Carver amps

[cs]

My home stereo system has a nice amp/pre-amp set up. I have a matched pair of Carver amps, a C-5 Pre-amp and a TFM-55 power amp. But I've been at odds witht the system here of late. It seems that the left channel is not working properly. At first I thought it might be the power amp, but after some cable changes and trying a few different things I do beleive that it is the pre-amp.

After switching speakers from left to the right and the bad sound went from one speaker to the other, ruling out bad speakers or bad speaker wire. I worked on the connections between the two amps and the Bose 901's convertor box with no sucess. Without another set of amps to help isolate the problem I was having a hard time figuring out where the problem was. Then it hit me, the C-5 has an output for a remote amp. With the C-5 you can basically run two different power amps off of the pre-amp and thus use the same equipment to run two systems (i.e. one in each room). So I took the power amp and moved the connections over to the remote amp output on the pre-amp and the problem went away. So this tells me that there is a problem in the pre-amp on the left channel output for the main power amp. Does this sound reasonable?

So with that in mind I'm wondering if I should go ahead and fix the Carver Pre-amp or look for another amp? I love my Carver amps and would hate to break up the set. I would probably spend about $100 to fix this pre-amp but I do believe that it is worth it.

What thinks you?

Chad

[Norman Bernstein]

Does this sound reasonable?

Yes.


So with that in mind I'm wondering if I should go ahead and fix the Carver Pre-amp or look for another amp? I love my Carver amps and would hate to break up the set. I would probably spend about $100 to fix this pre-amp but I do believe that it is worth it.


Only YOU can answer that question.... it's a judgment call, having to do with personal preference, not economics.

[delecta]

Is there some disadvantage to running with the amps in the remote inputs, if not why do anything?

[cs]

I guess the question was more of has the quality of pre-amps improved so much as to make the 20 year old Carver Pre-amp obsulte or is the Carver still considered top tier? I love the sound and power of the Carver amps and really the heart and soul of a system is in the power amp, but will a lesser quality pre-amp hurt the sound?

Chad

[cs]

Is there some disadvantage to running with the amps in the remote inputs, if not why do anything?

Yes there is a little disadvantage, stuff like the onboard bass and treble controls and sonic hologram on the pre-amp only work for the main amp.

BTW I don't have an external equalizer because with Bose 901's you are not supposed to run them.

Chad

[htom]

Fix it. The modern stuff isn't as good. Actually, most of the modern stuff is horrible.

[Norman Bernstein]

I guess the question was more of has the quality of pre-amps improved so much as to make the 20 year old Carver Pre-amp obsulte or is the Carver still considered top tier? I love the sound and power of the Carver amps and really the heart and soul of a system is in the power amp, but will a lesser quality pre-amp hurt the sound?


More likely, you'd probably dislike the 'modern stuff' because it doesn't have the pleasurable distortion characteristics of the relatively ancient Carver stuff. Modern op amps are so good these days, things like distortion, slew rate, noise and hum, etc., are ancient history.

Anyhow, where can you get it fixed for $100? From what I've heard, Carver is long since defunct. If you have the schematic, someone competent in circuitry might be able to fix it, presuming it's not some oddball component that has soiled the bed.... I've seen that earler Carver amps used motor pots for remote volume control... they've been obsolete for decades. Have you got the schematic?

[delecta]

Fix it. The modern stuff isn't as good. Actually, most of the modern stuff is horrible.

Depends on where you shop I suppose, lots of new tube gear out there that is fantastic.

[Norman Bernstein]

I did a bit of searching; it doesn't appear that the C-5 service manual (which contains schematics) is available for free on the web, although at least one site had it for sale for $30. The owner's manual is widely available, however.

Just for chuckles, I did take a look at the Carver C-2 and C-1 schematics.... they are typical of mid-80's design; discrete transistor pairs in the phono preamp inputs, coupled to fairly ordinary op-amps (this was done because really good op-amps with the kind of low noise and high gain characteristics needed for phono preamps had not yet been developed). The rest of the design is classic linear op-amp based design. Basically, if you're NOT using a turntable, any decent modern transistor pre-amp should sound exactly the same, plus or minus 'sonic holography' :)

[cs]

There is a high end audio shop here in town that can work on this for me. He has done some work for me in the past and he is real knowledgable in the Carver stuff.

