Page 1 of 2 12 LastLast
Results 1 to 10 of 18

Thread: Bob Carver & ESS Eclipse 500A Amplifier

  1. #1

    Bob Carver & ESS Eclipse 500A Amplifier

    I ran into the following ebay ad copy which someone posted for an ESS Eclipse 500A they had for sale. If my memory serves me correct, Dean mentioned that Bob Carver was working on an amplifier for ESS (at Norm McFadden's house) after he left Phase Linear. I will double-check this with Dean when I get a chance.


    http://www.ebay.ca/itm/ESS-Series-Ec...-/231810122495


    The History of the ESS Amplifier Line:
    The information on the internet regarding this amp is somewhat inaccurate and I’d like to clear it up:
    When I first bought the amp I read the posts that the amp was developed by the Late Bob Byrd. Nelson Pass told me that Bob Byrd was key and Pete Werbackalso worked in its development. I then emailed Bob Carver with some internal PICs of the amplifier…


    Bob got back to me and said “That is my Circuit”! We need totalk and he told me this:
    Back in the height of the Golden-Age Stereo days of the late 70’s,Dr. Oskar Heil was known to have the most advanced speaker systems with the Heil AMT 1. He needed an amplifier that would give what his superior speakers needed - lots of high-end power. Dr. Heil called his good friend Bob Carver and asked: “We need an amplifier to drive our Electrostatic speaker systems, would you be willing to help us? Bob agreed and traveled down to Sacramento and worked with ESS to design and build a prototype amplifier to properly drive the Heil tweeters/mids. This was after Bob sold Phase Linear to Pioneer and just as he was formulating plans for a new company which soon became Carver Corporation. In those days there were very few people who knew how to build high-end amplifiers. It was Bob Carver who was the driving force behind this project and Bob Byrd and Pete Werback continued the R& D once the amplifier circuitry proved itself in rigorous testing. In the early phase of development they were testing a prototype amp to drive a Heil driver to its maximum to see what it could handle. The driver caught on fire and they began work on a Speaker Protection circuit for this Amplifier. There were at least 3 generations of amplifiers before this Final Eclipse Series 500A. The Eclipse Series 500A was their last,best and most refined amp after many years of R & D and earlier amplifier production.

    PROTECTION:
    Active output transistor dissipation sensing circuit provides full performance into all load types either resistive or reactive, while maintaining absolute safety of the amplifier during direct short or extreme overload conditions. The amplifier is dual thermally controlled, to allow safe operation into extremely mismatched loads, and assure total de-energization in the event of continued operation into a short-circuit load.


    Complete protection is provided to speakers and all internal components in the event of any D-C latch-up condition of the amplifier,including a forced state induced from outside sources. This is achieved via solid state circuitry without the requirement of output switching relays which often require early replacement.
    Last edited by oldphaser; 04-12-2017 at 08:52 AM.

  2. #2
    Administrator
    laatsch55's Avatar
    Join Date
    Jan 2011
    Location
    Gillette, Wyo.
    Posts
    54,210
    Halfbiass...Electron Herder and Backass Woof
    Interesting stuff there Ed...
    taking something that's already good, and making it better...........and for the knowing smiles that cross their faces.......Nando-2011...

    "Silence cannot be Misquoted"--Lazarus Short-2012 "

    " I Just Collect Smiles Craig......Cheap Smiles!-----Fishoz-2017

    "anything can be done, it's finding the easiest way that's hard"-----Bobbysdad--2014

    " Synth percussion is deadly to children, house pets and shitty power supplies"---Stephen Evans 2014

    " You have not reached the point of diminishing returns, you've just ran out of money

    " The Pioneer U-24, unfortunately, is just too expensive and rare to find. That's why I have one."--Nando-2014

  3. #3
    Here are some internal pictures of an ESS Eclipse 500A as well as a sales brochure and schematic (from 1-74) for an earlier ESS Eclipse 500.

    Ed
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	30d9b4db71c5373ffc5a448ff799a216.jpg 
Views:	221 
Size:	69.6 KB 
ID:	28779   Click image for larger version. 

