FAQ  •  Register   •  Gallery •  Login

It is currently Wed Oct 22, 2014 3:06 am

Op-amp for Carver TFM-45

<<

gary_wong5

Newbie 50+

Posts: 70

Joined: Fri May 16, 2008 8:17 pm

Post Tue Mar 03, 2009 8:40 am

Op-amp for Carver TFM-45

I read and carefully studied the TFM-45 service manual in order to find out the reason of "hiss" noise and turn-off thumps and squeals. I came across these points:

(a) Page 21 - Bad TL081 op-amp (U1) on Amplifier Board causes "hiss" or "popcorn" noise
(b) Service Bulletin # TFM-45-6: To verify that 4558 IC's (U2) are either
XR4558 (Exar)
RC4558 (Raytheon)
whereby other brands 4558's can cause turn-off thumps and squeals

It is my surprise to see that the U2 op-amps' in my TFM-45 are of Japan Radio Corporation JRC4558D, non of above-mentioned. My question is why TFM-45 was factory-installed JRC4558D, instead of either one of above-mentioned. As both the Exar's and Raytheon's I believe is no longer available in Malaysia, is the RC4558P of Texas Instrument (Made in Malaysia :) ) identical in performance as compared to Raytheon RC4558?

I searched and found interesting information about the comparison between JRC4558D and RC4558P:

http://www.stinkfoot.se/andreas/diy/articles/opamps.htm

My second question is that will Texas' have less hiss or popcorn noise than JRC? In fact I have bought RC4558Ps' but still hesitate to give them a try. Is anyone here has experience on this regard?

I intend to change the U1 as well.
<<

BillD

User avatar

(pair of) SILVER-7 TUBE AMPs

Posts: 7295

Joined: Wed Jun 06, 2007 8:29 pm

Location: The west's most mid-western town, Scottsdale, Arizona

Post Tue Mar 03, 2009 12:59 pm

Re: Op-amp for Carver TFM-45

I'd just pop the RCs in there and give it a listen if the JRCs are giving you problems. Aren't the Raytheons available anymore? There are two TI chips available from Digi-Key, the RC4558P and IP. They cost less than 50¢. Or, you could try upgrading (especially that TL081) with better opamps. I'm quite fond of the OPA134 (or OPA2134). They are a little more expensive, but pin compatible with the opamps you're considering.
It should sound like it isn't there!
There is a difference between hearing and listening...
Making life enjoyable through expensive electronics.
_________________
Carver: C-4000 & C-1 preamps, PSC-60 preamp/tuner, TX-11a tuner, M-400 (2), C-500, M-500, M-500t, M-500t Mk.II, A-500x, AL-III loudspeakers (2 pr.)
Sunfire:Theater Grand III processor, Ultimate Receiver, Cinema Grand Signature 400 ~ seven, True Subwoofer Mk. II, D-10 Subwoofer
<<

gary_wong5

Newbie 50+

Posts: 70

Joined: Fri May 16, 2008 8:17 pm

Post Tue Mar 03, 2009 9:55 pm

Re: Op-amp for Carver TFM-45

BillD wrote:I'd just pop the RCs in there and give it a listen if the JRCs are giving you problems. Aren't the Raytheons available anymore? There are two TI chips available from Digi-Key, the RC4558P and IP. They cost less than 50¢. Or, you could try upgrading (especially that TL081) with better opamps. I'm quite fond of the OPA134 (or OPA2134). They are a little more expensive, but pin compatible with the opamps you're considering.


Dear BillD,
OPA134PA is available from RS Components made by Texas Instruments. Sure will give them a try. Is there any difference between TI OPA134 and Burr-Brown OPA134? Thanks a lot. :D
Last edited by gary_wong5 on Tue Mar 03, 2009 11:20 pm, edited 1 time in total.
<<

BillD

User avatar

(pair of) SILVER-7 TUBE AMPs

Posts: 7295

Joined: Wed Jun 06, 2007 8:29 pm

Location: The west's most mid-western town, Scottsdale, Arizona

Post Tue Mar 03, 2009 11:10 pm

Re: Op-amp for Carver TFM-45

For that RC4558P, make sure to get the OPA2134 (the dual). The TL081 the single (OPA134). If the originals aren't socketed, I'd put sockets in so you can swap opamps if these don't work out for you.
It should sound like it isn't there!
There is a difference between hearing and listening...
Making life enjoyable through expensive electronics.
_________________
Carver: C-4000 & C-1 preamps, PSC-60 preamp/tuner, TX-11a tuner, M-400 (2), C-500, M-500, M-500t, M-500t Mk.II, A-500x, AL-III loudspeakers (2 pr.)
Sunfire:Theater Grand III processor, Ultimate Receiver, Cinema Grand Signature 400 ~ seven, True Subwoofer Mk. II, D-10 Subwoofer
<<

Rainman

User avatar

SILVER-7t

Posts: 1023

Joined: Fri May 09, 2008 2:19 am

Post Thu Mar 05, 2009 1:08 am

Re: Op-amp for Carver TFM-45

I remember a thread some time ago regarding this exact topic, but I think it was something that came up during discussion under another topic. Someone replied that there was a service bulletin for this that had a very simple fix for it. If anyone remembers this please chime in...
In the meantime I will look further and see if I can find it. The TFM-45 that is in our main rig has no such issues, but one of our other amps that is a TFM-15 developed a similar turn off issue about a month or so before it stopped working. The problem ended up being the large main cap had bled out. I don't know it the two could be related or not, but I figured it was worth mentioning...

Rainman
Question: Do you know why turds are tapered on the ends? Answer: So your asshole doesn't slam shut..

