I think this is a bad idea: both from a standpoint of having high voltage cables strung across your room, and the extra capacitance this will introduce.
But...you sound as though you're stuck on the idea anyway, so I'll offer some advice. I seriously doubt you'll find flat cable that's up to the task. So I think you'll need to run three separate conductors, and create some mechanism yourself to keep them separated by about 1" between conductors. Perhaps you could glue or tape the wires to a thin plastic piece every foot or two? The distance between spacers will depend on the stiffness of the wire, and how well it would stay separated between spacers.
The wire should be rated for a minimum of 10 kV. The gauge is not important, as there is very little current flowing. eBay is crawling with all sorts of high voltage wire.
But really...don't try this at home.
I have a pair of 2+2 and a pair of 1+1 speakers (Medalion B interfaces) sitting in my mother's basement for 5 or so years now. Located outside of Boston.
I used to use the 2+2's, loving the distortion free clarity, but wishing they had more dynamic punch, and switched to dynamic speakers. I imagined someday I'd build sturdy stands to fix the dynamics problem, re-sock them, and modify the interfaces with better caps and perhaps resistors.
Its time to either sell or mod them. What are people doing now?
Suggestions?
I used to use the 2+2's, loving the distortion free clarity, but wishing they had more dynamic punch, and switched to dynamic speakers. I imagined someday I'd build sturdy stands to fix the dynamics problem, re-sock them, and modify the interfaces with better caps and perhaps resistors.
Its time to either sell or mod them. What are people doing now?
Suggestions?
With the right mods and the right amp, they are as dynamic as anyone would want, but stands wont fix dynamics, its about ensuring panels are getting enough voltage, and audio enough power.
Thanks for your reply. I've noticed many people have made sturdier stands, so thought it was important.
I'm still working my way through all the threads and posts, but learned more bias voltage is good, replacing old diodes/caps is good, upgrading the crossover between transformers is good, and bypassing the fuses sounds better.
I'm sure the panels are filthy and fear what may lie under the dirty socks. I loved the picture of one being washed in the bathtub and how dirty the water was.
If I keep the 2+2s, is there a market for the 1+1s, or just the interfaces? Prices? Or do I make a pair of 6's?!!!
I have a modified Crown Macro reference amp* I used with the 2+2s and still have. It has high damping factor and low impedance at all frequencies. It drove them well. I could play the speakers very loud with no trace of distortion that listeners couldn't really tell how loud they were, nor was the sound objectionable or "too loud". Our ears use distortion to perceive loudness and it was just absent. Trying to talk and be heard was the way to tell how loud it was. Maybe the answer is a good subwoofer or two for the dynamic punch.
* Mods to the Crown: Biggest (and easiest) improvement was putting 7uf MIT MPP caps across the output transistor banks (power rails) on both channels (smoother and more detailed). Adding 1uf RTX bypasses made the top end even better, but I removed because frequency range sounded disjointed. There are two electrolytics in the signal path, one I bridged, the other replaced with a Black Gate. Some other ps bypasses. Someday will replace +/- 15v 3-pin regulators for the front end with discrete ones and change ps rectifiers to low noise fast recovery types.
I'm still working my way through all the threads and posts, but learned more bias voltage is good, replacing old diodes/caps is good, upgrading the crossover between transformers is good, and bypassing the fuses sounds better.
I'm sure the panels are filthy and fear what may lie under the dirty socks. I loved the picture of one being washed in the bathtub and how dirty the water was.
If I keep the 2+2s, is there a market for the 1+1s, or just the interfaces? Prices? Or do I make a pair of 6's?!!!
I have a modified Crown Macro reference amp* I used with the 2+2s and still have. It has high damping factor and low impedance at all frequencies. It drove them well. I could play the speakers very loud with no trace of distortion that listeners couldn't really tell how loud they were, nor was the sound objectionable or "too loud". Our ears use distortion to perceive loudness and it was just absent. Trying to talk and be heard was the way to tell how loud it was. Maybe the answer is a good subwoofer or two for the dynamic punch.
* Mods to the Crown: Biggest (and easiest) improvement was putting 7uf MIT MPP caps across the output transistor banks (power rails) on both channels (smoother and more detailed). Adding 1uf RTX bypasses made the top end even better, but I removed because frequency range sounded disjointed. There are two electrolytics in the signal path, one I bridged, the other replaced with a Black Gate. Some other ps bypasses. Someday will replace +/- 15v 3-pin regulators for the front end with discrete ones and change ps rectifiers to low noise fast recovery types.
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1) Don't attempt to wash the panels. There's a very good chance you will harm them permanently. The only acceptable cleaning method is to blow them out (both sides) with a gentle application of compressed air.
2) While you're in there, make sure the felt blocks on the rear are firmly attached. If not, re-apply a spray contact adhesive to the felt and press back onto the louvers.
3) The audio and bias system fuses are there for important safety reasons. You can remove (bypass) them if you like, but I think it's unwise.
4) Replacing diodes and capacitors in the bias system is not a bad idea, but only if you have noticed a drop in efficiency, or have a way of verifying that the bias voltage is low. Otherwise why fix something that's not broken?
5) Certain people advocate raising the bias voltage. I don't, as the factory-set voltage is the optimum compromise between efficiency and potential bias leakage under conditions of high humidity.
6) If your speakers have never had the 'C-modification" done, I highly recommend it. It greatly improves the audio circuitry feeding the HF transformer, leading to lower transformer saturation and lower distortion.
