The Amp Garage

I'm not familiar with what you're proposing. Can you kindly provide a schematic? So far, I've been pleased with using the mosfet as a cathode follower and it's been successful. I just noticed this post, because you didn't quote it was me writing. The first that proposed this solution has been (to m...

6V6's working at 320V have good sound, no worries. yep, I agree. Another point that has not been touched until now is that, keeping the loadline stable (10k or 8k is standard for 6V6GT in PP) and the bias stable at the same percentage of max plate dissipation (80 to 90% is common with those loadlin...

Yes, you can use it and it will work fine. Being on the "not often seen in guitarland" scenario, you can also use a simple CCS from the common cathode to a negative voltage (obtained from raw bias) and avoid a coupling cap from the tonestack to the phase inverter. Target twice the current of each tr...

Hi, I'd suggest 82R on the cathodes to avoid pushing too much the EL84. Screen grids resistors depend on the voltage at which the amp runs and the loadline too (with lower loads you can lower this value because when g1 reaches zero, the anode is at a higher voltage compared to amps with higher Raa, ...

Everyone is and will speculate. This is how everyone always made money during and after crisis. Most of us will probably start experimenting unusual tubes to lower the budget of our hobby. Some will take tubes from unused amps to put them in the amp they'll use. Other will pay standard tubes 4 times...

Hi dorrisand, I didn't correlate the issue to the bias, I talked about oscillation in the first line of my first post. Then I just said what I'd suggest to do with that tube, and underlined an aspect that is no more written in any datasheet. Before being offensive, be sure to have understood what ot...

Concerning the voltage, it is clearly an oscillation that fakes the instrument. Is it this tube? https://www.jj-electronic.com/images/stories/product/power_tubes/pdf/6v6s.pdf It clearly says 14 W as maximum plate dissipation. Even if has been proven that some of them can do more, I wouldn't push the...

If you want to add a SS device, you can also use it as load for the second triode in gyrator configuration, and then go to the EQ, instead of adding it as source follower. On top of that, I'd use something more recent instead of the IRF820 that goes more into the Mosfet Follies territory (quite outd...

Why do you use an output voltage of 10 volts? I don’t know what the OP is attempting by any of this unless they are wanting to build something with similar gain but wouldn’t the output voltage be more like 40 volts @ 16 ohms (100 watts) or 50 volts @ 16 ohms (156 watts). I’m looking to get a better...

Alot of SS amps relies on diode/zener clipping for distortion, so the comparison will be unfair.
On top of that, it is not the amount of gain per-se that gives a specific tone, but how it is shaped in frequency, and how hard every stage is hit, together with other stages.

Calculating the gain manually is very time consuming, because at every frequency the AC loadline of each stage is different, and every voltage divider is different (considering the bright caps, miller capacitance, etc...).

My fault, you are right on this point.
But again, no safety margin is not a good idea, especially for heaters that are cold on startup, so their resistance is lower.

Ten Over wrote: ↑Wed Sep 28, 2022 7:40 pm Sec 1: 200V @ 85mA

Ok, so it is wrongly shown on the schematic. It should be 0-200V, not 200-200V.

Ten Over wrote: ↑Wed Sep 28, 2022 7:40 pm Sec 2: 6.3V @ 2A

This is another point. 4x 12AX7 plus one ECC99 make 3.2 A.

It appears that the CT is unconnected, and it's wired as a bridge rectifier, which would take .707(ish) times the total voltage (400), which would make it 283-ish volts, unloaded. Feel free to correct me if I'm wrong. You are indeed. Try with this if you do not believe me: https://www.falstad.com/c...

Well, the whole "clean" channel and the PI is a tweed Bassman circuit (save for the parallell V1) plus a well known PPIMV before the output tube. The load of the Bassman is 220k, not 1 MOhm. This is what I was pointing at. The response of the PI will be different. On top of that, are you sure the E...