The Amp Garage

There is a For Sale section... Just saying. Hrm, I am sorry. I was thinking that it might be best to post it here and see if the reaction was "hey, those are great for SSS, etc and someone may want them" or "yeah, we don't use those any more in current builds, try a hifi forum". Thanks for the inpu...

Here are some pictures. 12AX7 box for scale. 12AX7 box not included. Note I have the original boxes, one is unopened, the other I opened to take pics. NOTE: there is a pair of these, I will sell as singles if two people are interested Specs and info: http://mail.take5moment.com/forums/magnequest/mes...

So, I have not been here in a long time. A while back I had acquired a set of brand new Peerless built by MQ 16747 output transformers (2200ohm primary, 150W at 40hz, 2,4,8,16 ohm taps) that were originally commissioned by dumble. I am culling my inventory, and was wondering what the interest in som...

The PA-060 is for a Dynaco ST-70 stereo 35WPC Amp using four EL34s with a tube rectifier. "...the power supply tranny is the wrong choice for this amp." Most likely. It is designed to give about 520V DC on four EL34s biased pretty hot. Your choices are move to a bigger tube (KT88/EL34/etc) as the he...

My goal is to measure the two push-pull signals (after PI) to set the same amplitude! If that is the goal: Don't worry about all of this high input impedance, analog meter with a center zero stuff... get a used two channel Tek oscilloscope. Your worries of loading the PI will go away when you think...

This is a precision instrument that measures voltage with extremely high input impedance. Why is this needed? A modern DMM has input impedance of 10M or so. Ah, you did not say that initially... purchase a used high impedance voltmeter... Trek makes one that is 1x10^16ohms input. Or.. build your own.

I recently bought an old guitar amp (Vadis LB60 Extended Range) cheap, gave it a good looking over and fired it up. Here's an example pic and schem. I brought it up on a variac and noticed a fairly high B+ over 470V and 460V on the screens. The outputs are 2 x 6CA7, I was thinking the screen grid v...

What do you mean? All voltage meters (digital, analog, tube, solid state) are differential... meaning they measure the voltage difference between the positive and negative probes. e.g. if you have a circuit with -35V on one side of a resistor and +40 on the other, referenced to "ground" and you put ...

This reminds me... he may be playing a blood, but if he owns it (or uses it regularly) is another question. He uses all kinds of amps from time to time... here he is at a Crossroads event... see that wooden cabinet amp to the left of him with the towel on it? That is my (TheAirtightGarage) MaryJane ...

IIRC, and I am from South Louisiana and know people that know Sonny well, he uses a Demeter in addition to the ODS. Before he got the ODS around 95, he always used the Demeter. On stage and in the studio now, he is known to switch between heads, and use different speaker cabs from time to time. Ther...

This may sound ridiculous, but I tend to have a lot of vintage JBLs around the shop. I built a cab with a single 15, but it was not a D130... I knew it would not have enough top end, so I put four 3" full ranges in it, with a high pass filter at 1000hz. I played it side by side against a 2x12 cab th...

Hrm, I would consider what kind of power section tone you want. If you want that EL84 tone, do the 15W, if you want that 6V6 tone, do the 22W. Like the other poster said, you will find very little volume difference between 15W and 22W (in fact I built a two-amp amp with 2x12s, one amp had 6V6s at 22...

Nice build. why did you use such a wide piece of board? it looks like you could have ripped it down the center and made two. There is a ground buss wire and then under that is a HT buss... this helps to keep the HT line away from the circuit. Yes, I could cram everything closer, but like Dumble, ex...

Ok, so I was commissioned to build a ODS serial 124 by a customer. I do not normally do this, but I knew this customer well. I don't really use eyelet boards too much, so I built a turret board with a layout technique put forth by Doug Hoffman. Just wanted to let someone know that it sounds nice, an...