Tube Amp Archive

Also, here is the schematic. It is the 470k that runs from v1-7 to ground that I fooled with. Could be anything in that area as far I know.

[IMG684]http://i.imgur.com/Vz482ni.jpg[/img]

Did you put back the same resistor you took out? It sounds like you put back a much lower value resistor, maybe 4k7 or 470 ohms. The pedal has a low enough output impedance that it can drive that low of an input impedance, but it would make a regular guitar output sound dull and weak. 470k should b...

Have you tried replacing V1? If you removed the first triode's grid leak, you might have killed half the tube. Without a ground reference, they can run away. I have tried, but can't be sure that they are good backup tubes. Though, if it was a bad tube, why would it still sound good with the pedal e...

It is located on the row of resistors running east/west, right in the middle of the photo, just south of the red/gray/purple wires.

[IMG1944]http://i.imgur.com/MwFC3d0.jpg[/img]

printer2 wrote:Any chance of a picture of the area?

Sure. Give me a moment.

A while back I tried my hand at some minor amp mods on my Mesa Boogie Dual Caliber 50. (DC5) One of the mods involved removing a 470k resistor that was ran from v1-7 to ground. I did it and didn't like it, so I reversed the mod. After doing so, the amp sounds totally dull and lifeless, on both lead ...

Thanks for the input. I have a two different friends hooking me up with a matched set of Sovtek 6l6's and Winged C 6l6's later on tonight. So, my wife is just going to have to deal it once I get them. lol

Alright guys, thanks for the help.

I went with a 1meg to see how that sounds. In the process though, one of my two 6l6's went bad. I don't have any spares, so I can't even test it. lol The luck... Damn it.

I had a friend suggest that I remove the 470k resistor from v1-7 to ground, for improved clarity on my Mesa Dual Caliber 50. This is what he said: The 470k input resistor on the gain-channel is not a fundamental part of that channel. To be precisely, the 1M 500pf combination of the clean channel is ...

jestaudio wrote:Try PM,ing Monsta on the boogie board at Grail tone, he has a load off great mods for DC series Boogies and may well be able to point you in the direction you want to go

Andy(Monsta-Tone) is the one that gave me these ideas. lol

I have a friend that suggested some things. Can any of you tell me if they are good ideas? You can try messing with the resistor values in the 1st (fake) tone stack, just after V2a. - There is a 62K resistor where the mid pot would normally be, try decreasing this. - There is a 15k resistor where th...

Also, before you solder, have you tried your EQ pedal in the FX loop? I appreciate the suggestion. Thing is though, that will not have the same effect as sucking all the lows before the gain stages, instead of after, which is what putting it in the loop will do. There is just better clarity when th...

Also, assuming I get the desired results from the filter, do I have the correct location for the install?

Thank you both so much for the input.

Do you have in recommendations on what to try for my high pass filter?

Hi all, First post here. Awesome place, with tons of info. I have been reading up for a while on amp modding and have a question or two that maybe someone could help me with. The amp in question is a Mesa Dual Caliber 50. I use a MXR 10 band eq to suck out some lows before it hits the amp. Doing thi...