Name:	P1080525.jpg 
Views:	91 
Size:	83.9 KB 
ID:	28780   Click image for larger version. 

Name:	P1080526.jpg 
Views:	80 
Size:	74.6 KB 
ID:	28781   Click image for larger version. 

Name:	P1080527.jpg 
Views:	79 
Size:	88.8 KB 
ID:	28782   hfe_ess_amp_500_schematic_low_res.pdf   hfe_ess_500_spec_sheet_en.pdf  
    Last edited by oldphaser; 04-12-2017 at 08:06 AM.

  4. #4
    Here are the photos of the ESS Eclipse 500A taken from the ebay ad
    http://www.ebay.ca/itm/ESS-Series-Ec...-/231810122495

    I wonder who made the 4-1/2" wide VU meters that ESS used?

    The wood cabinets look like the ones Phil Poth (Poth Manufacturing) made for Phase Linear.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	$_57 (11).jpg 
Views:	79 
Size:	107.4 KB 
ID:	28797   Click image for larger version. 

Name:	$_57.jpg 
Views:	88 
Size:	103.5 KB 
ID:	28798   Click image for larger version. 

Name:	$_57 (10).jpg 
Views:	76 
Size:	97.1 KB 
ID:	28799   Click image for larger version. 

Name:	$_57 (7).jpg 
Views:	58 
Size:	97.7 KB 
ID:	28800   Click image for larger version. 

Name:	$_57 (5).jpg 
Views:	70 
Size:	99.6 KB 
ID:	28801   Click image for larger version. 

Name:	$_57 (1).jpg 
Views:	58 
Size:	100.6 KB 
ID:	28802   Click image for larger version. 

Name:	$_57 (3).jpg 
Views:	47 
Size:	101.0 KB 
ID:	28803   Click image for larger version. 

Name:	$_57 (2).jpg 
Views:	51 
Size:	102.2 KB 
ID:	28804   Click image for larger version. 

Name:	$_57 (4).jpg 
Views:	72 
Size:	98.4 KB 
ID:	28805   Click image for larger version. 

Name:	$_57 (9).jpg 
Views:	50 
Size:	106.7 KB 
ID:	28806  

    Click image for larger version. 

Name:	$_57 (8).jpg 
Views:	48 
Size:	108.7 KB 
ID:	28807  

  5. #5
    Administrator
    laatsch55's Avatar
    Join Date
    Jan 2011
    Location
    Gillette, Wyo.
    Posts
    54,210
    Halfbiass...Electron Herder and Backass Woof
    A 2 watt resistor in SERIES with positive speaker out?? That can't be right...
    taking something that's already good, and making it better...........and for the knowing smiles that cross their faces.......Nando-2011...

    "Silence cannot be Misquoted"--Lazarus Short-2012 "

    " I Just Collect Smiles Craig......Cheap Smiles!-----Fishoz-2017

    "anything can be done, it's finding the easiest way that's hard"-----Bobbysdad--2014

    " Synth percussion is deadly to children, house pets and shitty power supplies"---Stephen Evans 2014

    " You have not reached the point of diminishing returns, you've just ran out of money

    " The Pioneer U-24, unfortunately, is just too expensive and rare to find. That's why I have one."--Nando-2014

  6. #6
    Quote Originally Posted by laatsch55 View Post
    A 2 watt resistor in SERIES with positive speaker out?? That can't be right...
    Lee,

    If my memory serves me correct. Bob Carver did that sort of thing. I can't remember if the velocity switch on the 200 series 1 amps does that as well.
    Anyway, here are just a couple of posts from the many posts on the internet.....

    https://www.lifewire.com/output-impedance-3134904
    Incidentally, almost all tube power amplifiers use output transformers, and because output transformers are just coils of wire wrapped around a metal frame, they have substantial impedance of their own, sometimes as much as 0.5 ohm or even more. In fact, to simulate the sound of a tube amp in his Sunfire solid-state (transistor) amplifiers, famed designer Bob Carver added a “current mode” switch that placed a 1-ohm resistor in series with the output devices. Of course, this violated the 1-to-10 minimum ratio of output impedance to expected input impedance that we discussed above, and thus had a substantial effect on the frequency response of the connected speaker, but that’s what you get with many tube amps and it’s exactly what Carver wanted to simulate.

