Technics SB-6000A Restoration?

[larry777]

Been travelling, finally got a chance to see this picture, yuck at the original caps, those lavender ones are the only ones I've ever had explode with age in amplifier environments, even a Nichicon UES would do a better job. I know everyone likes their fancy crossover caps, bud judging by the bard layout here, and wanting to avoid extremely significant mods those Nichicon Bipolars may do pretty well, especially given the original caps are 100% off of the shelf, nt meant for crossover capacitors.

dzkfraser made another good suggestion for caps in post # 17, the Mundorf E-Caps made in Germany. Prices are pretty good, and another option to consider. If I don't go with poly caps I think I may go with the Mundorf. They have two different prices for each uf value though, so I am trying to determine the main reason for this. It looks like the more expensive ones are 50v (50vac) and the others seem to be 35V (35vac) except for the 68uf which may be 35 volts and not suitable. I think vac is the voltage for alternating current. I am still looking for a Mundorf 68uf at 50 volts so if I go with the Mundorf, all the caps will match. Maybe someone else may suggest another option for our consideration as well. I will also check out the Nichicon caps.

 

[pliskin]

Hey guys, so I recently picked up a set of technics SB-6000A off of a guy for $100. He also had a Marantz 2285B listed for $50 but by the time I contacted him, that was long gone.

They're not in too terrible shape:
View attachment 1690302 View attachment 1690303
Im planning on cleaning up the cabinets and drivers and getting that dust cap taken care of. The grills are excellent but not pictured.

I also noticed this:View attachment 1690301
Can I just glue that on with rubber cement? or pull it entirely? It looks to be a cosmetic piece that was previously either glued to the metal outer ring or glued to the top of the outer area of foam.

And lastly, does anyone have the schematic for the crossovers? I am planning on giving them a recap but could only find the schematic for the SB-6000 model, which I am guessing is different since those look to be sealed or rear ported rather than front ported.

For a second there I thought I was looking at my own basement. Audio and bikes everywhere. I even have a pair of the same Technics.

 

[larry777]

Been travelling, finally got a chance to see this picture, yuck at the original caps, those lavender ones are the only ones I've ever had explode with age in amplifier environments, even a Nichicon UES would do a better job. I know everyone likes their fancy crossover caps, bud judging by the bard layout here, and wanting to avoid extremely significant mods those Nichicon Bipolars may do pretty well, especially given the original caps are 100% off of the shelf, nt meant for crossover capacitors.

goldswimmerb, were you able to get a look at your SB-6000A crossover yet to confirm that the cap values are in fact 15uf, 22uf, 33uf and 68uf ?

 

[goldswimmerb]

goldswimmerb, were you able to get a look at your SB-6000A crossover yet to confirm that the cap values are in fact 15uf, 22uf, 33uf and 68uf ?

No, Haven't had a chance, will probably get to it after the holiday (s)

 

[goldswimmerb]

goldswimmerb, were you able to get a look at your SB-6000A crossover yet to confirm that the cap values are in fact 15uf, 22uf, 33uf and 68uf ?

I finally went to take a look and I cant figure out how to get these speakers apart, anyone have experience? I removed the 4 screws on the bakcboard but no dice.

 

[A400]

Often access will be through the woofer hole. Or are you trying to remove the terminal plate? Four screws doesn’t sound like enough for a back panel if that’s what you mean.

 

[larry777]

I finally went to take a look and I cant figure out how to get these speakers apart, anyone have experience? I removed the 4 screws on the bakcboard but no dice.

Pictures that I noticed on line showed the woofer removed and the crossover board was attached to the left side of the speaker. It looked like it would be easy to get at that way.

 

[kydog]

Here’s my set. Pickup some JB Weld with the brush on application and that will do the trick on the trim.

 

[dzkfraser]

Here’s my set. Pickup some JB Weld with the brush on application and that will do the trick on the trim.

Um, I think you have too much gear, you need to dispose of some of it, Fortunately, I have some extra space for it, you can drop it off this weekend. Thanks

 

[kydog]

Um, I think you have too much gear, you need to get dispose of some of it, Fortunately, I have some extra space for it, you can drop it off this weekend. Thanks

That’s only one side of the apartment!! Lol. Yeah I do have a lot of gear.

 

[goldswimmerb]

Here’s my set. Pickup some JB Weld with the brush on application and that will do the trick on the trim.

I reglued the gasket around the surround, there's a small gap between the outer ring and that gasket because I didn't have a good way to apply pressure when gluing, but they sound nice which is all I'm worried about.

I did finally pull the woofer out to look at the crossovers, looks to be:
22UF 50v BP
10UF 50V BP
68UF 50V BP x3
33UF 50V BP

Due to sizing I'm probably just going to use Nichicon UDB lytics since I don't see a clean or affordable way to fit in any film Capacitors. I'd rather use something that fits nicely than shoehorn in a bunch of Dayton Audio caps.

 

[RickeyM]

Just 'throwing something against the wall to see if it sticks". About the crossover, mount it in an external box? Make as much space as you need

 

[goldswimmerb]

Just 'throwing something against the wall to see if it sticks". About the crossover, mount it in an external box? Make as much space as you need

I'd rather not do too much modifying, there's definitely room to mount a 2nd board with the Capacitors attached, but a 68UF film would be cost prohibitive

 

[RickeyM]

I'd rather not do too much modifying, there's definitely room to mount a 2nd board with the Capacitors attached, but a 68UF film would be cost prohibitive

That's when you pair up a film cap with an electrolytic

 

[larry777]

I'd rather not do too much modifying, there's definitely room to mount a 2nd board with the Capacitors attached, but a 68UF film would be cost prohibitive

Did you ever finish recapping your speakers goldswimmerb ?

 

[goldswimmerb]

Did you ever finish recapping your speakers goldswimmerb ?

Yes sorry! Just went with Nichicon UDB since I didn't want to mod them, and the capacitance was pretty high.

 

[larry777]

Yes sorry! Just went with Nichicon UDB since I didn't want to mod them, and the capacitance was pretty high.
View attachment 1766808

It looks like you did a good clean job putting the new caps on the board. Were you able to do a before and after recap comparison of the sound and if yes did you hear any changes that stood out ? Were you also able to measure the old caps, to see how far they may have drifted from the original values ? It would be interesting to know the values.

 

[goldswimmerb]

It looks like you did a good clean job putting the new caps on the board. Were you able to do a before and after recap comparison of the sound and if yes did you hear any changes that stood out ? Were you also able to measure the old caps, to see how far they may have drifted from the original values ? It would be interesting to know the values.

Didn't bother testing, I stopped testing caps I pulled after my 3rd or 4th restoration, takes too much extra time to tell me what I already know.

As for sound, the high end definitely cleaned up a bit, they weren't bad sounding before but the new caps definitely helped.

 

[hooman]

Didn't bother testing, I stopped testing caps I pulled after my 3rd or 4th restoration, takes too much extra time to tell me what I already know.

As for sound, the high end definitely cleaned up a bit, they weren't bad sounding before but the new caps definitely helped.

I know this way late but what did you use for the 68 uf … I can’t find UDB 68uf .

 

[goldswimmerb]

I know this way late but what did you use for the 68 uf … I can’t find UDB 68uf .

I had used Nichicon UDB for that one, but I don't know if it got caught in their mass wave of discontinuations over the last year or so