Poll

Direct Drive ESL Amplifiers for all

I have ESLs and I would like to explore direct drive
10 (16.9%)
I can do basic re-wiring myself
11 (18.6%)
I need a technician to adapt my speakers
2 (3.4%)
I want to send my speakers for Roger to do it
1 (1.7%)
I want to make my own ESLs
6 (10.2%)
I have made ESLs and need a good way to drive them
1 (1.7%)
I find ESLs fascinating and want to know more about them
15 (25.4%)
I have read DIY articles and toyed with the idea of making some
6 (10.2%)
I think a DIY ESL can achieve excellent sound and is a rewarding project
6 (10.2%)
I have read DIY articles and find them confusing or unclear as to what to do
1 (1.7%)
The drive systems seem poorly conceived in the DYI articles
0 (0%)

Total Members Voted: 26

ESL Independence Day

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bpape

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Re: ESL Independence Day
« Reply #20 on: 8 Jul 2012, 05:07 pm »
I have a pair of the Monitor IV's Tom is referring to with the DD amps that have been rebuilt by a gentleman in Oklahoma City.  Absolutely no comparison to an amp running through transformers to the same panels.  Bass is tighter, that slight 'plasticy' (technical term...) sound isn't there. MUCH faster and more dynamic. 

Picked them up along with an AR preamp, Nakamichi tape deck, Sony CD player, and Yamaha tuner for $600 on Craigslist.  Sold pretty much all of the rest of it and basically have zero in the speakers before I paid for the amp rebuild/mods.  One of the best buys I've ever made in my audio journey.

Bryan

OzarkTom

Re: ESL Independence Day
« Reply #21 on: 8 Jul 2012, 05:20 pm »
I have a pair of the Monitor IV's Tom is referring to with the DD amps that have been rebuilt by a gentleman in Oklahoma City.  Absolutely no comparison to an amp running through transformers to the same panels.  Bass is tighter, that slight 'plasticy' (technical term...) sound isn't there. MUCH faster and more dynamic. 

Picked them up along with an AR preamp, Nakamichi tape deck, Sony CD player, and Yamaha tuner for $600 on Craigslist.  Sold pretty much all of the rest of it and basically have zero in the speakers before I paid for the amp rebuild/mods.  One of the best buys I've ever made in my audio journey.

Bryan

And I have really missed those Monitor IV's ever since. I sold those to Bryan about 30 years ago.

Freo-1

Re: ESL Independence Day
« Reply #22 on: 8 Jul 2012, 05:33 pm »
I owned Acoustat Spectra 33’s for many years.  Those speakers drove me crazy.  They had so much potential, yet, always found them difficult to coax out the best from them.  The amp choice was always difficult to find a good match.  For me, the Audio Research D115 was the best match I found for it.  Also, used an Infinity Servo subwoofer with them, which did help the overall sound (the Acoustat woofer designed to those was sorely lacking).

These days, I find the SEAS Excel drivers provide speed and detail much like a ESL, and provides dynamic contrasts most ESL’s just cannot each.  Still, ESL’s will always hold a special place in my audio journey, and are always a welcome sonic experience.

OzarkTom

Re: ESL Independence Day
« Reply #23 on: 8 Jul 2012, 05:56 pm »
I owned Acoustat Spectra 33’s for many years.  Those speakers drove me crazy.  They had so much potential, yet, always found them difficult to coax out the best from them.  The amp choice was always difficult to find a good match.  For me, the Audio Research D115 was the best match I found for it.  Also, used an Infinity Servo subwoofer with them, which did help the overall sound (the Acoustat woofer designed to those was sorely lacking).

These days, I find the SEAS Excel drivers provide speed and detail much like a ESL, and provides dynamic contrasts most ESL’s just cannot each.  Still, ESL’s will always hold a special place in my audio journey, and are always a welcome sonic experience.

I am afraid with any ESL's, there is only one way to listen. Get rid of the transformers and use DD amps. It is truly a night and day difference. When you hear the differnce, it will shock you. Transformers really makes an ESL sound very sluggish.