Chad

[Mrleft8]

Don't you think the stereo in your new car will be enough? Just park it under the bedroom window and roll the windows down. :D

[Bob Adams]

I guess the question was more of has the quality of pre-amps improved so much as to make the 20 year old Carver Pre-amp obsulte or is the Carver still considered top tier? I love the sound and power of the Carver amps and really the heart and soul of a system is in the power amp, but will a lesser quality pre-amp hurt the sound?

Chad

Total junk. Obsolete. Filled with hazardous substances, if you send them to me, I'll releive you of the enviro responsibility;)

[cs]

Not even sure if a car like that has a stereo. The rumble of engine and the squell of the tires is music enough.

Chad

[cs]

Total junk. Obsolete. Filled with hazardous substances, if you send them to me, I'll releive you of the enviro responsibility;)

And I bet you would even dispose of it for me without charging me a hazadorous material fee.

Chad

[Bob Adams]

And I bet you would even dispose of it for me without charging me a hazadorous material fee.

Chad
Only because I like you!:D

[P.I. Stazzer-Newt]

.... and really the heart and soul of a system is in the power amp, .....

Oh Goody - a truly pointless argument.

I have for a long time believed that the heart and soul of any domestic sound system which lacks a turntable - is the speakers - nothing else makes as big a different to the sound you hear.

The other hot contender for "heart and soul" - was my collection of recorded music - but now I have Spotify.

[cs]

The speakers are key, but good speakers without good clean power is useless. BTW I think that I'm okay in the speaker dept with Bose 901's.

Chad

[delecta]

The speakers are key, but good speakers without good clean power is useless. BTW I think that I'm okay in the speaker dept with Bose 901's.

Chad

Like an incredible meal, all the main ingredients need to be top notch for the end product to be delicious.

Paul Klipsch was walking down the street and saw Amar Bose on the other side, Paul cupped his hands together and yelled out Hello, Amar turned to face the store front and yelled back hello. To his dying day Paul has no idea why Amar never said hello back. :D

[cs]

Took me a second, but that was a good one! I would use that with other folks but they wouldn't get it.

Chad

[delecta]

I've lusted for a pair of 901's for some time now but with three pair of Klipsch I need more speakers like I need a hole in the head. From what research I've done the best ones to get are the series I which have the cloth surrounds on the drivers, the foam seems to deteriorate over time and with 18 drivers it gets expensive to repair. I also read that placement is really important and the need for at least 200 wpc to drive them because you need to play them quite loud. I understand the sound is more like being in an auditorium but this is just what I've read about them. I did hear a pair of 501's 25 years ago and was impressed with the sound but location and drunkenness so colors the memory.

I've also had two cars that required the Bose amps rebuilt for around $500.00 a piece and the cd player on my lifestyle stopped working. I'm glad I kept it though because the ipod has pretty much replaced the cd anyway.

[Lew Barrett]

What Norman said. Needs an op amp.

[cs]

One correction, I was going off memory. My Amp is not a TFM-55 but rather a TFM-35.

Placement is important for the 901's but I'm not going to say absolutely critical. No they don't need a perfect room and they do sound good at all volume levels. Now my amp at 8 ohms pushes 250 wpc. My 901's are Series VI and rated as a min of 10 watts per channel and the "Maximum power unlimited in a non-commercial applications." Yes it does sound more like an auditorium.

Chad

[cs]

I had always been told and I'm sure that I read it somewhere that you couldn't use an external EQ with 901's. Yesterday I did the live chat thing with a Bose rep and he said that you could. Of course you still have to use the Bose active EQ, but as long as you don't use something that distorts the sound it is okay. The last thing going to the speakers need to be the Bose active EQ so you would put the EQ between the power amp and the Bose active EQ.

