Tube Amp

[MacStevenXIII]

I have a 67 Bassman that I had a custom cabinet made for, now it's a 2x10 combo. Little too much for my mando.
It's little brother the Gretsch G5222, after a few mods, makes a decent low wattage tube amp for mandolin playing. I added an 8" weber speaker, changed out the grillcloth and tubes.

[MikeEdgerton]

Has anyone actually messed with the Fender Excelsior amp listed early on in this thread?

[Mark Seale]

Thanks, Mark. it rattles the entire first floor of the house on 6! Here's a pic of it from George's website when it was a newb several years ago.. the amp and cab has aged very nicely. it's a killer rig.

she's a beauty. A good friend of mine runs his Allessandro through a Fusco cabinet for his main jazz rig. The tone is rich and buttery, you could swim in it.

[mtucker]

she's a beauty. A good friend of mine runs his Allessandro through a Fusco cabinet for his main jazz rig. The tone is rich and buttery, you could swim in it.

i'm sure it sounds great, Mark. George is a talented guy. My cab has 4x10 Celestion Alnico's, really nice and creamy at lower volumes...and if you need to scratch an itch, it transforms into a beast. Gerald Weber makes some nice amps in your neck of the woods. I have a low watt from him that i really like.

[Ed Goist]

Really interesting you should mention Hughes & Kettner...
...snip...a very lightly used Hughes & Kettner 25th Anniversary Edition Tube Combo showed-up on my regional craigslist search. The price and condition of the amp both seemed very good, so I took the hour drive today to check it out.
Well, after playing through this amp for about 5 minutes, I knew I'd be buying it!
I got her home, got her set-up in my music room, and gave her a good workout...

[Ed Goist]

Here's a couple new Fenders for 2012 to toss into the mix:

Pawn Shop Special Excelsior Amp 2x6V6 power section, 15" speaker w/tremolo $299.99 MAP


Pawn Shop Special Greta Amp 12AT7 power section, 4" speaker $199.99 MAP

The infamous "Gear Mann Dude" just posted a demo video for the Greta.
Sounds pretty tasty, especially through the 4 X 12. I love that gauge on the front!

[nobullmando74]

I use to own a Swart Atomic Space tone Pro. Man I miss that amp. Not that I can complain too much. My current amp is a 1964 Fender Deluxe Reverb. Yeh it shocks ya sometimes but man it sounds great.

[MikeEdgerton]

Thanks Ed. The Pawn Shop Fender amps are looking real affordable.

[Ed Goist]

Pretty cool list:
"10 Classic Guitar Amps & The Songs That Made Them Famous"

[MikeEdgerton]

I stopped at a local music store at lunch today and they had an Excelsior amp in stock. Spent about an hour messing with it and pulled the trigger. I can't wait to get it home and play with it some more. First impression is that it's heavy as heck, well made, nice fit and finish, and that to my old ears it sounds good. It's about as basic as an amp can get. Reminds me of the stuff we had in the 60's when I first started playing. I'm excited... wait.... I'm stoked.

[journeybear]

OK, so after following this thread and some others and doing a bit of further research, I picked up a Fender Super Champ XD on ebay. The seller said it had never left his living room, a smoke-free environment. It is everything I wanted and more - lots of power and possibilities. Heck, I hardly ever run it higher than 4 on the gain and volume. Coupled with the Ryder EM-44 it has been an outstanding improvement in my sound. Real happy with it.

Just one thing, a pretty big one. It produces a horrible crackling, like radio static, intermittently, for 30-45 minutes after turning it on. It does this irrespective of the volume control. It will build in volume, then suddenly stop, only to build again soon after. The only thing that affects this (other than time) is a good hard slap to the cabinet - not all the time, but most of the time, and I doubt this is really that good for it. The way this builds and stops makes me think capacitor. I contacted the seller, who said he had never noticed this, and suggested checking the tubes - perhaps they had come a bit loose in shipping. One had indeed, but that didn't solve this. And of course the trial period had already passed. So far all I have been able to do is get to the gig early enough to let it warm up or whatever beyond the aforementioned time frame (not always possible). Since this is going through a PA via the line out, it is really annoying, and I have to be ready to attend to it fast - either hitting it or turning either the PA channel down or the amp off and on - which can be unsettling, especially if it strikes n the middle of a quiet song.

Any ideas as to cause and solution? Thanks!

[Michael H Geimer]

I heard a similar crackling sound with Super Champ XD. I found I could affect this sound by tapping the cabinet. Figuring it might just be a too loosely seated tube, I used a cloth to firmly push each tube into its socket. Cracking gone. In fact I totally forgot about that episode until just now.

[Verne Andru]

2 things come to mind - properly seated tubes and/or a bad solder joint somewhere on the board.

