New Chassis for my SCA35

[K-MAN]

I've recently upgraded some of my audio parts like my vintage speakers, added some nice gold plated five way binding posts :) And am redoing the speaker cables with something better plus getting better RCA cables. Sad part is that all the input and output jacks on my amp are pretty sad looking no matter how much I clean them. So I'm wondering if it would be hard to replace the rca inputs I use with nice gold ones and replace the speaker output with binding posts? With the amount of work it will take to bring this thing up to the level I want I'm beginning to think it might be best to scrap the chassis and get a new one and put my transformers and driver boards into that one. The one I'm liking most is this one, http://www.triodeelectronics.com/st35chas.html
I also need new driver boards so it would allow me to use the original type ST35 drivers. Only thing I'm wondering about is would it be possible to add a volume control to use until I get a preamp?

[EWBrown]

It would be easy to add a volume control, a 100K "stereo" pot, or two separate 100K pots (audio taper), all it takes is an extra 3/8 inch diameter hole (or two) and wire the inputs across the outer two terminals, and then the "wiper" center terminal and the "ground" side of teh pot to the driver boards' inputs.

A decent modest priced 100K pot is the "alps" unit sold at Rat Shack for around 3 or 4 bucks, just ignore the fourth terminal, which is for loudness compensation, which we don't need (or want) here.

If you want to go for broke, (in more ways than one) then stepped attenuators are advancing to the next level of excellence.

There are some very nice (and not overly costly) ladder-type SAs from Taiwan or Hong Kong, available on E-bay, these use Dale-Vishay 1% resistors and a very nice quality 23 position multipole rotary switch.

If these were built in the USA, at typical labor costs, the price would be prohibitive. The workmanship is excellent, and the price is a relative "steal" as compared to Goldpoints or other "boutique" attenuators.

/ed B in NH

[K-MAN]

What would be better for a beginner, the standard drivers and the chassis I linked or the diytube one that is advertised here? I like the newer one better but it looks a bit complicated to me or maybe it's just cause it's so different looking.

[paart]

For a beginner, I'd recommend the DIY35, which, while the circuit is essentially the same as the ST35, offers a number of improvements as far as the physical layout is concerned, and the ability to balance the output tubes. The DIY35 has an easy to follow manual, and there's plenty of help available, here, should you run into problems. Trying to modify an SCA-35 into a ST-35, while not difficult, is not as much of a "straight forward" procedure, as building a proven design. Either way, you will be stuffing board(s), which requires basic soldering skills The correct order of assembly, parts list, and start-up proceedure is spelled out in the DIY manual. Keep in mind that the most valuable part of your SCA35 is it's output transformers. Nearly all the other parts are of minimal value, as they can be replaced with newer, and often, better quality items.

I offer this, never having built a DIY35, although I have a friend who has. I used the convenional ST-35 layout on the Soundtastic chassis for two reasons. 1/ I hand built glass boards long before anything else was available, so rather than abandon this work, I used the earlier chassis.
2/ The original design lends itself a little better, to some of the extensive mods I have performed on the circuit. I hope to offer the results of these changes on this forum...........after the smoke clears!
Yellow_Light_Colorz_PDT_06

[K-MAN]

Yeah I'm thinking of going all out and buying the diy35 I'm just trying to figure out where the best place to order is as I've seen it listed on a few different places. I'd also like to order the nice chassis made for it but Triode Electronics has been sold out for awhile.

[SDS-PAGE]

What would be better for a beginner, the standard drivers and the chassis I linked or the diytube one that is advertised here? I like the newer one better but it looks a bit complicated to me or maybe it's just cause it's so different looking.

Putting together Shannon's board isn't complicated. All you need to do is import BOM into Mouser project manager and you have all the parts you need ready to go. You just gotta stuffed them and solder. Wiring is pretty simple too if you know how to read schematics. If you are going to get a commercially available chassis, you don't even need to drill/punch holes. Doesn't get any easier than this.

I built one, but didn't feel like I was learning much as I felt like I was putting togther a kit. If you really want get your feet wet, you might want to pick a simple SET schematic and build one from the scratch. Now, that's more fun.

[DuncanM]

Soundtastic has these listed on their webpage at:

http://www.soundtastick.com/product/DIYTUBEST35CHASSIS

You might want to check it out and give them a call. I bought a ST35 chassis from them that was very nice.

Duncan