Recapping a Fisher Spacexpander tube spring reverb unit

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EasyGo
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Recapping a Fisher Spacexpander tube spring reverb unit

Post by EasyGo » Mon Mar 12, 2012 6:13 pm

Image
(image borrowed from a post on gearslutz.com)

I'd like to get my Fisher SpaceXpander into good operating condition. For those who aren't familiar, it was a tube-driven spring reverb unit made by Fisher as an accessory for home stereos and even car audio systems during the early 60s. Supposedly they were also used in some Hammond organs. The Spacexpander was famously used by King Tubby as a studio effect in his dub reggae mixes, which is why I'm interested in bring this unit back to life. I know it's not hi-fi, but the sound fits the style.

I have put new tubes in, and I made a new control potentiometer cable to replace the missing original. The unit does pass signal and you can hear the reverb, but it sounds pretty tired and janky so far. The spring tank on its own sounds great when connected to a send/return.

Since I do have some experience soldering (I built the full-featured DI box from the Jensen Transformers site and I've made some of my own cables), I'm considering trying to recap this unit. Money is tight and I'm very interested in DIY.

I would like your suggestions on the following:

? Should I attempt this myself?

? Should I start with the electrolytic capacitors first?

? What advice would you give about values and brands of replacement capacitors?

Schematic and parts list (links are from interruptor.ch)

Thanks for your advice!

lethocerus
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Post by lethocerus » Tue Mar 13, 2012 12:08 pm

Looks like a fun project.
Read up on how to drain the filter caps, and always double check with a meter to make sure no voltage is present while you tinker.
You could start by replacing those - C5, A-D. Since they are in an old multi section cap can, it would be cheaper and easier to use separate discrete caps between a couple terminal strips. All sorts of guides on the internet for this..
http://www.instructables.com/id/Tube-Am ... apacitors/

I wouldn't worry so much about brands, just try to find the correct uf values with higher voltage ratings than the originals as a precaution against todays higher wall voltage.

While you're in there check and replace any drifted resistors too..

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EasyGo
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Post by EasyGo » Tue Mar 13, 2012 9:40 pm

Thanks for your advice and link the article on replacing filter caps. I will definitely have to read up on dealing with the multi-section cap. The terminal strip approach sounds like a plan.

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Post by telepathy » Wed Mar 14, 2012 1:21 pm

fortuitous post, dude. I was about to embark on this same project. my Spacexpander sounds great but it's noisy as hell and still has the 2-prong power cable. let's keep this thread updated.
get up with it

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EasyGo
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Post by EasyGo » Wed Mar 14, 2012 9:14 pm

Awesome. I'll probably be moving at a snail's pace (job search and young children) but I'll update my progress here.

If you haven't seen it already, be sure and check out the Dub Discussion Board forum on the Fisher SpaceXpander. There are some good threads on the restoration process of this particular unit. I think that the forum is pretty well dead, but a lot of good info nonetheless.

http://www.interruptor.ch/Php5/dubboard ... 7b582f4ce4

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