I am hoping all ESL owners start realizing what Roger is designing here. This would definitely be a game changer in the ESL audio world. There have been many, many thousands of Acoustats and Quads that have been sold over the past 35-55 years.

Oops! :duh:
Roger, can you make that many amps?

steve f

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Re: ESL Independence Day
« Reply #24 on: 8 Jul 2012, 08:12 pm »
Agreed that the best way to power ESL's is to drive them directly.

But... For best full range performance, a dynamic woofer is necessary.

This new amp could be a very big seller.

Addendum: I just got took to task by a buddy who prefers solid state power. He insists that a transformer coupled ESL driven by a bipolar solid state amp is more accurate, distortion free, than a direct drive tube amp. He did agree that not having a transformer in the speaker made for an easier design, especially for hobbyists. I questioned that since an ESL is such a difficult load, a good policy would be to design a specific use amp, and avoid generic product. This discussion has the potential to go on endlessly as there are too many variables to compare.
« Last Edit: 8 Jul 2012, 11:16 pm by steve f »

bpape

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Re: ESL Independence Day
« Reply #25 on: 9 Jul 2012, 02:08 pm »

But... For best full range performance, a dynamic woofer is necessary.



You should listen to the IV's.  The resonant frequency of the panels is 23Hz I believe. They have no problem at all going to and below 30Hz when required. One of the things I love about full range panels is the bottom end. It's just so much tighter, cleaner, faster, more detailed, more 'musical'.  Trying to get a dynamic woofer to keep up with a panel is pretty tough to do unless you do an OB or IB type.

Bryan

Roger A. Modjeski

Re: ESL Independence Day
« Reply #26 on: 9 Jul 2012, 05:26 pm »
Agreed that the best way to power ESL's is to drive them directly.

But... For best full range performance, a dynamic woofer is necessary.

This new amp could be a very big seller.

Addendum: I just got took to task by a buddy who prefers solid state power. He insists that a transformer coupled ESL driven by a bipolar solid state amp is more accurate, distortion free, than a direct drive tube amp. He did agree that not having a transformer in the speaker made for an easier design, especially for hobbyists. I questioned that since an ESL is such a difficult load, a good policy would be to design a specific use amp, and avoid generic product. This discussion has the potential to go on endlessly as there are too many variables to compare.

I would ask your buddy what direct drive amplifier he is comparing his solid state+transformer to?  I have seen many DD amp designs that are just horrible. For those he might be right. You might also tell him that I totally disagree about the distortion as the transformer is out of the loop. Also let him know that the transformer capacitance often eats up 1/3 to 1/2 the power of his SS amp.

Jazzman53

Re: ESL Independence Day
« Reply #27 on: 9 Jul 2012, 07:09 pm »
Wow!  Roger, what a great thread.  ESL's sound pretty fantastic anyway, but I gotta say the thought of pitching the trannys and driving my homebuilts directly really has me intrigued.  Not sure I could afford the amps, even if sold as kits, but I sure like the thought.     

BTW, if everyone knew how easy it is to roll your own ESL's (flat panels especially), I think there would be a lot more ESL owners here.

TONEPUB

Re: ESL Independence Day
« Reply #28 on: 9 Jul 2012, 08:38 pm »
I'll happily provide a pair of Quad 57's if you want a beta tester!


OzarkTom

Re: ESL Independence Day
« Reply #29 on: 9 Jul 2012, 10:59 pm »
I remember back in the early 80's, Frank Van Alstine said that the Acoustats with DD amps made all other ESL's sound broken.

It is too bad that Acoustat got greedy and went mid-fi with their speakers to sell more to the general public.

Roger A. Modjeski

Re: ESL Independence Day
« Reply #30 on: 10 Jul 2012, 12:41 am »
I remember back in the early 80's, Frank Van Alstine said that the Acoustats with DD amps made all other ESL's sound broken.

