Other Amps

63 Fender Blonde Bassman Volume Question

76

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!

77

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...

– TheNocturneBrain

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!

78

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:

79

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.

80

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

81

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.

82

What an awesome thread!

83

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.

84

Hey guys! long time since my last post. So, now that the amp has new capacitors, the correct tubes, a set of celestion vintage 30's, a nice 3 prong modern ground cable and removed that "mud" resistor on the bass channel... the amp is finally clear as a whistle and a pleasure to play....ALONE!

yes, alone...because if I turn that volume knob anywhere past the "1.5"-"2" setting, it becomes way too loud to just casually play in my living room when my wife is home.

otherwise, the amp sounds amazing when Im playing with a drummer (which at that point the volume goes as far up as "2.5")...anything close to the "3" position and im drowning out the drummer.

what else can i do?

most of the time I just set the amp at the "2" position and just work the volume from my Strymond Overdrive pedal...seems to do the trick, but whenever the pedal is engaged, the amp has that stupid high pitch hum tone.

85

Use the #2 input and you'll have more room on the volume knob.

86

Those are on the loud side amp wise, not really casual while the wife is home type of amp in the living room. What type of power tubes do you have in it? 5881 can lower output some (maybe you already have those) Even so with that amp and V30 speakers it's still won't be a living room amp per say. Other than a pedal to drive the amp at lower volumes or an attenuator or some type of circuit change (e.g. pentoide/triode switch but i wouldn't necessarily mod a vintage amp) you could try using the Normal Channel or as @winniethomas suggests input #2 could help. Another cab while in the living room with lower efficient speakers could help too.

87

You know there's a master volume knob on your guitar, right?

88

Try an attenuator or a VVR mod

89

Thanks guys, I have been slowly upgrading and repairing the amp as I go along with all the awesome advise and expertise this group has to offer.

I was reading some of the original posts from a few years back and missed to look over the output transformer that Tavo suggested.

He said that sometimes GC techs like to “Blackface” an amp so, I’d like to know if that could another problem with my amp.

And yes, those are 5881’s

91

I agree I have 1964 early blackface 6g6 b and doesn't get really loud until past 3 . I would get weber mass or thd plate to tame it if your too loud.

92

My wife suggested strongly that my JS77 on 3 was too loud, even when I was in the basement. Which is why I just use a 5w modelling amp and my pedal board. Not much harder on her ears than a strummed acoustic.

Happy wife...... well, you know.

And so the JS77 sits in under its cover in the rec room. Until she goes shopping, of course.

93

Well, looks like my pre-amp tubes were causing me grief all along. The amp always had this Constant high pitched sound even after all the changes that were suggested here which included changing the capacitors, the power tubes and the original 2 prong power cable.

I read somewhere someone having the same problem with a 64 baseman in another forum and they re-arranged the pre amp tubes. I decided to give that a shot since it’s easy enough To do. Well...low and behold, the amp sounds amazing now! As clear as can be. But since I changed the power tubes and all the other things, I may as well get new power tubes.

I read here: https://www.gad.net/Blog/20...

That Brian’s tone uses Ruby preamp Tube 12AX7A-C5...but these seem hard to come by now.

Is there any recommendations as to what preamp tube to use to get it close to Brian’s tone?

Right now mine is using the Russian Sovtech 7025 12ax7WA

94

Use 12AX7wa Sovteks and Sovtec 5881WXT's.


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