No if you put 50ma you gain some Henry....
you lose some optimization as the gap in the core if for 100ma but this add some flexibility if you will need more power for next amp....
don't use 100ma for 1w amp
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Thank you all for the insight. The 300B will be running around 90mA. James doesn't post their inductance numbers like Edcor does so I don't know how they're designed. But it sounds like, from what has been said, that they have been designed to work optimally at this current.
Understood. Not too concerned about LF because of separately powered subwoofers. I went ahead and purchased the lower current (90mA) James Audio JS-6123HS because of your input. The 5K primary tap is listed as 18-52KHz @ -2dB, so although maybe not perfectly ideal, it seems to be a good compromise between price and quality.
Thank you so much for your help
you can find the data here JS-6123HS JAME AUDIO TUBE OUTPUT TRANSFORMER for western electric 300B
If Silk's measuring is correct, even James 3k tap freq. response data is very optimistic.
SAC Thailand
http://www.sacthailand.com/Pic/Transformer_outputTestFC-JS6123.jpg
IMHO biggest problem is the resonance below 100kHz.
Thanks for the link. Why does it matter what the response is doing a couple of orders of magnitude higher than human hearing capability? Does it have ramifications lower in the spectrum?
SAC Thailand
As you can see in the (6123HS) 10kHz SQ picture, resonance below 100kHz causes some ringings (in the output signal upper and lower horizontal lines). These anomalies occurs distortions and discolourations in the music.
If possible (most manufactures hide frequency measurements) choose such an output transformer, which is free from resonances (at least below 100kHz).
That's a pretty neat website with some good info. Although I have no doubt that they are giving unskewed data, my cynical side says they're still trying to sell you something. Still, the James are nearly 300/pair, the Silks are nearly 300/piece. I tend expect greater things from something out of my price range. I wish they had tested Edcors but they probably perform about the same as the Hammond.
At SAC measurements the AN transformer is model 152.
http://www.sacthailand.com/Pic/Transformer_OutputTestFC-Trans152.jpg
I think that AN Trans152 is an average model, thus Silk transformer looks better.
ETF 2009:
European Triode Festival - ETF2009 Shootout
http://forums.melaudia.net/attachment.php?aid=1228
I'm not convinced that this comparison is realy correct in every respect. For example some of the transformers has not been examined by scope (for example AN300), thus its 10k SQ score not evaluable. Upper frequency limit was 20kHz. If 20-100kHz contains resonances, it's not visible on this picture (only 10k SQ pic shows these types of faults).
IMHO James frequency response and distortion score is better, than AN300's, but 80kHz resonance is visible in 10k SQ picture. It spoils the evaluation.
Attachments
Audio note make several OPTs, and they vary a lot in quality. I have the Trans-152 myself and I can tell you it's a big beast. Bass is good, midrange is average, treble a little less interesting than some other models.
Not as good as Lundahl LL1620 or LL1664. I haven't personally owned anything better than Lundahls, but I've never owned Tango, Tamura, Hashimoto or Monolith. These days I'd buy Monolith, or an older model of the Japanese classics if one came up at a good price on ebay.
>>I have not personally owned anything better than Lundahl,<<
Me too Andy. I have LL1620-PP in my PP amp.
12-13 years ago when I designed my SET, with help of local DIYers, I tried AN, Lundahl and James. The speaker was with FR driver without crossover.
From what I heard from speakers, and considering the price, I chose James. Little "limp" treble with 5K tap on James. But 3k5 is quite good.
JMO
Me too Andy. I have LL1620-PP in my PP amp.
12-13 years ago when I designed my SET, with help of local DIYers, I tried AN, Lundahl and James. The speaker was with FR driver without crossover.
From what I heard from speakers, and considering the price, I chose James. Little "limp" treble with 5K tap on James. But 3k5 is quite good.
JMO
Her are some measurements at the Lundahl 1664.
It sounds nice but "boring", higher copper losses the the Tango top range transformer.
Square wave 10kHz reasonable good.
It sounds nice but "boring", higher copper losses the the Tango top range transformer.
Square wave 10kHz reasonable good.
