JoeAArthur

Well, depends a lot on what you play. In the history of guitars, the majority of them with only one pickup place it in what would be considered the neck position. This would be the range of Jazz guitars down to the lowly Fender Musicmaster. The reason is a nice rich sound. Good for rhythm. The less than majority of guitars with only one pickup placed it in the bridge position. This would include the LP Junior and the Dan Armstrong among others. The reason is a sound that will cut through the rest of the band/mix. Good for lead. Then there was the third group, numbering even less than the less than majority of guitars. These single pickup models, mostly being made in Japan when that means something less than desirable, although there were a few German/English models that did the same, placed the pickup in the middle. Don't know the real reason for this one, probably as a compromise between the two. So, if you're a rhythm or backup guitarist, you can't beat the neck position. If your a lead or only guitarist, you really can't beat the bridge position. If you really can't decide - heck, put it in the middle. No matter where you put it, the tone will change as you move up and down the neck, where you pick the strings and how you pick them.

Because when the volume for the nexk/bridge is down, it grounds the hot lead going to the output jack - and the output from the blend control since they're connected together.. Looking at the diagram, swap the wire from the switch to the middle lug of the neck/bridge volume pot and reconnect the wire to the output jack (and your tone control if I understand your master wiring) to the right lug of the neck/bridge volume pot.

+1.

Sure, it's called a blend pot. You can read about them on the stewmac website: http://www.stewmac.com/shop/Electronics,_p...-Pull_Pots.html Click on the instructions tab at the bottom of the page. With a Les Paul style pickup selector it will be difficult if not downright impossible to get it to work "only" in the both pickup position.

The outside shield should be braided. Strip enough (about an inch) of the outside rubber insulation so you can unravel it and twist the individual wires of the shield together moving it out of the way of the inner conductor. Then strip the insulation away from the inner conductor (about 1/4 to 3/8 of an inch). The inner conductor is the hot output - connect it to where you want it to go... meaning selector switch lug or volume control. The outside shield is always grounded.

Seriously, they're worth whatever the buyer is willing to pay. What I would do is put them on ebay starting at 99 cents no reserve, include some great pictures, mention Tom Delonge and Blink 182 and his gibson signature model, talk about the reissues, etc. With the right bidders, and especially if your pickups are the double cremes, you could get $100+ apiece. I believe these were made from 1979 to what... 1981 maybe?

By any chance are you talking about a shielded cable?

Depends on how you want it to sound. If you're going to be playing full range music through this system, then you will really need a full range speaker system to reproduce it decently. Woofers, midrange, tweeters and the appropriate crossovers. Designing these systems ain't easy. It would be better, easier and probably cheaper in the long run just to purchase a well designed PA sound reinforcement speaker system. If you're planning to use a single speaker, then the first speaker link would be better than the second - as the second speaker has a reduced frequency range... only up to 250 hz.

For grins and giggles you might check the output jack wiring - you may have the ground and hot lead wired to the wrong jack terminals.

+1. This is getting way too over analyzed for something so minor. It's really hard to beat a 250K pot. Yes, a 500K might give more highs all the way up, but it will reduce treble faster than a 250K pot when it is turned down. As usual, this is a "personal preference" thing.

The only thing I can figure out why you wouldn't get any sound in position 1 and 2 is if you left off that jumper from switch terminals 2->4, or that connection is bad - like broken wire or bad solder joint. Another possibility is the switch itself - not making that connection at terminal 4, leaving it open.

No, the input wouldn't have voltage on it. The simple explanation is that maybe this old amp only has a two-prong power cord. When you plugged the amp in, it was incorrectly polarized to ground. When you tried to unplug it, you were also making contact with something that did have correct ground polarity. (Tell me you weren't standing on a damp concrete floor in your bare tootsies!!) How's that for an explanation?

A 1527? Could you post a link to the diagram you are trying to follow, and another to show what kind of switch you are trying to replace the Ibanez switch with? The problem with wiring diagrams is that unless you use the exact same parts as whoever drew the diagram - there is a good chance it might not work.

If you don't ground the "input to the amp", then you will get noise due to an open input. Try hanging a guitar cord out of your amp with no guitar plugged in to load it down. Just opening the circuit instead of grounding it gives you the same effect.

Since the ear is not sensitive to phase differences, it wouldn't matter if you placed the other diode in series with either D1 or D2. Just make sure you get it oriented correctly. Whether a tube amp stage clips symmetrically or asymmetrically is a function of it's bias point. If the bias of a tube stage is set so that the plate voltage is exactly 1/2 that of the supply B+, it will clip symmetrically. Two asymmetrically clipping stages in series will produce symmetrical clipping as a result of their combined action on opposite sides of the signal. A push-pull output stage will clip symmetrically. So if you're driving your output stage to clipping, it really doesn't matter how the signal was clipped prior. Despite popular opinion about tubes vs solid-state, the majority of the distortion being produced and recorded is clipped symmetrically (i.e. higher in odd order harmonics).

