Sony TA-E88B Preamp

[thermionic]

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/s...E88/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

[homemodder]

Could you post a schematic, would love to see the topology used.

[Cobra2]

I want it...if you decide to part with it...
Guess it is more a collectors item, than a audiophile unit in todays world.

Arne K

[thermionic]

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

[thermionic]

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