Transformer Position Question

[surfsup]

I am planning to do the Supre Eagle with some mods, per RJ's other thread. He mentioned in a post that he prefers to have both transformers up along the side of the chassis. I originally laid mine out with the OT somewhat center.

-He said his allows for a reverb tank by having the OT and PT away to the side
-I put mine in the middle. Reasons: 2ndary wires are shorter and away from the mains lines, close to B+ and the v1b cathode for the NFB

I am wondering why I wouldn't be able to put a reverb tank on my layout and what should be considered when initially positioning the OT? (Not saying I prefer mine, just looking to learn something). Thanks.

One preamp tube, one tremolo or reverb tube, one power tube and a tube recto. Ouput jack is centered between the trem tube and power tube on the back.

PS thanks guitarmike for the tube, switch and light jewel solids! Those would have taken me a long time to do.

[surfsup]

I think I may know now... if the second tube was used for reverb instead of tremolo, a reverb transformer will need to be mounted on top of the chassis, as well? however, isn't there still room for that, and a reverb tank? Or does the reverb tank need to be a good distance from the trannies?

[tubeswell]

The reverb tank ideally needs to be as far from all the trannies as possible, and the pan's output transducer needs to be as far from the trannies as possible.

All the trannies need to be as far from the input end of the amp as possible, but a BF type reverb tranny can be closer to the input than the others because it is small.

[Firestorm]

Or you could drive the reverb off a capacitor Ampeg-style and not worry about a reverb transformer. You still want the reverb tank output as far away from the trannies as possible. And mind the shielding and grounds there, too.

[surfsup]

Just in case someone is reading this for info, in addition to placement based on components, etc. I found this for reduced-hum placement in another thread and re-wrote/consolidated it - hopefully it is accurate:

OT placement Headphone trick to reduce HUM:

In the beginning stages of the build, with a blank chassis, have only the PT partially installed (connected to AC) by having the PT connected to the power switch...and the power switch wired to the IEC socket. That's it.

The OT is not connected to anything in the amp. With the PT "on" have only the 16ohm tap and ground wire loosely connected to a pair of headphones via the headphone jack (you can hold each of the wires in your hand, 16ohm to the tip, ground to the sleeve). With the OT sitting on the chassis (and your headphones connected to it), to find the place to mount the OT that will omit the least hum, just move it around on the chassis and listen. When it's the quietest, mark it, drill it, done.

The only minor detail is that you've got to power up the PT. Tape any other wires with bare metal exposed, otherwise they can hang there.

[Joost]

Just in case someone is reading this for info, in addition to placement based on components, etc. I found this for reduced-hum placement in another thread and re-wrote/consolidated it - hopefully it is accurate:

OT placement Headphone trick to reduce HUM:

In the beginning stages of the build, with a blank chassis, have only the PT partially installed (connected to AC) by having the PT connected to the power switch...and the power switch wired to the IEC socket. That's it.

The OT is not connected to anything in the amp. With the PT "on" have only the 16ohm tap and ground wire loosely connected to a pair of headphones via the headphone jack (you can hold each of the wires in your hand, 16ohm to the tip, ground to the sleeve). With the OT sitting on the chassis (and your headphones connected to it), to find the place to mount the OT that will omit the least hum, just move it around on the chassis and listen. When it's the quietest, mark it, drill it, done.

The only minor detail is that you've got to power up the PT. Tape any other wires with bare metal exposed, otherwise they can hang there.

Very cool! Do I need to use a bulb current limiter?

[jmohr58]

In the beginning stages of the build, with a blank chassis, have only the PT partially installed (connected to AC) by having the PT connected to the power switch...and the power switch wired to the IEC socket. That's it.

So what you are saying is the PT is loosely mounted in it's permanent postion in the Chassis and just the basics to power it are hooked up.
The goal is to pick up the electomagnetic field the PT is producing within the OT and headphones and move the OT to find the weakest point of the electomagnetic field and place the OT there.
If that is correct, it is a cool trick!

[Structo]

Correct and no need for the light bulb limiter.

You use that after the amp is built on the first power up to check for excessive current draw.

[jmohr58]

Thanks Structo for the clairafication.
I will commit this tidbit of info into my memory for sure.

[Zippy]

Just in case someone is reading this for info, in addition to placement based on components, etc. I found this for reduced-hum placement in another thread and re-wrote/consolidated it - hopefully it is accurate:

OT placement Headphone trick to reduce HUM:

In the beginning stages of the build, with a blank chassis, have only the PT partially installed (connected to AC) by having the PT connected to the power switch...and the power switch wired to the IEC socket. That's it.

The OT is not connected to anything in the amp. With the PT "on" have only the 16ohm tap and ground wire loosely connected to a pair of headphones via the headphone jack (you can hold each of the wires in your hand, 16ohm to the tip, ground to the sleeve). With the OT sitting on the chassis (and your headphones connected to it), to find the place to mount the OT that will omit the least hum, just move it around on the chassis and listen. When it's the quietest, mark it, drill it, done.

RJ already showed the "trick" in the Supre Eagle thread on the third page:

https://tubeamparchive.com/viewtopic.ph ... 9&start=30