Carver C-4000 recapping

P.L.F.

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#1
I'm planning to go for a little refurbishing of my Carver C-4000 pre-amp. In the service manual cannot find the list of parts though. And I'm too lazy to write down all caps values going page by page... Shame, I know...

Has anyone then come accross the parts' list for C-4000 (to be precise - it's not the C-4000t model with black knobs and some differences on mother / daughter boards)?

Many thx for help!

P.S. I may probably follow similar approach: http://www.audiokarma.org/forums/showthread.php?t=378306
 

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P.L.F.

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marcok

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#4
PLF ,
I have a C4000 1st series like yours and till now I have not changed any electrolitic caps ,
because I have not seen problems in signal path .
Changing op amps is useless because C 4000 uses TL 084/ TL 074 op amps and not RC 4136 ( better to say
quad 741 )
I replaced only the rear connectors of time delay power amp with banana connectors and
I bypassed phono 2 input to have another aux imput .
Till now ( about 30 years ) I have simply deoxed master volume and rear volume pots ,
and the switch for hologram angle located on rear panel .
This is my experience ; forget C1 , because it's an other device .
Ciao
Marco
P.S: the component list doesn't exist for C4000 1st series .
 

P.L.F.

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#5
PLF ,
I have a C4000 1st series like yours and till now I have not changed any electrolitic caps ,
because I have not seen problems in signal path .
Changing op amps is useless because C 4000 uses TL 084/ TL 074 op amps and not RC 4136 ( better to say
quad 741 )
I replaced only the rear connectors of time delay power amp with banana connectors and
I bypassed phono 2 input to have another aux imput .
Till now ( about 30 years ) I have simply deoxed master volume and rear volume pots ,
and the switch for hologram angle located on rear panel .
This is my experience ; forget C1 , because it's an other device .
Ciao
Marco
P.S: the component list doesn't exist for C4000 1st series .
Yes, I hear you Marco.
I think it's always a temptation either to wait until something in our +30Y pre-amp fails or to have some great time of restoring it today.... Electrolytic caps in power supply and in signal path are probably the first target in the latter case. As for the IC's, I do have a bunch of RC4136 in my C4000. Here is a good page to see possible options if you consider upgrade: http://cimarrontechnology.com/rc4136upgradeadapter.aspx. You can also pick what IC you wish to be pre-mounted: OPA2134, OPA2604, AD8620 or LM4562. Related read: http://www.head-fi.org/t/243849/rc-4136-and-tl074-opamp-replacement-question.
I'd need a second pre anyway so maybe I'll go for upgrading that newbe without disconnecting existing C4000 from my sound system daily used and then swapping the gears...? Still TBD.
Not a priority, unlike my own WOPL1000, which I cannot wait to hear :blob5:...

Attached there are few sexy pics of restored C4000...
 

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laatsch55

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I feel your pain Przem...I'll be getting on that project again as soon as I get my replacement woof in my K's this afternoon. The new woof is supposed to be in right after lunch, haven't had any music since Monday......it sucks...
 

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I feel your pain Przem...I'll be getting on that project again as soon as I get my replacement woof in my K's this afternoon. The new woof is supposed to be in right after lunch, haven't had any music since Monday......it sucks...
You blew a woof in one of the K's?
 

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Yes I did Ben....did not let the voice coils cool enough when going Mach 9 for too long...in the K's there is no place for the warm air to go, it's trappend in the sealed woofer chamber and it's not all that big. Thinking of wrapping the voice coil in copper tubing and running the tubing out the woofer door and circulating cold water through the tubing...a peltier cooling pad is another option..
 

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No I didn't because that hasn't been a problem. But Moby..."Play" track 4 has a phenomenal bass passage in it and with the WOPL's going to 10hz the woofs have been taking some punishment. Even had to get Joe's help in modifying the crossovers to shunt some more of that low fequency energy away from the mids as I was melting the solder on the swamping resistors in the crosses. I ordered a pair of woofs this time....and I have an ample supply of crossover parts now...
 

marcok

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#11
Przem,
I have just opened my C4000 and most of ICs are RC 4136 .
Phono 1 stage , subsonic filter and tone board use TL 074 and TL 072 .
I have also checked with my copy of 1st series service manual and everything is
congruent .
Sorry , for the incorrect info , but after 30 years or more ....
Ciao
Marco
 

