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previous: Troy What is it about Canada and their "... -- 8/27/2000 10:17 PM View Thread

Re: 6V6GT troubles

8/27/2000 10:41 PM
Randy Jamz
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Re: 6V6GT troubles
Troy;  
Gar Gillies and Pete Traynor fell head over heels for the Mallory FP can capacitors. The etched plated construction meant that the capacitor could fully bypass the AC signal. Gar has mentioned 101 times for me 'scope the first filter capacitor on a typical Fender and watch the guitar signal modulate the DC. I like them too, but the cost today makes me shudder. The other plus using FPs is that they virtually last forever. I've owned/tweaked 1,000 Garnets and Traynors and the original FPs were just fine.  
I disagree 100% that changing filters is just tech 'hogwash'. Electrolyte paste dries out. This stuff wasn't meant to last 50 years. How many of us are using a 50 year old toaster or vacuum?  
The way I was told how Traynor/Garnet bias an amplifier on the production was as follows;  
1)The prototype was built and the bias set using the method I get major sh*t for advocating.  
2)The production line amplifiers are built with resistor values matching the prototype.  
3)The bias is checked again on a 'scope and if needed the parallel resistor value is adjusted. Usually this is done by placing a 1 Meg or more resistor across the parallel resistor.  
I hope that helps a little. Pete Traynor today is a pretty private guy and an 'audience' with him is like an audience with the pope. There are a few select friends that he still does work for today. Gar Gillies I just lucked out and bought a house 3 minutes from his. I spend a least one day a week at Gar's, where he still has a bench set up and does custom work for a bigger crowd than Pete's. Both men take any amplier they work on and 'scope the output or listen to an audio signal through it as they bridge EVERY bypass capacitor. If the gain goes up, replace it. Ditto for hum from the power supply. This remind me of a funny story if I may yak away here;  
I while back I bought from Pete a '65 YBA1 Bass Master. The amplifier literally walked in the front door while I talked to him. The owner wanted to know if he could 'sell it back' to Pete. As soon as he left, I asked if I could buy it, without plugging it in. OK. I got it home and listened to the AC hum like you wouldn't believe. Inside someone had bridged most of the filters. But still it hummed. Why? There was a ground loop. 1,000,000uF of filtering wouldn't remove a ground loop. So I removed the extra filtering, cleaned up the amplifier, and took it back to Pete and asked if he had any tricks to remove ground loops. I may have found the problem in 10 years, but I wanted it fixed NOW! It took us.....well,.....yeah, US about 45 minutes to reroute the grounds and have a nice sounding amplifier. The FPs were still fine. True story. I still have that amplifier all this time later.

 
Replies:
Richie{~}==::: I think most of the older can caps ... -- 8/28/2000 12:44 AM