Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: ToneJunkie on July 17, 2016, 06:31:18 pm
-
Hey guys its been a year since I built an amp and I have the bug again... I'm hankering for a lunchbox style clean amp. So its gonna be a AB763 style bandmaster with only channel one. So no reverb and no trem. Form factor wise I want to try and fit it in a Hammond 12x8x2 with the cage on top. What layout would you guys choose? Maybe I'm being a jackass with the preamp tubes on the side but I was trying to keep them away from the OT. Or can you suggest something else to try. Do you think the layout is just too tight. So I drew everything to scale and placed them on a 12 x 8 piece of paper to get an idea of how things will fit.
-
Here are the ideas for the chassis...
-
Don't know if it will help but you can move the TMB caps and resistor off of the board and put them on a terminal strip mounted right at the pots. That will give you a little more board room. Can't tell where you have the bias circuit but you can put those components on a little board by themselves which might help some.
-
Yeah... this is a super general layout... I was even thinking of going straight point to point. Or maybe a hybrid of point to point and board. I feel pretty confident about getting the circuit in there but I'm more wondering if the transformers and tubes are too close. Most of my builds (7 amps and I need one more) have had a separate cap board and separate bias board. I did just see Steve Luckey's Deluxe Lite board layout that looks pretty cool.
-
I used a layout similar to that, with the tubes on the side. Everything was pretty cramped, but it's dead quiet. Little 5 watt, so different from yours though.
-
I hope you will supply us with updates and a final verdict. With a chassis shaped like this (meaning NOT long and skinny, but more like any one of a zillion 50's-60's hi-fi amps (that had NO TONE controls and took a 1 volt input so they typically had one less gain stage) that one might consider converting to a git amp...I am always hesitant about how exactly to get the tone controls in there without creating a hum monster. It always seem like I have to violate one or two of the "golden rules" to lay out the amp.
-
I like your second layout better. It would work nicely with my 7-1/2" x 2-3/16" AB763 Deluxe Lite board or many other boards that are about 8" long.
-
I also like #2 better, but I'd move the choke further towards the front, as far as I could to then move the cap can further away from the 2nd power tube.
Looks like you could get it another 3/4" to 1" away from the heat of that power tube?
-
Google Images "Frenzel Amps" ----he has no layout anxiety and he has the controls and preamp tubes all along the front, bunched up together. This style of layout makes more sense to me. Just saying and observing, that's all the way different than what you are proposing.
I am hesitant running preamp-tone control wires all over the place, but I would happy to hear a success story doing it that way.
-
So after all that I was looking over all the "new" Hoffman projects that I have not seen (Its been a while) and I saw the Stout chassis thats 12" wide and I think what I'm going to do is just put a AB763 Lite in one of those... And I still may use a Hammond cage to put right on to it. There will be a 1 1/2 inch overhang on the cage over the back side of the chassis but I don't think that would look too weird. Tubes would be up front and that would look cool and the holes are all there! Sweet less work... I found the Classictone transformers that will fit.
-
Aren't you going back & forth betw rev/no reverb?
Maybe Doug should offer a metal cage for his Stout as a catalog item.
-
Maybe Doug should offer a metal cage
my last 2 builds have been on stout chassis, and this last one I was seriously thinking about using actual chicken wire fencing, primed n painted.
-
Aren't you going back & forth betw rev/no reverb?
No I used to only use amps with reverb now I like my TC Hall of Fame more than on board spring reverbs (blasphemous ?) plus that lets me get "my sound" on backline gear.
I will do a good thread on this build and you guys can see what the cage looks like... It will be interesting with the flanges on the outside. So I will find a piece of .1" aluminum cut to size for the bottom with feet attached and I may put a couple pieces of stained wood on the sides to make the flanges not be so conspicuous. Doug can decide if he thinks it looks cool or not :-)
-
Maybe Doug should offer a metal cage
my last 2 builds have been on stout chassis, and this last one I was seriously thinking about using actual chicken wire fencing, primed n painted.
I've used something similar to this (but nicer pattern) for speaker grille. I bet it would make a nice cage too!
http://www.homedepot.com/p/MD-Building-Products-36-in-x-36-in-Union-Jack-Aluminum-in-Silver-57208/100351162 (http://www.homedepot.com/p/MD-Building-Products-36-in-x-36-in-Union-Jack-Aluminum-in-Silver-57208/100351162)
-
Parts ordered for $325 and that is without the bottom plate and cage (I have tubes, and resistors on hand). I will start a new thread when I start the build... Also I think I may purchase some perforated metal and have it bent for the cage.