Bi amping with a C-1

[WOPL Sniffer]

Has anybody tried this ???


Have you ever tried to run 2 amps with a c-1? I think since I'm running my speakers with my 400 WOPL on the L/R tweeters and mids, and I'm running my 700 WOPL on the L/R woofers (Horizontal Passive Bi-amping), that the main out 1 and 2 are not set up right to be able to do that. My Acurus RL-11, the pre-outs are exactly the same and bi-amping with it right now sounds excellent but the C-1 sound terrible. ???? Time to go over the C-1 skizmo. The main 2 circuitry seems to be a bit different than main 1 circuitry and this is without the gain being changed. Hmmmmm.

 

[Gepetto]

Main 1 and Main 2 originate from the same op amp output, Main 1 goes through a 200 ohm series resistor to the output with a 36K resistor to ground after the 200 ohm resistor. The Main 2 output is the same with a 200 ohm series resistor but no 36K resistor to ground. Are both outputs distorted?

Perhaps the 22uF electrolytic coupling cap is shot (dried out and high impedance). The Acurus uses a very large, high quality film cap to couple to the outputs.

 

[J!m]

Sounds like a high and low gain output.

 

[Gepetto]

Sounds like a high and low gain output.

Not really, they both share the 36K pulldown...

 

[WOPL Sniffer]

Main 1 and Main 2 originate from the same op amp output, Main 1 goes through a 200 ohm series resistor to the output with a 36K resistor to ground after the 200 ohm resistor. The Main 2 output is the same with a 200 ohm series resistor but no 36K resistor to ground. Are both outputs distorted?

Perhaps the 22uF electrolytic coupling cap is shot (dried out and high impedance). The Acurus uses a very large, high quality film cap to couple to the outputs.

Yeah, both outputs (so both amps) sound bad. What about the 2 pairs of transistors on the outputs at Main 2? Q205 and 305??

 

[WOPL Sniffer]

The headphones sound great.

 

[WOPL Sniffer]

All new coupling caps.

 

[WOPL Sniffer]

The book says you can use EITHER but it doesn't say you can use both at once.

 

[TimD]

Preamps are not designed to biamp - they lack a suitable crossover. Get one, drive it with the C1 (or any preamp of your choice) and big profits . . .

 

[WOPL Sniffer]

I know when we change the Gain on the pre, it only changes the gain for Main 1 and it doesn't change Main 2.

 

[J!m]

Seems easy enough to add a switch to make both sets either the same or “stock” configuration.

 

[WOPL Sniffer]

Preamps are not designed to biamp - they lack a suitable crossover. Get one, drive it with the C1 (or any preamp of your choice) and big profits . . .

The Acurus drives 2 amps no problem. The Martin Logans also say DO NOT USE ACTIVE crossovers as these cannot be Bypassed.

 

[WOPL Sniffer]

Comparing the C-1 to the Acurus, the Acurus has both Pre-Out Jacks wired exactly the same. Not so on the C-1 jacks. I'll have to look at the C-4000 and the 4000t but I think the circuit will be the same as the C-1. If I wasn't Vertical Bi-Amping The C-1 would be fine. The Output impedance between Main 1 and the Output Impedance on Main 2 and the 400 driving the Mids/Tweets and the 700 driving the woofers, there is an imbalance causing it.

 

[TimD]

The Acurus drives 2 amps no problem. The Martin Logans also say DO NOT USE ACTIVE crossovers as these cannot be Bypassed.

By professional standards, no signal level crossover means that you are *NOT* biamping . . . (Driving 2 amps with the same signal is *NOT* biamping, it is simply multiple amps.) Bi/Tri/Quad amping are line level crossover driving amps that feed one frequency range of drivers each. (Any other definition is audiophool bull$h1t!)

 

[Gepetto]

I know when we change the Gain on the pre, it only changes the gain for Main 1 and it doesn't change Main 2.

Main 1 and Main 2 are driven by the same op amp output Perry, I would expect any gain changes to affect both.

 

[TimD]

Main 1 and Main 2 are driven by the same op amp output Perry, I would expect any gain changes to affect both.

Same signal, likely same gain, no way that's a biamp out unless a crossover was inserted to drive the two outputs separately (which does not seem like too bad of an idea, actually . . . )

 

[J!m]

Lift that 36k.

 

[Gepetto]

The Acurus has a specified 50 ohm output impedance. Not so for the C-1 based on the way that Carver implemented the output muting circuit.

Inspection of the C-1 schematic shows that the C-1 has 51 (R241)+910 (R268)+200 (R258) ohms (1161 total) as an output impedance (23x the Acurus)

Advantage Acurus in this scoring category. I did not take into account any additional effect that the Hologram circuit contributes if it is switched in.

This output impedance difference goes a long way to explain the superior performance of the Acurus in driving 2 simultaneous amplifier input loads.

 

[marcok]

I don't understand why there is the 36k resistor only on main 1.
I have been using my C 4000 connected ( using both outputs ) to 2 x M400 A that power a pair of AR 9 in
passive bi amp mode . The sound is great .
Declared output impedance 910 Ohm ; very difficult to see if there is the 36 k resistor .
Perry try with a Y cable , I ' m very curious .
Ciao
Marco

 

[marcok]

Declared input impedance of M400 : 15 KOhm