1971 Marshall 100Watt Super Lead 1959 cap job

[TubeNV]

Funny you should mention the '74. What is going on with the intermittent thang? As coincidence would have it, I'm playin the crap out of an awesome '74 Marshall 50w bass head in a vintage gear driven classic rock group with some older dudes like myself. Being in that group opened the flood gates inside my heart for these older amps & my savings acct will never be the same, but what better to spend money on. As some lucky players know, there simply is nothing like twistin the V knob up up up on a well working vintage Marshall. And to think I would be missing out on that aural nirvana if not for getting together with these guys just makes me greatful for it all. God I'm glad I have a gig tonight. All this talk has me wantin to kick somethin out live raw. Some days, it feels so good to be still alive & well & makin the tunes happen. God bless America & Jim Marshall. Thanks.
So whats your take on the bias section affecting tone beyond maintaining proper balance & current? Ever notice any tonal changes using different caps there?

[Kazooman]

Replace them/it. Do what Marshall did: use the cheapest caps of correct rated value you can find. That may seem like a smart-ass comment but it's not.

Well, you can save a buck apiece by getting J&Js for $8.75 from Antique Electronic Supply. Don't know about differences in shipping.

[Gtr_tech]

The bias circuit either works or it don't. Types of caps/resistors/diodes won't make a lick of difference here. No effect on "tone" whatsoever, other than the voltage setting. Just like a certain brand of faucet won't make your water taste better.....either works or don't.....

[TubeNV]

Thats pretty much how I felt about it but ya never know. The most important element in this scenerio is the caps working as they should maintaining consistant voltage where as in the preamp section the caps would be coloring the actual signal itself because the signal is going thru them. Thanks, I do appreciate being able to verify this stuff with knowledged opinion.

[jmaf]

I started using JJ's last year and so far no problems with them. They're not too expensive. I have replaced some chinese caps off recent Marshalls, mostly the 10.000uF low voltage cap they use on the rectified tube heater on JCM's. I wouldn't go with cheap caps on the bias supply, though that's just my opinion, never seen a bad case because of the cap specifically, but others may have a different experience.

[riz]

I totally hear ya on being grateful to still be rockin'! I don't think it's a tonal consideration re: bias caps. They smooth out the negative d.c. voltage used for bias, that's all. They are not signal caps. I suppose if that cap is not doing it's job, you could get more buzz/hum. In turn your signal just modulates the bias voltage at the power tube grid, if I understand it properly.

[Steve Conner]

The thing about "different kinds of wire sound different" is pure placebo effect. It's just a psychological self-delusion to justify the prices of boutique amps. So, don't worry about it, just bung some new caps in there and rock.

Guitar amps obey the laws of physics, there is no black magic in there (apart from the transformers ) so any replacement caps of reasonable quality will enable it to function as designed and blow your socks off. The hardest part is getting them the right size and shape to fit.

It is possible for cheap caps to be better than boutique ones. The cheap ones are cheap because they're made by the million for other applications than tube amps. That gives great consistency.

[riz]

Steve, I generally agree with you on the "placebo" effect, I hope from my posts you get a sense of how little I concern myself with things like wire, caps, etc. when it comes to "tone". I'm into the circuit first and foremost. However, there are periodic posts from knowledgeable folks on the board--who I respect-- debunking the possibility that different wires, or tubes, or caps, or resistors, can generated audible differences in what we call "tone", specific to what we hear comin' outta our amps. Damn, do you guys just not listen, or are you over-educated?! Now, where are the big grinning smileys...

[TubeNV]

Clarifying the wire issue demonstrated to me it should be known that it concerned guage. length, sheilding, grounding point & path of an input signal & the result was a much quiter solid organic tone. Dont want anybody thinking anything else. He experimented with a lot of ideas & loved to use friends as ears to demonstrate & confirm his experiments. He definately opened my eyes & renewed a fascination with tubes amps. Its like mad science fired by an unquenchable lust for tone.

[Steve Conner]

I'd argue the opposite. You guys do not know how to listen because you don't understand the laws of physics. You waste your lives chasing ghosts, when you could be making beautiful music.

It is all utter bullshit, nobody can tell by listening what capacitors Hendrix used on the Radio 1 sessions or whatever. The beauty of music is in the soul of the musician and the listener, the guitar amp is just a simple electronic noise box. You don't have to listen to me, but you will save time, money and sanity if you do.

[jmaf]

I'd argue the opposite. You guys do not know how to listen because you don't understand the laws of physics. You waste your lives chasing ghosts, when you could be making beautiful music.