For the first I pull the tubes [1 at at time so they don't get mixed up], spray inside the socket and the legs of the tube with electronics contact cleaner - the zero residue type - then push the tube in and out of the socket 3 or 4 times. This works off any grime that might be causing an intermittent connection. This is the most likely scenario IME.

If its the second then I trust you have some sort of warranty cause you're not going to be able to do much about it.

Contact cleaner is available for under $10 in a spray can from most electronics places - Radio Shack comes to mind. You can use isopropanol alcohol in a pinch as long as it doesn't leave any residue.

[journeybear]

Thanks guys. The tubes aren't loose, but there could well be some residue on the tubes or in the sockets. I got this used (good old ebay) so no warranty, no idea (other than what the seller told me) of its history. Dontcha know my can of compressed air just recently ran out. Still not sure why it would respond to a good well-timed slap, but it does. I plugged it in, let it do its thing for a half hour - mostly just crackle, with two volume increases then snap to silence - and after a half hour gave it a slap and it's been quiet ever since. I appreciate this consstency - at least this method seems reliable - but I would much rather solve the problem once and for all. Some day it may not respond as is its custom, which would be a real drag. It may know I'm the boss, but it keeps acting up. And that just ain't right!

[Verne Andru]

Could be a bum tube as well. The only way to test the tubes is to replace each, one at a time. The good news is there are not many tubes in that amp. You could try this next if cleaning the sockets doesn't work.

[MikeEdgerton]

JB, contact cleaner and compressed air are two different animals.

[Jim Hilburn]

My SCXD does the crackle too. But it goes away.

[journeybear]

Mike - yes, I know that. It's just that I don't even have that to try, so a trip to Radio Shack is in order.

[Ed Goist]

Journeybear, you've probably already done this, but if not, be sure to Google Fender Super Champ XD crackle. Lots of forum hits will turn up.
Since it stops when you whack the cabinet, I'm guessing it's a bad tube or a faulty tube connection.
Keep us posted.

[journeybear]

Well, that made for some interesting reading. Gearheads! I did what several suggested - tap each tube to see if it caused a coincidental crackle - nope. That implies the tubes are OK. So the next step is to go through it with contact cleaner. And so far, as long as I get to the gig early enough and plug it in early enough so it can go through its cycle before we start, it's OK. Not perfect or resolved, but OK.

[Ed Goist]

I talked to a friend of mine who is a radio engineer about this, and in addition to checking the tube pins for tight and clean connection, he also suggested checking the power chord by wiggling it near where it goes into the amp to see it there is a bad connection there.

He said the chord was probably low on the suspect list here since the crackle goes away when the amp warms up, but he said you should still check it because it is an easy diagnostic (the crackle will get worse when the plug is wiggled), and it's a very a common problem.

Keep us posted.

[JimRichter]

I may be wrong, but based on personal experience with some old Fender Super Reverbs I've had, it sounds like possibly a resistor. I had a '66 Super that had a bad resistor on the plate of one of the preamp tubes. Once the resistor warmed up, crackling went away. I could also whack the amp and it would go away--for awhile. If you've determined it's not a tube issue, it's leading toward a cap or resistor issue. It could be filter caps going bad, though I would expect you'd hear something all the time as they're unable to filter the hum (though could be wrong). You could do an internal inspection to see if there is anything disconnected. I've done this before to see a resistor, cap, and wire lifted from the circuit board.

[journeybear]

Thanks for the tips. I'll take it apart and look through it. I am not fond of doing this sort of thing because after a certain point I am an unsteady ground and worry that not only do I not know enough about what I am doing, I could easily make things worse. And that threshold is a good bit lower than I would like. Fortunately I have a friend who, before he devoted himself to playing bass, had a long career in electronics engineering. So if I get in over my head or just don't see anything, I'll see what he can find. BTW Jim, a couple gearheads at those boards I found through Ed's suggestion mentioned resistors, too. I've been thinking capacitor, the way it seems to build up a charge and discharge it when slapped - but then, electronics was the only F I got in college, and the reason I switched my major from physics.

[Verne Andru]

Capacitors hum and resistors hiss. A poor solder joint on either will cause intermittent signal which will sound like crackle and static. I've had one instance where a cheap ceramic capacitor was causing crackling. Replaced it with a mica and the problem went away. Be forewarned, tracking down this sort of thing can be like the proverbial needle-in-the-haystack.

[journeybear]

I'm sure. That's why all I'm going to do is give it the old once-over, see if anything is loose or otherwise obviously wrong, and if the problem persists, hand it off to my friend. If he doesn't find anything fairly easily, I guess I'll just live with it.

BTW, something the gearheads went on at some length about was setting the bias. One went into quite a lot of detail, including a pic of the circuit board with the pot that had to be set for 40 milliamps (if I recall correctly; he was specific about being not 39 or 41). I don't care how foolproof you think your instructions are, in the hands of someone who isn't really hip to this stuff this is a road map to disaster.