lovekraft

OK, so it's a used high-gain amp of indeterminate age, and you've been playing for two years without checking it - sounds like it's probably time to call a tech. It could need power tubes, preamp tubes or even a cap job. You might also want to check to see what kind of speakers you have in your cabinet, as compared to what's in your partner's Engl cab, since speaker efficiency varies wildly between drivers, but theoretically you should be able to keep up with even a power drummer at the volume levels you're talking about - BTW, you're going to end up very deaf very quickly if you're not using hearing protection at those SPLs. And turn up the treble just a wee bit if you want to cut through the mix.

Make that massive treble loss - at the center of rotation, each pickup will only see a 50K load (in parallel with any other volume pots, etc., lowering it even further), and unless you're running active pickups, the high end rolloff is likely to be completely unacceptable. In other words, you'll redefine the term "tone suck"! Using a standard dual-ganged linear pot is problematic at best, but the additional impedance problems are likely to make a 100K dual linear unworkable - even a 100K Orban® style pan pot is a bad choice. Just my too sense - as always, YMMV.

You probably had trouble finding it because I posted it to the Tutorials section - in retrospect, that may not have been the optimal place to put it, since it's been pretty much universally ignored, at least until now!

Gee, Maiden, you get to visit all the garden spots of the world, don't you? Keep your head down, and be careful!

Strictly speaking, a shielded cavity is a Faraday cage. If done right, it's a grounded conductive box surrounding the controls.

+1 - There are descriptions of compensated nut techniques that go back to the 19th Century. Buzz simply got a patent and mounted a clever advertising campaign. My question has always been how a system that deliberately detunes open strings can be said to make the guitar play more in tune - sounds like an oxymoron to me.

First of all, turn down the amp (about half your current volume), or leave the room with the guitar - if the "feedback" doesn't stop completely, it's not feedback, and probably is a shielding/grounding problem. If it does, check the pickup mounting like Joe said - it's extremely unlikely that either of those pickups is microphonic, so it's quite likely that your mounting job has left them free to wave in the wind, and caused the feedback. Stiffer springs or surgical tubing will often solve the problem.

Alex, I didn't say it was always noisier, but you have to admit that introducing any large AC signal that isn't the audio input into the box will invite noise problems - even control LFOs are subject to introducing unwanted artifacts unless very carefully implemented, and a big 50/60Hz current inside the shield just isn't a good idea if it can be avoided, especially for high-gain circuits. Congrats on doing the extra work to make it viable, but keep in mind that most manufacturers (even boutique operations) simply can't afford that kind of extra expense - after all, even if your pedal retails for several hundred dollars, the margins aren't huge, so you have to sell a bunch simply to keep body and soul together, and a few extra pennies on each unit really adds up! As for everyone sticking to a standard power supply, the original fuzz effects were almost all positive ground, so if you want vintage mojo, you can't expect modern convenience.

This is mega-silly! The low B string on a standard-tuned 6 string bass is just above 30 Hz, and there are damned few transducers that can reproduce that at any worthwhile sound pressure level! The C# below that is 17 HZ, which is both subsonic and irreproducible by any conventional speaker system. Get a grip!!

Easier, maybe, but noisier, usually, and more expensive, always! Even at production quantity pricing, a battery clip's a lot less hassle and expense than a rectifier bridge and flter caps!

I've used the same technique with crimp-on lugs - it works well, and the joint integrity appears to be every bit as good as a solder joint, although I'm sure there are those who will debate that.

FWIW, I don't think anybody would recommend using wood for a tube amp chassis - it burns when it gets hot and it's very difficult to ground, just for starters.

No, you can't just reverse the leads, because it's a positive ground pedal, so connecting it to any negative ground pedal on the same power supply shorts out the power supply. The only solutions are to either ground-isolate the pedal at the input and the output (probably not practical), or power it from a separate supply. If you really like the sound of it, buy a box of 9 volt batteries and cruise on.

It's pretty simple to just use a plug-in transformer (if you're using a lo-impedance balanced mic) into a cheap overdrive pedal - with the prices of Bëhringër and D@nëlëctro pedals, it's hardly worth building your own. Shure makes a transformer-in-a-plug (the A85F, I believe) that adapts an XLR connector to a 1/4" plug (or vice-versa) and converts the impedance so you can use your PG58 to drive your favorite boutique distortion box, and if you buy a pair, you can run it inline just like a guitar effect, just stomp the switch to add the gusto! If ya gotta have something homebrew, try playing with Hemmo's Bazz Fuss (courtesy of Home-Wrecker.com/RunoffGroove.com) - it's simple, cheap, and capable of all kinds of sonic mayhem.

Why?

