GB: Sowter 10K:10K Input Transformer

[luvdunhill]

Originally posted by DaveM
I still have one question. What kind of modification will likely be needed to use the Sowter transformers?

SY hinted at something requiring a square wave generator and a scope in his article. Perhaps he can outline the general principle for both solid state (JFET) input and tube input stages?

[dsavitsk]

Originally posted by SY
Luvdunhill, if you go the Cinemag route, I'd certainly be in for a pair of those. Pretty much dead-on equivalents of the Jensens, and much cheaper.

I can't speak to this particular transformer, but I know that Cinemag winds some of Jensen's others. Indeed, there is a pair of transformers in the mail to me right now from Cinemag and stamped Jensen on the label.

[dsavitsk]

Originally posted by JimT
I would like a pair of Cinemag PCB mount.

I'd be in for a pair of Cinemags, but preferably with the 3/8" bushings. Maybe too complicated ...

[dsavitsk]

Originally posted by okapi
can the CMLI-15/15B or a similar transformer be used in place of the input and/or output coupling capacitors on the b1 buffer?

thanks

On the output, you still need a DC blocking cap. Or, you need to build the amp balanced. Also, a 600:600 transformer w/o shielding is a better choice as it has better bandwidth, lower distortion, and lower capacitance. Conceptually, this is the idea: http://headwize.com/ubb/showpage.php?fnum=3&tid=7740

On the input, at a glance, unless you balance it, you'll still need a DC blocking cap.

[dsavitsk]

Originally posted by luvdunhill


SY hinted at something requiring a square wave generator and a scope in his article. Perhaps he can outline the general principle for both solid state (JFET) input and tube input stages?

This is slightly controverial. Without a doubt, a filter will make a square wave look better. However, many people who work with and/or wind transformers (from Electra-Print to O-Netics to K&K) seem to think that ringing is not really an issue, and that these filters can do more harm than good.

http://electra-print.com/techblog.php?blogid=5

[luvdunhill]

Originally posted by dsavitsk



I'd be in for a pair of Cinemags, but preferably with the 3/8" bushings. Maybe too complicated ...

Doug: I have no problem requesting 3/8" bushings for all the wire leaded Cinemags.

Also, since the primary and secondary ratios are the same, I'm not sure how that article really applies here?

[DaveM]

Exactly my point. If I am going to end up having to redesign an input stage that I don't quite understand, it will be foolish for me to look at a Sowter. I have access to a scope, but no square wave generator. I guess I could use my computer and sound card. I would prefer the OCC wire, but don't want to make a big project of it.

[dsavitsk]

Originally posted by luvdunhill
Also, since the primary and secondary ratios are the same, I'm not sure how that article really applies here?

Yes, the citation is not perfect for what I was trying to say. The point is that all transformers ring (bifilar and quadfilar ring less), but that it isn't the end of the world and may not negatively influence sound quality. Some people think that the practice of stopping the ringing does more harm than good, so people should not be scared off from using input transformers just because they lack a scope and a square wave generator.

[SY]

seem to think that ringing is not really an issue, and that these filters can do more harm than good.

Well, might as well go back to my 1985 vintage Sony CD player. Seriously, I have an issue with a transformer adding stuff, but if someone likes that sound effect, well, it's their money and their ears.

BTW, the calibrator output of most scopes makes a dandy square wave source.

[jackinnj]

Originally posted by dweekie
Can somebody reference Jack's board for me?

Search under "Impasse"

I wish folks would comment on the orientation of the transformers on the left side of the board so i can send them out.