The Amp Garage

Jason, I've got the exact head cab shown on the ebay link that I bought new in '82 or so. A buddy of mine bought one in the early 90's that had EL34's and the distortion channel on his was a little meatier. Which version do you have? I'll caution you that it will be a real pain to work on / mod. As ...

You could always try emailing Weber for a recommendation or ask on his forum?

John

You could always try emailing Weber for a recommendation or ask on his forum?

John

Kevin, I don't doubt that a true bogner sounds good. I was just pointing out to the original poster some troubles he may encounter with the scheme posted. BTW throwing away half the signal twice as you pointed out, with the voltage divider, may not be enough as the gain stages are set up to have fai...

Hi ryan, I would caution building the Bogner circuit as shown. Even though I have not built this particular circuit, I have built many high gain stages. This scheme does not have enough control over the interstage attenuation, ie pots. The third and fourth stages will be railed resulting in a sticky...

Brian, My mistake, I didn't see the 12au7 in my browser. I have been interested in the dc drive since I first heard the Melissa project, but have not prototyped it. Way too many other irons in the fire. I'm still interested in how well the noise is contolled with that many cascaded stages. Also how ...

Guys, Trying to steer this back to the topic of the pre amp, I'm surprised at the total number of gain stages and seemingly minimal interstage attenuation. Soldano (and others) have been able to achieve the desired distortion, touch response and effects loop using the same amount of tubes. In my exp...

If you always thing "more notes are better" you might be a good guitarist, but you are a lousy musician. Some wise musician once said the spaces between the notes are as important as the notes, don't remember who said that. That's why I have always like Warren Haynes, his playing is very organic an...

That is a great sound clip, a little more output tube compression and he would have been a ringer for Eric Johnson's tone...

What a great tone buffet we have today!

John

Dragonbat, I did something very similar to a silverface bassman many years ago and it was well worth the time as it really "opened up" and made the amp very chimey. I used a switch to change between two sandbox cathode resitors for "gross" bias changes and then individual pots for final individual t...

Hi Bob, Looks like fun and you took everyones suggestions to heart. I see that you are using the input jacks to select half of V1 or the other jack to select V1 parallel. Cool idea. (I usually just tie the grid pins together) I have used this technique to cascade an additional gain stage though.... ...

I use a Hitachi (30Mhz) from the late 80's that is built like a tank. Definitely get a 10x probe if you are probing any plate or high voltage circuits. Most scopes have a 300 V max input. (This is my 3rd scope as I keep upgrading.) To get the most out of it you need a signal generator (as mentioned ...

Bob, My current "favorite" amp is structured very similar to my previous post. One thing that I find that I need to tweak on this type of circuit is the .002 coupling cap into the 150k load resistor. Sometimes I will jump (parallel) the .002 cap with a ceramic 100-300 puff cap to pull out more mids....

Bob, I've done a lot to these amps. First check your bias wiring on your drawing, rewire it to blackface spec. You should have 425 v or so on the plates. EL34s work too, yes the PT will get warm. The OT is fine, but won't have the bone crushing bottom end like a Marshall. Also the 100k FB is a littl...

Hi, it is unlikely to be the input shielded cable. What is the plate voltage on the output tubes? What is the voltage across the cathode resistor? What is the bias current through the resistor. Is the cathode cap polarity correct or blown? What are the other voltages? With the amp turned on and star...