7) Certain people advocate lowering the value of the 500Mohm bias supply out-feed resistor, claiming increases in efficiency. Poppycock. Although the value of this resistor is not critical, significantly lowering it violates the constant-charge principal upon which the speaker is designed, and hence increase distortion. Taking the resistor to a very low value could even lead to arcing, with potential and irreversible diaphragm damage.
8) There's a lot of "voodoo-science" out there regarding Acoustat speakers. Be careful.
Spectral 6600
Hi Andy,
I am new to not only this forum but to Acoustat. I purchased a I believe is a 6600. Before I even receive shipment there is one issue I need to address. There is only one interface MK 2146. What might you recommend? Try to find someone who has one or find some who would be able to build one?
Hi Andy,
I am new to not only this forum but to Acoustat. I purchased a I believe is a 6600. Before I even receive shipment there is one issue I need to address. There is only one interface MK 2146. What might you recommend? Try to find someone who has one or find some who would be able to build one?
Oh - so you bought that pair on eBay from Victorville CA? I was watching that auction with great lust, and even considered buying them myself. Congratulations on your purchase of Acoustat's best-ever speaker. You are in for a real treat!
Yes, you'll need another MK-2146, which won't be easy. I have seen an auction on eBay for a pair of the Spectra 44/66 transformers, and I don't think they've sold yet. So keep an eye out for them and snatch 'em up when they reappear. That'll solve the hardest part. You may be able to find another Spectra interface, doesn't matter which model, which can easily be modified by changing a few values of resistors and capacitors to suit the requirements of the Spectra 6600. But you need the audio transformers that are specifically designed for the 44/4400/66/6600.
Good luck, I'm here to help if you need further guidance with the project.
I do consider my self luck, I offered $700 and to my surprise he accepted my offer. Shipping was a bitch though. I search for an image of whats inside the interface but was unable to find one. So I hope 2 TTA-246B transformers mounted on wood rails is all I need? I may have a lead for a Spectra 22/33 interface box. If I do get it what parts would be required to replace?
Attached are the schematics for the Spectra 2200/3300 and 4400/6600.
Based on comparison, besides the transformers only a handful of parts would need to be changed.
The mixer capacitors, the first Spectra sectoring resistors, and one of the input capacitors.
Attachments
Only $700? Wow...what a sweet deal. The twelve Spectra panels alone (sold as individual parts) are worth considerably more than that. You are indeed a lucky fellow! But, you do have some work ahead of you in creating that missing interface.
Yes, the two TTA-246 transformers, mounted on wooden rails, is the item I was referring to in my previous post. Those are rarer than the proverbial hen's teeth, and if you can acquire them, you've accomplished the hardest part of creating a new interface.
Bolserst - thanks for posting the schematics. For some reason I haven't been able to attach items here for a while. I've done it in the past, so not sure what's wrong.
Again - let me know how I can help with this fun project. Only a very few of the Spectra 66/6600 were manufactured (definitely < 50 pairs), so to find an almost complete pair for such a low investment is something to feel very good about!
Yes, the two TTA-246 transformers, mounted on wooden rails, is the item I was referring to in my previous post. Those are rarer than the proverbial hen's teeth, and if you can acquire them, you've accomplished the hardest part of creating a new interface.
Bolserst - thanks for posting the schematics. For some reason I haven't been able to attach items here for a while. I've done it in the past, so not sure what's wrong.
Again - let me know how I can help with this fun project. Only a very few of the Spectra 66/6600 were manufactured (definitely < 50 pairs), so to find an almost complete pair for such a low investment is something to feel very good about!
Hmmmmm...what is missing? they(the transformers) look complete in the pics posted for the ebay listing.
Obviously the rest of the interface is missing, HV supply, mixer and spectra sectioning resistors, etc.
But I thought it was the transformers you were in need of, getting the rest of the interface parts from a donor Spectra 22/33.
What I was informed was, the wires shown on the eBay listing are not all complete as the one he has. There is one black wire from one end of the transformer and on the other end- 3 wires on one side (purple , black, grey, the other side has 5 wires purple, white, blue, green, yellow.
Correct. The wires exiting on the back side of each transformer should look like the attached pic.
I believe when they are assembled on the wooden rails, some of the wires are combined.
For example, the two sets of purples and the two sets of blacks may only have a single lead out wire for each set.
AAMan should be able to confirm this.
You might send the seller the attached pic just to confirm all the wires are there in the two-transformer rail assembly being sold.
I believe when they are assembled on the wooden rails, some of the wires are combined.
For example, the two sets of purples and the two sets of blacks may only have a single lead out wire for each set.
AAMan should be able to confirm this.
You might send the seller the attached pic just to confirm all the wires are there in the two-transformer rail assembly being sold.
Attachments
Hi I have Acoustat Spectra 44s. The interface is MK2146. The right channel bass output is lower than the left (can send Room EQ results measured from 1 meter in the center.) The bass tap (bottom of transformer) is green to the PC board. There are dip switches do these change anything? Can someone help with possible cause?
I have never heard of dip switches in Acoustat Interfaces, can you post a pic?
The green wire bass tap is the OEM setting for a 4 panel Spectra model.
You can adjust bass level by changing tap, but there is only a +1dB of bass increase available relative to the green wire.
See attached notes from AAMan on adjusting bass EQ for the Spectra models.
