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View Full Version : I just like recapping and restoring gear - my dbx 3bx S1


w1jim
04-01-2011, 09:16 PM
Like I said, I just like recapping and restoring my stereo gear.
I picked up this dbx 3bx Series I dynamic range expander and decided to restore it.
I replaced all of the electrolytic caps with new Nichicons, replaced the one 3.3uf tantalum with a electrolytic and the 13-1uf electrolytics with Wima poly film caps (the red ones in the picture).

Next I replaced the ancient RCA connector with new goldplated pieces.

Finally I did an LED upgrade - replacing the ancient LEDs with modern / brighter parts. Also I replaced the red power LED with a green one.

Finally a scope shot. The bottom waveform is the input signal and the top is the expanded waveform.

JimB




http://www.tapeheads.net/attachment.php?attachmentid=19875&stc=1&d=1301717630




http://www.tapeheads.net/attachment.php?attachmentid=19876&stc=1&d=1301717630




http://www.tapeheads.net/attachment.php?attachmentid=19877&stc=1&d=1301717630

Pentium100
04-01-2011, 10:42 PM
Well, it's either this or paying money (either paying somebody to do it or buying a new device), so I replace caps too, where needed. Especially in some USSR made devices - better replace the caps at once and not have to replace them one by one when they start failing.

However, I did pay to recap a couple of computer motherboards, but now I decided to learn how to do it myself so I won't need to pay. I found an old board that I am not using with bad capacitors and will try to replace them and see if the board works.

R-2-R
04-02-2011, 07:08 AM
Look's Sweet! Real sweet! Excellent restoration job, inside and out! I wish I had the time and space to do stuff like that. What else have you restored? Anything else that was 'not working' or just equipment that was working but was old and you felt, just that it was time to restore and recap?
Dude, keep up the good work!*bigthumbup*

Elite-ist
04-02-2011, 08:52 AM
Hi Jim,

Also a 3BX dbx owner. I hadn't looked at the innards until you exposed one. Do you use yours, regularly? Ideally, I find the 1.3 setting musically pleasing on the expansion slider. Which is your favourite dbx processor: dbx 20/20? I use old and new BBE Sonic Maximizers in my upstairs system.

Nando.

w1jim
04-02-2011, 09:53 AM
I have 4-dbx 3bx Series 2, one 1bx Series 3 and the 3bx Series 1 shown here. I like the bass restoration on the Series 3 but the lack of breathing on the 3bx's.
I agree - 1.3 seems right around the proper expansion level.

I also have a few of the BBE Maximizers - I find the effect of those satisfying with lower quality speakers but as you go up the audio foodchain they become less useful.

Same goes for equalizers - I have a dbx 10/14 which is similar to the 20/20 but I'm not using it and in fact will be trading it to a friend of mine shortly.

w1jim
04-02-2011, 10:06 AM
... What else have you restored? Anything else that was 'not working' or just equipment that was working but was old and you felt, just that it was time to restore and recap?

Oh, I've done a few - here's a picture I posted in my "Intro" thread. These are just some of the nicer units in the basement rack - there are more / nicer ones sprinkled liberally about the house,

These have been in various states when I received them. Some were not working and need a fair amount of work, others needed some basic cleaning - they ran the gambit.
Generally these have had all the electrolytics replaced, tantalums replaced with electrolytics and all electrolytics 1uf or less replaced with poly film caps.
Also most have had some or all of the incandescent bulbs replaced with LEDs.

Might be time for an intervention...



http://www.tapeheads.net/attachment.php?attachmentid=19874&stc=1&d=1301711430

Elite-ist
04-02-2011, 10:31 AM
I have 4-dbx 3bx Series 2, one 1bx Series 3 and the 3bx Series 1 shown here. I like the bass restoration on the Series 3 but the lack of breathing on the 3bx's.
I agree - 1.3 seems right around the proper expansion level.

I also have a few of the BBE Maximizers - I find the effect of those satisfying with lower quality speakers but as you go up the audio foodchain they become less useful.

Same goes for equalizers - I have a dbx 10/14 which is similar to the 20/20 but I'm not using it and in fact will be trading it to a friend of mine shortly.

Jim: Very nice assortment of dbx processors! Do you use any dbx components for NR on playback or recording? Although I haven't patched it in, I do have an NOS dbx 100 Subharmonic Sythesizer. With both the BBE units, I set the controls at the straight up control level settings to enhance the dynamics from some of my older pre-recorded cassettes. No need to overdo it, as my main system features a pair of Pioneer HPM-150s.

Nando.

w1jim
04-02-2011, 10:41 AM
I have a dbx 224 which I have used for tapes but mostly I use it for my dbx LPs - quite impressive!

Elite-ist
04-02-2011, 10:57 AM
I have a dbx 224 which I have used for tapes but mostly I use it for my dbx LPs - quite impressive!

Wow, I don't have any dbx encoded LPs, and I began collecting quadraphonic LPs and pre-recorded quad open reel tapes. Are there any classic rock titles you could tell me worth picking up, which are dbx encoded? Of all the analog formats, vinyl and open reel are my favourites. I picked up two more LPs, yesterday: EMI reissue of The Band's "Music From Big Pink," and Roxy Music's "Viva!" My youngest son, also, grabbed a Talking Heads "Little Creatures" LP.

Nando.