Because there are a lot less ST35s floating around, there aren't really any boards with modern circuits that fit into the original chassis. Shannon Parks of DIYTube has created a brand new circuit board that is similar to the ST35 circuit with some modern sensibilities if one would like to go that route. I prefer the looks of the original ST35 chassis myself, with the exposed PCBs on the ends. For this, I turned to Dynakit Parts. Dynakit Parts is a company based in Clifton, New Jersey and has an impressive selection of old school reproductions of Dynaco products. The kits are about as close to the originals as you can get, from the can capacitor to the screw-down terminal strips.
|Dynakit Parts ST35 Kit|
|The original Dynaco ST35 Schematic|
Rather than purchasing the whole kit, I purchased a number of the parts a la carte, as I was interested in adding a little bit of customization to the kit with a power choke, power switch, triode / ultra-linear switches, a C8 power inlet for a custom C7 removable power cord and a number of boutique parts. I also added the
|Brown Polymide boards with a few parts in place|
|A few chassis mods and a bit of sanding prep|
|Chokes masked off with painters tape|
|Chokes painted with copper Hammertone paint|
Once dry, I measured and cut some strips of black leather and used some epoxy to keep them in place, wrapping around the spool of the choke. I use a couple layers of leather when possible to give the spool a fuller look, it's more aesthetically pleasing.
|Completed chokes with leather wrapping the spool.|
|ST35 boards mostly populated and ready for installation|
|Getting started assembling the parts on the chassis|
|A 3 Amp power switch installed on the front of the unit|
|Wires run to the Bias Control Unit from DynakitParts|
The initial wiring was completed using Kimber TCSS 19 gauge stranded copper in teflon dielectric. I opted to drill out the area originally designated for the fuse holder and the cable in the interest of fitting a C8 power inlet. Because the re-purposed real estate on the chassis back was a little too large for the C8 inlet, I mounted it to a piece of FR-4 material and then mounted the combo to the chassis. This adds a degree of convenience, allowing a removable C7 power cord to be used to power the amp. The fuse was then moved inside the unit and mounted to one of the chassis braces, really a perfect place for it in my humble opinion. Grounding lugs were added to both chassis braces to connect to the RCA grounds (the Cardas RCAs are insulated from the chassis unlike the stock Dynaco RCAs) and the negative connector of the speaker binding posts.
|Initial wiring of the ST35 complete|
|Transformers wired in place, Solen bypass caps added|
|Triode mode switches wired up|
|Dynaco ST35 front view|
|Final Dynaco ST35 back view|
|Dynaco ST35 side view|
UPDATE 8/8/2011: I was able to have a pair of custom engravings made for the unit. A 1" gold circle with the word "Dynaco" engraved in black and a small rectangle with a Dynaco Stereo 35 logo that I made in Adobe Illustrator. These are the final touch.
|Final Dynaco ST-35 front view|
|Final Dynaco ST-35 top view|
|Engraving detail on quad-cap|
|Final Dynaco ST-35 rear view|
- Dynakit Parts ST35 BCU (Bias Control Unit)
- Front power switch
- Triode / Ultralinear Switches
- Cardas RCAs and Binding Posts
- C8 power inlet jack with custom C7 power cord
- Custom powdercoat color-scheme
- Alternate fuse holder and placement
- Custom Brass Engravings
The Fine Print:
Please remember that building circuits and performing circuit modifications can be dangerous to you and/or your surroundings and should only be performed by a certified technician. The owner of this blog and all associated parties can not / will not be held responsible if you attempt a build or modification posted above and cause physical harm to yourself or your surroundings. Many electronics contain high voltages that can kill, and mods, if performed improperly, can be a fire hazard. Please keep this in mind.