The Amp Garage

I was almost born into it. My dad was an electrician, and he loved to work with his hands,...did electrical, plumbing, woodwork,....you name it he'd learn it and learn it right. In the mid 60's he cobbled the first electrical powered garage opener I'd ever seen. He got a small electrical motor and a...

I'm surprised Dumble has that much pull. I've never seen any claims of patents on his amps or circuity, or the name, and he is not the first amp builder out there who has been cloned. But, I find it hard to believe any sane person would buy of of these amps. They may be great knock-offs, but there a...

I'm in the middle of a PTP, and it is going to be pretty,...neat inside. So far so good! But, if I had it do do again, I would have first made a neat drawing of the schematic, enlarged to fit the chassis size, then cut out each "section", and tape them to the chassis to fit. This is a pretty quick w...

Got a lot of basic similarities with the 2303 Marshall 50/100.

I think you're about 25 years behind. Check out the EXEF preamp with interchangeable preamp modules. A solid state preamp for the clean circuit, and 2 input internal circuit boards for the various (8-10) tube overdrive plugin modules. Also it included unpopulated plugins for designing your own circu...

Good luck with your rebuild. A friend turned me on to these and mine works fine,... very light and portable with a great Marshall 50 sound. My buddy later had a power tranny meltdown. While rebuilding his, I noticed the rear fuse on mine showed a 1.5 A FB, but his amp showed a 2.5 A FB. I replaced i...

Sorry, just trying to help. But you did not say what size battery you used, and that is why I noted a warning. I am certainly not the most experienced or best source on this site. But as for my knowledge, I've repaired over 1000 amps in my years, and I understood how to test and determine problems w...

It seemed obvious that the sender is fairly inexperienced, and I just put the note on batteries as a "flag" for him.

We all used to be NUBIES,..Information and learning are why we're here.

You will not get any reading on your DVM if the speaker is blown.

You didn't mention how much battery voltage you put on the speaker, but you probably burned up the voice coil at some time. While I've done it, testing a speaker with a battery, rather than a DVM, is not a good idea.

I've been using only DC heaters for 10 years. It's almost "idiot proof" and the parts required are cheap. I use a large FWB and mount four small 3300uf caps to it. Output is marginally below 6VDC, but that's only a 6% drop from optimum. Check it on my current build. (Blue Caps mounted on the FWB and...

I haven't a clue what your trouble is, but I purchased one of the Vox "lunch-box" 15s a couple of years ago. The basic sound was cool, but there was a persistent "ripping" sound as the signal would start to fade. Checking the internet, I found page after page of comments on the same problem, along w...

Sounds very good. Gonna' spread the joy and post info of the amp design?

ampdoc

Hans, Attached are a couple of pics of the original amp and my new build in progress. The original amp was built in a Fender Bandmaster Reverb TFL chassis, which is 23.7" x 7.5" x 2". You'll get a laugh at the original,...again, it was pretty much built on the fly, a little at a time. HOWEVER, as cr...

I put in the tubes as shown initially, but when I got the amp back a couple months ago (I borrowed it from the owner as I am making a copy of the original for myself) it had 12AXs throughout. I haven't changed them out, as the amp works fine. Re the loop,..I'd recommend keeping it. That design was o...

I assume you are referring to the Trim pot between the PI output pins? I tried this years ago after I saw it here, and have added it to several Express type amps. I generally like the sound better with a little imbalance to find the "sweet" spot that accentuates the bloom of higher harmonics. Beside...