The Amp Garage

FUCHSAUDIO wrote: ↑Tue May 07, 2024 4:31 pm No reason you can't. I would add a 100 ohm series gate resistor on each, and also keep the 10 ohm source resistors on each, the input drain leads can simply tie to the same point.

So, like this?

I'd like to convert another Traynor YGL-3a that I have to a #102 High-Plate Skyliner. It's already been modded a bit to take a couple KT88s. This is it currently: 20240504_140745.jpg YGL with KT88 screen VVR.jpg I'm first trying to theorize what a built-in Dumbleator in a #102 would look like and I ...

So, this is the regular VVR I use in Cathode biased amps: VVR.jpg If power handling is a worry and I'm worried about that MosFET, can I just add a second MosFET in parallel? Like this?: Parallel MosFET VVR.jpg Do MosFETs work like that, or does that screw up the circuit? I imagine that the heat diss...

Pretty similar to ODS. A branch from B+2 before the VVR could be used to supply the D'lator... I guess that's what you're thinking, and that's a proven approach. Since I'm not really sure what model I should use for a 2x KT88 ODS power section. I'll start by making a schematic with the current powe...

Since this is going to be some sort of ODS conversion, I think it would be appropriate that I start a thread with my plan in the Dumble Discussion. This is beginning to become the wrong section for such talk.

Just looking at the actual power section of this YGL:

I want to forget about adding reverb for now... but am still obsessing about trying to build in a Dumbleator. I am maybe redoing someone's work, but I haven't found it exactly... so I messed around with Paint to theorize how one would add a dumbleator to a 102 circuit: 102 with Dumbleator Theorized....

Since KT8K8 are beam tubes like 6L6, and the power amp is a clean Hi-Fi type, I don't think it would matter. That's what I figured. Mostly it's something like the 183 or HRM that get a little different. I'm getting a little mixed up keeping track of all the different models and trying to hear the d...

I'm becoming quite happy with my other YGL-3a that was completely gutted and converted to an SSS... I'm feeling like this YGL-3a finally deserves a proper conversion to an ODS circuit. I'm thinking I'd like to keep it running these 2 KT-88s. It seems to be working well, with this VVR for the screen ...

I just installed a slightly less comical looking 20k 5 watt dropping resister instead of these 2 in series. I'm looking forward to running this all through its paces in a variety of settings to see if it's hype-worthy yet.

In the diagram the switch is set to fast ( higher gain) mode. https://ampgarage.com/forum/files/Express_pre_amp_variation.jpg OK, thanks. So I guess since I'm wired to the plate load being split, I'm in the lower gain mode as far as the plate is concerned. But mine's not that circuit otherwise, bec...

The resistor values are 82K and 22K. Yes, that's the values I currently have in there.. with no switch.. just hardwired in with a 0.005uF cap and a 150K resister to ground. The 82k is not visible in the picture because it is wired over the edge of the board right to the tube socket. 20240424_221042...

Well, I did a bit more tweaking and I think I should button this up and play it for a little while in some different settings. Where it's at compared to the original MHartman layout (aside from the physical chassis layout being different and having the separate CF Driver and Bias power supply): 2024...

martin manning wrote: ↑Wed Apr 17, 2024 1:00 pm To be strictly correct in eliminating position 1 you would do this:

OK, great, that's what I was thinking I would do.

I realized that I had tweaked the wrong cathode resister when I thought I was doing the stage after the filters. Wires to V4 cathode components were hidden under the board, so I was actually lowering the headroom for the reverb I think. I had just put its value back to 1.5k when my soldering iron ti...