Acoustat servo amps ??

BTW, Kubla, I'm not certain that you can use the servos correctly with Spectra-series panels, plus I'm not sure that Spectra panels are actually as good as the late 5-wire Acoustat panels.

Additionally, the servos come with different EQ curves depending on whether you are using stacked panels (e.g., 2+2s, 1+1s, or 6s) or non-stacked (1s, 2s, 3s). The bass EQ is increased to drive the taller models, I believe.

A passive preamp will drive stock servos OK, but then, the stock servos have adjustable input pots. Some modified servos have an input driver stage (and volume pot) removed and need a lot of input voltage -- these would not work well with passives but would sound better because the suboptimal active gain stage is deleted.

hey plato thanks again for all the great info.

i'm not sure the vintage of my model IIIs. they were bought new by my father in '81 or '82 i believe but they may have been store demos and older than that however. receipts are long gone unfortunately (i hooked up with a guy at rockford corp who could have replaced the panels for free if i had it. crap.) how can i check to find out which version i have? -these aren't the medallion btw and have the 'internally wired by monster cable' sticker on the back if that provides a clue to their year.

that same guy at rockford can do the medallion upgrades ($700 including shipping) and upgrade the caps and wire if i supply him with the parts (i figure about $3-400 including cardas posts, etc. that option is what im debating against the servos. he recommended infinicaps and solens (47uf) but i've been told by an acoustat freak NOT to go with the infinicaps for this application because they sound thin. someone once told me they personally only use black gate in their acoustats but i cant seem to find any w/ sufficient voltage.

thanks again.

My luck has been with the model X. I like the sound and value so much, I bought a second pair. Besides upgrading the tube recipticals, I have left both pair in original condition. Some time back, returning home, one amp was making a terible noise. The Antique Radio Store fixed me up. But now, I feel better killing the power when they are not being used. Also I found out that they must be grounded. I was using one of those three to two plug adapters. Doing this lets the groung charge build up. My cloth was worn on one pair of the X's. No luck finding the same cloth until I bought a pair of Klipschorns. Noticed the cloth is a match and still avalible from Klipsch.

waveriding, thanks for the klipschorn idea. i'll probably do that. there is a company still making acoustat socks for virtually any model but they dont have a great selection of colors. For your records just in case you ever get a cat keep this handy: "The Upholstery Co" in mesa arizona 480-898-9521

I think Plato may be a little confused, or I do not understand what he is saying. Spectra's include 33's and 3300's, Mdl. 3's are not spectras. I have Mdl. 3's and 3300's. I am using a slightly modified Moscode 600 amp to drive them. I intend to upgrade it to a 500 watt a side amp, and believe that will finally satisfy the Acoustats. If you have a contact at Rockford who can get transformers, I am considering bi-amping, but would need 4 more Spectra transformers to do so....

Thanks,

Lou