Acoustat Answer Man is here

[DeltaStar]

The cap bank was to big to put inside without moving the PCB. I don't ever plan to sell them, and yes I put in a groumat in the hole . soldering was done properly, I air cool leads to protect the caps. Caps are bi polar, but put them all in same way. I do somehow remember way back, that when you switch out an electrolytic with film oil that you take a percentage of it's uf value. I think I might be filtering off my HF. I've built enough amps and so fourth and change in break in is never that dramatic. Their attached to that variable resister, so I gather they are filtering something, I'll be generous and give them a 100 hrs, their on 24hrs a day. Thanks Moray for your help. I WILL sort this out Al

[moray james]

Give them three weeks and have a great Christmas. Best regards Moray James.

[tinnitusintx]

I recently acquired some Spectra 22's in excellent physical and operational condition (as far as I can tell). I've had Magnepan MMG's and currently have MG-IIIa's though I didn't get any more than about a week of listening time with the -IIIa's before they lost a ribbon and I was able to determine they have a little bit of delam going on (I've sidelined them until I can get new ribbons and repair the delam).

My impressions of the 22's after a few weeks of ownership are quite favorable. They do all the things I love about line source dipoles (realistic scale, three dimensional soundstage, well defined imaging) and I'm enjoying the sonic personality of my first ESL's. Clarity and detail is very good and mid range melodic content a little on the laid back side, but certainly not held back or withdrawn.....nice and musical, actually. Mid range percussion content could stand to be a tad more physical (compared to my Infinity QLS-1's) to achieve more realism, but being a drummer I'm perhaps a bit more critical of this than most. By and large they do most everything very well with exception to LF dynamics....which I'm not expecting as I understand that's not a performance characteristic the design should be able to deliver.

I use a pair of H-frame OB subs (w/ 15" Eminence Alpha LF drivers) with low pass on the xover set to about 90 hz and they integrate very nicely with the 22's. Amplification comes from an Aragon 8008 and I've been using my Grant Fidelity tube DAC-09 as the pre but recently acquired an Acurus RL11 preamp and am just now doing my initial listening with it....so no opinion of that piece in the chain as of yet (though I am enjoying the gain boost from the pre as the tube DAC wouldn't get peak SPL over 85db).

I'm wanting to know more about my 22's as info out there is a little scarce. How is the division of bandwidth allocated to the panels? I think I understand there is a full range panel, a panel that does mid and low, and a low (woofer) panel but would like clarification on this.

Also, I'd be interested in hearing about any proven mods to the interfaces or the panels...i.e. cap upgrades or rigid frames.

And finally, how did the Spectra 22/2200 rank wrt performance compared to all other models of Acoustats and some of the more popular and successful ESL designs (Quads, etc)? Any notable strengths or weaknesses?

Thanks,
Michael

[MrAcoustat]

Home made Acoustat Spectra 8800s yep 800 pounds of pure pleasure AWESOME.

[DeltaStar]

Michael QLS me to

[MrAcoustat]

Originally Posted by MrAcoustat

Home made Acoustat Spectra 8800s yep 800 pounds of pure pleasure AWESOME.

Received the final version tonight here it is sorry no way for me to remove the first picture. MrAcoustat

[hella356]

Originally Posted by MrAcoustat

Received the final version tonight here it is sorry no way for me to remove the first picture. MrAcoustat

Oh, it's an addition to the existing speaker. Interesting. Any info on how it is attached?

[MrAcoustat]

Originally Posted by hella356

Oh, it's an addition to the existing speaker. Interesting. Any info on how it is attached?

Yes you're correct, a pair of Spectra 6600s and a pair of 1+1s all steel frame covered with mahogany wood bolted together with a special steel bracket and all steel parts powder painted in a pro shop i will be at his place friday and should come back with more photos.

[danielm]

I have a pr of 1+1s that I bought back in the 80s when they were released. For the last several years they have been at my cabin and have been used by several 'friends' that have spent weekends there.
Last time I checked them they sounded very lifeless, inefficient and had very little output. My first thought was the HV bias supply had failed. I've checked with a crude diy HV probe and it looks to be fine. At this point I am wondering if one of the audio xformers has been damaged.
Can I use a scope and check the transformers at low levels? If so, What should the step up ratio be?

Great thread! I would love to get them working how I remember them!

[AcoustatAnswerMan]

Originally Posted by danielm

I have a pr of 1+1s that I bought back in the 80s when they were released. For the last several years they have been at my cabin and have been used by several 'friends' that have spent weekends there.
Last time I checked them they sounded very lifeless, inefficient and had very little output. My first thought was the HV bias supply had failed. I've checked with a crude diy HV probe and it looks to be fine. At this point I am wondering if one of the audio xformers has been damaged.
Can I use a scope and check the transformers at low levels? If so, What should the step up ratio be?

Great thread! I would love to get them working how I remember them!

Based on your description of the problem, my first thought would have been a problem with the bias supply. But it sounds like you've already ruled out that possibility. However, do make sure that the speakers have been energized and playing for at least several hours before making any judgements - they do take a while to reach 'full bloom', especially if they haven't been energized in a while.

Bad transformers rarely cause this sort of problem. When they do go bad, it's usually a problem of high-voltage arcing at high volumes, or if bad enough, fuse blowing at all levels. This is good news for you, since replacement transformers are difficult (but not impossible) to find...but they are expensive! I'm not saying for sure that the problem is not in the transformers - just that it's unlikely based on the symptoms.

My suggestion would be to check all the capacitors first, especially the large .01-uF caps on the PC board. Be sure they are fully discharged before checking! If they are okay, check the resistors. Also make sure that the bass transformer tap is making a good connection - it should be on the RED tap for the Model 1+1. Also check the contact on the sliding resistor that is part of the HF balance control - these can oxidize over time and cause problems.

Let me know how this goes - we'll get your speakers working again!