My Beveridge Electrostatic Speaker System

BruceD

VIP/Donor
Dec 13, 2013
985
45
28
#21
Yes Bruce,

ML would be easy with a direct drive amp against the DW requirements!,

DW was a Canadian as well and he built those speaker a short drive up the road from me. They were certainly an experience as well. A few of them around here still working after 40 years .

What is it with Canadians and Electrostatic speakers anway?
Sheesh K--Don't get me started on Canuck Willam Michael's creation!--I fought with those for many times than I care to remember !:mad: I had 4 complete panels replaced FOC--

Plus updated power Supply-- we repaired the fizzing spots by punching thru the Mylar with long Crochet needles dipping in Silicon while getting high on the escaping SF6 Gas

Do you want to know more?

No I thought not!:p Self Flagellation would've been preferable!

BruceD
 

Kcin

Active Member
Mar 27, 2016
184
87
28
Canada
#22
Sheesh K--Don't get me started on Canuck Willam Michael's creation!--I fought with those for many times than I care to remember !:mad: I had 4 complete panels replaced FOC--

Plus updated power Supply-- we repaired the fizzing spots by punching thru the Mylar with long Crochet needles dipping in Silicon while getting high on the escaping SF6 Gas

Do you want to know more?

No I thought not!:p Self Flagellation would've been preferable!

BruceD
Ah, but when they worked........................:)
 

christoph

Well-Known Member
Dec 12, 2015
1,195
615
113
Principality of Liechtenstein
#24
Hi micro
You have a manufacturer in Holland who sells this type of amplifiers for Martin Logan - see http://twinstaticaudio.com/elektronica/twin-otl/ Unfortunately Soundlab's seem to be out of the range of these amplifiers - they need around 9-12 KV HV with around 8kV peak to peak voltage.
Do you have experience with this Dutch company.
For quite some time I've been sporadically thinking of getting such a pair for my Acoustat Spectra 22.
But I have never read of someone actually using those OTL amps...
 
May 30, 2010
15,427
665
113
Portugal
#25
Hi micro

Do you have experience with this Dutch company. (...)
Unfortunately no.

I did a lot of search about electrostatic speakers looking for someone who would be able to repair old Soundlab's in Europe - sending large panels to US is expensive and needs a lot of paperwork, but no one here works with low resistivity panels. At that time I needed a low resistivity coating around 10 kohm per square and usual electrostatics use hundreds of Mohm per square coatings.
 

christoph

Well-Known Member
Dec 12, 2015
1,195
615
113
Principality of Liechtenstein
#26

gian60

Well-Known Member
Apr 17, 2016
1,677
440
83
#27
You can check from Italy

www.the sound of the valve.it
enter and check
club Italia Beveridge audio

you can find near all about Beveridge and all models
 

Bev1

New Member
Dec 12, 2018
1
1
3
64
#28
Just in case anyone is interested....I own a pair of Beveridge Model 2s complete with mono amps (spare matched output tubes also).

I don't have a proper room for them now.

Stored for years.

Would like to find a good home for them.
 
Likes: christoph

Avwerks

New Member
Jul 8, 2018
1
0
1
#29
Just in case anyone is interested....I own a pair of Beveridge Model 2s complete with mono amps (spare matched output tubes also).

I don't have a proper room for them now.

Stored for years.

Would like to find a good home for them.

Did you ever sell them and if not where are you located ?

David
 
#30
I've read much about Harold Beveridge and his marvelous speakers but never had an opportunity to hear them. Your's appear to be in great shape!

The concept of running the panels via direct drive is intriguing and I would love to do it. Unfortunately; I haven't the smarts to build such an amp myself, nor the budget to have one built.

My system is lower-budget than most on this forum but it works for me. I have homebuilt hybrid wire-stator ESLs driven with inexpensive toroidal power transformers. The stat panels are artfully built, the electronics less so, and I can only imagine how they might sound driven directly, like your Beveridge speakers.

Thanks for posting--- it's a fascinating read!

Charlie
 
Last edited:
Likes: Kcin

Janek36

New Member
Jun 13, 2019
10
12
3
82
#31
Hi all,
I had the pleasure of speaking with @Ron Resnick today. Ron, I must say that I've met many enthusiasts over my over 30 years in this hobby but I don't think I've spoken to anyone as gracious and engaging.

Ron encouraged me to introduce my system to the group in a little more detail after having a great discussion around his choices around the building of his new system- which should be--- absolutely fabulous.

While certainly not state of the art anymore, I am a little reticent to post about them among a group with such high standards - I believe that the Beveridge Electrostatics still perform at a very high level of resolution and do things that are still not approachable by many transducers today at any price.

I wrote, a little while ago, a short story on my speakers & system - which have a bit of personal history- to a member of the local audio group.





Here's the story:

The Beveridge Model III speakers are the last true wave launch full range speakers the Harold Beveridge produced in the early 1980’s. Beveridge was a Canadian that studied Engineering at McGill University in Montreal and was hired by Raytheon to design Radar systems and electronic counter measure systems for the US military programs.

