Hi All,
While building my Deluxe Reverb, I had a hard time finding reference photos of other builds using AA Electronics PCBs, so I thought I'd start a thread with my progress that I will update as I continue through the project. Little bit of a build report, and a little bit of a photo reference for others. I am fairly new to tube amp building. This is my third build, and I have been messing around with music-based electronics for years, but just a disclaimer there may be better or more correct ways to do things. Please feel free to suggest if you see something glaringly wrong!
Suggestion to @Andrea Antonello : A "Builds" category might be a better place for posts like this, and a great repository of helpful photos/content/marketing materials. :-)
So, to recap: I am doing the Deluxe Reverb build. So far, I have my cabinet ready with reverb tank and speaker installed (cabinet from guitarcabinetsdirect.com). I got the speaker directly from Jupiter and the reverb tank (and most of the parts) from AmplifiedParts. Chassis was bought from an independent chassis builder on eBay. They are sized/drilled to Mojotone specs.
For transformers, I got the TDR output transformer from Soursound here in Portland. It's their "experimental" Deluxe Reverb OT. Since Bryan Sours can explain it much better than I can, here is how it differs from the standard OT:
SST125A1A vs. SSTDR :
So the TDR design is essentially supposed to be a better bridge between the 1839/50246 & 108 outputs used in the 50’s for the Deluxes and the 60’s 125A1A outputs. The 50’s ones are much simpler in design and geometry which limits their top end response but also over compensates on the low end in order to keep the core from saturating. The 60’s 125A1A is much the opposite with a more complicated geometry, reduced leakage inductance, and compensated capacitance. High frequency is extended greatly, insulation is different, insertion loss is wayyy less - its just a much more open and louder output design. Very different than the 50s outputs. Enter the TDR - instead of making that giant design jump between the 50s and 60s, the TDR is something more in between. Insertion loss is lower like the 125A1A, but the geometry isn’t so complicated as to make the top end extension as high. It’s paper insulation throughout so capacitance is lower - but not as a result of complicated geometry. It’s very mid-forward but more open than all the 50’s stuff, and a bit quicker on transient response as well. More tweed sounding (unlike the 125A1A) but the core config is more like the 125A1A so the low end is tighter and more articulate. The secondary has two leads to change the reflected primary impedance between 6K6 and 8K (both 8ohm load). The higher primary Z requires more inductance for a given low frequency response so you can “tune” the low end in a bit (plus clipping dynamics change).
It’s a killer sounding OT in my opinion.
Since I am not super concerned with making an exact replica and I embrace this having its own character, this OT makes sense for me. I also plan to put the two secondaries on a switch (using the ground switch hole on the chassis) so I can swap between the 6.6k and 8k reflected impedance for different gain styles.
I ordered my other transformers from Pacific Audio Magnetics, and those should show up early this week.
Faceplate will be a piece of laser cut and engraved Padauk with inlaid silver laser cut acrylic type.
So far, I have most of the hardware installed/mounted, PCB populated, and flying leads installed on the PCB. Once I get my faceplate cut (waiting on some more wood to make some changes to the design and sizing a little bit), I can start wiring everything up inside the chassis. I'm excited to get this thing done, but also am taking my time and trying hard not to rush as I can be wont to do.
Another build update: It's pretty much done, with the exception of some annoying 120 cycle hum that is pervasive and some odd buzzing on an open A note, as well as a big BUZZ/ZAP sound when switching out of standby. I followed the ground specs in the layout to the letter, so I'm going to have to dig around for the cause. It could be I missed something in the Reverb jacks/grounding, although the hum is there even when reverb is off/disconnected.
Build update:
I received my remaining transformers from Pacific Audio Magnetics, and managed to get those installed, along with the remaining hardware. Pacific Audio Magnetics winds transformers to order, which I thought was cool.
Also got the faceplate finalized and mounted, so it's all prepped for me to start the wiring process. I plan to take my time with that portion, both to make sure I can keep things as tidy as possible, and also for the sake of accuracy. The faceplate thickness was a tiny bit challenging due to the 1/8" thickness. If I had a planer, I'd try to shave it down closer to 3/8". I managed to get all the pots installed, but on a few of the shorter shaft ones, I had to omit the exterior washer to get a good, tight fit.
Also designed and cut/engraved a little label plate for the transformer reflected impedance switch that will take the place of the ground switch.
Gluing in the cut acrylic letters proved to be messy and not as good of results as I had hoped. Too much CA glue residue, which through some gentle sanding and more application of shellac and a few thin layers of Poly, are mostly concealed to the casual viewer.
Some photos below.
Looks great! I really like the faceplate, can I ask where I could get one? Thanks!
Looks incredible! Amazing job, so proud to be the supplier of the board in such a great project 😊
Keeps us posted on the progress!
Cheers
Andrea
AA Electronics