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#13
Przem,
I have just opened my C4000 and most of ICs are RC 4136 .
Phono 1 stage , subsonic filter and tone board use TL 074 and TL 072 .
I have also checked with my copy of 1st series service manual and everything is
congruent .
Sorry , for the incorrect info , but after 30 years or more ....
Ciao
Marco
Hi Marco, I didn't take your info as incorrect. It appeared ("Carversite! board" -> http://thecarversite.com) that they were indeed versions with Ti TL075, which I believe have similar pinouts to RC4136. Unfortunately the available Service Manuals on the Internet are missing 4-5 pages and do not address C4000's variations over time. An example of retrieved page(s) is enclosed, not all unfortunately...
Thank you for your contribution!
Przem
 

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JustMike

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Yes, I hear you Marco.
I think it's always a temptation either to wait until something in our +30Y pre-amp fails or to have some great time of restoring it today.... Electrolytic caps in power supply and in signal path are probably the first target in the latter case. As for the IC's, I do have a bunch of RC4136 in my C4000. Here is a good page to see possible options if you consider upgrade: http://cimarrontechnology.com/rc4136upgradeadapter.aspx. You can also pick what IC you wish to be pre-mounted: OPA2134, OPA2604, AD8620 or LM4562. Related read: http://www.head-fi.org/t/243849/rc-4136-and-tl074-opamp-replacement-question.
I'd need a second pre anyway so maybe I'll go for upgrading that newbe without disconnecting existing C4000 from my sound system daily used and then swapping the gears...? Still TBD.
Not a priority, unlike my own WOPL1000, which I cannot wait to hear :blob5:...

Attached there are few sexy pics of restored C4000...
Przem, Are those pics from the one that is on Ebay? Did you buy it?
I have the same model c4000 and thought about an upgrade.
 

marcok

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#16
Przem,
the schematics in the Carversite are related to C4000t and not to C4000 .
The main differences in C4000t are :
-no peak unlimeter
-acoustic lens feature
-different delay time unit .
Anyways I remerered the presence of TL 074 .
A personal consideration :
C4000 is normal preamp with 4 special features .
Good if you use and appreciate these special features just like me .
If you don't use correlator ,hologram , etc . it's better to change preamp .
( I suggest AGI 511 ) . Changing moreless 20 ICs with the piggy back socket
problably is not a convenient solution ,but it's only my opinion .
Restoring or upgrading ? That's the question .
Ciao
Marco
 

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#17
And if Rick doesn't have it we'll get ahold of Ed , he'll have it if it exists...
 

P.L.F.

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#18
Przem, Are those pics from the one that is on Ebay? Did you buy it?
I have the same model c4000 and thought about an upgrade.
Yep, same source for the pics. But I didn't buy it - too expensive for me. Fair 'as is' price for C4000 in very good shape seems to be 200-250$, parts about 100$ without opamps and say 200$ with them included (AD8620). The ebay price is 900$, so it seems to bear a high margin, I think. But maybe I'm wrong...? Naturally, by definition I do respect the market rules, so nothing wrong on the seller.
 

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#20
Restoring or upgrading ? That's the question .
Yes Marco, I'll rather go for restoring. On my hipothetical 'to do list' there would be:
- replacing rail power supply electrolytic caps with long life 105ºC Nichicon 10,000 hour (HE) caps and all other power related caps on main board with long life 105ºC Nichicon (PW) caps;
- replacing signal-path electrolytic capacitors with Nichicon Muse or Panasonic FC series caps;
- replacing 10% ceramic disk capacitors with 5% poly caps in the op-amp’s feedback loops and Phono, Line, Tone sections;
- replacing RC4136 op-amps in Phono (IC6) and Line sections (IC7) with paired OPA2134s (AD8620's seem to be sonically better but are sensible to supply voltage higher than 13VDC - so in case of power supply floating there might be some issues...) mounted on Brown Dog adapters + installing IC sockets only for them.
- replacing 4 rectifier diodes of the rectifier bridge to go for the Ultra Fast Recovery version of the 1N4004;
As far as the pots and switches, I did De-Oxit and Fader Lube intervention about 2 years ago and they work smoothly so far.
Not sure if the RCA sockets replacement / chassis rebuilding is worth to follow...?
Ciao!
 

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