This confirms my suspicions - I don't think anybody's saying that there aren't any differences in linearity between the various types of caps, but I'm not convinced that even one out of a hundred thousand people can reliably pick out any audible differences without visual cues (ie, in a double blind test), and I doubt seriously that anybody can hear any difference from the third row. Use whatever makes you most comfortable - I'll admit to an irrational (and embarrassing) personal bias towards film caps, but there are plenty of older guitars that sound absolutely incredible with cheap Asian ceramic discs in them, and I doubt that they would improve noticably from the installation of a Hovland on the tone pot. Better is only truly better if it improves the result - anything else is just hubris!

+1 - you can use 12 AWG solid Romex if you'd like, and it'll never affect the sound of the guitar (other than the result of all that body mass you'd have to remove to fit that much 12 AWG into the cavity!). All this "special" wire/pot/cap mojo obsession is simply designed to separate you from your hard-earned cash - remember, all those exceptionally sweet-sounding vintage guitars were built with the cheapest available wire, caps, pots and often wood back in the Fifties!

Personally, I think darn near anything would be better than those stock Epi pickups (but that's just me...). All the GFS pickups I've heard sound pretty good, and are great value for the money - sure. you can buy better, but not for the price! Out of curiosity, are you the Aharon that hangs out over at AX84?

Gotta agree with that! I usually buy at least 10 of any component I pick up, not only because I break/fry/lose them, but the quantity discounts are often too good to pass up! I'm glad to hear that Steve hooked you up - he's one of the (few) good guys in DIY supply, and he's building a well-deserved reputation for going the extra mile to help his customers, so don't hesitate to buy from him if he's got what you need.

Any voltage that is well above the supply voltage - for a 9 volt supply, 15 volt caps should be fine, although I occasionally use 50 volt or even 63 volt caps if they're less expensive or easier to get. You could actually use 630 volt Orange Drops in this circuit, but it would make the board huge, so i can't recommend it. Other JFETs that might work fairly well include BF245A, 2N5484 or just about any GP audio device, although the J201 is probably about optimal in this case. You may have difficulty finding any JFETs whatsoever at Circuit City - check to see if there isn't a store in your area that does radio repairs and such, they usually stock a few parts, and might have what you need. If not, I'm sure somebody in Toronto has something suitable, and there are several internet sources, notably Steve Daniels at Small Bear Electronics. If none of that gets you what you want, PM me - I'm sure we can come up with something workable to get you started.

Ah yes, the Holy Grail of audiophile caps - if Orange Drops are a wee bit silly, Hovlands are at least an order of magnitude sillier! For fifteen bucks, you can get either one Musicap™ or 100 or so 100v Xicon polyesters - that had better be a really good cap! Oh, and if you're into "designer" colors, check out the Wima FKM/MKM or FKP/MKP series for a really striking red hue (might go well with a cherry sunburst?). Short leads might be a hassle, but they're high quality, and very pretty!

The only caps that aren't suitable for passive guitar electronics are polar electrolytics and tantalums. Film caps are without dispute superior to most ceramic disc caps in performance, and should be preferred in most precision applications, but this isn't exactly Mission Control work we're doing. As for audible differences between types, only you can decide if there are any - I personally doubt it, but I'm willing to see evidence to the contrary (provided it involves repeatable double-blind testing and results significantly above chance ). IMO, using Hovlands or Orange Drops or any other sort of audiophile specialty caps says more about the mindset of the buyer ("This one goes to eleven!! ") than the sound of the guitar. The only valid way to find out for sure if you have a preference is to install both types on a switch, make sure they're fairly closely matched, and listen while somebody else plays the guitar out of your sight, randomly flipping the switch for a few thousand trials. Anything short of that invites self-delusion and conformation bias. Me, I don't have the time, so I reckon those little greenies will have to do, at least until I run out of 'em.

You've miswired something somewhere - surely there's a decent amp tech in LA who can get it back to you in a couple of weeks! Even I could get it done in less than a month (but shipping to and from Alabama would kill ya! )!

The general consensus on vintage gear repair is to leave everything as close to original as possible, to preserve "vintage tone" (or, probably more aptly, resale value). The electros do need replacing, since they do have a short lifespan, and can wreak havoc when they fail, but most of the other components will probably outlive our species, provided they're not abused. My rule of thumb is not to replace anything (except electros) unless the unit sounds bad, and my own experience has led me to believe that better quality components don't necessarily make an older amp sound better - some of these designs apparently relied on the limitations of existing components for their signature sound, and installing a bunch of good stuff has made many a nice old amp sound positively generic. If it ain't broke, don't fix it, unless you're Howard Dumble. But that's just my take on it - as always, YMMV.