It is all utter bullshit, nobody can tell by listening what capacitors Hendrix used on the Radio 1 sessions or whatever. The beauty of music is in the soul of the musician and the listener, the guitar amp is just a simple electronic noise box. You don't have to listen to me, but you will save time, money and sanity if you do.

It's good to hear this from someone the forum really listens to. The market insanity, trying to sell you crap 24/7, leads to the kind of BS we see and hear every day. Guitar magazines basically tell you if you buy brand XXX you'll sound like guitarist YYY. That is a lie, a lie that is constantly repeated in marketing and that folks simply don't question.

You can buy Van Halen's amp, SRV's guitar and Michael Jordan's shoes, you are not going to play like any of them because of it.

[Gtr_tech]

I'd argue the opposite. You guys do not know how to listen because you don't understand the laws of physics. You waste your lives chasing ghosts, when you could be making beautiful music.

It is all utter bullshit, nobody can tell by listening what capacitors Hendrix used on the Radio 1 sessions or whatever. The beauty of music is in the soul of the musician and the listener, the guitar amp is just a simple electronic noise box. You don't have to listen to me, but you will save time, money and sanity if you do.

+1...

The internet has really made this "cork sniffer" syndrome get waaayyy outta control. Coming from a technical background, but a lifelong musician as well and fairly picky about my tone, I believe the design of the amp is far more important than "magic" caps or resistors. I don't want cheap ceramic disc caps in the signal path, but thats about it.

"Shut up an' play yer guitar" - Frank Zappa

[Jazz P Bass]

It's good to hear this from someone the forum really listens to. The market insanity, trying to sell you crap 24/7, leads to the kind of BS we see and hear every day. Guitar magazines basically tell you if you buy brand XXX you'll sound like guitarist YYY. That is a lie, a lie that is constantly repeated in marketing and that folks simply don't question.

You can buy Van Halen's amp, SRV's guitar and Michael Jordan's shoes, you are not going to play like any of them because of it.

It is no different than marketing cosmetics.
Be this, Be that.
How about Be Yourself.

[jrfrond]

From a reliability standpoint, and nothing more, I'd stick to either F & T or J-J. There's a Taiwan-made version of these caps available from CE Dist/AES, but I'm not sure what the quality is. Probably decent.

I tend to look at reliability first, which is why it irks me that so many pricey production line and custom shop amps use cheap components.

[riz]

I don't have to understand the laws of physics to listen--my ears work just fine, and so do the dog's. I do read physics books for fun. I also work on my own amps and pedals and guitars for fun, and I hang out here on AMPAGE for fun. I wrote my last post for fun. I use cheap caps for fun. And I don't give a rat's ass about what anybody else uses, or used, or whatever, except that sometimes I'm curious to know about stuff because I love gear, and have since I was 8 years old. My music rocks. I have long hair and don't bathe everyday. I have some nice gear but I don't consider myself a corksniffer--but I'll let others do the judging. Most of it is old crap, really. One time, when working on an old Big Muff, I noticed a profound difference in sound when I changed a piece of wire for another. Then I changed it back by the end of the job. Then much later I made mention of that experience here, in conjunction with a curious conversation I had with some dude who had mist in his eyes... Just on this thread alone, there's guys from all over the world who I'd love to meet someday. Ya'll are my teachers in a way. Maybe some of you are right, that I'm not looking hard enough for the facts, but I work toward seeing at least one new facet of the "truth" every day. However, I'm not here promulgating ghost-chasing and B.S. I'm just open-minded and curious, and when I'm not being logical, I'm an artist. This is the internet. There is a responsibility to present all sides on these threads--that usually gets taken care of by the members here at large. But if folks wanna believe stuff without doing their own research, and crosschecking, then that's their problem. I'm not a believer, trust me... People come to this forum for different reasons, and with different perspectives. It's obvious the OP does not yet possess the ability to understand a schematic, and that leads him to be concerned with some of the things he's asked about here. But, it's gonna float his boat getting this amp going, and he has taken the time to try to hang out with people who know more than him. Plus, he seems like an o.k. guy! Maybe he'll learn a little something from having visited here, I know I sure have--hell I'm here everyday whether I'm posting or not, and I ain't going anywhere. Did I not suggest using the cheapest caps he could find? That's what I do, because I know the smell of the cork ain't as nice as the buzz, and not nearly as important as the music, which relies on properly functioning equipment--that I can help with. Convincing folks to play music, and not gear, that's a whole 'nother battle. Peace to you all today!