audio-talk

If you want to get ahead get a big top hat. IKB dates from a time when Engineers were entrepreneurs, businessmen and risk takers. There weren't any design codes, it was based on experience and nous. Masonry arches have had millennia of development of what is essentially a very simple but ultimately ...

Will wrote:GOT THEM IN MY PHONO they are tuned to the coupling cap giving a clear as in tight boost to LFreq.

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GOOD FOR YOU

Dave the bass wrote:I'm trying a few just to see what happens to the sound 'cos I'm like that

Do tell

Aye, working in a 400kV substation is an interesting experience. All that buzzing, and everything seems to vibrate to the touch .

Yeah, that's pretty much what I was thinking Mike. I'd prefer a smaller tx rather than burning volts but looking around there don't seem to be too many smallish txs about. Couldn't help but notice the 240-0-240 VT342 you have. Don't suppose you have anything smaller?

Right, I'm back :D Okay, I'm shooting for 150V HT and each channel draws 15/16mA. The HT regulator circuit is probably buried on JRB's Tubecad website somewhere, but it looks very much like a heater voltage reg to me, so a series type with 150uF before and after a LD1085, which is protected from the...

That's not so easy Mike - it's one of Broskie's pcbs all neatly populated and soldered - it was meant to make things easier! Funny thing is, when I tested the pcb when I first built it it was fine. It seems the smaller tx isn't appropriate (he said hopefully crossing his fingers).

At a loss as to work out what was happening I tried running the tx as centre tapped. The tranny buzz stopped but it was only able to hold the HT very briefly. It became very hot very quickly too. So I tried using a much bigger 600V ct tx. And it works. Or it did for the couple of minutes I had to tr...

Read this It's a Hammond 369AX, good for 100mA supposedly. I guess the 6CG7/6DJ8 Aikido draws about 30mA, so dividing by 2 and then 0.62 for cap input is about the maximum. :wink: :lol: It's a 40VA tx, and the HT is regulated. Ideally I want something about 180V but this was the closest I had to hand.

Only had a few minutes to play last night, but the first problem is the 7.5V tx I'm using for the regulated heaters doesn't work. It's a brand spanker from Rapid too - I checked both primary and secondary for continuity before bolting it in to the case and they seemed fine. Ho hum. Substituting a di...

Yes, what did you think of the Buffalo Nick? I've wondered about the Twisted Pear stuff...

It's a Hammond 369AX, good for 100mA supposedly. I guess the 6CG7/6DJ8 Aikido draws about 30mA, so dividing by 2 and then 0.62 for cap input is about the maximum.

Hopefully I'll get a better idea when I check some voltages - if something hasn't gone pop somewhere...

Thanks chaps, good to know I'm not completely incompetant.

The diodes are the right way round - I was really hoping I'd stuffed that up as that would be simple to fix. I'll have to have another look another night now I've had a drink...

Wonder how many mis-hits that'll get in Google? I have a 120-0-120 mains tx that I want to use as a 240V with a bridge. I haven't use a tx in this configuration but assumed that I just ignored the centre tap, soldering it to an empty solder tag. Switching on, the tx wasn't happy making a vibrating/b...

Good stuff Mike, keep it coming