Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: hesamadman on April 13, 2014, 09:40:02 am
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Hey guys. Been a while. Starting my Gretsch 5 watt project back up. Soldering Iron took a poop and I just got it back from repair. I ordered a new chassis. I had some things a little too close to others. Can you guys give me some suggestions as what to avoid when placing my xfmr/tube sockets/board/ect. in my chassis. This chassis is a bit smaller. So…..my xfmr wires will most likely be under my board. Anything you guys can suggest will be help. Thanks everyone.
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Starting my Gretsch 5 watt project back up. ... I ordered a new chassis. I had some things a little too close to others. ...
This amp (http://el34world.com/Forum/index.php?topic=16578)? Why get a new chassis? Except for the pilot light being on the wrong end of the control panel, it looks done.
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From the pics you previously posted, it looked like the transformers were mounted with parallel laminations. You can set them at 90° from each other. If possible, put one on one side of the chassis and one on the other.
Main input, fuse and power switch are usually all on one side of the chassis with the PT. Instrument input, first preamp tube and usually on the other side of the chassis.
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Some time ago I was looking for a similar purpose on the net
one of the possible solutions is this (also if there are many others
K
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Well guys I had multiple reasons for the new chassis. One is the below mentioned. About my transformers being parallel. I was suggested to do otherwise. My other reason is because I am not a metal guy. Im a great wood guy but not metal. So I fell i did a pretty terrible job punching out the chassis. Plus it was huge. So I got a smaller one. Working with a machinist to help with the punch out. Also its a nicer chassis. And its black. so will look nicer in the cabinet I am building for it.
So....I had my input backwards also. I was hoping to get input on layout. Now I know where to put and not to put my input. But is there any suggestions on transformers and tubes?
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In the image I attached you can see that transformers are rotated 90°, near power tubes and far from preamp tubes
all the tubes are on the back side of the chassis as to be near the open space in the back of the cabinet for ventilations reasons
K
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For some reason the attachment isn't working. Here is the layout that I have. So if you can, tell me what I should do or shouldn't do. Or if its ok.
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In the image I attached you can see that transformers are rotated 90°, near power tubes and far from preamp tubes
all the tubes are on the back side of the chassis as to be near the open space in the back of the cabinet for ventilations reasons
K
Appreciate the help. Can you attach the image again. I can't see it on my computer.
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I modified my previous post, before was a fake attachment, it was an image link
now I've loaded on the server of EL34world the image as a real attachment
can you see it now ?
Looking to your layout the thing that I'll try to do is to move the OT a bit more on the right till the PT and OT angles are near each other
this because your chassis is a bit short, if it was larger i'll go on moving the OT on the right side a bit more
K
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Here's an amp I'm building that has a PT and OT that are stand up types. The small 1 in the middle is the choke.
K's picture has a lay down PT and a stand up OT.
Brad :icon_biggrin:
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K's picture has a lay down PT and a stand up OT.
Yes but the plan seems similar to your's (Ciao Brad)
K
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Yes he might be using a laydown PT.
(But if he is then I don't think it matters which way he mounts the OT.)
I was just adding another example.
Brad :icon_biggrin:
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I have stand up PT and OT. About to Post a photo of my layout before I punch it.
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Well. Heres my layout. Hoping that my output transformer is far enough away from the preamp circuitry. What do you guys think? Anything anyone can add would be appreciated! Thanks Guys!
(http://i89.photobucket.com/albums/k205/fratbasher/amplayout.jpg)
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Layout is missing speaker wires
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Well. Heres my layout. Hoping that my output transformer is far enough away from the preamp circuitry. What do you guys think?
Seems fine. You want the OT close to the output tube. The preamp circuitry is lagely a non-issue, because the chassis shields that circuitry from the preamp components.
An exception would be if you had the OT on the preamp end of the chassis, ran OT wires into the chassis in the preamp area, and tried to route them inside the cabinet over to the output tube.
Bottom-line: keep the input jack away from the power cord, have the circuit flow from one end of the chassis to the other, place related parts near each other to make all wiring as short as reasonable.
Your first attempt was fine except for having the input jack placement swapped with the pilot light.