audio-talk

Still have pauls sv811-10 s here, bang them in it, the old one had my old 300b's in it for a time and they were alright even running a 2.5v heater
Need a shitload of heater current though so those dc supplies wouldnt be up to the job.

IslandPink wrote: ↑Fri Aug 11, 2017 8:42 pm I liked that 572b amp a lot Ed. Something about thoriated really filaments works.
Might have to haul the poor-man's Quasars over, at this rate.

Yes,
That 572B was really good. last time I heard that, was at Owston, going through some VoFos IIRC.

Going to hopefully finish clearing out the shit tip of a room that I used to build amps in. Once I can actually see the floor, then I can start setting up the hobby room again.

Cressy Snr wrote: ↑Fri Aug 11, 2017 9:11 pm

IslandPink wrote: ↑Fri Aug 11, 2017 8:42 pm I liked that 572b amp a lot Ed. Something about thoriated really filaments works.
Might have to haul the poor-man's Quasars over, at this rate.

Yes,
That 572B was really good. last time I heard that, was at Owston, going through some VoFos IIRC.

seems to be a recurring problem or misrepresentation around these parts....

It wasn't a 572b, if it's mine you're referring to.....it was, and still is, a Svetlana sv572, which is an entirely different animal.
twin choke power supply, Coleman reg heaters driven by heavy duty smps, aikido driver, fixed bias with AVR monitor.....still the best valve unit I've built. Doesn't hold a candle to the F6 though.

ho hum, onwards and upwards

Clearing out the shit tip, I found a pair of cute little short bottle NOS, 1960s Hitachi round plate 6SL7 I didn't know I had. I also found the DIYHS DHT filament supply module I was looking for.
Hmmm...
6SL7 into a 5687 CF, driving 6B4G sounds like a fun little project.

Or 5687, DC coupled to trioded EL84, driving 6B4G, for a nice bit of welly.

Yes, but then it wouldn't be the same amp. Don't underestimate the qualities of a high-Gm pentode driver ! - for instance with 6HG7 you've got one driver stage with enough gain to run without a cathode by-pass cap, so no low-frequency high-pass.

You beat me to it there Mark.
If is is going to be a resurrection, then it needs to be the same amp, otherwise why bother?

Just one difference between this and the old version of the 6B4G SE:

The resurrection shuffle version will be stereo rather than two monoblocks, simply because I want it to fit on the TV unit, so that it can be, with relative ease, switched with the solid state amplifier, in and out of the system as the mood takes me.

Because the amp will be stereo then the HT series regulator will be carrying twice the current the old ones did.
I have a couple of choices for series pass tubes; either, one of my 6336As or to go really exotic, one of my 13E1s.

The thought of a beautiful 13E1 series pass tube, with its giant twin cathodes all aglow, sitting symmetrical between a pair of 6B4Gs makes the old knees go weak with desire
It has to be 13E1 doesn't it, this recreation deserves the best of the best in regulator tubes. Now, where are those nice English Electric Valve, square ceramic septar sockets I stashed away after breaking down the Alexandra Palace amplifier?

The Ally Pally - that was another lovely creation.

Go for it - nice valve . But the 6080 (both sections ) should have no trouble with 2x 6B4G and 12HG7 , I had that for the 300B stereo amp before the shunt-reg. I still seem to think you had shunt-reg on that Owston amp but memory is a funny thing as I've found recently

Cressy Snr wrote: ↑Fri Aug 18, 2017 10:25 pm Because the amp will be stereo then the HT series regulator will be carrying twice the current the old ones did.
I have a couple of choices for series pass tubes; either, one of my 6336As or to go really exotic, one of my 13E1s.

The thought of a beautiful 13E1 series pass tube, with its giant twin cathodes all aglow, sitting symmetrical between a pair of 6B4Gs makes the old knees go weak with desire
It has to be 13E1 doesn't it, this recreation deserves the best of the best in regulator tubes. Now, where are those nice English Electric Valve, square ceramic septar sockets I stashed away after breaking down the Alexandra Palace amplifier?

The Ally Pally - that was another lovely creation.

Yes it was Steve, lovely looking creation!

It looked beastly!

The 13E1 was originally designed for series pass regulation. Never tried it like that myself - would be interested in the results - it is beautiful. Originally got mine with the intention of building a Crystal Palace, but it never happened...

You wouldn't consider a shunt reg instead?

IslandPink wrote: ↑Fri Aug 18, 2017 10:59 pm Go for it - nice valve . But the 6080 (both sections ) should have no trouble with 2x 6B4G and 12HG7.

I know, but I want to get back to that it might be daft but I'm doing it because I can vibe, and those 13E1 valves just look incredible lit up.

I can understand using a shunt reg where there are comparatively small currents flowing, such as regulating pentode screen grids or a preamp's HT, but a whole stereo power amp?

A decent output bypass cap can work wonders with a series reg.
I have been guilty in the past of "breaking" the series reg a bit too much with innapropriate values of bypass cap.
The last time I did anything of my own with regs was five years ago. Re-reading the threads I was involved with, I was shocked at how much I had forgotten and needed to brush up on. Age has not been kind to my ability to retain stuff.

Looking at the series reg on my schematic and Mark's comments, I had a search through my backups and found a series to shunt reg using a series 6080, followed by a shunt using an 807. I don't remember ever implementing it on the 6B4G monos, but I could be wrong. It was all a while ago now.