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BCorbett

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Everything posted by BCorbett

  1. Hey Myles, That trouble shooting realy worked out. I finally got the channel working properly. The mod I installed was from Aspen Pittman's Tube Amp Book and the directions and diagrams are completly wrong. I learned alot in the process though, Thanks for your help. Do you Know where I get get the specs on my Electro Harmonics 5U4GB rectifier ? I want to find out if it can handle 100uf filter caps run in series. Thanks again, Brendan
  2. Myles, I purchaced a fine Radio Shack DVM and checked my B+ voltage and it came up Short; 371v for V1 and 323 for V2 and V3. The Power tubes and rectifier were at 390. My schematic says 420 is what I should be getting. I diconnected V1, my Tweed mod from the voltage see if it was grounding out some of the voltage but nothing changed. If you have any Ideas, aside from buy a knew amp let me know. Thanks, Brendan
  3. Hey Myles, I have a 81 Fender DRRI that I put a tweed circuit on the normal channel and have both channel going through the reverb. The vibrato channel sounds a bit distorted now and the tweed channel gets garbled and cuts out if the volume or tone are turned up passed five. My Theory is I need to upgrade my filter caps from 80uf. If you have a better theory let me know. Can the transformer handle a bigger rectifier (5AR4) and 220uf filter caps ? Or do I need to stick with the 5U4GBEH and 100uf filtercaps. The amp has 5881WXT output tubes in it. What kind of meter can I get for checking voltages ? Thanks, Brendan
  4. Hey Myles, I went back and read Dave Hunter's book. It was his book that mentioned the tweed mod in Aspen's book. It was helpful and I thought I had it all figured out but once both channels were hooked to the reverb and vibrato, all I got was a loud hum weather a guitar was plugged in or not and no sound from a guitar. Does this sound like a ground issue ? The ground for the potentiometers I soldered onto an existing spot because it would not stick any where else. Brendan
  5. Hey Myles, I am working on a adding a Tweed channel as explained on page 152-153 of The Tube Amp Book, to a 1981 Deluxe Reverb. I noticed you are the technical cosultant for this book so I hope you can help me. This era of "Blackface" has the pull boost on the reverb channel. My amp does not have point X in the diagram, the treble capacitor is closer to the tubes instead of the middle of the board. Of course I wanted to add reverb to both channels and it looks like in doing so I need to pull the treble cap back any way, but I have not figured out where to put the wire to get sound from point D on the AB763 Layout, to point Z. Can you explain how to make this all work or where I can find the info, pictures are helpful. Thanks, Brendan
  6. Hey Myles, I have just been putting in tubes and hoping I don't blow things up. Do you have any books you could recomend on guitar amp basics, modification and so forth ? Is this something someone with no electrical training can pick up or best left to people that know what they are doing ? Brendan
  7. Myles, Thanks for the advice, on the 12AT7's. I am still trying out different tubes and the Tung Sol 12AX7 may be all the Agression I need. Brendan
  8. Hey Miles, I have mid 80's fender deluxe reverb black face. It has a boost pull knob for the reverb channel. I recently had it modified so that the volume knob for channel one is Now a Master volume Knob - no more channel one. I just put in an 12AT7 in the pre amp and love the clean sound with a mellow distortion. Here is the question: Could the boost function by used to kick in the pre amp (V1) in series with (V2) for more distortion ? My local Amp tech said this would be a major mod and would not sound good and I would be better off just buying a different amp. So I would have to learn to do this myself if it was at all posible. The boost function is just too sharp, bright and harsh and does not get used in the 20 years I have had the amp. I am thinking maybe 2 12AT7's might be sweet and if i could use the two Tone knobs for the BOOSTED tone this could be all the more better. Thanks, Brendan
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