    http://forum.polkaudio.com/discussio...w-speaker-wire

    http://www.classicspeakerpages.net/I...late-tube-amp/

    Ed

  7. #7
    I found a few pictures on ebay of an ESS Eclipse 500AX. It appears to be the same as the 500A without the meters and meter range buttons.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	ESS Eclipse.jpg 
Views:	67 
Size:	39.7 KB 
ID:	28808   Click image for larger version. 

Name:	Model Number 500AX.jpg 
Views:	47 
Size:	49.7 KB 
ID:	28809   Click image for larger version. 

Name:	s-l1600 (1).jpg 
Views:	52 
Size:	95.6 KB 
ID:	28810   Click image for larger version. 

Name:	s-l1600 (2).jpg 
Views:	46 
Size:	54.5 KB 
ID:	28811   Click image for larger version. 

Name:	s-l1600.jpg 
Views:	54 
Size:	43.7 KB 
ID:	28812  

  8. #8
    Forum Veteran JustMike's Avatar
    Join Date
    Aug 2014
    Location
    "wherever she lets me"
    Posts
    850
    "Just Passin thru"
    Thanks for posting ED. The 500A was a good looking amp.
    Looking at the first pics, I noticed that the heat sink was in two parts. An aluminum plate for the outputs and joined to the cast fin sink.
    I wonder how well this design transferred the heat to the fins?
    Last edited by JustMike; 04-12-2017 at 12:06 PM.


    " There is only two kinds of songs; there's the Blues, and there's Zip-a-dee-doo-dah." -- Townes Van Zandt







  9. #9
    Here are some more pictures and info I found on the ESS 500's and 500M's...

    NOTE: (It appears that someone may have used some RCA1B04's or RCA1B05's as replacements for the MJ410 output transistors in the photos below)


    Here is a link to a repair that someone did on a ESS M500.
    https://translate.google.com/transla...0/&prev=search
    NOTE: This link has comments and photos not associated with any of the photos I have attached below. Included are also some screen shots (DHT and SNR, Bandwidth, Slew Rate, and Square Wave Respone) taken utilizing Picoscope6 oscilloscope software.


    There may have been some additional models in the ESS 500 series of amplifiers:
    500-C (500C)
    500-MS (500MS)
    500-S (500S)
    500-W (500W)
    504A
    504-C (504C)
    I haven't been able to locate much information on these models yet.


    Ed
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	photo 1.jpg 
Views:	56 
Size:	55.2 KB 
ID:	28815   Click image for larger version. 

Name:	photo 2.jpg 
Views:	63 
Size:	74.5 KB 
ID:	28816   Click image for larger version. 

Name:	Photo 3.jpg 
Views:	67 
Size:	71.2 KB 
ID:	28817   Click image for larger version. 

Name:	Photo 4.jpg 
Views:	74 
Size:	96.5 KB 
ID:	28818   Click image for larger version. 

Name:	Photo 5.jpg 
Views:	45 
Size:	96.3 KB 
ID:	28819   Click image for larger version. 

Name:	Photo 6.jpg 
Views:	53 
Size:	96.2 KB 
ID:	28820   Click image for larger version. 

Name:	Photo 7.jpg 
Views:	70 
Size:	92.7 KB 
ID:	28821   Click image for larger version. 

Name:	Photo 8.jpg 
Views:	45 
Size:	93.6 KB 
ID:	28822   Click image for larger version. 

Name:	Photo 9.jpg 
Views:	63 
Size:	89.8 KB 
ID:	28823   Click image for larger version. 

Name:	Photo 10.jpg 
Views:	43 
Size:	74.2 KB 
ID:	28824  

    Click image for larger version. 

Name:	Photo 11.jpg 
Views:	41 
Size:	85.1 KB 
ID:	28825   Click image for larger version. 

