Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: hesamadman on March 29, 2015, 10:53:28 pm
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So obviously...working on a few projects at once. I have my 30 watt with reverb working great. But i am not happy with my build. The chassis is 17" x 10" x 3". So its huge. I found a 13.5' x 5" x 2" and I thought I might try and make it fit in their. My wire leads are too long in the current housing. I have a perf board with reverb components installed. Its messy. And its just bothering me way to much. You guys know ive been working on this design for many months so I cant leave something if it bugs me.
So what I would like to do is....consolidate my layout a bit. Now I dont know how I will do it yet because I cant put an IC socket on turrets (my reverb is solid state) but I do have a few ideas. And I hate perf board. So I want to put my reverb components on my circuit board. I will have my few and small power supply components on a separate board just under my original power supply (shown in photo). What I am still learning is (and Im paranoid about this) noise caused by lead dress and incorrect layout. I just want some opinions on this idea. If it could yield any noise where I plan to land the reverb. I do plan to send the +VCC and -VCC on the outside of the chassis and come in just under the reverb section of the board.
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I cant put an IC socket on turrets
Which kind of IC do you refer ?
if you refer to 3 legs TO220 ...
(http://el34world.com/Forum/index.php?action=dlattach;topic=11427.0;attach=31838;image)
For other IC you can use a PCB like this
(http://www.smcelectronics.com/PICTURES/PERF06-L.JPG)
http://www.smcelectronics.com/perf.htm (http://www.smcelectronics.com/perf.htm)
K
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Hey thanks. Thats a cool idea. The IC I use is an 8 terminal TL072 or a 4560.
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Those PCB can be a solution
but if you are able to build your own, you can add turret as wire connection points
like in Doug's Relays PCB
(http://hoffmanamps.com/MyStore/catalog/images/IMG_7173.jpg)
K
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Do you see any reason why I couldnt lay out my circuit board this way? With the reverb components just underneath the pre amp?
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I think it will be better if you arrange on the layout also the position of tubes and connections to the board
looking to the whole thing is easier that someone can say something about
K
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Thanks for your input. I just have no knowledge on where to place reverb components inside an amp.
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I can have your doubts, but, as an example, if your tubes are on the top side of the layout
may be all is fine, on the contrary if your tubes are on the bottom of the layout may be you encounter problems
also the path of the wires of the pots can be a problem
I say can be, not is a problem
My thought will be that it will be better if the reverb circuit is inserted between the components that feeds the reverb and which the reverb feeds
but the info you give aren't so much detailed
K
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I found a 13.5' x 5" x 2"
Sounds like a Hammond 1444-18. There's a reason it is so affordable. That's a very flimsy chassis. You can literally twist it like a pretzel between your hands. They are fine for lightweight projects but I think it's too light for an AC30 poweramp plus the preamp. And it will be a real challenge to stuff all that iron, 7 tubes, caps, and a board in that small box. You can probably do it, but your layout better be perfect.
I would recommend using a 17 x 6.5 x 2.5 chassis for a bit more breathing room and design your layout to fit. Hoffman sells a sturdy chassis that size.
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You propose putting a power supply right-next to your sensitive preamp parts.
That is usually unwise.
I'd put it to the *left* of your other power supply parts. Yes, that makes an even longer board, still with "spare" space. But there's more important things than cramming a maximum of stuff in a too-small car/chassis. I got my Big Dog in the back of my car, but she bumped the dome-light switch and I found the light running all night; also shed all over the car. (My little dog fits fine except he climbs on the arm-rest and lowers the power window...)
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I found a 13.5' x 5" x 2"
Sounds like a Hammond 1444-18. There's a reason it is so affordable. That's a very flimsy chassis. You can literally twist it like a pretzel between your hands. They are fine for lightweight projects but I think it's too light for an AC30 poweramp plus the preamp. And it will be a real challenge to stuff all that iron, 7 tubes, caps, and a board in that small box. You can probably do it, but your layout better be perfect.
I would recommend using a 17 x 6.5 x 2.5 chassis for a bit more breathing room and design your layout to fit. Hoffman sells a sturdy chassis that size.
Sluckey you read my mind! I didnt know about the flimsy part but I thought s 17x6x2.5 would be better. I see the enclosure you mentioned is .040 thick aluminum. I found an enclosure the dimensions you suggested at .050" thickness. Would that be better?
You propose putting a power supply right-next to your sensitive preamp parts.
That is usually unwise.
I'd put it to the *left* of your other power supply parts. Yes, that makes an even longer board, still with "spare" space. But there's more important things than cramming a maximum of stuff in a too-small car/chassis. I got my Big Dog in the back of my car, but she bumped the dome-light switch and I found the light running all night; also shed all over the car. (My little dog fits fine except he climbs on the arm-rest and lowers the power window...)
:l2: Thats a great example!!! I think I will put my power supply under my power supply. Im at max width on my board right now with the new layout unless I get a wider chassis.But the power supply parts for reverb is so small I could add a 2" wide hoffman board just under my power supply so it would keep it all away from the pre amp.
Here is my new layout. My goal to fit reverb on the circuit board is fitting ok. But hope that the way i have it layed out seams ok.
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I found an enclosure the dimensions you suggested at .050" thickness.
The chassis I suggested is .09" thick. I would not go less than .08" for your amp if using aluminum. .05" may be stiff enough for steel. I'd have to see one to make that call.
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I found an enclosure the dimensions you suggested at .050" thickness.
The chassis I suggested is .09" thick. I would not go less than .08" for your amp if using aluminum. .05" may be stiff enough for steel. I'd have to see one to make that call.
You wouldn't happen to have a model number would you? I haven't found one that size other than a .050
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Just click the "Chassis/Boxes" link at the bottom of this page.
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Chassis page link is here.
http://hoffmanamps.com/MyStore/catalog/Chassis.htm (http://hoffmanamps.com/MyStore/catalog/Chassis.htm)