dcgillespie
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  • Hi Dave, you are a legend in vint. audio circles. I feel very privileged to write you.

    I’m not abrupt but only have 420 characters - I’m inq. abt a thread from 2013 re: Bogen MO-A series amps. You did a restore on a 200A w/8417s, & taking meas. of the unit. Could you post your findings AND impressions? Many would be very grateful. Certain your time is very valuable- any help is NOT taken for granted.

    W/Respect
    Dan
    Old thread, but a question. On my 8601-20 Maggi, Pins 3&4 of the 6EU7 are soldered together. I see no other posts about this. Should this remain?
    hi dave. opportunity to get a nice kx90 in woodcase. will be serviced by pro. do you know if primary can be switched to 230v? thanks for your input-phil
    Hey Mr. Gillespie...I recently bought a Fisher FM 200B that I'm gonna recap and i would like to have it aligned and tweaked by someone who really knows what they are doing..I asked Larry Derouin and he said thats you.
    Would you be willing to help me and about how much would cost? Thanks!

    Orville
    Dave, on the W2 write up, first page, last post...you get into dissipation, and list P+S at 25.2 mA. Suspecting you meant Watts...:)
    Douglas
    Hi Mike -- If you will, please contact me via regular PM to discuss. Message size is very limited with profile posts. Dave
    Hi Dave, Several AK members recommended you as a person (wizard, guru, etc.!) that could restore a Fisher X-202-B amplifier back to life....would you have time in the near future to take a look? I live in Warner Robins and travel to North GA several times a year....so I could bring it to you. Please advise, thanks! Mike
    Hi Dave
    How can I contact via pm.... I can't find it listed here anywhere. User error I'm sure.

    Thanks- Doug
    Hi - I have my 1962 Fisher Futura III RE: the front pilot light on the bottom front of the cabinet. Released the pilot light's yellow/black wires from underneath the cab - there's a recess the black tube that holds the #47 fits in - was there an outer light bezel? Does the #47 bulb remove from the tube. Tube rotates 360 on the base - did I damage the bulb's connection when I tried to remove? Thanks, Mo
    Hello All, New to the forum - have a 1962 Fisher Futura III stereo 660 amp/480 tuner with mpx 70. Won't power up. The 3 amp fuse on the amp appears blown. I realize something caused the fuse to blow. DCGillespie, The console is located in rural Georgia at my parents, can't locate anyone qualified to look at it. I've removed the 3 units, cleaned the tubes pins/wring - nothing. Would appreciate any help. Thanks, Mo
    Greetings Dave, and how are you? I have an issue with a HH Scott 299A amplifier, it seems to be producing too much gain to the point of over modulating and causing distortion at the speakers. This occurs even when the volume pot is only turned up a pinch. Any Ideas as to what could be causing this issue? Please let me know.

    Thank you,
    Jim
    Hi Dave: I'd like to put an EFB into my Fisher 400, but I'm still not sure what components go into the EFB circuit. Perhaps I've missed something. Is there a schematic somewhere? Are you selling one?
    Thanks. Fitzgreen505
    Dave - I contacted you about 18 months ago about you updating/reconditioning my original Fisher 400, Serial #72,094, but you were busy. Would you please put me on it for working on my 400. It as been "resting" since about 1975, with the exception of a short ~1 minute run to check out its potential.. No problems then. As I am close to you in Roswell, I can bring the unit up to you any time.
    Hey Dave, I'm doing some research and trying to put plans together to build an amp using transformers from an eico st-40. I am going to stay with the 7591 output tubes and will drive them with an ecc83 and a 6sn7. I would like to do something a little bit better than a simple cathode resistor and regulated screens.Then I came across EFB. Is there a way to implement it without getting too complicated? Thanks
    dcgillespie
    dcgillespie
    The change in current draw from 0 to full power doesn't change as much with cathode vrs fixed bias, but it does still change.

    Use cathode bias, but use the EFB screen grid regulator to power the screens. That will keep the screen grids locked into place relative to the plate supply regardless of the current they draw.

    You'll find examples of the EFB screen grid regulator in my Fisher 400 and X-101C threads.

    Dave
    L
    leland331
    I reviewed your schematics and it seems to make overall sense to me. Couple quick questions though.
    I'll use your sa-100 as an example. the screen regulator portion, the source of FQP9n50c is attatched to the bias supply which i dont have. Do i omit that part of the connection?
    dcgillespie
    dcgillespie
    Correct. Then you can tailor the resistor supplying the Gate to produce the screen voltage you want.

    Dave
    Hi Jim -- I am happy to help with your Pilot, but must tell you that at this point, I'm about 2 months out with firm commitments with existing clients -- after that, it's just inquiries, but of course the holiday season will be upon us by then so it's very hard at this point to establish a definite time I could do the work.

    Please understand that I am not trying to put you off in any way. But I wouldn't be fair to you if I told you to send it, and it just sat here for several months. I simply don't and won't work like that. I will be happy to put on on the waiting list, which costs nothing to do. This work is purely a hobby to fund my hobby, so if someone falls out of line for some reason, it doesn't affect me one way or the other. Everybody else just moves up. I'm sorry this may not be as quick as you would like, but this year has kept me jumping from right out of the chute. If you would like me to place you on the list, just let me know, and thanks for the interest!

    Dave
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