The Amp Garage

If I were in your position and had decided that the WGS ET65/ET90 was a good candidate, but a concern about power handling was the only thing keeping me from placing an order, then I would contact WGS to hear what they have to say. Give them the details of the amp you're building (TW Express?)... Th...

I use a stereo microscope like this: https://www.ebay.com/itm/AmScope-3-5X-90X-Zoom-Binocular-Stereo-Microscope-on-Boom-Stand-w-80-LED-Light/190807584758?epid=27031085054&hash=item2c6d04aff6:g:5ewAAOSwcapcFL5l I started using a microscope for small smd work, but I use it for everything now, even sol...

Using fiberboard instead of FR4 or garolite to build a board is like using leather brake pads in your car. It makes sense only if you have a really good reason to be historically accurate.

Not that Sluckey's work needs my verification, but I bought the same meter as him, wired it the same way as him, and can confirm that it works beautifully right down to 0V.

Tuners usually have a high input impedance. That means you can can connect them in parallel without loading the signal. Simplest case, just use a Y cable, but that won't give you mute capabilities. To include a mute switch you can use a stomp box enclosure with a switch and three jacks: 1. Input 2. ...

Yeah. I'm a diehard fan of analog. Much of my music collection is vinyl and I appreciate the difference. But, I don't think that digital is evil, or inorganic, or anything like that. I do think that it needs to mature; "CD quality" is actually piss-poor by the standards of today's technology. What m...

[Ah I see, so SoulFetish is saying that because I have the neutral going through the sense resistor (rather than the hot/wiper), I'm getting a current reading even with no load, which is apparently the magnetizing current. So if I switch this around to match the schematic I posted, namely the wiper...

turbofeedus wrote: ↑Mon Aug 26, 2019 12:39 am Does this look correct?

Yes. And the 5th wire connects to the protected side of the fuse.

So this makes sense to me, except that all the current will be going through the meter, and I'm not sure it's designed to work like that? All of the current is supposed to go through the meter. That's how it measures current! :) Also how will this effect the mod that allows the 0V reading? It shoul...

If you want the meter to work, do this: (Starting with the variac wired as it came from the factory) disconnect the two power wires at the output jack, but leave the earth ground in place. Connect those wires to the inside terminals on your meter (2 & 3). Connect two new wires from the outside termi...

It's not the failure modes of direct coupled CF that bother me; that's just an add-on. What turns me off of the idea is that they just don't provide the real-world performance advantages that they seem to promise. A LOT of work for not much gain (no pun.)

I've build ported cabinets several times, any required size, based on Theile cabs. In fact, you can change the aspect ratio, but without changing the internal volume. Only two parameters are really important - the internal volume and the size of the port opening. They determine the resonant peak in...

As Phil said, you need lots of gain in that 12AX7. This is one case where a really big cathode bypass cap can help. Try a 100uF or even 220uF if you happen to have one laying around.

Or try Sluckey's LED bias.

The old Mullard datasheet says 54W with 400V B+, so there must be something wrong with your amp.

I'm not sure a cathode follower makes as awesome a driver as it looks on a schematic. They'll drive the crap out of miller capacitance, so bandwidth won't be a problem, but it isn't a problem anyway. If you try to drive the OP grids much positive the CF falls on it's face. They run out of current, N...