Ask Amp Tech Expert Skip Simmons

Hi Skip, first of all thanks for your advice on the Vibrolux, I think I will just run it as it is. I actually haven't really had any complaints. I play in a five piece and as long as the amp is mic'd I haven't had any problems on the bandstand, the band is loud but I never have problems getting thru the mix or experiencing feedback. continue reading...

i'm a beginner and a i would like to start with a mini amp, even because i don´t have money to buy a pro amp.

I was looking this two models, Pignose 7-100 and Vox Mini 3.

Which one is better to play with a harmonica?

Both, none, or there is another one?

Thank you.

I have a few amps(more than i really need). Should i turn the ones on that I havent been using and let them warm up? My question is will the caps and resistors get crusty or out of spec if i dont run them and should the amps be turned on every week or month ect.? Thanks

The pots on my '73 Princeton Reverb have gotten "scratchy". Can they be cleaned up without removing them from the chassis? Contact cleaner spray or something like that?

Thanks!

Hi skip,
I purchased a Holland custom amp many years ago. It has two twelve inch speakers It has volume normal, volume bright, treble, bass, middle and presence nobs. To be honest I have hardly ever used it because it screeches even at low volume. I have worked on dialing it in to no avail. I have tried numerous microphones. It's been sitting for years. Any ideas? Tim

Hi, Skip.

Can you explain the differences between inputs 1 and 2 on the normal channel of a Bassman 59 RI? Input 1 definitely sounds louder, but it also seems like there are other tone quality differences...or is that my imagination?

And if the input circuits are different, how does it affect bridging options from the normal channel to the bright channel, if at all?

Thanks.

Mark H.

Hey, Skip.

What do you think about using a 12DW7 in the V3 position of, say, a Bassman RI?

I have read that this is a "hybrid" tube, like a 12ax7 on one side and a 12au7 on the other, that causes the power tubes to be driven "out of synch" and gives more/different distortion in the power amp stage. Sounds magical to me.

Okay, so you drop the input V1 from 12AX7 to 12AU7/ECC802S, or something like that? I've done this and my amp is lust quieter throughout the volume range. The 6L6's don't go into overdrive until the volume knob is up around 8-10. Used to be 4-5 with the 12AX7's. The amp is still at the same SPL when breakup occurs. So really what is the purpose of this mod?

Thanks!

Hello Skip,
I purchased a used '59 Bassman LTD amp. The pre-amp tubes are 12AX7's. I noted that in the Bassman Chronicles, Submission #10, "Resistor Change", that Mark Overman recommended upgrading the resistors in Positions #R28 and #R29 from 1/2 Watt to a full Watt due to the low gain tubes being used. I got the impression that he was most concerned because the phase inverter tube (V3?) he was using was a 12AU7, which is only about 20% of the gain value of the original 12AX7. continue reading...

I'm thinking of buying a Fishman Loudbox Artist, 120W, bi-amped solid state amp built specifically for acoustic guitar. I would most likely front it with a Harp Commander IV, Harp Attack, LW Delay or Carl Martin Delayla xII, and a Martin Compressor. Being bi-amped, it has two completely independent sets of EQ and effects controls; one for each XLR/1/4" input. I'm thinking I could run my harp mic into one side and run my Tricone mic into to the other, and have just one fairly lightweight amp to deal with. continue reading...