audio-talk

“The Footage Detectives,” on Talking Pictures TV.
It’s become a Sunday evening ritual. Reminds me of tinned peaches with Carnation milk followed by a bath at six o’clock, then the immortal words “drink your horlicks, it’s school in t’ morning!”
I love it.

brig001 wrote: ↑Sun Mar 19, 2023 10:59 am Is it something to do with warp (and weft), or is Jean-Luc Jacquard?

Brian

Make it sew.

I just bought this bad boy. The idea is to design a mono power amp and power supply around it, specifically for playing Meredith's 78rpm records and other early mono stuff, probably into a big single-driver corner speaker. (Mr Cresswell Jr you will likely have mail soon). Cost me less than I though...

+1

AAAAARRRRRGH!
You have to take the rough with the smooth with Grandad Radio.

Happiness is…

Valves, an old record player and Boom Radio: …“So catch me if you can... I’m going back!”

You know, I think it might be safe to put the KT66s back in. The sacrificial new production 7581As have done their job admirably whilst the redevelopment has been in progress.Time some proper valves were brought back into the fold.

I threw away a box of of ef80's 20 years ago steve, probably still got a few somewhere, there where that many about they where worthless ! It will be interesting to see what the e180f is like amplifying at driver signal voltages and i would guess easy to overhead the input. I know Nick has used the...

For the sake of completeness, here is the PSU:

I've been working on this over the last couple of days and have ended up dispensing with the services of the D3a driver valves, in favour of (as Nick suggested) something that would be a little bit easier to work with. I found a stash of 1950s, Brimar EF80, so thought I'd use those as drivers instea...

It all makes work for the working man to do. Nothing changes.

Got a bit of volume control rustle where there was none before. There may be some residual oscillation going on. I had the same years ago with the 12GN7 front end on the 6B4G monos. Once I got the right values of grid stoppers, the rustle disappeared. So two jobs tomorrow then : the first being the ...

In the interest of ideas from the past, you could try taking the cathode of the OA2 to the cathode of the d3a. This will allow you to both reduce the cathode resistor valve because of the extra current and also the g2 voltage will be fixed with respect to the cathode as it should be and not wanderi...

This is where I'm at now: Screenshot 2023-03-12 at 16.56.41.png Have yet to audition it properly, I just gave it a quick blast, to check there was no obvious distortion, but the main thing is that it now works properly, has a decent amount of gain, the D3as are no longer microphonic and are where th...

Nick wrote: ↑Sun Mar 12, 2023 4:10 pm It probably would, but you would need to invert the feedback.

What you could do was connect the b+ to the ul tap, then take the unused tap that used to be b+ and use that to feed g2. Would invert the feedback.

Thick as pigsh*t that's me. Never mind.