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Demented is the Word hahaha

4/6/2004 6:51 PM
Demented is the Word hahaha
I really had planned to take some precautions about not being an alternate ground. I'll let you know how it works YIKES!!! I have an empty chassis out in the garage with some nice solder mountains on it that will make a great test bed.  
I used to lite ciggies all the time with my welding torch. It's a Man Thing, Dude. Like sticking your face in a campfire to light a cigar. Deal with it. ;)  
If you don't hear from me for a while ......  
4/6/2004 8:56 PM

Nice to see someone else modding a 75.I bought mine new and it no longer resembles itself.What do you hope to gain by dumping the low power option?I have found it useful to get this baby to overdrive at a resonable level.I agree that it is a confusing amp for a newbie like me to hack at.I have rarely had use for the lead channel as it is just too harsh and the reverb almost disappears when lead is used,it must be part of the overdrive gain stage.I will be keeping an eye on your posts.
4/6/2004 9:08 PM
John G
I can send you the schem of my re-make that I posted to Charlie. It addresses both of the issues that you mention.  
I have ben running mine in low power mode but have increased the current to the same plate dissapation as the full power mode. Makes for a fuller smoother sound IMHO.  
John G
4/7/2004 1:40 PM
Kevin St.Pierre

That would be great,I love tweakin this amp it has always had a great clean sound.The last mod I did was to rebuild the PI to Dan Torres moddified BF version as shown in his tube amp book,much improved sound.My e-mail is posted.Thanks
4/7/2004 10:36 PM
John G
I have tried to mail you twice but it has been returned "Invalid mail recipient".  
Any ideas ?  
John G
4/7/2004 4:18 PM
Kevin, that low power thing
seemed to not be doing much. It was still really loud so I figured WTF and eliminated s pile of wire and two switches that seem to be a source of problems from what I have read on other boards about it. And I really didn't like the way those two double switches were jammed down on the rectifier either. I still may move the rectifier over a bit, and prolly will if I rebuild it. Or maybe rip it and just toss in a Weber CopperCap.  
I'm really not sure what I'm going to try with the lead chan. John's mods are a bit more ambitious than I am right now ;) but trying lower gain tubes will be my first go.  
Last nite I finished replacing the heater wires to everything. I ripped the Fender overhead scheme and replaced it with a run down the bottom back corner of the chassis now that I have gotten all the other wiring out of there. I think I am going to put in another tag strip in where the one cement resistor was at the end of the eyelet board. I had moved the one cement thing to between the PT and the power cord/fuse box since there were already holes drilled in the chassis there (for guess what in another model?). I need another couple spots to rearrange the bias and another couple other things just to make a cleaner layout. Still, that chassis is crammed full.  
Going to warm up the bias a bit and give it another test drive tonite and see what is happening. I hope to replace those switching pots and the tonestack BF'd over the weekend. If that wll works OK, then it'll be time to start snipping and cleaning up that snakepit style lead dress that is in there now. Oh boy.  
Y'all take care  
4/7/2004 10:59 PM

"Or maybe rip it and just toss in a Weber CopperCap."
Just fair warning. I tried this recently in an '83 Concert and after a couple different modules, it didn't work out. (The two amps are related by the Ed Jahns connection.) Anyway, it dropped too much B+. I never really understood why, but my guess is that the amp runs at a higher idle current because of all the switching stuff. The "tube rectifier" characteristic is based on a series resistor, so it makes some sense.

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