Search found 163 matches

by MarkB
Thu Nov 30, 2006 3:00 am
Forum: Technical Discussion
Topic: AMPWARES ???
Replies: 5
Views: 2225

Re: AMPWARES ???

Somehow you've missed the many posts from people who have been through the same thing. This has been going on for a long time now. I've seen guys ask about Ampwares, get the warning, and still order from him - go figure. :D
by MarkB
Fri Nov 24, 2006 7:57 pm
Forum: Technical Discussion
Topic: Randall Aiken, cascode vs. pentode, ??
Replies: 45
Views: 26313

Re: Randall Aiken, cascode vs. pentode, ??

What if you DC bias the Heater center tap to lets say 70VDC Good for the hum and heater to cathode voltage no??? Sure, if you do it for the one stage that has it cathode "way up in the air." But if you do it across the board, now you're stressing all the other cathodes (which probably have 2-3v on ...
by MarkB
Wed Nov 22, 2006 6:40 pm
Forum: Technical Discussion
Topic: Liability in amp building
Replies: 17
Views: 5517

Re: Liability in amp building

Even if you get a buyer to sign a contract to accept responsibility, that doesn't mean you are protected. Courts don't generally let people sign away their rights. Even when it is specifically allowed, like pre-nuptial agreements, judges still will throw them out under the right circumstances. The w...
by MarkB
Tue Nov 21, 2006 10:36 pm
Forum: Technical Discussion
Topic: Randall Aiken, cascode vs. pentode, ??
Replies: 45
Views: 26313

Re: Randall Aiken, cascode vs. pentode, ??

The design is similar to a pentode in the sense that the gain and the plate output impedence are high. The sound will be different - just like two pentodes are different - but it's more similar to a pentode than a cascaded twin triode. I think that beyond that, you'd just have to build one and liste...
by MarkB
Tue Nov 21, 2006 10:30 pm
Forum: Technical Discussion
Topic: Liability in amp building
Replies: 17
Views: 5517

Re: Liability in amp building

Many guys sell amps to friends, local musicians, etc. but I think this is an important issue. If someone's child gets shocked, or a house burns down, I wouldn't want to take responsibility. If you run DIY electrical devices in your house, insurers can refuse to pay off on a claim. That means somes l...
by MarkB
Tue Nov 21, 2006 8:57 pm
Forum: Technical Discussion
Topic: Randall Aiken, cascode vs. pentode, ??
Replies: 45
Views: 26313

Re: Randall Aiken, cascode vs. pentode, ??

The Firefly has a cascode boost input stage - I'm not sure which bias method it uses. A search of the ax84.com forum should get you plenty of information. As stated above, the 6N1P and 6922 are designed to suit cascode use, and fit the application much better than a 12AX7. This guy has what looks li...
by MarkB
Sat Nov 18, 2006 8:46 pm
Forum: Technical Discussion
Topic: Ted Webers amp parts
Replies: 10
Views: 3115

Re: Ted Webers amp parts

Bob's comments on components seem mostly spot on to me, although I've had no problems with the filter caps. I go to Ted for the products he does best, and I"ve always been happy with them, just like thousands of other buyers have. He's had a super reputation for years now as a helpful, generous guy,...
by MarkB
Sat Nov 18, 2006 2:41 am
Forum: Technical Discussion
Topic: Tube Socket Tricks?
Replies: 3
Views: 1943

Re: Tube Socket Tricks?

Pin sockets can sometimes be tightened by prying out the leaf with a dental pick or similar device. it's called retentioning. Of course, the voltage needs to be drained before you can safely do this.
by MarkB
Tue Nov 14, 2006 11:41 pm
Forum: Garage Talk
Topic: teaser of a new amp
Replies: 30
Views: 9923

Re: teaser of a new amp

I built a push-pull 12AU7 amp for practicing - pretty good sound. The distortion is a little ratty, so I have to go back into it some day. I put it into my old Peavey Rage 158 combo with a Weber Sig speaker, but it sounds a lot better into a GH12-30.
by MarkB
Sat Nov 11, 2006 5:44 pm
Forum: Technical Discussion
Topic: Question for the Double E's in the group
Replies: 18
Views: 4270

Re: Question for the Double E's in the group

You might want to start here:

http://www.amptone.com/
by MarkB
Tue Nov 07, 2006 10:36 pm
Forum: Technical Discussion
Topic: Carmen Ghia schematic/layout?
Replies: 101
Views: 43719

Re: Carmen Ghia schematic/layout?

Pretty amazing really, that you have to be both famous and approved to be allowed to buy an amp from him :) HAD is one of the people I'd really like to meed, if I ever got the chance to make a whish..:) i whish Guitar Player would try to make a story about him again... Tommy Are you familiar with t...
by MarkB
Sat Nov 04, 2006 5:18 pm
Forum: Technical Discussion
Topic: Technical questions--need help
Replies: 25
Views: 6357

Re: Technical questions--need help

Actually, tubes do have a vacuum inside them - that's why they're called vacuum tubes, after all. :D Sorry Mark, but no they don't have a vacuum in them. They're called vacuum tubes because the early tube makers attempted to get the oxygen out of them. Edison himself failed at that so he started ex...
by MarkB
Sat Nov 04, 2006 3:26 am
Forum: Technical Discussion
Topic: Technical questions--need help
Replies: 25
Views: 6357

Re: Technical questions--need help

Let me try to answer a few. The two 6L6s had bluish-purplish halos inside the tube. It seemed to ringh the inside of the glass. Tubes don't actually have a vacuum in them. The oxygen is displaced with another inert gas. Often these gasses glow in odd colors. Ignore it. Bright RED is the only thing ...
by MarkB
Fri Nov 03, 2006 11:42 pm
Forum: Dumble Discussion
Topic: overdrive special/supreme
Replies: 4
Views: 931

Re: overdrive special/supreme

A guitar amp is made up of a schematic design, the kind of parts used, the layout used, the speakers, guitar, etc. Changes in one could possibly make up for differences in another. If you know the sound you're going for, you could make changes in layout, component brand, or component value to get th...
by MarkB
Tue Oct 31, 2006 5:24 pm
Forum: Technical Discussion
Topic: What would cause heater voltage to rise?
Replies: 6
Views: 2102

Re: What would cause heater voltage to rise?

That's fine. Plus or minus 10% is the general rule. I wouldn't be concerned until it got to 6.9V or higher.