soens
To answer a year late, I'd say: An amp that makes -0- noise (no fans - no hums) and delivers clean sound at all frequencies at an affordable price. ...
 
But I want too much.

One of my design goals was to make the amp dead quiet for studio use. It really is dead quiet. I also used an output transformer that's rated from 40 Hz to 18 KHz. I've tested it with a 4 string bass and I'll be visiting a great Canadian bass designer very soon to see how it works with active and passive 5 string models. When using bass I run a 6550 or KT88 output tube. When I use guitars it's usually anything from a 6V6 to 6550. I have a dual range bias control to enhance each type.
 
Affordable is tough to answer, but I will do a proper accounting of the build.

wst3
That's a really cool looking design. I might just have to give this a try... I will be waiting (patiently of course) for your approach to a switch-able output tube design. I've tried in the past, but never been happy with the compromises I had to make.
 
Very nice of you to share the fruits of your labors!!! I hope to return the favor.

Thanks, I don't do it for money. The market is so saturated with Chinese product that I can't sell handmade stuff at a store. I hope others will share their stuff with the forum. I can't write code and I'm not a great musician so this is how I contribute to the industry I love. 

This is awesome, John and thank you for sharing. As I said to you before I am no electronics talking guy but am very interested in learning... specifically about things like this. One of the things I'd like to do if I get the chance is to take some basic electrical engineering courses so I can actually understand things like this and toss together simple preamps to use in my modest home studio. I've known guys that do this type of work and some of the boutique shops I used to poke around in carried custom tube pres (one of the coolest I saw was tube preamps built into old army surplus ammo boxes). I also like screwing around with old, obscure gear that people don't give a crap about because it's broken and/or they are recognizable names. I've gotten very cool and useable stuff that way and just tossing a few bucks at repairs. If I knew a bit about repairing and modding such things I could rebuild my dark army of backline gear just by scrounging around Craigslist or whatever.
 
Anyhoo... it's awesome you are willing to share your insights and experience with us.
 
Cheers.

Thanks Beeps. I know the amp co. you're talking about. They make a few models in that line and "the sarge" is one built into an ammo box. I'm one of many in Canada that makes unique amps but I never got into using surplus gear. A friend of mine named Bernie Raunig made these incredible little amps out of movie projectors and called them Filmo's. The guitar player in The Tragically Hip, Danny Lanois and Collin Cripps (Bryan Adams, Blue Rodeo) all bought them and used them as secret weapons. He never got any recognition and now people are using his name and some reverse engineering to make and sell them online. He gets nothing. Kind of like the music business in general.
 
I share stuff here because there's a few guys that are into it. After this amp, the next project will be an all tube reverb and overdrive unit to compliment the amp. After that I'm thinking an LA2A comp.

I think I have heard of these Filmo's through some of those gearheads I was telling you about. I was always an "Is it loud? Does it work?" kind of guy because I just wanted plug in and play but now that things are going to tape I wish I had paid more attention. Need to see if there are any electronic supply shops around here but I doubt it. I guess all that stuff is available online now though. Ain't the same as picking the brains of the guys behind the counter.
 
I'm guessing you've meandered through Active Surplus when it was still going. That was a wacky place.
 
 

Great read....
 
I built some homebrewed stuff in the past.... in fact I still have the transformers in my shop on the shelf in a box...
 
reading this kinda makes me want to go out there. find them and start a new build just for grins.... it's been a long time since the last amp build and perhaps this time I could get a decent chassis.

Are you planning to post the schematic with values?
 
 

Guitarhacker
Great read....
 
 
Are you planning to post the schematic with values?
 

 
You know what? The schematic is in my head, I never did write it down. It might be a good idea to draw it all out.

What's the output AMperage?
 
Do you make dual channel (stereo) main studio amps as well? Mine should be rackmounted, unless it needs more than 3 spaces.

The choice of 2 bias ranges allows for operation at 10 watts or 15 watts. If I only had 1 bias setting then a 6V6 could be run over its maximum output rating or bigger tubes could run cold. 2 ranges allows for a good balance and keeps everything running cool. I've thought about stereo type amps before but I have no plans to build one.
 
In upcoming articles I will be doing the building in detail, with lots of pictures and explanations of my choices. It will be about 2 weeks before the next part gets posted.