The Amp Garage

Hey guys, was just surfing ebay and found this:

http://www.ebay.com/itm/KOMET-PROTOTYPE ... 3a9a79241f

Some fun gut shots in there thought I'd share.

Hey I think I figured it out last night. I had previously resoldered all my grounds - or so I thought. Turns out I never touched the ground to the chassis of the cap in the bias supply. Got out he big iron, reflowed it, and presto - the waveform looks OK. Much more balanced. Oh, and it sounds pretty...

OK! Ignore everything I said about a parasitic oscillation in the PI. I got dirty with the scope last night and that's not actually happening. I think it was actually introduced by the probe. Sorry for the false alarm, I'm new to this oscilloscope thing but am getting so into it. Also, I have tried ...

Hey, I can't answer all your questions, but I know a lot of people think the 47k plate resistors on the PI are something the Fender actually got right in the silver face years. I've got a SF vibrolux that I tried both the BF and SF values in and preferred the SF. Glad to hear you're making progress!

Thanks again for the tips everyone. Big news - I got a scope over the weekend. It's a Tektronixs 2215, it's a little beat up but works fine, and it even came with a Tek 10x probe. All for super cheap from a old school Russian dude with an old school TV repair shop, deep in Brooklyn. Playing with it ...

That cap across the plate resistor is essentially a shunt to ground for AC. I forgot about that. Mine apparently never came with it on the guitar channel (it's a very early 1965), but does have one on the bass channel. I found that I liked the amp more without that cap for guitar. Sparklier. I can't...

Yeah removing that 470k local negative feedback resistor will not remotely reduce gain. I personally like what it and v2 in general do for a guitar. That stage definitely adds some gain and compression, but I think that's part of the charm of a bassman, particularly for grindy rhythm guitar. With me...

I totally love rangemasters. I've built a few and have found that I like them biased a little dirty. Biasing to -7v or -7.2v (I forget what this exact value is, whatever is generally recommended for the cleanest output), seems to lack a little character to me. But lower than that and look out. I als...

Hey all, here's an update on what I did last night. Spoiler alert: the buzz is still there. Also I tested for the the buzz in between each step. First I cleaned the PI tube socket with deoxit and a round wound low e string and then retensioned it. Then I tried a 100k resistor on the grid (soldered d...

Also - johnnyreece, how did you end up fixing your buzz? It does sound similar to mine. Thanks!

Thanks for the leads everyone. I'll definitely try cleaning the PI tube socket with a string before getting out the soldering iron tonight. I got some tattoo needle brushes for this purpose a while back but they don't have the constitution to get the job done. I've got one question regarding a grid ...

Thanks guys. Yeah I've tried different speakers, no luck. It does do it on the normal channel as well as the vibrato channel. I don't yet have a scope (working on that) but a while ago I listened with a signal probe at the PI input and heard it there. I'll go over that section again tonight. I actua...

Parasite? Bad ground? Leaky cap? Tequila? Man I hate tequila. And I hate this buzz. I've attached a crappy phone recording of it. It's kind of a fuzziness that abruptly "squelches" out as the note decays. The amp is a beat up 64 Bandmaster. A brief history of my buzz: it only presented itself after ...

FWIW, if you read lots of threads and do some not-so-creative googling (hint hint), you can find everything you need to build an Asteroid. There's an amazing amount of information on here, thanks everyone. Worked for me and I love my amp. Just finished the head cab:

Hi guys, forgive me for the tardiness but I thought I'd share some interesting info regarding Monterey and Hendrix's tone. I work for a co that releases classic movies and when we did Jimi's set at Monterey Pop we had to have Eddie Kramer oversee the new 5.1 and 2.0 mixes for the discs (all things H...