He was a genius. In his retirement from Military work he used what he learned from radar wave technology and adapted it to his love of electrostatic speakers.

I heard the very same speakers I own today at local audiophile’s place when they were current over 35 years ago. He ran them with an Audio Research D79 and SP 6 with a Goldmund Studio Turntable. ( this system 35 years ago would give most current systems a run for their money!) This was the height of state of the art at the time.

When that needle dropped to the record way back then I knew that everything I was trying to accomplish with tube electronics ( not cool back then) and even my Acoustat X’s and model 3’s was a waste of time. They had left an impression on me that I could not duplicate for over 30 years of trying along with listening at dozens of audio shows and multi-kilobuck systems .

Through chance, those speakers were still local and were sold just one more time to another audiophile that the original owner had kept in touch with. Once I heard they were available I had to have them at almost any cost. The second owner was in his early eighties and he was happy to have them go to someone who could appreciate them.

Beveridge’s original efforts were constant charge electrostatic panels where the sound waves were forced through a wave guide to disperse at 180 degrees across the room. These are not dipoles so the room does not impact the sound launch from the speakers a la Martin Logan, Sound Labs, Acoustat etc. The speakers point at each other directly facing!

These panels were fed by dedicated built in servo Output Transformerless (OTL) amps that directly charged the panels at +/- 2000vdc to modulate the audio signal. No step up transformers to step up the audio signal as in Martin Logans, Sound Labs or Quads etc. The audio signal was fed directly from the plates of the tubes to the stators of the electrostatic panels with no transformer losses on the speaker nor audio output transformer for the tube amplifiers.

The signal could not be clearer. Other added benefit: lab grade silicon high voltage wires to carry the polarizing voltage to stators as well as the audio signal that rides on it. No expensive speaker cable trials anymore.

The cost of these units in the late 70’s was over $15K – hideously expensive. Beveridge was forced to eliminate the integral OTL amps and develop a step up transformer based full range model to compete at a lower price point. These are the Model IIIs that I have.

The Model IIIs have two 10” woofers upward and downward firing in a hemholtz configuration with a 6’6” line source electrostatic element in front with a wave guide to disperse the sound about 180 degrees.

To Beveridge’s credit, although the Model IIIs were a compromise to his original design,- no OTL amps- they had the same type of step up transformer as all electrostatics have- he designed the unit so that the elements of the electrostatic panel and the woofers could be driven by 1 amp or bi-amplified with an internal crossover or bi-amplified with an external crossover.

Not leaving well enough alone. I abandoned the internal woofers and deployed a pair of modern subs with internal amp with 200wpc each on the subs.

Subwoofer technology has advanced tremendously in 30 years.

Roger Modjeski who was a young engineer at the time working with Beveridge designed a Direct Drive tube amplifier to eliminate the internal cross over and step up of the Model IIIs .

It is passively 1 st order high pass limited with a single copper V cap to allow everything from about 100Khz up to the panels and I feed the woofers everything below that through a second output.

So effectively, I have the electrostatic panels driven by +/- 2kv directly with no step and no audio output transformer from the tube amps. The only other amp I have had that approached this purity was the Berning ZOTL 270.

If you’ve ever heard an electrostatic panel driven by an OTL amp you’ll get ½ the story… the other half is that the step up in the speaker is eliminated as well- big difference in resolution and clarity.

Pretty complex but I am optimizing it and it sounds real nice. The difference with the Beveridge is its ability to hang an instrument in space it is a bit uncanny. Add this to the low mass diaphragm of an electrostatic -no step up transformers or audio output transformers of any kind and you get a very pure output.

The heart of the analog system is the 150lb 3 box Aesthetix Io Eclipse with volume controls.

No required line stage no step up transformers no extra cables for greater purity- it drives low output cartridges no problem. I have spent years optimizing the tube choices it is exceptionally quiet.

For up front transducers I’ve have added the Clearaudio Goldfinger Statement- I also have on hand the Lyra Atlas, Lyra Etna SL and the Koetsu RSP.
The table is the Brinkman La Grange with Kuzma 4pt and Brinkman 12.1 The room is about 18x 40 purpose built with 9 1/2’ ceilings.

Thanks for listening to this long story of this relatively modest system by today's standards. Even though the Beveridges are over 30 years old they are still widely coveted today and many have them in top class systems across the world. Very few of them were produced as they were built by hand but those that survived still make some great music today.
 
