ADJUSTABLE Bias mod on vintage fender amplifiers (easy)

ADJUSTABLE Bias mod on vintage fender amplifiers (easy) | PART 1

Рет қаралды 924

Күн бұрын

Part 2: • Comparing Bias setting...
In this video I show you how to make your bias adjustable on a Fender Princeton. This also works for Fender Champ and Vibrochamp models which are fixed bias like the princeton is. To see more work done to this amp, check out the playlist here: • 1968 Fender Princeton ...
00:00 - The subject!
00:30 - Parts list
02:56 - Adjustable bias pot discussion
04:02 - Why adjustable bias is good
05:17 - How to remove the original components
08:00 - Discussion about solder domes
09:14 - Something else to look out for
10:41 - Installing the new components
13:58 - Solder I recommend / use
16:42 - Bias cap install
19:20 - Trim pot install how-to
20:55 - Overview of the bias circuit
22:42 - Last of the solder connections
23:24 - Check resistance range
24:22 - All done! ... for now
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Пікірлер: 20

@YeatzeeGuitar Ай бұрын

Part 2 can be found here: kzfaq.info/get/bejne/r9mAjKpos76mqas.htmlsi=j59D11UxLcwZUFQP

@offkilter Ай бұрын

The camera angles and pacing of your walkthroughs are the best on YT. You're killing it

@YeatzeeGuitar Ай бұрын

🙏🙏🙏

@user-tz6wj2bw9i Ай бұрын

This was an excellent video. Just what I was looking for. Great work!!!

@YeatzeeGuitar Ай бұрын

Oh good, I'm glad!

@sgt.grinch3299 Ай бұрын

Thank you.

@jjshouseofjams522 Ай бұрын

Awesome 🤘

@nbosticiii Ай бұрын

Very well done. Thank you. What overhead camera are you using?

@YeatzeeGuitar Ай бұрын

Sony A7III. Thanks for watching!

@huddyskiba1 Ай бұрын

You know I was wondering why you didn’t “strap” the wiper to the other lug of the trim pot so in the rare event of a trim pot failure you wouldn’t lose bias. But after thinking about it, if the trim pot loses its ground reference the bias voltage just goes more negative, right? So it doesn’t really matter if the ground reference is lost, right? Gets a cooler bias, might not sound as good if it dumps to 35% but it won’t hurt anything… Maybe?

@YeatzeeGuitar Ай бұрын

You're right, it'd be better to ground that lead along with the wiper in a catastrophic failure event

@BCEpedals Ай бұрын

The PTx and Those cathode bypass caps are original?? Great video, btw!

@YeatzeeGuitar Ай бұрын

Yes sir, replacing all of the filter caps was done in different videos already uploaded to the channel.

@BCEpedals Ай бұрын

@@YeatzeeGuitar Nice! That’s a clean amp!

@nedsheats4600 Ай бұрын

Since you are improving the circuit why not replace the 100K 1/2 W with a 1 Watt 5% metal film. since it is connected to the HV secondary it is under more stress than most other 1/2 watt resistors in the amp?

@YeatzeeGuitar Ай бұрын

I don't swap carbon comps for metal films in all original clean vintage amps like this. This adjustable bias is about the only thing I like to do beyond following vintage spec on these. Ymmv

@BCEpedals Ай бұрын

(Not trying to be negative or facetious) ; but That 22k joint opposite the trim pot is definitely a cold joint. You can tell by the solder is formed around, not with, the resistor lead. Being educational, some people might not know the difference or the need to reheat the joint. Just trying to be helpful!

@YeatzeeGuitar Ай бұрын

That's caused by the old lead of the resistor being dirty so the solder doesn't want to stick to it as much as clean fresh components, not because it's a cold solder joint. The resistor is crimped around the eyelet with a solid mechanical connection and solder flowed freely across the eyelet. That being said, I knew and as you'll see in Pt 2 releasing shortly today, 22k was never going to be the right value for a usable range in a Princeton so it was always going to get swapped.

@YeatzeeGuitar Ай бұрын

My mistake, its already out: kzfaq.info/get/bejne/r9mAjKpos76mqas.html

@BCEpedals Ай бұрын

@@YeatzeeGuitar right on man! Iron sharpens iron, I think you’re doing a great job!