RC 4136N with PL 1000

[marcok]

Hi all,
after one week I discovered that RC 4136 N causes distorsion at very low level in my PL 1000 series 1.
After replacing it with a new one the unit seems O.K.
Now I ask you if it's better to replace the RC 4136 N with a TL 074 or others using the adapter .
My doubt is that RC 4136 N is very low noise ( 8 nV / sq Hz ) and that a TL 074 is 16 nV / sq Hz .
and the difference is the slew rate ( 0.7V / us vs 12 V / us ) .
For this application is it better low noise or high slew rate ?
The guilty is locateted on the mother board and it's used as voltage follower .
( RC 4136N has been designed for voltage follower applications )
I know that it's a difficult question , but ...
Thank you in advance and ciao
Marco

 

[Gepetto]

Hi all,
after one week I discovered that RC 4136 N causes distorsion at very low level in my PL 1000 series 1.
After replacing it with a new one the unit seems O.K.
Now I ask you if it's better to replace the RC 4136 N with a TL 074 or others using the adapter .
My doubt is that RC 4136 N is very low noise ( 8 nV / sq Hz ) and that a TL 074 is 16 nV / sq Hz .
and the difference is the slew rate ( 0.7V / us vs 12 V / us ) .
For this application is it better low noise or high slew rate ?
The guilty is locateted on the mother board and it's used as voltage follower .
( RC 4136N has been designed for voltage follower applications )
I know that it's a difficult question , but ...
Thank you in advance and ciao
Marco

Almost any modern op amp is better than the RC4136 which was a utility, general purpose op amp created in the early 1980s (I used them for DC motor control back then). Unfortunately because they were new tech at the time, they found their way into numerous audio applications.

Time has marched on...

 

[marcok]

I do agree Joe .
I'm thinking to build an adapter or to buy the adapter by Cimarron .
What IC do you suggest for this purpose ?
Ciao
Marco

 

[WOPL Sniffer]

The C-4000 and 4000t are FULL of them. I replace certain ones with the cimarron (brown dog adaptor). They are not cheap so replacement (especially for the phono section) is limited.

 

[WOPL Sniffer]

I use these with 2 OPA2136 opamps mounted on it

https://02b9b87.netsolstores.com/rc4136upgradeadapter.aspx

 

[Gepetto]

I use these with 2 OPA2136 opamps mounted on it

https://02b9b87.netsolstores.com/rc4136upgradeadapter.aspx

I think you mean OPA2134 op amps Perry. I agree, that is the recommended choice for me.

 

[WOPL Sniffer]

Yep, OPA2134 Joe, my phat phingers......

 

[Bradrock]

Do you buy the pre mounted package from them? Or just the adapter & look for a better price on the op amps elsewhere? Seems odd that they offer a quantity discount on the adapters, but apparently not on the opamps?

Thanks, Brad

I use these with 2 OPA2136 opamps mounted on it

https://02b9b87.netsolstores.com/rc4136upgradeadapter.aspx

 

[laatsch55]

Unless you have had some experience soldering REALLY SMALL surface mount stuff........buy em mounted.....

 

[laatsch55]

Do you buy the pre mounted package from them? Or just the adapter & look for a better price on the op amps elsewhere? Seems odd that they offer a quantity discount on the adapters, but apparently not on the opamps?

Thanks, Brad

They manufacture the adapters, but not the op-amps. They have to buy the op-amps from someone else and their ability to discount those is limited...

 

[Bradrock]

Got it & understood. Thanks
Probably don't have to worry about Chinese knockoffs either.

 

[laatsch55]

Sure don't....

 

[WOPL Sniffer]

I've bought them mounted, and i have bought and soldered my own. I have yet to find a better price except for CINA, but i have not been brave enough to order.... I'm afraid of getting knockoffs. So i buy from digi-key....

 

[WOPL Sniffer]

Was thinking of getting a group buy together for the adaptors but may not be many who need or want them. I go through a fair amount.

 

[grapplesaw]

http://cimarrontechnology.com/search.aspx?find=Rc4136

$5 each for board. Add$17 for two opa2314 added

 

[WOPL Sniffer]

Yup, I only have 2 left.....

 

[marcok]

Thank you guys !
I have tested the new one and the right channel is little noisy ( much better than before )
I' m sure that the guilty is RC 4136 located on the mother board , because
I also replaced the Peak Unlimiter board and I found the same issue .
Concernig C4000 you can see that the first stage of Riaa ( Phono 1 ) ,
tone amp and sonic hologram use TL074 .
Furthermore you can see that the tone circuit of PL2000 has a socket
for replacing it easily .
The conclusion is that it's critic op amp and that the problem was well known.
My opinion is that it's not compasated op amp .
At present I have ordered 3 Rc 4136 by TI
and now I order an adapter to fix the issue for ever ( I hope )
To be honest now you can hear the noise only with phones at
very very low levels when peak unlimeter is on .
Ciao
Marco

 

[marcok]

Just ordered an adapter with OPA 2134 pre mounted . ( 32.95 $ )
"Expansive" but necessary .I want to fix this issue for ever and ever .
Now I can easily test everything , because I mounted a socket .
Thank you again and ciao
Marco

 

[marcok]

Yesterday I replaced the RCA connectors in my PL 1000 ,waiting for Cimirron adapter
and now it works well : no noise , no distorsion .
Obviously before I had cleaned connectors many times , replaced 3 of them and so on .
It took me 10 days to find the issue .
The RCA connectors of PL 1000 and PL 4000 series 1 are a really plague !!!
Ciao
Marco

 

[WOPL Sniffer]

I just ordered 62 of the cimarron adaptor's and 2 OPA2134UA oamps for each of the Adaptors (124 opamps). I have 2 Carver 4000t preamps which are stripped and undergoing treatment which include replacing all the RC4136 chips. The specs on the 2134's blow the old 4136's outta the water. The treatment also includes adding a remote volume control kit to the unit so you can adjust the volume from across the room. As far as i know, nobody has done that with a 4000t so I'm having to "wing it". I'm just waiting on the 20k motorized pots to get here. They are hard to find in 20k ohms and most other units used either 50k or 100k so I've had to hunt hard. And, there is not much real estate availabe inside around the power supply so not just any remote board will fit. I'll post up some pics. Ive been testing the heat generated by the +12 vdc voltage regulator during cycling the vulume control motor. It comes up a few degrees and the +12 volts is very stable, so it should work pretty well. I got rid of the cheesy stamped tin heatsinks and doubled up on the biggest aluminum heat sinks i could fit in there. So he power supplies got totally rebuilt and i raised all the heat generating compnents up off the board. Fun fun fun.