The Amp Garage

No, unfortunately

I should also add that the topology is Input -> 1st Stage -> Scratchy gain control -> 2nd Stage, etc.

The amp otherwise works normally, and it's the only control that scratches.

I just finished a build, and am having a an issue with a scratchy gain control. There is no DC on the pot, and I've tried the following with no improvement: - Changed 12AX7 whose grid is connected to pot - Changed pot - Changed ground wire from pot and tried different ground points - Drastically alt...

I actually like the ambiance of the long 3 spring, but if I were repairing an old Fender, I would use 2 spring like in sluckey's link just to keep it legit. I've had good experience with MOD tanks from AES.

I really want to have some metal control panels made with white text on black. Really not too dissimilar from a Fender. Does anyone know how these kind of panels are actually made? My presumption is that steel is die cut or water jet, then painted (or silkscreened?) black, then white text is silkscr...

It's totally normal for the screens to over dissipate with that plate voltage, however ultimately it's not a good thing.

So if I read you right you like them when you have a need to play thru a amp that sounds like shit, is that what I should walk away with? Well, I was exaggerating a bit for effect, or course. I personally think the charm of these amps IS their looseness, and ability to fall apart at the seams in a ...

I would personally think twice about 'beefing up' one of these amps, the whole allure of them personally is that they fall apart and sound like shit. If I want an amp too sound really good (in a more hifi sense), I don't think or trying to polish the proverbial turd that is the 1484. I would go for ...

Interrupting the plate supply is not really that good idea in the first place. Yes, it prevents cathode stripping in transmitter tubes that work with plate voltages in excess of 1KV, but "guitar amp tubes" are not transmitter tubes and B+ voltages are never that high so cathode stripping is really ...

I was just reading Kevin O'Connor's article on standby switches http://www.londonpower.com/standby-switch , and noticed this short paragraph: "In a Power Scaled amp, the standby should be rewired into the screen circuit after the Power Scale regulator. This is especially important in amps with a gro...

You need a Fluke with a relative button function ! Not at all! That function is an offset measurement feature for voltages and resistance! Not the issue here! The problem is loading the circuit with the meter! Just don't measure from grid to ground! If you measure cathode to grid, does that agree w...

Thanks Lou, that really helps!

Unless you are using a high input impedance meter, such as a VTVM, or a FET input meter, you cannot measure the grid voltage directly. Your Fluke's input impedance is too low, and it is pulling the bias voltage reading toward ground. Your best bet is to measure the grid voltage at the voltage divid...

Yes, nothing to do with the power tubes, just the LTP phase inverter. Trying to set the bias with a typical voltage divider, but getting two different readings depending on if I measure between cathode and grid, or instead cathode to ground and grid to ground, and then measuring the difference betwe...

I'm trying a fixed bias LTP for the first time, using a voltage divider/filter off the B+ rail for my bias voltage. It works fine, but I'm just trying to dial-in the bias voltage to about -2V, but am get some discrepancies in my readings. For example, when I measure from grid to cathode I get -1.85V...

I've been using stainless hardware for a while with an aluminum chassis. I know there's risk of galvanic corrosion, but I just don't see that as a big risk. I really use SS because of the strength, but I am using low grade 18-8 from McMaster Carr, and I'm wondering if it's really any stronger than z...