It is when the peaks of the signal get clipped off - don't go above a certain level. It usually refers to a means of creating distortion. Clipping can occur in an over driven amplifier stage or by means of diodes across the signal or feedback path in an opamp stage. Think of a tall mountain with a jagged top representing your clean signal. When you clip the peak you wind up with a "mesa" - a distorted mountain or signal.

You might check out this page: http://www.mif.pg.gda.pl/homepages/tom/schematics.htm About halfway down the page it has an entry for Marshall Valvestate 8080/8100.

Yes, a varitone switch is one of those big knobs found on various Gibson guitars. It does switch between different capacitor values, but it is not attached to the tone pot. The tone pot is just a plain old simple tone pot and is independent from the varitone. There is an inductor in series with the varitone caps. This creates an LC circuit that passes various bands of midrange to ground. Sort of like having a selection of notch filters. Position 1 disconnects the circuit. Position 2 connects the circuit and has the smallest capacitor and the least effect. It mellows out the upper midrange without making it muddy. Positions 3 through 6 go through progressively larger caps giving the sound different notch frequencies. Position 6, with the largest cap gives a pretty good single coil imitation. On the Gibson varitone, there is a 100K resistor that gets switched in. This drops the volume too much so I always replace it with a straight piece of wire.

One often overlooked cause of less bright sound is the cable. One too long or with too high a capacitance can really dull your sound. One guy I know went through 3 pickup changes before realizing it was his cable causing his lack of bright sound.

Yep, But if you lost those or never had them, a quick check of the EMG website will give you this: PA2 instructions

http://www.cebik.com/edu/edu4.html RMS of .282 peak is .199, so roughly .2 but not .1 You are of course absolute correct in what you are saying. However it appears that you missed a rather significant point: the discussion was about "Peak To Peak" and RMS - not "Peak". Peak to peak sometimes just P-P or even PP, for a sine wave is twice the peak. So as an example, in order to pass a 10 volt peak sine wave signal without clipping, the circuit has to be able to pass 20 volts peak to peak. The RMS value will be 7.07 volts. I "call" your website, but I don't care to "raise" RMS AND PEAK TO PEAK VOLTAGES

That's interesting - I use 250mV P-P input as an informal design center, figure 500mV P-P for "clean" boosters, and try to make sure I've got at least 1 volt P-P transients handled unclipped for pristine stuff like compressors and EQs - not always easy, especially with a 9 volt supply. I doubt that the 50mV figure was typical for humbuckers even in Darr's heyday, but I suspect that since tube amps handle transients a lot more gracefully, it wasn't much of a problem until 9 volt stompboxes (and cheap, under-designed solid state amps) became prevalent, and any discrepancies could be largely ignored. Jack Orman has some interesting figures on his Pickup Signals page, indicating that "moderately hot" humbuckers give an initial attack of over 1 volt P-P. I'd be really interested to know if anybody else has done any serious measurments, and what their results have been. Sorry... I use RMS and not peak-to-peak. Since .1 volt RMS roughly equals .282 p-p I think we're talking the same thing at least for "design center" considerations. Sure, I love headroom and agree about stompboxes... and the need to allow for extra voltage input. I don't know how Darr got his figures - humbucker, single coil or whatever pickup. But he did recommend a 50 milivolt signal (which I took to be RMS, only because that's the way I think... and I don't remember if he specified) as an average guitar signal level when substituting a signal generator for the input over a guitar so as not to introduce unintentional distortion.

Can only be two things really. Measure the open switch with a meter. 1) A reading less than infinity: dirt and crud that has built up and become conductive. Clean with contact cleaner. 2) A reading of infinity: capacitive coupling. A cap is two conductors separated by an insulator. Each side of those leaf switches have two conductors, some of which run parallel and real close to each other for some distance, and some have "leafs" of relatively large area. Area and distance determines the capacitance value. This can also happen running parallel unshielded wires close to each other over a distance. A pickup with a broken winding roughly in the center of the coil can sometimes still produce sound for the same reason.

Doesn't matter if it is passive or active. The voltage across the diodes (assuming a clipping pair arrangement) will remain at the forward voltage level. After all, the diode doesn't know what kind of circuit it is in. If you look at the waveform you presented - the resultant frequency due to the diode shorting everything to ground would be double the input frequency - if it actually worked that way. Octave fuzzes normally have a full wave rectifier configuration to provide that double the input frequency generation. IIRC... germanium devices usually have about a 0.2 volt forward voltage. The 0.6-7 volt range for silicon seems a bit high for passive pickups to reach on anything but the initial peaks and that's considering a high output pickup. I normally figure 0.050 - 0.1 volts the average output level for passive pickups. Jack Darr liked the 50 millivolt figure, but I think the average output has increased since his time.

I'd want some verification that the Fender reverb tank did indeed have the same specs as the original Peavey. Sometimes, if they get bounced around enough, the inside "tray" that holds the springs can get thrown up over the locator pin that normally tries to prevent excess movement. This will cause a solid mechanical connection with the outside of the unit which shouldn't exist and can cause feedback problems because the vibrations are more easily transferred to the inside tray. Check this out by inspecting the inside of the unit. You should see the two pins and they should be centered in two round holes cut into the center of the tray. Also make sure the springs that float the tray at both ends haven't been stretched out of shape.