The Amp Garage

3000pF/3nF vs 3300pF/3.3nF

Difference could be audible depending on how it's being utilized in the circuit, but neither one will make or break an amp, IMO.

I don't understand the tube power. I already use tube amps. All loaded, all sub-mixed, effected, and stereo to massive power and sixteen 12s. Slew matters for impact and clarity. The extra tube output is actually anything but transparent at unity. I admit that the device makes me angry. lol For ins...

This thing wants to run hot. with 120VAC line, the plate V is 455, when tubes are idling 26/30 mA with bias V -50.8V. With the price of tubes throught the roof these days, I'd really like to make them last. Is there a relatively painless way to lower B+ down some? Just use JJ's. Datasheets spec the...

Here is a pdf and link to various articles and tests regarding different dielectrics vs voltage stress on capacitors. CC are known to have a higher voltage coefficient, and some people point to that and say they will add sweet-sounding second harmonic (thanks, RG), but IMO it's negligible. I tried ...

This is one of my favorite pics to demonstrate measurable differences exist between different dielectrics. Now, the hard part is quantifying that, and translating to how it will sound in a guitar amp. It's clear that one of these caps is superior if you're going for minimum THD, for something like H...

EL34's should be good to 800VDC on the plates and 500VDC on the screens if they meet datasheet spec (which any decent quality tube should be able to meet.)

The 400VDC coupling caps in the PI are a bad idea. Mesas fail all the time because of this. 630VDC will be better. It's because the -bias voltage is cumulative with the positive plate voltage. The cap 'sees' both these voltages added together. So if we had a -50VDC bias voltage and a 250VDC plate vo...

Not only do you want the Zeners on the input, but, IMO, you also want a coupling cap on the input to block DC in either direction. This will protect the MOSFET as well as the player, in the event the LND150 shorts, it's possible to get DC from the B+ line on the tip of the input jack.

Oh yay. More $14-$25 coupling caps that'll definitely sound better than the $0.15 cent films you can get off Mouser :roll: I'd maybe consider using them for repairs if the customer wants to keep the aesthetics, and doesn't mind overpaying for caps. I can't ever see myself doing a build with these, u...

for any output tube cathode follower directly coupled, +150 -100V will be enough blind guess, also mosfet can easily work there But with the MOSFET, you won't get the unique DC coupled CF 'distortion' achievable with the tube. In some cases that may be desirable, but it's worth noting. A note about...

some people hear differences some not. That depends on the listener... As you wrote, "its a hard yes or no for one or the other". But that does not mean good or bad over all. To finish the build lgehrig4 can use any suuitable capacitor and it will sound fine. When the types he really like to use ar...

Yup, hit up tubes and more for these and don't go buying 600 volt caps for where you don't need then , like preamp tube plates other then the PI output coupling caps. It's good to have the high AC rating of a 600 volt cap there. I'd go 600/630 all around unless the plates run particularly low. We a...

I did a high voltage LND150 setup that worked well. I intentionally gave it an EQ curve you'd expect from an OD pedal (shave some highs and lows) rather than a flat response. It works well in place of a pedal in front of the amp, which is a very common setup.

That is a nice trick there Martin! I have absolutely no idea how to implement it in Fender's two tube design though. Here is another way to skin it: Start with the -A, and eliminate the cathode follower. As above, the 10M RA is eliminated by controlling the intensity at the input to the cathodyne s...

Thank you i understand now. I have added a 220k before pin 7 and replaced the bypass cap switch and feedback resistor. ok it is working like it should i see you want more gain but this is limited topology.. need more tubes for more gain. You can actually get quite a bit of gain/distortion from the ...