mikhailgtrski

Thanks for the advice, I'll plan on wearing gloves. Any specific type of soap you use, garehanman? I would prefer not to use mineral spirits or naptha if if possible, although it seems some of you strongly reccomend that. Mikhailgtrski, so you recommend that I just use water, and keep the excess water away from the spots with bare wood? Also, if it matters, I used Deft to spray the body, and its been drying for a few weeks now.

Water is fine as long as you are careful. I use a little Murphy's oil soap for final sanding. But avoid soap if there's any possibility that you might need to respray - not that you'd plan to, but if your finish is thin and you get too aggressive with the sandpaper it's easy to sand through.

hello,

i've just seen a post in a forum selling an ada mp1 for 100 euros and i'm about to go for it, but need your help.

The user claims that the distortion channel has lost strength and volume "probably" because of a bad tube. Now, this probably seems a bit suspicious, but anyhow, is it posible??

i think it is a good price por the unit, and i'm willing to use it with my poweramp. Any help would be really appreciated.

Thank you

A worn out preamp tube could be the cause, but you wouldn't know for sure until you swapped out the tube. Not a bad price if it's in good shape. I have a dead one in my attic.

I crank up the amp and use the guitar volume to clean it up - no channel switching. Someday I might try a clean boost to goose the front end a bit, but it's still tube amp distortion.

it is possible for water to soak into the wood, through screw holes, and crack the finish.

+1

Absolutely... you have to be very careful to keep excess water away from any exposed wood (including 5-way switch slots!) or it can swell up on you... If you're lucky it will shrink back and you can sand out any wavy spots in the lacquer. If you're not so lucky it can crack the lacquer.

I got a little cavalier with the water and found out the hard way, even though I knew better.

You can use mineral spirits (with ventilation - and not with MicroMesh pads - it'll separate the mesh from the foam pad) but I'd go with straight H₂0 and a good dose of hyper-viligance. Avoid using any type of soap until you are sure you're done spraying lacquer coats.

Mike

man no one wants to give props to PETER FRAMPTON

I would have, but it said "hero" singular.

Alex Lifeson

Michael Schenker

Peter Frampton

With the headphone output, I don't think it's that simple. You want to wire in something that switches the speaker OFF and switches on a resistance in place of the speaker (something like a 10 ohm 20w resistor). The amp's power section needs to see some kind of load similar to what it's designed to see. With that set up, I think you could then do the pot and headphone jack.

Good call - I was thinking of a line out.

If you want to silence the amp while using headphones, yes, you'd need a switching jack and a resistor load in there someplace.

Glad you're settled in! Congrats - it looks great!

I believe you'd have to replace the output transformer with one that has multiple secondary taps. Unless the Blues Jr. OT already has them and Fender decided to just cap them off.

A headphone out could be tapped off the speaker output jack - a resistor feeding a potentiometer, wired to a jack.

Yeah, I noticed yesterday that there's still a slight bleed from the mags into the piezo...

And I'm getting some distortion when playing hard - probably need to remove one of the input resistors to reduce the gain.

I think I've got a little switcheroo going on ... now the low-impedance piezo is bleeding into the magnetic signal when I have them on together, and it affects the magnetic tone. The mags sound normal when the piezo is grounded out by the selector switch.

Perhaps a stereo cable with individually shielded conductors will reduce the crosstalk. Fishman makes one.

and where I could find them such as at a Home Depot, Lowes, or Rockler type of retail store.

Doubtful any of those would have what you need. A scroll saw won't accept the very fine blades you need.

I bought a good adjustable frame jewelers saw at a local jewelry supply shop for about $15, but there are a number of online supply houses with the same stuff. Google "jewelry supplies".

If anything, it should have helped with the mag PUPs...

That's the thing, I'm wondering if it did "help" by reducing some sort of common impedance or capacitance/inductance (I'm not totally up on my electronics theory) that was occuring without the buffer.

Also, you have to be aware of the dangers of building valve equipment - the plate voltages that they operate at is extremely lethal

+1

My HIWATT clone carries 450vdc on the plates - gotta be VERY CAREFUL and keep one hand in your pocket at all times when probing around inside a live amp.

If in doubt unplug it and let it sit for a few minutes before working on it.

The filter capacitors in some amps can hold a very large charge for a long time... you should always check with a voltage meter to make sure the caps are drained BEFORE tinkering!

i wonder how much i could put that parts list together for if i ordered everything myself individually?

I don't think you'd save that much, assuming components of equal quality. The transformers and cabinet are the big $$ items.

This DIY cost around $800 in parts that I sourced myself:

Check it out: metroamp forum

Dunlop nylon .88 mm for electrics, usually .60 or .46 for acoustic.

Hey, just noticed their nylon MIDI line with in-between gauges.

Not sure, it's the Helmke "Mintbox" circuit.

follow up...

We know that without the buffer the magnetic signal was bleeding into the high-impedance piezo signal. Fixed that with the buffer.

Now, with the buffer in place is it possible that I've also somehow reduced the capacitance (or some other factor) in the "other side" of the stereo cable, affecting the tone of the magnetic signal? I'm noticing a definite change - the two-humbucker sound is more Les Paul-ish (good) but the split coil Strat "two" position is now less "stratty" (not so good). Hmmm...

I think the buffer kills two birds with one stone, though.

Indeed it does. Works great - great tone, no more crosstalk.

Thanks again, Paul.

I needed a 25K pot for my buffered piezo circuit... RadShack didn't have that value (of course) and the music store only had 250K (of course).

Just for grins I tried a 47.5K resistor in parallel with the 250K to get a 39K pot. It does indeed change the value to 39K, but it's odd watching the resistance change through the sweep... it starts at zero, about halfway through the range it ramps up to 70K, then down to 39K.

I'm sure there's a mathematical explanation for this phenomenon... any of the experts want to chime in?

Alex Lifeson

I was just pointing out that non-active piezos are way higher impedance than magnetic pickups.

Thanks... so running the magnetic and passive piezo signals through a stereo cable could cause crosstalk? If so, it sounds like I need to build that buffer!

That's true if your piezos are active. Otherwise, your piezo pickups want to see four times the input impedance that magnetic pickups want to see to keep your high end sounding good.

The piezo is passive, and is connected to a 5 meg pot. It's still a very high impedance signal traveling down the cable, isn't it?

On the crosstalk issue, I'm not sure that it would help anything. I'm inclined to think that the problem may lie in the wiring somewhere.

FWIW - Found this in the LR Baggs MixPro manual:

"4.2 Crosstalk: Crosstalk is interference or "bleed" between two signals within a common shield, such as a stereo guitar cable. This common

problem is often encountered when a high-impedance piezo pickup is mixed with a low-impedance active source, such as a mini-mic. The bleed

signal from the mic mixes in the cord with the pickup signal and appears in the pickup channel. The higher the amount of amplification (gain)

required for the pickup (and longer the cable), the more of the mic signal will be present in the pickup channel. It is common to encounter 25% to

50% mic bleed into a clean pickup channel."

The mag pickup signal isn't active and is probably higher impedance than a mic, but I'm sure it's a lot lower impedance than the piezo.

Go Mesa.

Please...

HIWATT!

or Marshall Plexi.