Chad

Sent from my DROIDX using Forum Runner

[htom]

I had always been told and I'm sure that I read it somewhere that you couldn't use an external EQ with 901's. Yesterday I did the live chat thing with a Bose rep and he said that you could. Of course you still have to use the Bose active EQ, but as long as you don't use something that distorts the sound it is okay. The last thing going to the speakers need to be the Bose active EQ so you would put the EQ between the power amp and the Bose active EQ.

Chad

Sent from my DROIDX using Forum Runner

? I suspect something got lost there.

pre-amp --> equalizer --> Bose Active EQ --> power amp --> speakers

or

pre-amp --> equalizer --> power amp --> Bose Active EQ -->speakers

(I'm not sure where in the chain Active EQ goes, or what it does.)

[P.I. Stazzer-Newt]

? I suspect something got lost there.

pre-amp --> equalizer --> Bose Active EQ --> power amp --> speakers

or

pre-amp --> equalizer --> power amp --> Bose Active EQ -->speakers

(I'm not sure where in the chain Active EQ goes, or what it does.)

http://www.scribd.com/doc/29319328/Bose-901-Series-l-Ll-Service-Manual

[Flying Orca]

I just have one, very tangential observation for this thread: musicians don't tend to be audiophiles. I don't know why, but pretty much without exception, the only time musicians care about the quality of a recording is when it's their own or when they're playing the "how did they do that" game. Maybe it's because they're listening to the performance and not the recording, if you know what I mean by the distinction... but I've long found it interesting that there's so little overlap between musicians and audiophiles.

[Gerarddm]

You could never pry me away from my pair of JBL Century 100s. Never. Dinosaurs yes, but big LOUD dinos, baby. Can they ever take it.

[htom]

Ahh. Thanks for the link. Some of them are actually both before and after the power amp. This way, then:

pre-amp --> equalizer --> Bose Active EQ --> power amp --> speakers

[cs]

I couldn't see the link on my phone but here is the way I am now.

Preamp-power amp- Bose active EQ

If I do an external EQ I will probably go

Preamp-power amp -EQ-Bose active EQ

The Bose active EQ is supposed to be the last in line prior to the speakers. Aside from minimal base and treble controls the active EQ filters out the poor quality sound. This is what helps give the 901's their quality sound and that is another reason that a quality amp with a low THD is important.

Chad

Sent from my DROIDX using Forum Runner

[htom]

If you've connected the Bose Active EQ between the power amp outputs and the speaker system inputs, you've probably blown parts of the insides of the Active EQ; it's designed to be before the power amp in the signal chain. There are EQ devices that do work on that high-level signal, but this isn't one of those; there are other EQ devices that work at both the input end and output end of the power amp(s), this isn't one of those, either. It goes before the power amp (and after the pre-amp; on the back of an integrated amp should be connectors labeled "pre-amp out" and "power amp in", or like that, and it plugs in there.)

[cs]

Your right, I had a brain fart. The pre amp goes to the eq which goes to the power amp and then the speakers. I don't know what I was thinking, I just was around the back of it the other day fooling around with connections.

Chad

Sent from my DROIDX using Forum Runner

[Lew Barrett]

The reason the Bose take an active eq is because they use a multiplicity of full range drivers (4", if I recall for the 901), the bulk of whose energy is then asked to careen off the back wall. "Full range" is a bit of a misnomer in the sense that a 4 inch driver usually has relative difficulty reproducing flat response at the extremes. In Bose's case, by the time you couple nine 4" drivers, you probably have a reasonable crack at extended bass, but the high end will not be extended unless you equalize it back in, especially if you are not transmitting it directly. E.Q. is applied to get them back to flat, and (possibly) the single forward firing 4 inch driver would not likely do much for high frequencies without e.q. as well. This is all part of the scheme to compensate for their unusual driver arrangement. It's also likely the reason (coupled with the fact that theirs is sealed box) that the 901s are not highly efficient. The design suggest that Bose is shooting for flat power response in the room as well (that is broad dispersion). Any additional e.q. added by the user will be to compensate for program deficiencies or taste and should certainly be kosher. The thing is, you can't do without their e.q. if you want flat power or flat frequency response as defined by them for the system. Their processor is specifically designed to compensate for irregularities in their room response, nothing more.