audio-talk

Allow 4v for regulation. So for a 300B (5v + 4v) is 9v peak, over 1.414 is 6.36v RMS 6.3v tx should be ok. 6v might be if your primary is 5% high. I went for a dual 7v toroidal with 4.4A secondaries to give plenty of headroom. I also used the 63mm heatsinks for the 300B. These are onboard the smalle...

I can also highly recommend Andrews boards. I run the standard boards (as opposed to the large) with 300B no issue. Make sure you size the transformer with plenty to spare - I had a buzz which eventually tracked back to toroidal overload.

Very nice. Next Owston?

I have a MOTH machine. Haven't used it for ages.

Nice work and nice result.

I know it's obvious, but won't the change of rectifier change the operating points of the valves? Especially changing tube to SS.

If you're really wanting to compare the sounds of rectifier circuits wouldn't you need to regulate the HV ? Maybe you already do?

Page 483 of the RDH v4 confirms... not that I've yet grokked the other formulae on that page

470nf into 39k gives 9Hz, about right. Maybe could be lower, but its parts box stuff. Again I'm showing where my understanding may be flaky - I just love doing that ! :D I thought the equation for the -3db frequency corner was 1/(2pi*R*C)... where R is the parallel resistance of anode load and grid...

Thanks for sharing the circuits. I would love to try an OTL in a year or so, watching this with interest. What speakers do you intend to drive with this? I’m driving my 8 Ohm Fane single driver speakers. These are 100dB efficient have a flat impedance characteristic and never drop below 7.4 Ohms. T...

coupling caps are 470nF ? Am I reading that right ? Should it be uF ? 470nf into 39k gives 9Hz, about right. Maybe could be lower, but its parts box stuff. Again I'm showing where my understanding may be flaky - I just love doing that ! :D I thought the equation for the -3db frequency corner was 1/...

Thanks for sharing the circuits. I would love to try an OTL in a year or so, watching this with interest.

What speakers do you intend to drive with this?

coupling caps are 470nF ? Am I reading that right ? Should it be uF ?

Mike H wrote: ↑

Sat Nov 16, 2019 10:16 pm

Likewise!



Here's some possible inspiration...
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Cholmondeley Arms_2078c.jpg
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It's a lamp, is all

Brilliant

Watching

Cressy Snr wrote: ↑

Thu Nov 14, 2019 7:29 pm

Nah it looks fecking horrible.
I took it off. It looked like a pair of chokes with a chip basket over them.

It’s now been cut down in height, and turned through 90 deg.
Much better.

I actually spat my tea then ... ROFL