If I'm looking at, say, 1000V does anybody know what AE chokes are rated at? I guess I could put them in the earth rail to be sure.
Don't know for sure, Kim would be the one to ask, but I have used them without problems above that. You could always mount them on Nylon.
I would be aware that the choke in the ground line isnt without problems, it does mean the secondary of the mains transformer is moving with respect to ground at the ripple signal before the choke, so this can induce noise elsewhere. When I built that electrostatic amp for Ali, I had the hammond chokes in the 0v line, and had all sours of insane problems with induced earth current. There was a lot of radiated something. My meter was reading > 1kv between the ends of a 12 bit of wire IF teh meter probes took a path from one end to the other that went the other side of the chokes.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
Hmmm, I thought it probably wouldn't be ideal putting chokes in the earth rail but there sounds to be more problems than I thought. Think I'll try to keep the chokes in the HT.
I wondered what the rating of the choke wire enamel is? Perhaps that's not an issue but I was going to check with Kimm anyway. Just weighing up a possible ordee for some OPTs.
Its not the enamel thats the issue, the voltage turn to turn is very low. The enamel is good for >1000v or so anyway I think. Its the coil to core insulation that matters. AE use nylon(?) bobbins so it should not be a issue.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
A thought occurs. A little more HT and bias for the 10Y I currently have in Madness and it'll swing 160V... So I could replace the 300Bs with GM70 and bung a load of HT in and the amp's nearly there - 26-10Y-GM70.
A question though as I'm not completely sure I've got the first stage set up right. What I've done is assume 2VRMS input, or +- 1VRMS. Or 2.8V peak to peak on the grid. Is this right? If so I might be a bit short of gain with the 26, a 76 might do the job perhaps.
simon wrote:A thought occurs. A little more HT and bias for the 10Y I currently have in Madness and it'll swing 160V... So I could replace the 300Bs with GM70 and bung a load of HT in and the amp's nearly there - 26-10Y-GM70.
A question though as I'm not completely sure I've got the first stage set up right. What I've done is assume 2VRMS input, or +- 1VRMS. Or 2.8V peak to peak on the grid. Is this right? If so I might be a bit short of gain with the 26, a 76 might do the job perhaps.
I try to aim for a bit higher sensitivity, but depends if you use a pre. Its not wrong though.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
6EM7 would be good, I always thought it might make a good 300B driver, so why not a GM70.
Go for it....
-- Andrew
Hi all
Is this of interest to you a 6EM7/2A3 with CCS on the 6EM7? I suppose the 2a3 could be changed for a GM70 just an idea
forgot the schematic oops