Name:	Photo 12.jpg 
Views:	39 
Size:	72.8 KB 
ID:	28826   Click image for larger version. 

Name:	Photo 13.jpg 
Views:	40 
Size:	88.5 KB 
ID:	28827   Click image for larger version. 

Name:	Photo 14.jpg 
Views:	37 
Size:	59.8 KB 
ID:	28828   Click image for larger version. 

Name:	Photo 15.jpg 
Views:	36 
Size:	62.7 KB 
ID:	28829   Click image for larger version. 

Name:	Photo 16.jpg 
Views:	40 
Size:	87.7 KB 
ID:	28830   Click image for larger version. 

Name:	Photo 17.jpg 
Views:	33 
Size:	89.7 KB 
ID:	28831   Click image for larger version. 

Name:	Photo 18.jpg 
Views:	33 
Size:	69.7 KB 
ID:	28832   Click image for larger version. 

Name:	Photo 19.jpg 
Views:	38 
Size:	60.7 KB 
ID:	28833   Click image for larger version. 

Name:	Photo 20.jpg 
Views:	37 
Size:	81.7 KB 
ID:	28834  

    Click image for larger version. 

Name:	Photo 21.jpg 
Views:	37 
Size:	72.9 KB 
ID:	28835   Click image for larger version. 

Name:	Photo 22.jpg 
Views:	34 
Size:	73.8 KB 
ID:	28836   Click image for larger version. 

Name:	Photo 23.jpg 
Views:	36 
Size:	81.3 KB 
ID:	28837   Click image for larger version. 

Name:	Photo 24.jpg 
Views:	35 
Size:	74.2 KB 
ID:	28838   Click image for larger version. 

Name:	Photo 25.jpg 
Views:	42 
Size:	75.4 KB 
ID:	28839   Click image for larger version. 

Name:	Photo 26.jpg 
Views:	34 
Size:	74.4 KB 
ID:	28840   Click image for larger version. 

Name:	Photo 27.jpg 
Views:	32 
Size:	53.1 KB 
ID:	28841   Click image for larger version. 

Name:	Photo 28.jpg 
Views:	44 
Size:	88.3 KB 
ID:	28842   Click image for larger version. 

Name:	Photo 29.jpg 
Views:	42 
Size:	97.2 KB 
ID:	28843  
    Last edited by oldphaser; 04-14-2017 at 06:03 AM.

  10. #10
    Forum Veteran stuwee's Avatar
    Join Date
    Jun 2010
    Location
    Deep in the Sonoran Desert SW
    Posts
    8,130
    First off, Awesome thread!! Amazing pics

    I notice the heat sinks are close together like on PL gear, how is that effective that set up? Was it meant for fans to be on it?

    Roger Sanders Magtech amps seem like a very nice updated version of this design, some differences tho...


    Being from the speakers have to be difficult to sound righteous group, that amp is up my alley
    Documented SAE Fanatic

    Owner of Martin Logan Summits, aka 'The Slabs' driven by the SAE A1001

    It's always the beautiful ones that smash the picture ~ Teena Marie

    Huh? What?? Hmmmmmmm

    I'll never get over you, you'll never get under me ~ A-Ha

    To the bat cave 'stat boy wonder!!!! ~ Finebar4


    If you aren't royally pissed, You are not paying attention!!!! Justice has been served as of now...

Similar Threads

  1. For Sale: Carver TFM-15 Amplifier
    By Netfly in forum Forum Buy/Sell/Trade
    Replies: 4
    Last Post: 10-07-2017, 07:13 PM
  2. The Great American Eclipse 8/21/17
    By stuwee in forum Lounge Lizard Central
    Replies: 104
    Last Post: 08-25-2017, 04:50 AM
  3. Tina J Carver (Bob Carver's Mom) Motion Pictures & TV Appearances
    By oldphaser in forum Phase Linear History
    Replies: 3
    Last Post: 08-17-2017, 07:46 AM
  4. power amplifier PL400 and Pre-amplifier 2000 from TMZ2
    By changdangnz in forum Trade Feedback
    Replies: 1
    Last Post: 10-25-2015, 06:13 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •