Introduction and Franken Fender AA1164D Build

[xtian]

Seems weird - unless being run near some serious power distribution transformers, I expect a decent buffer to be able to feed a 30’ unbalanced cable without any hum being picked up.

Totally agree. However, it's really common for people trying stereo rigs to hear bad ground-loop hum when you connect that second amp. A transformer isolated A/B/Y switcher is a must have in such situations. E.g., Radial Big Shot ABY, Lehle, etc.

[Slumpin]

I'll do a bit of digging and try a couple different things, should be easy enough to find a solution. Thanks for the input, appreciated. I'll post later with my findings/progress.

[Slumpin]

Seems weird - unless being run near some serious power distribution transformers, I expect a decent buffer to be able to feed a 30’ unbalanced cable without any hum being picked up.

Turns out I had the desk end connected to the wrong patch. So it was floating, hence the hum.

Either way I did some reading and I think using a 4:1 Xmer like the JLM circuit looks like it will suit my needs just fine. Impedance pot is useless so that is gone.

- Retains the balanced desk output
- Attenuates the line level
- Deliver a 10K output to the amp
- Provide a 160K or so input for the line
- I happen to have them on hand

I've got a couple other reamping boxes here to compare my results with, so when I get it all together I will compare my hack job to a real piece of equipment and see where I'm at.

If any one is having trouble sleeping:
Audio Transformers --> https://www.jensen-transformers.com/wp- ... hapter.pdf
Balanced/Unbalanced Interconnection --> https://www.jhbrandt.net/wp-content/upl ... ipment.pdf

[thetragichero]

- I happen to have them on hand

this is an important factor for builds. sometimes i find it guides what to build to use up something I've been staring at

[Slumpin]

A little update on this project.

I've settled on a starting point for my schematic and started working on a layout. Apologies for the spaghetti wires, just something to get me started. I'll clean things up after I put one together.

Modifications to the AA1164 circuit are pretty straightforward so far:

-Trem/Reverb delete
-470K Grid Resistor added to PI
-470R Screen resistors added to output tubes
-1.5K Grid Resistors added to output tubes
-First B+ Cap changed to 40uf
-Adjustable bias
-Added balanced input and line level output
-Output attenuation for quiet time (tried this circuit out with my 5E3 last night, and it works good. Most of the fun, less tinnitus.)

Once I get one together I'll play around with some coupling cap values etc.
Also, just to anger some tube amp god somewhere, I'm going to make these things rack mounted. I've got all the necessary junk lying around to make it happen. They're just the perfect size for it.

These things are gonna be real ugly BTW! Those white panels are some painted steel I had lying around. Couldn't find a decent place to mount the cap can so I "made" one. Function over form.

Hammond AO-43 Destruction.jpg

Studio Slump Layout R0.png

Studio Slump Schematic R2.png