Likes: christoph

Janek36

New Member
Jun 13, 2019
10
12
3
82
#32
Hi all, I am new to this forum but found the discussion on Beveridge ESLs interesting. I owned a pair of the original 2SW Bevs in the early 1970"S when they were first sold. Loved them and owned them for many years and always felt that they were the best speakers I had ever owned. After they died, and Bev was out of business, I owned some quads and Sound labs, both of which were fine speakers but not the same as the Bevs. After I retired, I spent 2 years working out the details on a modified lens to reproduce the same type of wall of sound that the Bevs produced. I also thought that the woofer arrangement that the 2SW's had could be improved, So I built my own version of a Beveridge speaker. I hybridized the design with a crossover to a 6.5" midwoofer between 300and 500 Hz and used a subwoofer below 70Hz. I triamp using Bryston 2B-LP amps which are very stable with capacitive loads. Since it's been years since I last owned real Bevs, I can't tell if they are truly equivalent, but they sure sound similar and have the same characteristic wall of sound and to boot the bass is much better. Although I don't usually play music that loud, I been able to exceed 100db with pink noise testing; something the original Bevs couldn't do.
 

steve williams

Site Founder, Site Owner, Administrator
#33
Hi all, I am new to this forum but found the discussion on Beveridge ESLs interesting. I owned a pair of the original 2SW Bevs in the early 1970"S when they were first sold. Loved them and owned them for many years and always felt that they were the best speakers I had ever owned. After they died, and Bev was out of business, I owned some quads and Sound labs, both of which were fine speakers but not the same as the Bevs. After I retired, I spent 2 years working out the details on a modified lens to reproduce the same type of wall of sound that the Bevs produced. I also thought that the woofer arrangement that the 2SW's had could be improved, So I built my own version of a Beveridge speaker. I hybridized the design with a crossover to a 6.5" midwoofer between 300and 500 Hz and used a subwoofer below 70Hz. I triamp using Bryston 2B-LP amps which are very stable with capacitive loads. Since it's been years since I last owned real Bevs, I can't tell if they are truly equivalent, but they sure sound similar and have the same characteristic wall of sound and to boot the bass is much better. Although I don't usually play music that loud, I been able to exceed 100db with pink noise testing; something the original Bevs couldn't do.
Know that era well

Welcome to WBF
 

Kcin

Active Member
Mar 27, 2016
184
87
28
Canada
#34
Hi all, I am new to this forum but found the discussion on Beveridge ESLs interesting. I owned a pair of the original 2SW Bevs in the early 1970"S when they were first sold. Loved them and owned them for many years and always felt that they were the best speakers I had ever owned. After they died, and Bev was out of business, I owned some quads and Sound labs, both of which were fine speakers but not the same as the Bevs. After I retired, I spent 2 years working out the details on a modified lens to reproduce the same type of wall of sound that the Bevs produced. I also thought that the woofer arrangement that the 2SW's had could be improved, So I built my own version of a Beveridge speaker. I hybridized the design with a crossover to a 6.5" midwoofer between 300and 500 Hz and used a subwoofer below 70Hz. I triamp using Bryston 2B-LP amps which are very stable with capacitive loads. Since it's been years since I last owned real Bevs, I can't tell if they are truly equivalent, but they sure sound similar and have the same characteristic wall of sound and to boot the bass is much better. Although I don't usually play music that loud, I been able to exceed 100db with pink noise testing; something the original Bevs couldn't do.
Sounds like a great effort. I'd love to see pictures.

My Bevs are highly modified with direct drive amps which really transforms them especially when you cross them over to modern subs as you do. 100 db is not a problem.

Congratulations
 

Janek36

New Member
Jun 13, 2019
10
12
3
82
#38
Hi folks, As you can see I have posted some photos of my pseudo bevs. Due to my inexperience with computer usage, they didn't transmit the way I intended. However, you can see the main listening room system with the proper arrangement for Bevs. The speakers are a bit over 6' tall with a 1'x4' ESL mid/tweeter array within the top cabinet . The mid woofer is in a separate cabinet below. The other pictures are of an smaller prototype using a similar lens but only 2' high. The high end worked very well but the blend with the mid woofer was not good enough w/o DSP, so I am redesigning the low end to be more like the big speakers. Nevertheless, you can see what the lens looks like in the rough so to speak.
 
Likes: Kcin
#39
Nice work, Ted
I was admiring your room too, especially the wooden structure on the back wall which I'm guessing is some kind of cabinetry?
Also, the two items on pedestals behind your mains caught my attention-- are those additional speakers or bass traps?
And are you still using those same Triad toroidal transformers?
Charlie
 

Janek36

New Member
Jun 13, 2019
10
12
3
82
#40
Nice work, Ted
I was admiring your room too, especially the wooden structure on the back wall which I'm guessing is some kind of cabinetry?
Also, the two items on pedestals behind your mains caught my attention-- are those additional speakers or bass traps?
And are you still using those same Triad toroidal transformers?
Charlie
Hi Charlie,
the wooden wall hides a 65" TV. the curved portion slides open to allow viewing. Normally it is closed for music listening as I usually watch TV with my wife in the living room. The black cylinders in each corner are indeed acoustic traps. They act both as a bass trap and diffuser of higher frequencies which solved a room acoustic problem I had. I am not using the triads anymore but rebuilt the polarizing supplies with the European standard toroids that you use. Part of the problem was getting them as the US distributer rarely keeps them in stock and even the UK distributer is often out of stock. I run the polarizing supply at approximately 2.5KV which seems adequate for the design and decreases the chance of arcing. Good to hear from you again
Ted
 
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