The Amp Garage

Hahaha, now that's some nice looking prototyping!

Wait, you actually did it all in 2 hours?

I guess that's the beauty of this circuit. Too simple not to try!

Fun.... that vr1, looks like a neat way to control gain with a zero bias stage. How long does the battery last running the fil.? wasn't there a takimine guitar pre that did something like that? What I don't get is the absence of a bias resistor on the 2nd stage... Unless this is not the final schem...

Andy Le Blanc wrote: Got a link to that 12v pre?

And yes it works! Search for "ValveCaster" on Youtube

[img:606:357]http://www.beavisaudio.com/Projects/Val ... Caster.gif[/img]

There is a popular pedal design on the internet that runs a 12AU7 at 12V (sometimes even 9V!). It's very dirty obviously, no headroom.

l'll probably give the metro loop a try and modify it to fit. Thanks again for the suggestions. I seriously can't see a loop being any smaller than the Metro. Its size is basically the 2 Cliff jacks with a small PCB linking the two and extending just a little on each side. It actually goes OVER the...

I replaced the mains fuse, the power switch was on and the amp was still plugged in. My finger touched the metal outer ring while my other hand was holding the chassis... 120V 60Hz right through the chest. NOT fun! I live alone so I spent the rest of the evening with a phone right beside me in case ...

As a final note in case anyone ever see this, I removed the 220K attenuating resistor to the PI, I removed the phase cancelling MV and replaced it with a central labs 10k pot. I put in an 8.2K 2W resistor in place of the original 10K and ran that in series to the 10K pot so that this mids bleeder r...

So if I get this right, the switch lifts the cathodes on one pair at a time? As long as it's properly wired, that should work pretty well I guess... (Mesa uses the same scheme for their multiple power options) I'm assuming you double and triple checked the way it's wired? Also, I find the use of a s...

So are these recommended or not? I also need an 18W Marshall good output transformer, AND a PT,OT and Choke for a Peavey Windsor High gain monster I am working on. If not MC, then who would you suggest? The one odd thing about the 18W OT is the weird impedance taps. It's actually 3/7/15 taps (not 4...

Thanks Badside, yes, putting in 10M (essentially removing it) puts a huge deep, pointy dip in the mid range. I don't think that is what I'm after. People forget, a guitar is a mid range instrument, chopping out the mid range is like chopping off a runners foot. Thanks for the tip! Actually... when ...

No schem but the solid-state loop Metroamp do is very well regarded and inexpensive. I concur! After looking around for a DIY option, I went with that. It's all nicely packed on a tiny PCB that holds the two jacks. It comes with a variety of decoupling resistors so you can get the proper B+ (it run...

It is leaking signal to ground, that's its use. It's basically your missing mid control, hardwired in a mid-scooping position. Depending on whether your Bass control bottom lug is grounded or not (technically, it should not, but the classic Top Boost circuit had an "error" there that is now part of ...

BTW, other caps have small innards too. Apparently these caps expand when they heat up. It seems to me that this expansion would affect their capacitance... Meaning they could lose some at high-temperature. Not good (I hate amps that don't sound the same during the 2nd set. Back when I had a JCM200...

The current Express schematic suggests a Hammond 1650H. I wonder if the "H" stands for hi-fi?! Nope, but 1650 does though ;) The 1650 series is their generic hi-fi transformers. The real guitar specific OTs are the 1750/1760 series. But there's no 1750/1760 that fits the required specs for an Express

Do the make a ac30 trans ? I seen Marshall but 660v is to much for my amp. I need 290 o 290 4el84 two preamp tube reverb tube and trem tube Magnetic Components you mean? They don't But Hammond does (the 290 series, not the "universal" 269-270). I just built an AC30 clone with a 290MX PT and 1750V O...