April 24th, 2009 - Update: "Who Are You again?"
While I did "pop up" for a few posts on the Technics SP-10 repair, that really isn't my *usual* "turf." As most of you know, I'm gradually going through my Dynaco acquisitions and rebuilding them in order to make SURE they will remain functional for "another lifetime." I've been away for a few months while my time was occupied by "family needs", but you can expect a LOT of "activity" on the Dynaco rebuild front during the next few months. Here are some items that are "in the pipeline" and scheduled for a build, or rebuild "chronicle":
1. We'll be finishing up our "listening tests" on the "Ultimate Stereo 70" build, during the next few days. I'm looking forward to find out if a NOS matched Quad of Mullard EL34's will "spank" those Electro-Harmonix EL34EH's in the Van Alstine "Ultimate Stereo 70." (Those Electro-Harmonix tubes actually sounded darned good in it.) I've been holding off on the "Mullard Test" until I could spend a reasonable amount of time to A-B the different tube types available for testing. I *hope* to have that wrapped up this weekend! (We'll see how THAT bit of scheduling goes!)
2. We have one "project" only half-way completed. Our "Double Dose of Fine Tuning" stalled out due to a "capacitor shortage." Well, you've probably noticed that the problem is no longer an issue, thanks to the Sheldon Stokes' design for a replacement capacitor board for the FM-3.
We'll be building up our "Second Dose of Fine Tuning" during the next week. This version will feature "vintage" NOS Allen-Bradley carbon-composition resistors. Since I'm using Sheldon Stokes' design for a replacement capacitor board, I'll also be using his design for the PEC replacement boards. Our first tuner turned out to be EXTREMELY sensitive (for an FM-3). We'll see how this second tuner "stacks up."
3. After our next FM-3 tuner, we will have another SCA-35 rebuild. This will be a bit different than our first build. We're going to use Sheldon Stokes' circuit board design to replace the two can capacitors. This design REALLY "beefs up" the Power Supply with MUCH larger capacitors. It also allows the use of two matched pairs of 6BQ5/EL84's, rather than a fully matched quad. (It also means that if a tube "runs away", you'll only have to replace two tubes instead of four!) We'll also be increasing the values of the coupling capacitors in the Power Amplifier section. This will be ONE SCA-35 that WON'T be accused of being "light" in the bass region!
4. We'll also have another Stereo 70 build! Nothing TOO "radical", just good ol' fashioned "meat and potatoes" construction for a second lifetime of use. If you've seen my previous "standard rebuilds", you'll have a pretty good idea what's coming up with this one. (I'm thinking about one little "twist" but we'll see about that as the rebuild progresses.)
5. Need a preamplifier? We'll be doing another PAS preamplifier. As a matter of fact, we'll actually be doing TWO PAS preamplifiers. One will be relatively stock, but the other one will be anything BUT stock! Both of them ought to be interesting projects!
6. Aww, C'mon! You think I'm really planning THAT far ahead? These five (actually SIX) projects ought to take us up to the beginning of Summer!
Be prepared to get back into "Tunerland" during the next week. Another FM-3 is mere days from being "reborn." MUCH more to come!
Sincerely,
Bill Thomas
