Transparent passive pre-amps?

jon

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I'd like a passive pre to use with a Behringer a500. The output volume of my sources and sensitivity of the Behringer's inputs is high enough that there's ample room to attenuate. Will it be hard to find a transparent passive pre (transparent in the sense of attenuating the volume while other changes remain too small to hear) - any suggestions? A lot of pre-amps seem to be sold with unconvincing claims about cable quality etc...

The sources are Cambridge Audio CDP and DVD, and a Sony TV - so don't know if I need to worry about impedance matching?

 

myles

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Couldn't be further away unfortunately. For info I am using an NVA P50 passive pre and it seems pretty good.

 

Man in a van

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NAM

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i used this between a dacmagic and active speakers- http://www.tcelectronic.com/level-pilot/

it's balanced but 1 in 1 out so you might need a separate source selector

This one does balance and unbalanced http://www.dv247.com/studio-equipment/sm-pro-nano-patchplus--passive-stereo-volume-controller-silver--83351

I reckon both of those will be completely transparent. Certainly the TC electronics was well built, looked good and did the job. Both get good write ups on pro sites. I would've probably preferentially gone for the nanopatch but I could buy the TC one in Edinburgh and I was impatient :p You can get the nanopatch for £50 delivered from dv247. I got the TC level pilot for £70 or so

 

SergeAuckland

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i used this between a dacmagic and active speakers- http://www.tcelectronic.com/level-pilot/it's balanced but 1 in 1 out so you might need a separate source selector

This one does balance and unbalanced http://www.dv247.com/studio-equipment/sm-pro-nano-patchplus--passive-stereo-volume-controller-silver--83351

I reckon both of those will be completely transparent. Certainly the TC electronics was well built, looked good and did the job. Both get good write ups on pro sites. I would've probably preferentially gone for the nanopatch but I could buy the TC one in Edinburgh and I was impatient :p
I use a Level Pilot for my Genelecs, and have used resistive passive controllers with various amplifiers and active 'speakers.

ALL of them are transparent in that there is no added noise or distortion, at all, none, (and before anybody pipes up, what about thermal noise, yes OK then.) As to frequency response variations, that depends on the value of the volume pot and the length and capacitance of the cable from the volume control to the amplifier. With a 10K pot, you can happily put about 5m of RG59 or RG6 cable with no effect in the audio band.

The nice thing about the Level Pilot is that it's balanced, and has a good knob-feel!

As to transformer passives, those should also be transparent, but with a tapped transformer there are rather more variables than a simple pot.

S.

 

NAM

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I use a Level Pilot for my Genelecs, and have used resistive passive controllers with various amplifiers and active 'speakers.ALL of them are transparent in that there is no added noise or distortion, at all, none, (and before anybody pipes up, what about thermal noise, yes OK then.) As to frequency response variations, that depends on the value of the volume pot and the length and capacitance of the cable from the volume control to the amplifier. With a 10K pot, you can happily put about 5m of RG59 or RG6 cable with no effect in the audio band.

The nice thing about the Level Pilot is that it's balanced, and has a good knob-feel!

As to transformer passives, those should also be transparent, but with a tapped transformer there are rather more variables than a simple pot.

S.
It is a really nice knob to feel. Smooth with just enough resistance...not too easy. Enough to make you feel like you're working for it.

 

jon

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*blush* 'knob-feel'

Anyway, both look good - thanks! The level pilot only does balanced input? In which case, the SM Pro Nano seems a better better - save getting cables to go from unbalanced to balanced inputs.

And thanks Myles - but, as you say, a good way away from me!

 

SergeAuckland

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*blush* 'knob-feel'Anyway, both look good - thanks! The level pilot only does balanced input? In which case, the SM Pro Nano seems a better better - save getting cables to go from unbalanced to balanced inputs.

And thanks Myles - but, as you say, a good way away from me!
You can unbalance the ins and outs of the Level Pilot just by connecting pin 1 to Pin3 on the XLRs. I'm using mine that way on the input, going from a DVD player unbalanced output to the Genelecs. With the A500, I suggest you go into the Level Pilot unbalanced and come out balanced into the A500, unless you want to use the A500's phono inputs.

S.

 

NAM

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You can unbalance the ins and outs of the Level Pilot just by connecting pin 1 to Pin3 on the XLRs. I'm using mine that way on the input, going from a DVD player unbalanced output to the Genelecs. With the A500, I suggest you go into the Level Pilot unbalanced and come out balanced into the A500, unless you want to use the A500's phono inputs.S.
Is it a £30 Tesco DVD player?

 

pgarrish

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You can cobble together a passive based around an Alps pot for about 30-40 quid. I've just built one around a DACT stepped attenuator and find it much better, but the attenuator is £130 on it's own. A transformer (TVC) passive will add gain if you need it (your A500 may be sensitive but your input signal may not be that large)

 

jon

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You can unbalance the ins and outs of the Level Pilot just by connecting pin 1 to Pin3 on the XLRs. I'm using mine that way on the input, going from a DVD player unbalanced output to the Genelecs. With the A500, I suggest you go into the Level Pilot unbalanced and come out balanced into the A500, unless you want to use the A500's phono inputs.
Thanks. Would I still need a phono to xlr cable to make the connection, though, or does the level pilot have phono inputs?

 

vacdac

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Using your existing phono leads with Neutrik Phono sockets to XLR adapters should also work they're v high quality & less than a tenner each. I've used them myself in the past to give added hookup flexibility.

Given your eqpmt I'm fairly sure this would be fine as its all mainstream stuff & there shouldn't be any odd pin configurations.......safest to check with Serge I should think. :^

Thanks. Would I still need a phono to xlr cable to make the connection, though, or does the level pilot have phono inputs?
 

NAM

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Using your existing phono leads with Neutrik Phono sockets to XLR adapters should also work they're v high quality & less than a tenner each. I've used them myself in the past to give added hookup flexibility.Given your eqpmt I'm fairly sure this would be fine as its all mainstream stuff & there shouldn't be any odd pin configurations.......safest to check with Serge I should think. :^
...or likewise you can easily get phono to jack adapters like this for pennies

preview.jpg


You can order 4 of these for £2.56 from DV247

 

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