Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 25

Thread: Carver C-500 - valid candidate for White Oak Audio upgrade???

  1. #11
    Forum Veteran grapplesaw's Avatar
    Join Date
    Aug 2014
    Location
    Vancouver
    Posts
    1,099
    ---
    Quote Originally Posted by savaden View Post
    This is my first post, so be kind... Anyway, I picked up a C-500 at the local thrift, and it appears not to have been messed with. Hooked it up and verified working properly. Until it let all the steam out of one of the power supply caps. Sounded just like my espresso machine blowing the pressure relief valve. Easy to disassemble and I think the WOA capacitor upgrade would fit right in there, or if I could find a new home for the diode bridge, 2" diameter caps would seem to fit. From the descriptions I have read this does not need the output protection relay upgrade? Not sure. Also not sure if the driver board is the same as the PL400. Pics attached. Not really in order, but you get the idea.
    Attachment 27693Attachment 27694Attachment 27695 Attachment 27691Attachment 27692

    Sterling Vaden
    Black Mountain, NC
    i just redid one. You can use the WhiteOak capacitor setup. I have a 10,000 plus 6,800 paired for each rail.
    Here is some photos.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	IMG_5723.jpg 
Views:	42 
Size:	93.4 KB 
ID:	27696   Click image for larger version. 

Name:	IMG_5728.jpg 
Views:	39 
Size:	87.0 KB 
ID:	27697  
    try the Lightening Bolt WOPL 1000 for a hair lifting experience today

    Warning !!! Use only when you want to blown the town down

    proud father of the only WOPL Fully Comp dual 500

  2. #12
    Forum Veteran grapplesaw's Avatar
    Join Date
    Aug 2014
    Location
    Vancouver
    Posts
    1,099
    ---
    The carver board has protection but not for DCP on the outputs.
    Here is a full conversion to Dons board with Joe's control board and full complimentary setup
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	IMG_5727.jpg 
Views:	43 
Size:	105.2 KB 
ID:	27698  
    Last edited by grapplesaw; 01-05-2017 at 06:55 PM.
    try the Lightening Bolt WOPL 1000 for a hair lifting experience today

    Warning !!! Use only when you want to blown the town down

    proud father of the only WOPL Fully Comp dual 500

  3. #13
    New Around These Parts
    Join Date
    Jan 2017
    Posts
    5
    ---
    BTW this thing came with the original user manual attached. Ser# 0033. Where is a link to the output protection board? Is the Rev E control board a pin for pin replacement or needs some other mods. I have downloaded the service manual. In general I like to keep things original if possible, but you know sometimes that is not possible or doesn't make sense, especially when you've got all those transistors wired in parallel. Sheesh.

    I have reworked two Denon PRA 1000 pre-amps now and it is fun hunting down the glitches in those things. They have parallel wired Fets in the mc phono preamp. Had to re-solder every single connection. Twice. Recapped one, didn't bother with the other one. They both work the same.

    I don't have a distortion analyzer, though.

    Sterling Vaden
    Black Mountain, NC.

  4. #14
    Forum Veteran grapplesaw's Avatar
    Join Date
    Aug 2014
    Location
    Vancouver
    Posts
    1,099
    ---
    Quote Originally Posted by savaden View Post
    BTW this thing came with the original user manual attached. Ser# 0033. Where is a link to the output protection board? Is the Rev E control board a pin for pin replacement or needs some other mods. I have downloaded the service manual. In general I like to keep things original if possible, but you know sometimes that is not possible or doesn't make sense, especially when you've got all those transistors wired in parallel. Sheesh.

    I have reworked two Denon PRA 1000 pre-amps now and it is fun hunting down the glitches in those things. They have parallel wired Fets in the mc phono preamp. Had to re-solder every single connection. Twice. Recapped one, didn't bother with the other one. They both work the same.

    I don't have a distortion analyzer, though.

    Sterling Vaden
    Black Mountain, NC.
    Hi Sterling

    If you want to keep it original then just change the power caps and Bridge rectifier add the smoothing caps to the bridge and use some 10,000 100 volt 33mm OD Capacitors and you will be happy. There is no information on upgrading the amp short of my thread here

    http://forums.phxaudiotape.com/showt...t=carver+c-500
    Last edited by grapplesaw; 01-05-2017 at 07:43 PM.
    try the Lightening Bolt WOPL 1000 for a hair lifting experience today

    Warning !!! Use only when you want to blown the town down

    proud father of the only WOPL Fully Comp dual 500

  5. #15
    Forum Veteran grapplesaw's Avatar
    Join Date
    Aug 2014
    Location
    Vancouver
    Posts
    1,099
    ---
    I used a Whiteoaks REv D board in my build ( sounds great) the E board is the same wiring there is a couple of wires not required from the output of each channel that the Carver board used in its protection circuit if you go WO. You can sort the rest easily using the schematic of each..

