hiraga's build of the amp at the shop in Paris. Heavy booger! And it sounded very nice. Mono blocks, IIRC.
Now that we have a new article and new transistor, let's return to the transformer. What can be done about it? Bud P's remarks are discouraging, as he certainly knows his transformers. But transformers for this DID exist - I saw and heard them, Jan bought them and used them.
Could we approach Edcor for a design? They would charge $40 for the custom design, then transformer costs. If they are similar to the GXSE series then they'd be about $40 a piece for a 15W transformer.
Edcor asks for:
- Input/Primary (voltage or impedance)
- Output/Secondary (voltage or impedance, and any taps)
- Total power or current of the transformer
- Frequency Response
- A drawn schematic
We should be able to supply those, right?
Pano,
This transformer has a DC current of about 1A so needs an air gap which means a lot more iron than you think for 15W.
Lundahl informally quoted several times the price you mentioned.
Don't know what Elektraprint were asking.
jan
OK - the current is high so the gap needs to be bigger and thus the core needs to be bigger. Is that what you mean? So an EI core the size of the Edcor GXSE15-8-1.7K would not have good bass response at Nemesis powers?
What's the size of the transfos you have? Have you measured the primary inductance? That would be a huge help in building a new one.
What's the size of the transfos you have? Have you measured the primary inductance? That would be a huge help in building a new one.
Just had another read of the two original Nemesis articles from 1985. The transformer is a bit of a "cheat". It would have been 1H and weighed 50Kg if done full on. But a little bit of NFB saves the day and an OPT of 250mH primary inductance was used. The gap is 0.4mm. Weight was said to be 6Kg. I remembered it was heavy!
Very low DCR on primary and secondary windings.
Very low DCR on primary and secondary windings.
Yes it is heavy! I just measured the dimensions and the core is about 5*4*3 inch.
You can see some pics here: http://www.linearaudio.nl/nemesis-1.htm .
Note that Nelson put quite some effort in optimizing the transformer and the primary and secondary termination impedances. Reading his article it is clear that you probably can't just calculate a new transformer and plug it in; you surely need to do some measurements and optimization.
jan didden
Please don't let the 1000 word article delay the publishing of an informative chart or graph. (Deeply embedded is the implication of a yet-to-be-designed/fabricated SIT device that would best triodes when connected to a 5-40/1 transformer ---- the single device amp of all single device amps.)
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