Ask Amp Tech Expert Skip Simmons

This used amp is made for guitar has gain control input/output jacks for external speaker and head phones.  Selling for 75.00 at our local music shop.  Want to use it as a practice amp.  Any qualms or considerations?  Nice full sound.    Not used for blues playing but harmonica melody and jazz.

Thanaks

Chuck

Hi Skip, how goes the battle. I know, I know, you think I should be practicing. Well I would be, but the truth is I can't, I have had strep throat for over two months now, with no relief in site. So it has left me lots of time to tinker, and learn more about amps and tubes, plus listening to lots of the old greats play. My question is, can you run vintage 5881 power tubes like tung sol's in a bassman reissue. I read that they are a 400 volt plate tubes and the bassman reissue requires tubes that are 450 volt. continue reading...

Hi Skip, i got a mid 50s danelectro 272 centurion amp and the original speaker just craped out, i think its original.  I noticed that the OT has 3 wires going to a terminal strip with 3 posts, what  is the extra ohm tap?  Is there a way to test it with a multimeter ?

Hi Skip, can you tell me if it's safe to use a 5R4GY in place of a 5AR4 or a 5U4GB, in my Bassman reissue. Maybe if you have the time, you could compile a list of tubes that are safe to use, starting with the rectifiers, output tubes and last the pre-amp tubes, as there are so many different numbers and makes. I tried checking on the web but one guy says you can use a certain tube and the next guy says you can't, so I would like to here it from you, because everyone knows that you know what your talking about.  Thanks 

Hi Skip, I was hoping that you could answer a few questions for me. I just purchased a new 1991 Bassman that had maybe 5 hours playing on it, it looks as though it just came off the assembly line. My questions are do I have to be concerned that any of the components need to be replaced because it's been siting in a box for 22 years unused, like caps drying up and such. Also should I change the inputs and pots to better quality ones like switchcraft. continue reading...

Hi Skip, 

A reissue Bassman I have recently acquired is has very microphonic tubes with an obvious audible ringing. This is the 1st large amp I have had so was wondering what the best solution is I.e what tubes aremost prone to ringing and what the best swap is without sacrificing anythiNg if possible.

Thanks

Gareth

Good morning, Skip.

Dave recommended I write. I have a 1976 Fender Silverface Princeton Reverb. I'm playing through a custom wood mic from Greg Hueman with a 1950 controlled magnetic element.

I've always felt the amp was too clean. I really like a dirty harmonica sound. Musselwhite is my hero.

I've already changed the power tubes to a lower headroom rating, I forget what those ratings are. I've also changed two of the preamp tubes to 12AU7. They are in the far left and far right slots at the moment. The preamp swapped helped lower the feedback to some degree. continue reading...

Hi Skip, I got a danelectro 272 centurion amp and 2 of the t-bolts holding the speaker broke through the masonite baffle, so only 2 bolts holding speaker on. I wanted to replace the masonite baffle with wood. I have some 1/4in plyboard that i was thinking about using. What is the best size wood to use 1/2 ply? The cabnet is made of that press board crap but its in great shape, i was thinking the 1/2in plywood might be to big/heavy so thats why i figured on the 1/4 , what do you think?

Hi,

I am not shure about this, so correct me if I am wrong.

Acording to this:
http://www.musiccenters.com/vol.html

a +7db increase equal to (kind of)4x power.

So, if my Laney Cub10, 10w tube amp, has a 10" 94db speaker (Celestion Tube 10), and I change that speaker for a 12" 101 db one (Eminence Patriot red white blues), that is the same (in theory) as having a 40w amp?

I am not looking to turn a 10w amp into a 40w amp, I just want to increase my volume enough to hear my self on a jam, whit guitar player who use 25-30w amps.

I am in the right direction?

Thxs!! continue reading...

Hi, Skip.
Lately, I've noticed that when I mic. my Kalamazoo for recording, I get a hum that seems to change with positioning of the microphone (seems to get louder the closer the mic is to the power transformer of the amp, and changes some with direction). The amp itself is very quiet, but I can't record it without the hum (I tried a couple of different mics).
Also, when I try to record with my speaker-driven line out, I get a hum as well (also when I plug the speaker-driven line out into a PA). Again, the amp is quiet as a mouse (humless) all by itself.
Any suggestions?

Thanks. continue reading...