Search found 1197 matches

by jaysg
Mon May 29, 2006 11:06 pm
Forum: Trainwreck Discussion
Topic: fast recovery
Replies: 5
Views: 1356

Re: fast recovery

Part of my confusion :? is that I can't find any info about The Trainwreck Pages after the late 80's. I don't recall FREDs being around back then.
by jaysg
Thu May 25, 2006 5:25 pm
Forum: Garage Talk
Topic: Buying Garolite from McMaster-Carr..
Replies: 18
Views: 10784

Re: Buying Garolite from McMaster-Carr..

Just to warn you, G10 is hard on tools. 1/8" will have to be cut with a band saw. There's some 1/4" at place I used to work. It ruined a bandsaw blade. I've heard of scoring and breaking 1/16", but I've only sawed it or cut in on a sheet metal cutter. I can use a hand held hole punch with the thin s...
by jaysg
Tue May 23, 2006 5:54 pm
Forum: Trainwreck Discussion
Topic: First gig, ... Nice!
Replies: 13
Views: 2222

Re: First gig, ... Nice!

Thanks - that's very encouraging. From another thread, I caught that the OT is probably responsible for taming the high end. With the right iron, the outlook is good. :D
by jaysg
Tue May 23, 2006 5:51 pm
Forum: Trainwreck Discussion
Topic: fast recovery
Replies: 5
Views: 1356

Re: fast recovery

The Trainwreck Pages mentions that you should not use them on the output sockets to suppress spikes but I can't find any mention of them here otherwise. Is that here somewhere? Some time ago, Rick Erickson drove a thread on ampage to the conclusion that 1N4007's are probably not fast enough in that...
by jaysg
Mon May 22, 2006 4:46 pm
Forum: Trainwreck Discussion
Topic: First gig, ... Nice!
Replies: 13
Views: 2222

Re: First gig, ... Nice!

Phil, is your Express true to the Kelly schematic (with correct bias) or did it take tweaking?
by jaysg
Thu May 18, 2006 5:45 pm
Forum: Dumble Discussion
Topic: '80s Dumble?
Replies: 8
Views: 1581

Re: '80s Dumble?

what were the difference in sound (louder, smoother, more detailed, more bass/treble etc.)? I have heard from other sources about Allen and Mercury being the top replacement sources for Fender type OTs. The big difference is with the clean channel, which I blackfaced, instead of dumblizing. When di...
by jaysg
Thu May 18, 2006 2:11 am
Forum: Dumble Discussion
Topic: '80s Dumble?
Replies: 8
Views: 1581

Re: '80s Dumble?

A friend of mine is building a mod on a Fender Concert "II" platform using the Hybrid A schematics that sounds very promising at the current state. I'll report how it develops. Please do. That's what I have. Fwiw, I was extremely pleased when I replaced the OT with an Allen TO2/4/8. The problem the...
by jaysg
Tue May 16, 2006 11:13 pm
Forum: Trainwreck Discussion
Topic: What determines output ... OT or PT
Replies: 4
Views: 1202

Re: What determines output ... OT or PT

Both and more. Assuming you mean an 50W transformer set , then you'd probably get more power. The circuit itself can change the point of clipping. In the case of the KF amps, the PT's have current to spare, so distortion isn't caused by a flagging PT. For another amp, that might be the limiting fact...
by jaysg
Thu May 11, 2006 11:47 pm
Forum: Technical Discussion
Topic: log / lin?
Replies: 3
Views: 2439

Re: log / lin?

I have an old fender where the Reverb comes up too fast. I never thought about it, but it's a linear pot, soon to be replaced.
by jaysg
Thu May 11, 2006 6:38 pm
Forum: Trainwreck Discussion
Topic: Express -- please help me distill it down
Replies: 20
Views: 4089

Re: Express -- please help me distill it down

Fwiw, carbon comp are better for power surges than an equivalently rated carbon film. I've been contemplating slight modifications/experiments. I plan on using UF4007's instead of 1N4007's. Rick Erickson (Ampage) had some ideas about why they would be better in the output tube spike suppression. I w...
by jaysg
Thu May 11, 2006 12:11 am
Forum: Trainwreck Discussion
Topic: Express -- please help me distill it down
Replies: 20
Views: 4089

Re: Express -- please help me distill it down

In the Francesca 2 pics, it looks like the 1k5 grid resistors are 1/2W, or at least the same as the bulk of 'em: DSC01159, ..60, ..63, and ..65. In DSC01164, it looks like the PI's 470 and 10k are 1W. In the Two Rock pics, only the 470 is larger. I kind of doubt that the carbon comp-ness of the 47k ...
by jaysg
Wed May 10, 2006 9:19 pm
Forum: Trainwreck Discussion
Topic: Express -- please help me distill it down
Replies: 20
Views: 4089

Re: Express -- please help me distill it down

The 1K5/2W are on the grids of the power tubes. (clip) FYI: I usually use 1W carbon film resistors by default. Okay, so the bleeder [470k vs. 200k] really just has to be something reasonable and...I've never heard of using 2W resistors for grid inputs...maybe it's what he had on hand or maybe he th...
by jaysg
Wed May 10, 2006 4:19 pm
Forum: Trainwreck Discussion
Topic: Express -- please help me distill it down
Replies: 20
Views: 4089

Re: Express -- please help me distill it down

MooreCowbelle wrote: Here is my list of resistors:

1 470R
2 1K5/2W
2 100K/3W
4 9.1K/3W
Thanks for the help. It's stuff like these that I can't resolve. I have:
1 470R/1W
all 1k5 @ 1/2W
10k/1W in the PI
Where do 3W 100k's go? :?
by jaysg
Tue May 09, 2006 11:12 pm
Forum: Trainwreck Discussion
Topic: Express -- please help me distill it down
Replies: 20
Views: 4089

Express -- please help me distill it down

I've been trying to come up to speed with the Express. I've bought a set of TS iron and am trying to create a more accurate BOM than I've found. The lists I've seen appear to have extra parts and substitutions. Is the Kelly bmp schematic definitive, with the exception of the bias circuit? It looks l...
by jaysg
Wed May 03, 2006 9:41 pm
Forum: Dumble Discussion
Topic: problem: getting sound with volume set to 0
Replies: 21
Views: 4379

Re: problem: getting sound with volume set to 0

This is usually caused by wiring. Remember there's no volume knob until there's been some gain. The first stage boosts the signal and despite knob settings, a later stage is picking it up. Parallel stretches of wire can behave like transmitter/receiver RF pairs. Study the wires from B+ to the plate ...