It is too bad that Acoustat got greedy and went mid-fi with their speakers to sell more to the general public.

Frank was right about that. The sound was certainly better and much much better than with the transformer box that replaced the DD amp.

Besides being more expensive than the transformer they later provided, I believe that Acoustat abandoned the DD amp because their's was not reliable.... at all. They had a plug in cathode resistor which failed often (hense the plug in). They also built the sockets out of indivdual pins on a PC board which didn't hold the tubes tight and for some reason used the smallest of the horizontal output tubes available, without a plate cap no less. The front end was a TL-074 and some transistors to drive the tube. It was more like a High Voltage power supply design than an audio amplifier.

I have opted for the larger tubes, with plate caps which gets the high voltage away from the low. Also mine is all hardwired, real tube sockets screwed to the chassis and a reliable circuit (of course).

I think Acoustat realized early on that the amp was a big problem and would inhibit both the production and reliability of the broad line of speakers they produced over time. Even before the Spectra series there was every possible combination of panels from one to eight. Now we can buy these speakers at incredibly low prices and drive them properly.

OzarkTom

Re: ESL Independence Day
« Reply #31 on: 10 Jul 2012, 03:14 am »
If anyone here is in Chicago area, this deal is a steal on Acoustats with DD amps on Ebay. The seller first listed them at $1500, then $1200, now $900. Only if Chicago wasn't so far away. :(

Hey Brian, how about going up there and picking these up for me?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=130726826241

steve f

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Re: ESL Independence Day
« Reply #32 on: 10 Jul 2012, 09:46 am »
I live in a Chicago suburb.
We are talking just a few miles away.
Steve

OzarkTom

Re: ESL Independence Day
« Reply #33 on: 10 Jul 2012, 11:30 am »
I live in a Chicago suburb.
We are talking just a few miles away.
Steve

The speakers are in Bellwood, Il. They look like they are in very nice condition.

airhead

Re: ESL Independence Day
« Reply #34 on: 10 Jul 2012, 03:41 pm »
Perhaps I should add to this thread the fact that Harvey Rosenberg was toying with the idea
of a Futterman-Stax  dedicated combination, which I imagine would have been direct drive.
He never implemented it though.

steve f

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Re: ESL Independence Day
« Reply #35 on: 10 Jul 2012, 04:04 pm »
Naturally the guy who lives closest to the speakers (Riverside, IL) doesn't want them. I'm way too much of a DIY speaker kind of guy. I would be willing to store those speakers for another forum member for a few months until he could make pick up arrangements though. Seriously.

Steve

bpape

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Re: ESL Independence Day
« Reply #36 on: 10 Jul 2012, 06:09 pm »
Maybe I'll buy them so I can do surround sound Acoustats!  Somehow, I don't think my wife would think that's a great idea....  :nono:

Bryan

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Re: ESL Independence Day
« Reply #37 on: 10 Jul 2012, 08:13 pm »
Would someone knowlegeable about that acoustat deal PM me and tell me why this is a good deal? I was just looking at Magnepans... so not sure what these are. (--planar Newb) I live near them.

OzarkTom

Re: ESL Independence Day
« Reply #38 on: 11 Jul 2012, 02:59 am »
 :o
Wow, what a deal this was in Canada last April. A free pair of Acoustat X's and DD amps if you picked them up at his place.

http://www.canuckaudiomart.com/details/648994386-acoustat_x_speakers_servocharge_amps_conradjohnson_preamp/

Roger A. Modjeski

Re: ESL Independence Day
« Reply #39 on: 11 Jul 2012, 04:05 am »
:o
Wow, what a deal this was in Canada last April. A free pair of Acoustat X's and DD amps if you picked them up at his place.

http://www.canuckaudiomart.com/details/648994386-acoustat_x_speakers_servocharge_amps_conradjohnson_preamp/

That was a great deal. Sometime people do give things away and because they are giving them away others may not realize that they are of great value. I hope I have alerted those reading this thread what you are missing in fooling around with Electrostats.