Carver- SDA490t, SDA450, 2 TFM45's, TFM15, CT23, CT28v, CT27v, Linn Kaber speakers, Sunfire crm2's, PS Audio Statement speaker cables and I/C's, A.P.C. power
<<

gary_wong5

Newbie 50+

Posts: 70

Joined: Fri May 16, 2008 8:17 pm

Post Thu Mar 05, 2009 3:26 am

Re: Op-amp for Carver TFM-45

Now I recalled that the top side of one of the 2,200uF 80V has very slight bulge comparing to other piece. I always pay attention to all of the capacitors. :) Could be the reason of turn-off thumps. I shall recap and see if the problem resolve.
<<

gary_wong5

Newbie 50+

Posts: 70

Joined: Fri May 16, 2008 8:17 pm

Post Fri Mar 13, 2009 5:07 am

Re: Op-amp for Carver TFM-45

My ICs' have arrived today. OPA134PA Made in USA (in fact Made in Thailand) and OPA2134PA Made in Malaysia. I shall change all of them tonight. Eager to know how my TFM-45 will "sing" after modification. :)
<<

TNRabbit

User avatar

(pair of) SILVER-7 TUBE AMPs

Posts: 13335

Joined: Sun Jan 14, 2007 11:53 am

Location: TN Native Languishing in VA

Post Fri Mar 13, 2009 5:16 am

Re: Op-amp for Carver TFM-45

Did you already re-cap as well? Good luck!
TNRabbit
Image

From FrankieD's lips to your ears: Sunfire - a quiet box of endless power.

Sunfire TG-IV/400~7 Amp
Carver SD/A-360 CDP
Benchmark DAC-1
Sony SACD/DVD-A
Active bi-amp: Ashly XR-1001 & 2 Rane PEQ-15s
Main: HotRodded AL-IIIs
Sub: Klipsch RT-12d
Center: Sunfire CRS-3c
Surround: Sunfire CRS-3 (x 2)

OconeeOrange wrote:"Gary likes to play it 'loud' as do I. His system begs you turn it up until you die"

RIP WIlliam B. Dibble, 1948-2012. I'll miss you my friend.
<<

gary_wong5

Newbie 50+

Posts: 70

Joined: Fri May 16, 2008 8:17 pm

Post Fri Mar 13, 2009 10:17 am

Re: Op-amp for Carver TFM-45

Have not recap yet. Only 2200uF 90V available. The original spec 2200uF 80V only available from RS Components which require longer time. Can I use 90V instead of 80V?
<<

TNRabbit

User avatar

(pair of) SILVER-7 TUBE AMPs

Posts: 13335

Joined: Sun Jan 14, 2007 11:53 am

Location: TN Native Languishing in VA

Post Fri Mar 13, 2009 11:38 am

Re: Op-amp for Carver TFM-45

I'm not positive about that, but believe that shouldn't be an issue. We have a few resident experts techs who will be able to tell you for sure....give it a few days.
TNRabbit
Image

From FrankieD's lips to your ears: Sunfire - a quiet box of endless power.

Sunfire TG-IV/400~7 Amp
Carver SD/A-360 CDP
Benchmark DAC-1
Sony SACD/DVD-A
Active bi-amp: Ashly XR-1001 & 2 Rane PEQ-15s
Main: HotRodded AL-IIIs
Sub: Klipsch RT-12d
Center: Sunfire CRS-3c
Surround: Sunfire CRS-3 (x 2)

OconeeOrange wrote:"Gary likes to play it 'loud' as do I. His system begs you turn it up until you die"

RIP WIlliam B. Dibble, 1948-2012. I'll miss you my friend.
<<

gary_wong5

Newbie 50+

Posts: 70

Joined: Fri May 16, 2008 8:17 pm

Post Sat Mar 14, 2009 2:50 am

Re: Op-amp for Carver TFM-45

What is the magic have done by all these ICs'?!! Great! I have now very wide, precise and deep sound stage after putting them in my TFM-45.

No more high frequency squeal sound and the hiss noise is very little now. They really work. FANTASTIC!

The remaining problem is turn-off thump. [-o<
Attachments
14032009274.jpg
14032009274.jpg (614.28 KiB) Viewed 499 times
<<

engtaz

User avatar

"TAZ"

Posts: 5223

Joined: Sat Jun 30, 2007 1:43 pm

Location: Tampa, FL

Post Sat Mar 14, 2009 7:37 am

Re: Op-amp for Carver TFM-45

Congrats
engtaz


Carver M4.0T in front channels to Caver AL VI's in SACD & 2 Channel setup
C 16, PT 2400, Slim Device, Carver TX-8, 490T and Rega TT w Grado Gold cart in the 2 channel setup
Bogen SRB20 is computer amp
Carver PM-350 donated for youth church use
<<

gary_wong5

Newbie 50+

Posts: 70

Joined: Fri May 16, 2008 8:17 pm

Post Sat Mar 14, 2009 8:02 am

Re: Op-amp for Carver TFM-45

BillD, thank you very much for recommending these ICs'. I suggested that all TFM owners must try out this upgrade. =D>
<<

gary_wong5

Newbie 50+

Posts: 70

Joined: Fri May 16, 2008 8:17 pm

Post Sat Mar 14, 2009 8:11 am

Re: Op-amp for Carver TFM-45

I have bought shielded power cable Supra LoRad 2.5 for upgrading. Better performance? Any comment?

Return to CARVER Equipment Repair/Help Forum

Who is online

Users browsing this forum: Bing [Bot] and 1 guest

Powered by phpBB © 2011 phpBB Group.