check out my 1st build.

[leadfootdriver]

I used my Crate V58 as a platform. I added a 12AX7, and a 3 knob tone stack. It's a TON of work. After building it, I have a new respect for amps made on PCB's. You're saving a fortune on labor going with a PCB, and I don't blame amp makers for doing it at all.

I'm still learning, so I need to fine tune it a bit, but it's a lot easier now that the parts easy to get to. It's real quiet, and doesn't hum at all, so that's good. I need to get some knobs for it tho!

[imaradiostar]

Looks really good, especially for a first effort. How does it sound?

jamie

[leadfootdriver]

It sounds a lot like my Boogie TA-15 on the Marshall 1974 mode with way more gain, but a lighter on the bass. I guess that dyna watt power is pretty good. I did 3 gain stages with a cathode follower. I liked an AT7 in the CF spot as it retains more glassiness in the tone. I tried bypassing the tonestack and master volume by running 2 gain stages right into the power section, and liked that tone a lot! But it was loud and only loud! I tried putting a 1 meg pot on it going in on 1, out on 2, and grounding 3, but it didn't work right. The TS really eats your tone a lot I'm discovering.

I tried to get more bass out of it by fully bypassing the cathodes, but it's a bit bloated that way. I think I'll gra a 100n cap tomorrow for the bass and go lighter on the cathode bypassing. I seen a 100n in a Mesa Lonestart tone stack, so I'll give it a go.

Maybe I could do a parallel cathode follower into the TS? I'll have to see if that will even work, and how to make it work.

[imaradiostar]

If you've got plenty of drive into the output tube (and you do) you might try cathode feedback. It's often helpful in linearizing the bass on a smallish output transformer. Instead of connecting the output tube cathode bypass cap to ground, connect it to the speaker output. If it howls/squeels, swap the two ends of the output primary. A google search should yield more info but the simplest thing is to just try it since it would require either one or three connection changes.

jamie

[leadfootdriver]

Thanks for the reply. I guess I made a rookie mistake. I had .047 uf coupling cap between the master volume, and the power tube. I took that out, and got all the bass I need!

I also re biased the 12AT7 cathode follower, which really pushed the tone through the tone stack.

I used 10k resistors on the plate and cathode follower cathode resistor. I biased the plate with a 560 resistor, and a 2.2 uf bypass cap. I'm getting a bias of about 1.93 volts, and it's pushing about 4.5 ma's! It works great, and I get a nice solid tone.

[jfutral]

Man. I'm still too embarrassed to post any pictures of my work. Maybe if I use the pixelated "secret witness" filter to hide what things really look like. Nice work.

Joe

[leadfootdriver]

Man. I'm still too embarrassed to post any pictures of my work. Maybe if I use the pixelated "secret witness" filter to hide what things really look like. Nice work.

Joe

Thank you sir!

I warmed up the bias of the AT7 to about 1.3 volts, so it's pushing 6+ ma's! It added a warmer character to the sound that complimented the cooler biased early stages. A little change in bias makes a big difference in the tone I'm finding. I don't wanna get to greedy as I'm liking the sound, but the GE 6201 I'm using has a max spec of 10ma's. I almost wanna try upping the ante on it even more...

I like the sound a lot. Single notes have a firm, yet molten feel to the them like hot lava. The tone controls seem to have a lot of variety after I learned how they work from using the Duncan tone stack calculator. Admittedly I didn't like the FMV tonestack at first. Plus, I dialed it in to how I like too.

I think I have it dialed in after about 60 hours of work. I'm going to leave it for a while to see how it gels on me. Frankly, I'm sick of working on it!

[überfuzz]

Man. I'm still too embarrassed to post any pictures of my work. Maybe if I use the pixelated "secret witness" filter to hide what things really look like. Nice work.

Joe

I tell you what. I did a java applet that pixels pictures. Up load your pictures and I'll make sure to pixel them. *Fingers crossed behind the back.*