In Reply to: RE: Weekend eye candy (prototypes) posted by hvbias on March 16, 2015 at 08:03:12:
Hello hvbias;None of the TL-404's have ever been built on nickel.
And they perform exceptionally well on the core material which we use for them.
Check out http://magnequest.blogspot.com/(hot link provided below)and scroll down a few entries and you'll find some square wave and frequency response test results on a pair of our TL-404's. And these results were with a source (driving) impedance of 2400 ohms.
rounding off a bit... the 404 is within half a db from 20 hz to 100 khz. And,again,that is with a relatively high driving source impedance.Had that source impedance been say 800 ohms it probably would have gone down a further octave on the bottom end.
Which tells me that the core material we are using is good for this design. And for some historical perspective... This design dates back to 1946 and was built for MGM recording studios.
Our current production uses a lamination grade with greater perm and lower core losses than the original design from 1946.
I'm pretty happy with the design the way it is. And we've had a lot of builders who have been very pleased with the TL-404's.
The XL version is the same as the non XL except that it has more stack. The larger stack is offered for those who would like to build with a 45 SE output tube (or say a 71A) and has a two watt MOL.
And you can still use the XL version as a line level (i.e. preamp) output.
The XL's are $600 a pair. And I have some in stock. I am sold out of the smaller cored TL-404's for the time being.
MSL
Builder of MagneQuest & Peerless transformers since 1989
Edits: 03/26/15 03/26/15 03/26/15 03/26/15 03/26/15 03/26/15 03/26/15
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Follow Ups
- RE: Weekend eye candy (prototypes) - mqracing 05:47:26 03/26/15 (0)