Other Amps

63 Fender Blonde Bassman Volume Question

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was wondering about discharging the caps to avoid electrocution and so I ran across this video, looks simple enough to do:

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I never bother except with SVT's because they don't bleed down, but you can just short them to the chassis with a screwdriver. It won't hurt anything...that's an internet myth.

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I never bother except with SVT's because they don't bleed down, but you can just short them to the chassis with a screwdriver. It won't hurt anything...that's an internet myth.

– Billy Zoom

Awesome thanks! will do!

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I Finally replaced the capacitors! had a few hours to spare so decided to work on it.

OMG! the sound is Night and Day difference! its finally playable in the living room and the quality coming out of it is second to none!

Big thanks to all of you guys for all your help! I honestly could not have done this without your expertise.

the amp sounds clear as day...bright and chimey as a fender amp should with beautiful low end thump and grunt that Ive been so desperately wanting. no more static and crackle sounds and the "bogged down, muddy" sounds is gone!

So let me start off with what I noticed from under the dog pan (now that I have a better grasp on what to look for)... As I was inspecting the Caps, I noticed that some looked as if they were leaking! there was oxidization popping out of several caps and it looks like any more time with the amp running like this and those caps would have exploded or melted or something...(see in the pics)

as I was replacing the caps with the new F&T caps I did notice the "size" difference between the two, and as nice as it would have been to go the sprague route, these worked out just fine...I measured, cut and soldered them into place pretty quickly...since im used to working on small electronics, soldering these huge parts together was a breath of fresh air.

Literally took me longer to set up, get the area nice and prepped for working and disassembling the amp head than it did to replace the parts.

since I was pressed for time, I just dedicated the time to replacing the caps themselves...I left the resistors in place since they looked perfectly fine to me. need to replace those random mini caps on the top but for now they all looked fine.

I also added a layer of thick foam tape to better keep the caps in place instead of them vibrating around when the sound gets too loud.

A huge difference since the first day I got it with the incorrect tubes and the bleeding capacitors...now this amp is truly what I was expecting when I first laid eyes on it...theres still some more mods obviously like adding a grounded 3 prong power cable and replacing the rest of the small caps but for now, she's sounding great.

Nuff said...heres the pics.

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Heres The link to the rest of the pics...(cant seem to post multiple pics in one reply)

Link

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Finished the Job...the bias caps are now soldered in place and the amp is running perfectly! sounds so much more rich and clear. amazing how such an easy job of replacing all the capacitors can make such a huge difference.

Again, Thank you all so very much for all your help!

Now, onto the ground cable and hopefully Tavo will chime in to talk about bringing the voltage down as stated previously.

I think im going to have to invest in one of his pedals as well...I just cant get that setzer overdrive tone with my Strymon Riverside.

The speakers seem fine to me but I may also change out the stock ones for some vintage celestions and thicken up the speaker cable.

Equipment wise, Im running a Gretsch Hot Rod and that insane 60ft cable. would love to complete the package with the Roland Tape Echo but wow is that little thing expensive!

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The light sabers just made you 5% cooler :)

Ya if you can solder.. get those astrons out(and realize you'll be using 2 E-caps to replace the duel Astrons on the circuit board), but please please leave the blue molded caps in there. If they are all good, doing their job then you could ask for a better capacitor. Even if you got new blue molded sozos, those caps need near 300hrs of current running through them before they'll ever bloom and give you the dimension of the originals. Oh and for the bias cap, up it to 100uf-100v. When its all done.. lets chat about keeping the amp on 110V instead of 120v. I got one of these Brownie gig masters for my vintage amps.

http://www.amprx.net/upload...

– THE NOCTURNE BRAIN™

sweet! so all is done (kind of) I just saw that you recommended the 100uf bias cap...I just installed the 50umf that the kit supplied...ugh!

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one last issue regarding the amp...

now that all is said and done, I'm having this incredibly annoying Amp Buzz...the Buzz actually sounds worse coming from the treble knob (as seen in the video).

heres the link:

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I can't believe I have to ask this again a year later, but did you ever replace the power cable in this amp? That may solve your noise problem, and it will definitely make the amp saver.

The buzz sounds an awful lot like an amp that's biased way too hot. What's the bias set at?

I hate to harp on the same things over and over, but those are like basic amp maintenance, and should be done right away when you buy a vintage amp.

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I can't believe I have to ask this again a year later, but did you ever replace the power cable in this amp? That may solve your noise problem, and it will definitely make the amp saver.

The buzz sounds an awful lot like an amp that's biased way too hot. What's the bias set at?

I hate to harp on the same things over and over, but those are like basic amp maintenance, and should be done right away when you buy a vintage amp.

– Otter

Sorry man, really haven't had a lot of time this past year for much...and living in miami, its hard to trust anyone with a vintage amp...let alone take the time to look for a reputable amp tech. Im lucky enough that Im a quick learner and I'm good at working with my hands.

So...I did replace that ground cable after that video. The buzz sort of went away...I have to be honest that its not biased. This amp does not have a Bias Pot so even if I had a bias adjusting tool, I couldn't do it. I've also had no luck finding solid info regarding biasing a vintage amp without a bias pot.

all I found out is that these amps have a balance type of bias so that making tube changes did not require biasing. and something about changing out resistors for properly biasing them???

So my next question would be, how the hell do I bias my amp???? even if I did find an amp tech, I still would like to know how to do it myself for future reference and knowledge.

but if my experience in forums serves me correctly...the answer to my question maybe to just install an adjustable bias pot on my amp. This may or may not be the answer but I would like to know regardless.

Thanks

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but if my experience in forums serves me correctly...the answer to my question maybe to just install an adjustable bias pot on my amp. This may or may not be the answer but I would like to know regardless.

That is correct, you're supposed to install the bias pot. Look at the bias circuit for, say, an AB763 with diode rectifier and 2x 6L6s:

Full Size

I would replace everything in your amp's bias circuit between the transformer and the 220k splitters with the circuit in the Bandmaster. Ignore, of course, the vibrato switch. You can probably reuse some of the original parts, like the diode, because those old metal can diodes in the vintage Fenders look super cool.

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What an awesome thread!

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you mean outside the amp? and it just drops down?

– erick lopez

It slides out the back.Once you have the plastic power cord retainer(if there is one) unscrewed and the strap screws out,the chassis will be resting on the cleats.With the back of the amp facing you,reach in with both hands,one on each end,lift slightly and slip it out towards you.


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