new to forum, static like sound at all volumes

[überfuzz]

Hold the presses!

Don't start modding it before you've got it fixed. What if it sounds divine without mods!? You don't know that, do you..? Ease of the mods and have it in your arsenal for some months. Then if you're not pleased, sell it and get a real black face... Sell it to someone how happily owns a silver face.

[m-fine]

I disagree. The best use for a silverface is as a lower cost way to get a blackface or as a budget modding platform. They do not fetch any vintage premium unlike the factory blackface amps, in fact they usually can be found for less than the parts to build one. Fixing the circuit is cheap and easy, and most of the other maintenance expense, like cap replacement, needs to be done on most blackface amps you can buy anyway. For a few extra $$$ you can turn them into great sounding amps and they still have the road wear/relicing/mojo or whastever it is that makes "vintage" gear cool.

My biggest regret about modding my silverface twin was waiting so long to do it! I struggled to get good tone out of it for years, then rip out the horrid MV, swap a few resistors and wow, it sounds great. I done more to it since and now I have even bigger plans for it, but I will spare you the horror of what this vintage (NON)collectible has in its near future!

[überfuzz]

m-fine - Well thats nice and all, but that was for your amplifier. Remember? You don't even know how this amp sounds. For all I know, you don't even know what model it is? There are loads of great sounding Silver faced amps out there. Just because some seminal tinkers, or what have you, says black face are better don't justify crippling a silver faced amp. Some of the most well known songs in history have silver faced amps in lead and comp guitar.

[überfuzz]

m-fine - Well thats nice and all, but that was for your amplifier. Remember? You don't even know how this amp sounds. For all I know, you don't even know what model it is? There are loads of great sounding Silver faced amps out there. Just because some seminal tinkers, or what have you, says black face are better don't justify crippling a silver faced amp. Some of the most well known songs in history have silver faced amps in lead and comp guitar.

If you wanna do stuff to a dull sounding silver face see to it that you have good tubes and good speakers. Then, and only then... if even then consider a mod. Well, that's my humble opinion...

[m-fine]

I don't need to know how his amp sounds to know I would mod the silverface circuit and why. Yes I have a pretty good idea what model it is from the first sentence in the first post, a bassman 10 with the mid control. That narrows it down pretty good.

What is wrong with that circuit? For starters, there is no bias control, only a bias balance. If you do not have a bias balance you can buy matched tubes. If you do not have a bias control, you either buy a bunch of tubes and keep trying until you find some that work well, or you rely on dumb luck on one good pair. Better yet, you spend a couple bucks and put a bias control pot in place of or in addition to the balance control. Not putting in a bias pot for nostalgia reasons is not quite as dumb as not putting in a ground wire and removing the death cap, but it certainly makes no sense not to do it.

The other big difference is the coupling cap and grid resistors on the earlier amps rolled off the bass heading into the phase inverter starting at 80 hz or 160hz and the late silverface design rolls it off starting at about 24 hz. You would think lower is better for a bass amp, but with 10" speakers in the Fender cab, you are not going to get decent clean output at less than 40 hz. Amplifying any signal down there and then asking the speakers to try to produce it will degrade the amps ability to produce higher frequencies. The rolloff of 160 hz may be a little high for use as a bass amp, but I would definitely try intermediate values between 40 and 80 hz here to clean up the low end noise and reduce the effort to produce frequencies that the speakers cant handle anyway. You can do this simply by replacing the .01 coupling cap and leaving the 330k resistors in place so we are not talking major invasive surgery, and nothing that can be reversed with a few drops of solder.

Finally comes the tone stacks. This is where personal taste will come in to play, but I would probably up the 10k mid pot to a 25k. Keeping in mind these things have 2 different tone stacks, I would probably use that to get two pretty different sounds rather than follow an old schematic to a T.

[überfuzz]

Mhmm... All I'm saying is, don't start to cripple an amp before you excluded bad tubes and dull speakers. I've seen many cases where a amp owner has gotten the chance to play his amp through a good speaker, not only Fender amps. The difference is often massive. This Tuesday night, or evening maybe, I lent a silver face owner some preamp tubes. The sound, or the result, was pretty much a... well I'll link a picture since a picture says more than my ever so poetic description of it.



I'm not saying that things like a bias mod is bad. Just that there are other stuff to do before you start poking around doing stuff like re-voicing, etc. And definitely if your a non-tinkerer, this fella probably don't even know what you're talking about and what the effects would be on his amplifier...

Cheers!

[m-fine]

The speaker is definitely going to change the tone more than the SF to BF mods, and many SF amps came with pretty crappy speakers (some BF amps did too). That said, I would do the speakers last. Fix the circuit issues which are cheap. Next make sure you have good tubes and they are biased how you like them (some people like a mismatched sound, some like it hot, some like it cool etc.). Finally, the most expensive part, find speakers that give your amp the tone you are looking for. Plus, lets not forget that he is already having a tech open it up and get in there with a hot iron. Now is the time to do the mods because it will be pretty cheap once the tech is in there burning hours already.

[oregonblues]

Yeah, thats right. I know more than I gave myself credit for, I have been looking for a decent Bassman ten for some time simply because it was a cheap entry to tube heaven and figured on playing it a short while until it needed a fix and then doing the whole thing at once rather than a little now and a little later, paying the shop minimum ten times. Unfortunately, I thought i was buying a simple fix, but instead I had a basket case on my hands. I am aware that having a bias adjustment will save me money in a very short time, and the blackface conversion is a very common and rarely reversed mod. All that and new caps, tubes and necessary resistors, then I want to play it awhile to see how it sounds with the original speakers.
Sure, just fixing it and playing it for awhile might be cheaper and I might find out I have the best amp I ever owned, but I am obviously not that lucky. I am pretty sure the speaker package is OK, but that might change when the amp is pushing with new tubes.
I thank everyone for the advice, unfortunately I was not able to easily fix it myself. I hired one of the most respected amp guys around, mostly because he establishes and maintains relationships with repeat customers and I am thinking I will be buying more amps. This could be a great hobby, this could be a very useful forum, thanks again to everyone.

[oregonblues]

just got it home today. The amp is capable of clean bright and loud, I would have been happier with a little more break up at a lower level, but it does OK for the first night with a new amp. It might take awhile to find my tone on it, but I have to beleive it will come. The original speakers are OK, but could be better obviously. I am pleasantly surprised by the quality of the bass channel, but even with the amp in totally restored condition it would be working hard to keep up with a drummer.
Total bill for a complete cap job, replacement of worn resistors, new JJ's all around, modified to be biasable, resolder where necessary, a new power cord and cleaning up of the pots, and the original purchase price comes in right around 650 bucks. More than I wanted to spend on a bassman ten, but I should have lot's of time to get my moneys worth out of this one.