Belle attenuation advice sought

[TommyK]

Greetings,

I have a pair of beautiful Belles (vintage 1976) in the family room. I am running a Nobis Cantabile (el34 pp 35 watt) amp and matching Proteus pre amp thru the line stage. My source is a PS Audio Ultra Link DAC and sony NSV500 DVD player. My problem is the Belles are just so efficient that I can't set the volume to moderate levels. They sound great mind you, but even turned up a RCH, I am blown away. I have swapped out the Pre for a pair of EVS volume attenuators and I can control the volume slightly better, but still not to a point that allows me to control volume as one would expect.

What are my options?

I have other amps in other systems in the house, eg, mc30, Bottlehead SETS, MAC MA 6100, Marantz 2275, etc, but the Nobis is the one that gets the Wife's nod for aesthetic, so I am loathe to burn 'credits' bringing in something else to pole position in the family room.

Thanks in advance.

TommyK, New Jersey

[leok]

Interesting other amps of yours with similar power capabilities dont have similar gain (the Nobis Cantabile claims about 1.12V sensitivity (for the full 35W I assume). It's not unusual for an amp to have "sensitivity" of just over a Volt for full output.

I wonder if your sources put out over a Volt at full output. I think around 2V is "spec" for cd players. Do the sources have low output level options?

All I can think of is using fixed resistors to additionally pad the passive gain or get into the Nobis Cantabile itself and reduce its gain (might not be a reasonable thing to do depending on the circuitry).

Leo

[D-MAN]

Pre-amp. Try for an impedance "mismatch" by using aux-in, phono-in or other input (each has a different impedance). This may help. Or not.

DM

[TommyK]

Thanks for the reply. I tried the Bottlehead SETs (parabees and paramours) on the Belles and the gain was not too much) though not using the Foreplay pre, which has a gain problem as well. But the SETs are not wife friendly - and lately I like a little Negative Feed Back - from my amps - not my wife.

My Mac MA 6100, doesnt have the gain problem, but is SS and I really like the sound of the Belles with tubes.

I will try a different input - stranger things have worked before.

Peace,

TommyK

[3dzapper]

Tommy, A pair of inline attenuators might do the trick like these from Rothwell. I know there are more a quick Google search came up with these.

http://forums.klipsch.com/idealbb/files/attenuators1.jpg

http://www.rothwellaudioproducts.co.uk/html/attenuators.html

Rick

[Erik Mandaville]

Hi, Tommy:

In addition to what Rick has suggested, the inline attenuators, it's possible to get some better control of the problem on the input of the preamp rather than the output. Adding series resistance between the preamp and amplifier can reduce volume as well as sometimes improve signal to noise ratio characteristics, but sometimes at a small cost -- possible mild roll-off of HF information. It would certainly be the easiest way to do it.

Another would be to pad the input of the preamp (you're using a Foreplay)by using lower value volume controls. The Foreplay comes with a 100K ohm potentiometer, and I use two 10K ohm pots (well, I did when I was building different examples of the Foreplay...I'm not using any of them now). In other words, the higher the input impedance of the preamp, the greater the sensitivity -- which can translate into very hyperactive volume controls. Another thing you can do, which does work well, is use level controls for each channel in conjunction with the main volume control on the preamp. To keep it simple, Rick's idea should do the trick. I've got another idea, too.

If you really like the Foreplay, I'd be glad to help you with it if I can. I have the schematic for it etched into my memory like an intaglio print!

Good luck, it should be easy to remedy. The horns are nice, though, aren't they!?

Erik