    So if you want to have a great amp for 30 more years consider upgrading it you can leave it Quasi Comp or go full complimentary as I did. This amp is used every day now with my TV.


    To add one of Don Imlays DCP boards you have to change the outputs. as well I had to build it with all the components on the opposite side. if you do put one in it works great just watch how you flip the IC as the bevel edge goes from inside to outside when inverted. see post 11 in this link

    http://forums.phxaudiotape.com/showt...t=carver+c-500
    try the Lightening Bolt WOPL 1000 for a hair lifting experience today

    Warning !!! Use only when you want to blown the town down

    proud father of the only WOPL Fully Comp dual 500

  6. #16
    New Around These Parts
    Join Date
    Jan 2017
    Posts
    5
    ---

    Found suitable PS caps.

    I think I found a couple suitable PS caps. Thanks for the 160V tip. I was looking at 100V parts. Looks like pretty close to a drop-in replacement with 20% more capacity.

    http://www.tedss.com/2020063499


    • capacitance: 7,100 uf
    • voltage: 160 vdc
    • lead style: screw
    • diameter: 1.75 IN, length: 4.625 IN


    Met a guy at GW today that used to work for HP at the original factory.

    Sterling Vaden
    Black Mountain, NC.

  7. #17
    New Around These Parts
    Join Date
    Feb 2017
    Posts
    2
    ---

    Two C-500 vertaclly bi-amped

    Great thread. Very encouraging the many WO parts work. One of mine needs some repair.

  8. #18
    New Around These Parts
    Join Date
    Feb 2017
    Posts
    2
    ---

    I own 2 C-500's Love em!

    Delete duplicate please.
    Last edited by Funky54; 02-24-2017 at 06:16 PM. Reason: Delete duplicate please

  9. #19
    Forum Veteran grapplesaw's Avatar
    Join Date
    Aug 2014
    Location
    Vancouver
    Posts
    1,099
    ---
    Quote Originally Posted by Funky54 View Post
    Great thread. Very encouraging the many WO parts work. One of mine needs some repair.
    Welcome Funky54 to the site. I have sent you a PM about your amp. You will find a lot of help on the site
    Glen
    try the Lightening Bolt WOPL 1000 for a hair lifting experience today

    Warning !!! Use only when you want to blown the town down

    proud father of the only WOPL Fully Comp dual 500

  10. #20
    New Around These Parts
    Join Date
    Jan 2017
    Posts
    5
    ---

    Carver C-500-033 update.

    OK, I purchased and installed the output protection relay board and after firing it up I had some hum on the right channel. . So in the process of trying to track down the source, I managed to touch something that bricked it. (DC at output) Well, not really, because I painstakingly went through all of the components and circuits trying to find a bad component, and everything looked fine. Grrr. Then I decided that I needed to figure out how the thing is supposed to work so that I could track the voltages through the driver board. (driver board had to be the culprit) I took a photo of the trace layout, flipped it and overlayed with the component layout photo. I brought those into Visio and added components and traces. You know how much a PITA it is to reverse engineer even a fairly simple circuit? Well this circuit is not all that simple... Anyway I then got a copy of LTSpice and entered the circuit from the service manual (there are two versions in the manual), then compared the actual circuit from the unit to the spice drawing. Not the same. A third version! They are all fairly similar but there are some differences mainly at the signal input and somewhat different resistor values in various places. I wanted to try to get the DC bias analysis from the spice model to figure out why I had DC at the output. I never really got that to work, partly I think because the amp uses a transient at startup to bootstrap the driver into an "on" state. That is what I think, anyway.

    Result. I gave up on the spice model but I learned a lot about the circuit in the process. Carver inverts the signal to the right channel at the input. There is an op-amp at the input to each channel (LF356) and in the manual he drives the left side into the non-inverting input and the right side into the inverting input. On my amp, it is different. He drives both on the non-inverting input. He then added another op amp with unity gain to the right channel to invert the input phase. This turned out to be the problem as that op amp must have gotten fried and was putting out about 2V DC with zero volts input. What I did for now was just to hook the right input directly to the non-inverted input op-amp and bypass the extra op-amp. That seemed to set everything straight.

    My question then is... Why did Carver invert the right channel phase? I mean he makes a big deal of it in the output connectors and in the service manual, but is it really necessary? Is this a trick to even out the power draw in the amp reducing distortion?

    Oh, and I now have driver board layouts and circuit schematics. I still have no idea how the protection circuits are supposed to work, and I don't really understand the signal flow from input to output of the driver board.

    Anyway, the beast works, and I'll probably order an RC4136N quad op-amp if they still make them. It's funny that he had used this extra quad op amp on the right side but only used one section and shorted the other three.

    Sterling

Posting Permissions

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