Sony TA-E88B Preamp

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Hi,

I was given one of these by a client this week. It had a minor mechanical fault which was easily repaired. http://www.thevintageknob.org/SONY/sonyesprit/TAE88/TAE88.html I was given a schematic and, in my humble opinion, it appears that Sony must've thrown a serious R+D budget at this thing. I dread to think what a modern equivalent would cost to sell. I haven't had a chance to really study the topology yet.

It appears to work fine on the bench and passes an assortment of wave shapes into the 'scope quite nicely, with pretty good L/R matching. I haven't listened to it yet, and was planning a re-cap to give it an honest trial. The client said he didn't like its sound, and hence gave it to me.

My question is: after 30-odd years, what preventative maintenance should be performed? I regularly restore gear of this age, but the TAE-88B strikes me as esoteric, so I intend to do some homework. The electrolytic caps could easily be replaced. I've had a 'scope on the DC rails, and whilst I didn't observe any obvious anomalies such as AC harmonics, there was a hundred-or-so uV of hash - certainly not as clean as I'd expect to see from a modern monolithic Vreg + generous capacitance.

Is it straightforward to open and clean / regrease (Cailube fader grease) the ALPS attenuators? They may not need it, but did seem to be slightly noisy on the 'scope.

Obviously, I will use my own ears, but do you think the TA-E88B is worth keeping? What's one worth? Is it collectable or is it a just a nice looking boat anchor?

Thanks in advance.

Justin
 
If you click on the buttons on the right in the VintageKnob link, you'll see a diagram of the RIAA circuit.

My biggest concern is whether there's anything to look out for if I decide to clean the attenuators, i.e. any parts that are tricky to disassemble / reassemble. The plan would be to open them, bathe with pure Isoprophyl, and then re-grease with Cailube Fader Grease. I have a couple of desoldering guns (Hakko and De-non), so if the lugs need de-soldering I can go in and out quickly. Replacing the electrolytics appears to be a pretty basic procedure.

Once it's re-capped and 100% I'll give it a listen. I'm not sure it's fair to base listening impressions on something with 30-yr old electrolytics, so I'm avoiding temptation to listen to it at the moment. The raw DC waveform pre-Vreg appears pretty bumpy - I'd expect something cleaner, so I do suspect new electrolytics may yield benefits.

Aside from electrolytics and fader / attenuators, is there anything else that needs attention? If, as the link says, Sony sold thousands of these things, there must be plenty of info out there?

Thanks,
Justin
 
I'm being very conservative here, but - before I start the service - can anyone see any concerns with the plan outlined above?

I guess the attenuators will feel slightly different if I don't use the same grade of grease as Sony used, but how would I get that info? Cailube fader grease is industry standard in studio circles and I've yet to hear of it damaging a contact.

If you have any tips, I'd like to thank you in advance.

Justin
 
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