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mjlewis22

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About mjlewis22

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  1. Word of warning: (not that anyone is paying attn) If your re-verb sounds re-pressed, make sure you didnt wire it backwards. Works much better now.
  2. I ended up going with the MOD 4AB3C1D. It was a little cheaper than the accutronics unit, and it had gotten good reviews. I had to replace its plastic mounting grommets with the rubber ones on the stock unit because the plastic ones are taller and the mounting screws wouldn't bite. It took me a few minutes to figure it out but after that it went back together pretty easily. As far as sound goes the reverb is pleasant, but subtle even with the reverb knob cranked. But it does make reverb so that's an improvement. Just wish I could turn it up to about 13. To fix the speaker cable I just cut the molded end off and replaced it with a 90 degree switchcraft plug. Looks good and works well. That plug was easier to install than any other replacement plug I've done. I'm a believer. I was pretty happy with all my testing on channel 1, but when I switched it over to ch2 it sounded terrible. The more I turned up the drive knob and hit a chord the more it sounded like sitting on a whoopee cushion. Is it time for a tube change? They have a lot of hours on them...maybe 200 or so. Does it matter that the clean sound pretty good but overdrive is weak and flabby? I did mod this amp a little bit back in 2011, and when I was all done it sounded pretty good, I thought. I suspect it just needs new bottles, so Ill try that first. It isn't my main rig anymore, and I thought of selling it but I just really like it so I wanna fix it.
  3. I messed up the speaker cable with the two crimp on connectors and the 1/4" plug. The stock model is lamp cord with a molded right angle plug. Does anyone know where to find one of these? I can only seem to find shielded instrument cable, which is difficult to put crimp connectors on. Thanks
  4. Wiggy, Thanks for the reply, I found the indicated thread. The spec reverb is Accutronics 4AB1C1B, which is a short decay model. It seems though that the long decay model 4AB3C1B is more common, so I may replace with that.
  5. I gutted the bc30 in an emergency to use it as a cab for a different head. When I took out the reverb I noticed that one of the magnet wires had broken and the spring isnt attached, so its fubar. Now I want to put the amp back together. Anyone have a suggestion on a replacement tank that would be an improvement?
  6. I assume youve taken all the screws out of the back panel and pulled it down at a 45 degree angle so that the back is open. To remove the chassis do the following 1) remove the mains power cable 2) remove the guitar cable from the input 3) remove the speaker cable from the output 4) remove the reverb RCA cables from the underside of the chassis 5) pry off the 4 plastic covers on top of the amp with a small flat blade screwdriver 6) remove the machine screws with a #2 phillips screwdriver 7) grab the HT and OT and gently pull out while lifting up then, 8) connect one lead of an alligator clip to the chassis, and the other end to the common of a multimeter. probe the power tube solder joints making sure to leave one hand in your pocket and confirm the meter reads 0V *if you arent sure about this step read back through this thread* 9) mod like hell...
  7. It appears that I have fixed it accidentally... I suspected that the signal was not making into the first preamp valve because pin 7 of V1 was always near ground potential no matter how the drive and level controls were set. The drive control (VR2) is a variable grid leak resistor that adjusts the gain into V1b, and it never could develop any resistance to ground. I hooked the multimeter from pin 7 to ground using alligator clips and turned the amp on. To my surprise the OD channel was working. As soon as I disconnected the ground lead the volume immediately dropped out. Next I clipped around both legs of C6 to bypass the cap. Still nothing. At that point I got confused and decided to clip farther back, on the leg of C2. Then I accidentally touched the other lead to the chassis and like magic it started working. I took all the leads off, and it kept working. Turned the knobs, switched channels, put it on standby, power cycled it, and its still working. I'm pretty confused about what happened here, but my theory is that the coupling cap C2 had developed a short that was affecting the signal, but by providing a direct path to ground the cap heated up rapidly and the thermal energy was enough to clear the short. Anyway I hope it keeps going. I did the Master Volume mod several months ago and I have been very pleased with the amp ever since. --ML
  8. All the resistors checked out. I also checked for continuity between tube socket and appropriate board components. I cant check the caps without removing the board, which I'd rather not do. I will do it though if someone can convince me that it is necessary. Also, I dont understand the channel switching part of the circuit. I'm at a loss for what to do next. I'm going to reconnect the amp and rotate the drive and level knobs (VR2 and VR4) to make sure they function. Maybe that will give me some insight. Any help or thoughts would be appreciated.
  9. Found this in the mods thread from jefrs: Drive channel uses V1b and V2a, and, anode (plate?) resistor sets the gain. Gonna check r7, r8, r14, and c8 as well.
  10. UPDATE: I switched the preamp tubes in V1 and V2 sockets, but the problem still persisted on the OD channel. I'm going to check the cathode resistors R15 and R21 and cathode bypass cap C15 for loose connection or open. It would be really cool if someone could provide some feedback...
  11. I havent played the bc30 in awhile so I decided to give it a go for a gig this weekend. Clean channel worked fine, but when I switched to OD channel the volume dropped almost completely out, even though the red LED came on. All the valves light up. Anyone have any ideas on what I might be probing with the multimeter?
  12. I found an Amperex Bugle Boy 5AR4 in an electronics storage closet two days ago. I asked the engineer if I could have it and he said fine so long as I wasnt going to try and make my car payment with it. When I told him my intentions he said: "I can see changing the preamp tubes to get different tone but changing out the rectifier is like putting a new gas pedal in your car and expecting it to go faster." I changed them out anyway, and upon doing so I felt that the amp gained a little more clarity and perhaps warmth, and less buzzing at high gain, but I couldnt swear to it. Thoughts?
  13. I rock my 2006 faded tuned down a step--I have kind of a deep voice so that makes it perfect for solo gigs due to its lightweight and versatility. The chunky neck took me awhile to get used to but I'm all about it now.
  14. What do you think of this link: 62 SG Click here
  15. I would have liked to had that SG he smashed. It was a lot nicer than my faded that I could barely afford to purchase. How bout some real engineering on these guitars instead of blowing smoke up our ***. For example: Advanced adhesives that promote increased resonance and sustain; Lightweight composites that mimic/combine the attributes of genuine tonewoods; Modal analysis to optimize body shape, routing/bracing, and component placement; Wear/Corrosion resistant finishes; High Temperature Coatings for robot guitars to protect them while they burn in hell...etc. I looked through some databases for scholarly articles pertaining to the above topics and found basically nothing. There is a lot of potential in this area. Instead of sticking technology on a guitar and calling it revolution, they could use it to improve a traditional design and let it speak for itself. My $0.02
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