The Amp Garage

Awesome. In that case I will just change the tail, and it wouldn’t be an amp build for me without squealing leads on initial power up. Seems that no matter how closely I follow the the diagram, I always have to reverse the primary leads

This comes up all the time. You can keep the same feedback resistor on the same tap, and put the speaker on whichever one it matches, or, move the feedback resistor to the tap the speaker is on, and adjust it's value by (New Spkr Tap/Old Spkr Tap)^0.5 Given the secondary hookup for the 1620, you wi...

I bit on Ian's suggestion to try the Hammond OT, so waiting for that to arrive. The multiple taps open up some options for me, and I'm probably going to use a Celestion vintage 30 that I have. I love that amp for mid level amps like this. Anyway, it's a 16 ohm speaker. If I want to keep the feedback...

My point with that is that if I was building it for myself, having quite a bit of recording experience, I would keep it “as is” and use it in the studio, where I am often looking for unusual and unique sounds. For my kid, who will have one amp for all his use, I want the widest usage and most practi...

Hello again -- Hello -- Wondering what type of tube is presently installed in the PI position? Either V4 or V6 depending on reference schematic. Best .. Ian Ian! My dear old friend Ian McClagan would say "Us Ian's gotta stick together!" so passing that down the line in his honor. I have 2 old stock...

So Just to clarify where you ended up, using 190K in place of the 330K on your original schematic addressed the issue? I haven't actually put a 190k in yet, but that is the value that gets my build right in the lane of where the voltages should be. It also maximizes the design to my ears. I messed ...

Hello again -- Hello -- Wondering what type of tube is presently installed in the PI position? Either V4 or V6 depending on reference schematic. Best .. Ian Ian! My dear old friend Ian McClagan would say "Us Ian's gotta stick together!" so passing that down the line in his honor. I have 2 old stock...

Glad the amp is working how you wanted it to! Also really cool to hear the OT worked out -- the concept kind of reminds me of JTM45 OTs with high Z ratios. I'm still curious as to why the 47k and 330k to ground weren't enough to tame the input to the PI The 47k and 330k to ground aren't truly in pa...

With the pot at 190k, the voltages fell much closer in line with Rob's expected voltages. I went out to the studio, plugged it into a nice 8 ohm speaker and the amp sounded amazing! I was able to use the volume knob all the way to the top of its range, and at the top it had that warm, loose feel of ...

there is a good way to test the amp how good is , lift tone controls up from the gnd, and see how good amp behaves in higher gain, must be excelent..otherwise there are problems in the amp stages (lead dress probably) I don't think there are any issues with lead dress. Its a clean build with good s...

Out of curiosity, what does the amp sound like with the master on 10? Mine sounds terrible. Regardless of whether i implement this or not, I would like to have a somewhat usable amp through the volume sweep. I mostly played the amp with the MV on 10, but the volume pot was down below 5. I only play...

Rob lists 1.9V AC as being the equivalant to 5.3V peak to peak. This is an error, yes? No, Rob is correct. 1.9Vrms = 1.414 x 1.9 = 2.69Vpeak = 2 x 2.69 = 5.38Vpeak to peak Typical Ian error. I fiddle with this stuff just enough to miss these kind of things. Totally clear now, but did not catch it

Hello -- Wondering what type of tube is presently installed in the PI position? Either V4 or V6 depending on reference schematic. Best .. Ian Ian! My dear old friend Ian McClagan would say "Us Ian's gotta stick together!" so passing that down the line in his honor. I have 2 old stock At7's I was us...

... I biased the 6V6 to around 415V and 20mA, so basically 20mV of current ... TP 37 and 38 206V AC TP39 11.4 So your HT voltage is higher than the Fender schematic you're referencing. I guess the Z HT node voltage will be higher too. More voltage on the screen grids means a higher stage gain for t...

I just installed a 100K master volume pot in my single channel DR. Lets you control how much signal is sent to the PI. Works fine for me. Take a look... https://sluckeyamps.com/tdr/tdr.pdf Thats nice! Its good to see a similar circuit to mine in action. Out of curiosity, what does the amp sound lik...