Pioneer SA-8800/Electrostatic speakers?

[combwork]

I've got a cosmetically A1 but dead in the water Pioneer SA-8800. This is a pre/power combination that I think puts out some 80 watts per channel into 8 ohms and a fair bit more into 4 ohms. Does anyone know how comfortable it would be (once repaired) driving a pair of B & W DM70's? These are a hybrid electrostatic with the bass carried by a 12" woofer and everything else by a curved array of electrostatic panels. I've not got them yet but the deal is done; I've paid the deposit and once I get paid I'll pay the balance. For now, I could maybe use my NAD 3020B. It's a great `little' amp perfectly happy with the Quad ESL57, but the seller says it's maybe a bit underpowered for the B & Ws. In an ideal world a pair of monoblock valve power amps would be ideal, but I'd have to sell another kidney to go that route

[Filterlab]

Hehehehe "little amp".

I love the styling of the SA-8800, a real powerhouse look. In my opinion I'd say it was easily powerful enough to drive the DM70s, 80wrms per channel is more than enough to drive most speakers happily enough, unless you like stadium volume levels of course. I would imagine the impedance of the DM70s is going to drop quite low in the very upper frequency range but the Pioneer amps generally have plenty of current anyway so it shouldn't be a problem.

I'm just trying to find some specs for the DM70s.

[Filterlab]

Just found this PDF on the DM70s, the specs are limited (i.e. no impedance curve) but it does state that the nominal impedance is 8ohms. Given that the SA-8800 is comfortable at 4ohms it should be fine driving them.

DM70 PDF

...and some specifications for the SA-8800:

Power: 2 x 80 W into 8 Ohms
Freq res: 10 Hz-20 kHz
THD: 0.005%
Inputs: Phono 1, Phono 2, Tuner, AUX, Tape 1 Rec/Play, Tape 2 Rec/Play, Pre/Power: Pre OUT / Power Amp
Controls: Loudness, Filter: Subsonic/High, Phones, Cartridge Load, Tape Monitor, Tape Duplicate, Interference Filter
Dimensions: 420x380x150mm
Weight: 16kg
Miscellaneous: 4 x AC Outlets, AC: 110/120/220/240V, 50/60Hz

[combwork]

Just found this PDF on the DM70s, the specs are limited (i.e. no impedance curve) but it does state that the nominal impedance is 8ohms. Given that the SA-8800 is comfortable at 4ohms it should be fine driving them.

DM70 PDF

...and some specifications for the SA-8800:

Power: 2 x 80 W into 8 Ohms
Freq res: 10 Hz-20 kHz
THD: 0.005%
Inputs: Phono 1, Phono 2, Tuner, AUX, Tape 1 Rec/Play, Tape 2 Rec/Play, Pre/Power: Pre OUT / Power Amp
Controls: Loudness, Filter: Subsonic/High, Phones, Cartridge Load, Tape Monitor, Tape Duplicate, Interference Filter
Dimensions: 420x380x150mm
Weight: 16kg
Miscellaneous: 4 x AC Outlets, AC: 110/120/220/240V, 50/60Hz

Thank you. Just a thought; if the impedance curve at high frequencies dropped dangerously low, could I solve this by using amps high filter? Incidentally, the 'little amp' I was referring to was the NAD..... When I still had the SX-1980, I used its pre-amp section to drive the ESL57s via the NAD's power amp. Worked very well and sounded better than using the NAD on its own. More detail clearly heard, like the bell on the bus in Pink Floyd's "Division Bell".

[Filterlab]

Thank you. Just a thought; if the impedance curve at high frequencies dropped dangerously low, could I solve this by using amps high filter?

I wouldn't go so far as to say dangerously low, but it will go low. Using the amp's high filter will of course cut frequencies in that range from being amplified but you may find it rolls off the treble too much and makes the sound too soft - and the DM70s don't go particularly high as it is. Give it a whirl without the filters switched in, the protection circuit will always cut the amp off if the impedance drop causes a problem.

[greenhomeelectronics]

I concur with everything that Rob says, be careful with the NAD though, they can tend towards fragility and when they blow they blow big time. They are DC coupled and have been known to blow every transistor right back to the pre amp. We get lots of them in and have repaired dozens, it takes best part of a day to fix one properly. The Pioneer should do the job nicely, from what I recall it delivers a lot of peak current without self destructing, something that may not be obvious from the tech specs.
Dave.

[nat8808]

Hi,

Would you mind me asking how much the DM70s were (PM me perhaps)? I would like to try some out but as they come up so rarely it's hard to tell what a good price is when they do..

Thanks

P.S. I did have a Pioneer 9500 once - a different style of amp but am sure they are similar - I would think that had enough grunt to handle DM70s judging by the internals (from memory).

[combwork]

Hi,

Would you mind me asking how much the DM70s were (PM me perhaps)? I would like to try some out but as they come up so rarely it's hard to tell what a good price is when they do..

Thanks

P.S. I did have a Pioneer 9500 once - a different style of amp but am sure they are similar - I would think that had enough grunt to handle DM70s judging by the internals (from memory).

No problem. I bought them by a putting a 'wanted' add in Hi-Fi World classifieds. Total outlay including transport (they had to be shipped up to Scotland from Southampton) came to around £400. Walnut cabinets, cosmetically good but what the seller did not know was one of the cells on one electrostatic unit had arced badly and for long enough to burn the inside of the mesh grill. To sort this I'm having to buy a diy kit from a specialist in Australia at a further cost of some £200. When new, the bass unit had a foam surround that rots with age, irrespective of whether the speaker has been used or not. I'm lucky; seller said he had put new surrounds on both bass drivers himself some while ago.

As to how they sound, first impressions before I realised they needed attention was treble not as clean as the Quad ESL 57, but a good clean bass that went a lot deeper than the Quads.

One thing to be aware of is that B & W did not design the treble panels to be dismantled. You can do it, but it involves a lot of un-gluing and drilling out of small rivets. I've not got the rebuild kit yet, but apparently it contains everything needed to fully rebuild panels on both speakers.

They seem to turn up on Ebay infrequently; ones I've seen have gone for anything from £250 to £1100 for a pair. There are two models, the standard or 'English' and the 'Continental'. The Continental has a curved front with central bass driver, the English has a flat front with the speaker at one end. Both are said to sound very good. How much of this is I've spent my money so they must be good is anyones guess

[Primalsea]

If you haven't got one already theres a service manual for the SA8800 on the Hifi Engine website.

It is highly unlikely that you will suffer this with the SA8800 but some older amps are not unconditionally stable on all loads. The main culprits are ESL's and the Speaker level inputs on subs.

This seems to be partly to do with the high load of panels at high frequencies and also the nature of the complex reactive load that some devices have. Sometimes you just get the killer combination, and I mean killer as in it will kill your amp.

This is very rare though and you can check for the problem by monitoring the temperature of the amps heatsinks.

[StanleyB]

Some of the older amps do not have the Zobel network in the speaker output, which can cause stability problem. But it is a simple thing to add, consisting of just a cap and a resistor. The service manual should however give an answer to this.

The 8800 is a collector's item these days and can fetch big money on fleebay.