45 amps current thinking

[rockdoc]

I'm missing my 45 amps, have a bunch of 45 tubes, looking to do another build. I had 45 paraglows, and sadly sold them.....   Who can compare Stereomour II/45 with Korneff clones, Bugle, Single ended glory, others etc?  Thanks!

Steve T

[Paul Birkeland]

All of the other 45 amps you'd look at will have sound quality fiercely dependent on the quality of the output transformers.  The requirements of #45 iron will tend to leave you with an output transformer that either has very little low frequency response, too much primary DCR (poor damping/insertion loss), or that is far larger than required for the job.  Really this application is what I use to explain the benefits of parallel feed, as you can get the primary inductance that you need to load a #45 at 5K without having 500 ohms of primary winding copper or a transformer that's 10 lbs.

The Korneff and the Bugle are ancient designs that look a lot like our Paramour I amplifiers that we put out around the same time.  There's absolutely nothing stopping us from making the Stereomour II in the exact same fashion, but the design has evolved in ways that we believe sound a lot better (though admittedly these alterations also nudge up the cost and complication).   I think you could e-mail Gordon Rankin about the Bugle and he might offer the same advice... 

I don't know anything about the Single Ended Glory, do you have a link? 

[rockdoc]

Thanks Paul,

I've only heard the 45 in para feed, so I'll go with your assessment, having heard the 2A3 and 300 B only in plain old SE, and having the 45 and parafeed win me over by a big margin.

Steve T

[rockdoc]

I don't know anything about the Single Ended Glory, do you have a link?

It was Eric Barbour in GA, here's a scan of one page

And you're right; almost 30 years ago, ancient history.....

[Paul Birkeland]

The 6SN7 driving a #45 is a lot like our SR-45, but of course without the shunt regulated power supply that helps it sound so good.   The shared cathode bias resistor in that circuit is a big red flag, but again, this is from 1995 and things have progressed a bit.   Here's a short (and incomplete IMO) blurb from a completely different source on why one wouldn't want to do this:
https://www.jacmusic.com/techcorner/ERRORZ/One-Bias-Resistor/Index-One-Bias-Resistor.html

[Doc B.]

The circuit that will likely be closest sounding to the Paraglow you liked is the StereomourII with the shunt regulator upgrade and 45 tubes, since it and Paraglow with 45s are quite similar designs.

[rockdoc]

The circuit that will likely be closest sounding to the Paraglow you liked is the StereomourII with the shunt regulator upgrade and 45 tubes, since it and Paraglow with 45s are quite similar designs.

Thanks Doc; just saving up for it.

Steve T