B1 Buffer Preamp

Here's the stuffed boards from above.
I call it a B1 6 pack
:cheers:
Bob
 

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It Works!

I finally got around to testing the Cigar Box B1. I inserted it into my bathroom system where normally a Tivoli Audio Songbook plays through a T-Amp into speakers mounted in the wall. I am using my Nokia 810 Internet Tablet as the source and the T-Amp cranked up all the way as the power amp.

Right now I am listening to a flac file of John Mayall's Bluesbreakers playing loud and clear.

This system is certainly not a big test of high fidelity, but it sounds pretty darn good. I am so psyched!:)
 

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I am thinking about using a B1 buffer directly after my attenuator, to lower the impedance so i wont suffer from any wiring problems to my preamp, as i plan to put the attenuator in a seperate enclosure, before my preamp input (preamp has no method of volume control).

Is there any problem with using the B1 before my voltage gain preamp?
 
AndrewT said:
Hi,
the B1 buffer will drive the cables and input of your pre-amp OK. But the output impedance is not very low. It's ~1kohms and needs you to be sensible with capacitance to avoid rolling off the treble.

But, do you need a gain stage in the pre-amp?
Do you need the pre-amp?

Yes, i do need the preamp. My sources have suprisingly low voltage outputs, the diffrence when using a active preamp is phenomenal. The prime purpose of using the B1 was not as a preamp, but to be able to use a external attenuator. I allmost definitely need a gain stage.

What would i need to do to avoid rolling off the treble? The B1 would have around 6 inches of cable between it and the preamp.
 
AndrewT said:
Hi,
would you be better off placing the volume pot after the pre-amp and then buffer the pot output to send it on it's way to the power amps?

6inches (150mm) of cable should have no audible effect on frequency response. 6m might have. Try using a very long cable and listen for treble loss.

Dont think this would be the best idea, as my pre doubles up as a headphone amplifier. :(

What problems may i run into putting the pot before the pre? My preamp doesnt really care about having a high Z input, i just dont want any degration of the signal on its way there!
 
taking a low level signal and boosting it and then adjusting the attenuation will result in an improved S/N ratio.

The earlier the low signal is boosted the better for S/N ratio.
Why do they have masthead amps outside to brave the weather?
Why do MM & MC pre-pre perform better when located at the turntable rather than in the integrated amp?

If S/N is not an issue then ignore all this.