Carver C1 going through rework

[laatsch55]

Nice work Perry. What's the residual noise number when you're done?

 

[laatsch55]

Did you run just a noise measurement, without distortion?

 

[WOPL Sniffer]

Did you run just a noise measurement, without distortion?

Sorry Lee, those numbers are not correct.

I set the AP for 250mv @1Khz, both channels driven, and turned the volume knob up for 525mv out (it puts the volume knob @the 2 o'clock position with my gain jumpers down to the 3db setting which is the sweet spot for the volume pot which I experimented with). Unweighted swept from 2-25Khz. shes very flat.


The THD + N is way down.

 

[laatsch55]

Try shorting whatever input you want to monitor, volume control all the way down, put the AP on noise and run a sweep. That'll be residual noise. You can also run a level sweep with no input. Noise selection on the AP is more accurate IIRC.
GOOD NUMBERS ON THE THD & N.

 

[WOPL Sniffer]

I think the THD + N reveals pretty much what to expect out of the Pre.... I think the residual sounds Moot.

The Noise while "In Work" (THD + N) is what you want to know. I want to know what the distortion and noise are during use.

 

[laatsch55]

I think residual gives a good baseline on the
unit under test...basically how well the circuit is designed and how noise in general is treated by the designer.
Throughout Joe's introduction and revision of the driver boards and backplane there has been a steady decline in residual noise. And we know because we tested for it. I think it's a handy measurement.

 

[WOPL Sniffer]

Even the mfg didn't show that.... As a designer, Joe may want to measure EVERYTHING but as a tech It's unnecessary.

 

[laatsch55]

Unnecessary? Maybe, but I like to know..

 

[WOPL Sniffer]

and what would you do with the results if your residual noise was bad, and How would you know it's bad since the book does NOT say what it should be? And, if you had a pre that had .005% THD+ N, would you care?

 

[laatsch55]

You wouldn't know it was bad without a published spec. But a lot of stuff I own has a spec for residual noise so i like to see how other stuff measures up.

And we all know that specs aren't the be all end all for judgement of how good a unit will sound. A Spec 2, spec wise, wipes the floor on a 700 except for power, and sounds"sterile" to how a WOPL sounds. No comnparison to which one I like. But noise is a different animal. It does matter when you can start hearing it. IIRC it was about 1mv with volume all the way down on my horns. And like I said, it's a pretty good indicator of how well designed a unit is. I've had the AP hooked up, in noise mode, to a WOPL while moving the control board into and away from the backplanes, or moving the pot wires around in the chassis, and it became evident, that wiring placement had an effect on noise. So, it has its place as something to measure...

 

[WOPL Sniffer]

You keep talking about the engineering of a WOPL..... which this aint.

 

[laatsch55]

Yes, I understand that Perry....,

 

[MarkWComer]

What the hell, though- Why did Mr. Carver put separate bass/treble controls for l/r channels?
More knobs make his components look more impressive?

...just don’t get that one.

 

[MarkWComer]

The 4000t is by far a way better Pre amp with more bells and whistles. The C-1 (and the C-2 for that matter) are no frills pre's and respond well to the mods but you can't beat the 4000t for looks and features. Skip the Carver C-4000 if you can since the rear speaker amp and crappy power supply adds to the complexities when upgrading.

Advice well taken, and as a crow is attracted to shiny things, so am I toward “bells and whistles.”
But... isn’t the 4000t of similar architecture to the PL4000? Filled with daughtercards and edge connectors?
Better to avoid the headache than to stock up on aspirin!

 

[WOPL Sniffer]

Advice well taken, and as a crow is attracted to shiny things, so am I toward “bells and whistles.”
But... isn’t the 4000t of similar architecture to the PL4000? Filled with daughtercards and edge connectors?
Better to avoid the headache than to stock up on aspirin!

The 4000t does have motherboard/daughter cards however, that is where the comparison ends. Carver used real connectors not the troublesome junk that the PL4000 (with joystick) had. The Noise issues were straightened out from the C-4000 and they got rid of the rear amp. The 4000t is Da Bomb....

I have never had issues with the connectors on a 4000t.

 

[MarkWComer]

The 4000t does have motherboard/daughter cards however, that is where the comparison ends. Carver used real connectors not the troublesome junk that the PL4000 (with joystick) had. The Noise issues were straightened out from the C-4000 and they got rid of the rear amp. The 4000t is Da Bomb....

I have never had issues with the connectors on a 4000t.

(Mark changes his mind about the C1, then...)

 

[oldphaser]

Here is a copy of the Carver C-1 service manual; 6.15 "Noise Tests" along with 6.1 "Pre-Sets".

 

[WOPL Sniffer]

Here is a copy of the Carver C-1 service manual; 6.15 "Noise Tests" along with 6.1 "Pre-Sets".

SO what's your point? and who pulled your chain?

 

[WOPL Sniffer]

and what would you do with the results if your residual noise was bad, and How would you know it's bad since the book does NOT say what it should be? And, if you had a pre that had .005% THD+ N, would you care?

According to the Service manual, individual tests may be ran if needed. The ones so kindly pointed out by old phaser were not needed. My amplifier fits into none of those conditions so I RAN THE BARE MINIMUM .

This is MY personal C-1, not one coming in to be serviced from the field. You run what you want to run, and I'll run what I WANT to run. If the unit is not exhibiting any issues, there is NO need to run all that shit.

Section III and associated test set ups/functional verification as pointed out by him addresses complaints of the customer or noticed sound issues (OF WHICH MY PRE HAS NONE). Now if you have nothing constructive to say, go away and post somewhere else. Causing shit and arguing here serves no purpose.

 

[laatsch55]

Perry, I don't get it man. Nobody's up in your face, no one is trying to gig ya, no one is trying to trip you up on anything, we're just trying to have a conversation about noise, plain and simple. I think youre a helluva hand, I'm running one of YOUR amps! And I love the thing...I guess I don't get why you get defensive. I see no reason for it most of the time. Your work is exemplary, but dude chill a bit and don't take things so serious....I'd asak a lot more questions, but I don't seem to be able to phrase em right to keep from triggering you. A simple question about noise Perry.....