The Amp Garage

If you determine it is just proximity hum from the transformer, you can effectively shield it with mu-metal. I have done this many times in the past on the TOL100 amps. These used toroid power transformer that were supposed to reduce the radiated field. Ha.... all they did was narrow the field into...

Other than being led on a bit by playing dumb (neophyte in Gerry's terms) and wasting some time in the process, I can't say he's really causing any harm. I also can't stay out of that thread. It's one of those once in a blue moon, all encompassing threads. You've got anger, humor, great information ...

Funny shit. Coincidentally, IT at my work banned this site today. So, I'll be around much less and missing out on much more. Oh well, onward and forward. Since we post nothing on this site even remotely NSFW (unless you count amp porn), you can probably request that they remove that block. Just say...

The Rocket input consists of a 1M resistor to ground, and a 33K resistor in series with the grid. This is effectively the same input as a Fender. Why would it be any more likely to leak DC to the guitar? The lower the plate voltage, the more likely the grid will leak DCV. I've never heard of this. ...

How about 6 6v6s ? I've never ran the coke bottle ones. I dont know what you hqve for a pt But I've experimented with running some black plate sylvainas at 480 volts on the plates andthe screens around 420 and they seemed to hold up fine. I bet it will be nearly as loud the 100 wattr though I've ha...

M Fowler wrote:Oh I didn't read that right thought it was a JCM900 amp, sorry.

Get a different transformer.

If he were to run mismatched impedances to get the primary impedance up, this would work great for a 4-banger. A bit excessive size-wize but that will help not hurt.

M Fowler wrote:I would just leave the amp alone and turn the volume knob down or sell it and get want you want.

Wrong thread? It's a transformer not an amp..

5C3/5D3 Deluxe with 6SL7's is a raunchy little fucker. Cool circuit too but very picky about layout.

Once you put more than a few tubes in parallel, they start fighting each other. You can of course take precautions to prevent this but then you start sapping a bit of power away from each individual tube (usually in the form of some cathode resistance). Then you have to somehow allow for each tube t...

The 70% rule is more for fixed bias. Cathode bias amps are typically run higher (close to 100%) since the cathode voltage will rise when signal is applied. I think we just went through a similar discussion on another forum, IIRC, whether cathode biased output stage could be biased hotter (as some h...

I like the sound of aggressively dropped screen voltages. Makes the pentodes act more like pentodes and brightens up the overall response of the amp. You should gain a little in output power too because the pentodes will be operating more efficiently. Sounds like a really fun build, please keep us u...

The 5ExA amps that share the same lineage (Twin, Pro and Bandmaster IIRC) are such great sounding amps. Love that circuit, especially with the dual 5U4 configuration. Have you considered making this an option? Makes a very noticeable difference in feel and sound (like what most tight/loose switches ...

Don't get me wrong, I love the idea of switchers with tubes. Just don't like DC in preamps where it isn't needed as a general rule. Takes a lot of gain to get to the point where good lead dress won't get you by and I don't necessarily like things to get that complicated/gainy. At that point might as...

Congrats! My youngest child turned 18 back in December. Eighteen is an awkward age when kids think they actually know everything, and can't be convinced otherwise. :wink: I guess they all mature differently. My 18 year old thought he knew everything at 16. Now he has thankfully realized he doesn't ...

Most of the modern SMPS use pretty high switching frequencies (say 40-100kHz), so they are un-likely to be audible, especially in geetar amps. I built an amp (albeit not high gain) with 12V for the filament and 12V-300V DC-DC converter for the HV, and there was no detectable buzz/noise, but YMMV......