audio-talk

Clearlight Symphony - Cyrille Verdeaux (1975) IMG_0502.jpeg On Part 1 (part 2 on the CD version) Verdeaux uses three members of Gong as session musicians. Psychedelic electronic space jazz rock; far out man, as is the cover, which is a good representation of what's in my head these days. :lol: :lol:...

Yeah, It might very well act as a cross-feed setup. I remember cross-feeds being quite popular in the 1970s. At that time, cross-feed manufacturers seemed to be selling the idea of a more natural soundstage when listening to stereo via headphones. As you say Nick, there will probably be a frequency ...

Yet more schematics: LED bias doubles as the on/off indicator light 1626HPA_6AU6Driver.png PSU has an additional 8uF as the first cap, so that the maximum 'condenser' value for the UU4 rectifier is not exceeded. The supply is therefore CRCLCRC. The 1k5 resistance has been equally split over the supp...

Cheers Andrew, More movement on the headphone amp front. Only because I can, there are no other reasons other than I like to mess about. Anyway, by carrying out these mods, I've put the fume extraction through its paces over the past couple of days and I've had no further health problems. I've given...

It sounds good. Lovely valves 1626s.
As I said earlier, these flea powered SETs make perfect headphone amps.

Inside: Rectifier heater transformer on the left.
12V heater toroidal transformer on the right.

OK, Listening to the headphone amp last night in the dark I noticed a subtle red glow from the anodes of both 1626 valves. Now, both Epstein and Danielak reckoned the 5W dissipation limit could be exceeded and the valves would run happily at 6WPd. Mine were dissipating 5.6W so I'd thought that would...

Power supply for HPA:

I followed the Darling style build philosophy, including shared cathode resistors on the input and output stages and both stages fed from the same HT node without any decoupling. Input valve is the ECC81 which has a similar distortion pattern to the 1626, so I was hoping for some cancellation, thoug...

It’s all working and free of hum: I had to remove the cover from the mains toroidal transformer as it was causing mechanical noise.

A pet’s veterinary cone from the late moggie, duck taped to the end of the extractor pipe, gives more effective and wider coverage for the fume extraction: IMG_0491.jpeg The reason for this setup, is that after years of exposure to solder fumes, I’ve developed an allergy to the smoke, so that I’ve e...

The chassis now: IMG_0490.jpeg I had to kludge a piece of aluminium over the carnage at the rear of the chassis after the removal of the Hammond mains transformer and choke. It looks reasonable I think. There was a Darling amp with James output transformers at the Darling Fest 1999 but not the 6123H...

Better late than never.

So now I have half a dozen 1626, courtesy of Mr I and Paul B (thanks a lot chaps) and I’m on with building a headphone amp with them. This means a complete strip-down of the existing 6V6 HPA, and a re-think of the whole power supply setup, as the mains transformer produces far too high an HT value f...

Steve, the N in the post code was probably the clerk misreading my H as an N because the address in my address book is correct. So a clerical error I didnt spot. I dont know what they do about this, but my address is on the pasel, so if they dont spot the mistake they will send it back to me, and I...