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Siberia 10th February 2011 09:12 AM

To gain or not to gain / B1 vs B3?

New and excited of venturing into DIY world. I'm about to go for my first project (building cables doesn't count, I guess), but I'm a little bit lost in desicion, which of preamps would suit me best.

Mostly, I listen to vinyl.

The signal path is TT to Graham Slee Revelation phono pre:

Nominal output: 532 mV rms
Maximum output: 5.3 V rms prior to clipping at any frequency
Gain: 42.5 dB (Suitable for Moving Magnets and High Outputs Moving Coils)
Recommended minimum load impedance (output): 10k Ohms

Revelation to Passive Volume controler and this one to QUAD 707 current dumping amplifier:

130 watts into 8 ohm
775mV input for maximum power out
20K ohm input impedance

Amp to three-way, reflex-loaded, Spendor S100 speakers:

Sensitivity: 89.5dB/W/m (2.83V). Nominal impedance: 8 ohms (minimum 5.7 ohms). Amplifier requirements: 15-150W

I'm not listening to music on high colume levels, but when I reach certain point I feel like higher frequencies are rolling off.

My question is, which of DIY Pass preamps would suit my current setup best? Knowing that it will be my first project, and I'm not that experienced...

Best regards

ra7 10th February 2011 04:01 PM

You can try the b1. Phenomenal sounding preamp. It will slot right in place of passive pre. It is easy to build also.

AndrewT 10th February 2011 04:16 PM

Yes, the B1 is an excellent buffer.

If you want a complete PSU and buffer with start up and shut down muting then you can use the DCB1, available in (black) Hypnotize and Blue Hypnotize.

The buffer must be at the output of the source. In your case source is the volume pot.
The B1 drives the cables to the Quad.

ra7 10th February 2011 05:07 PM

The B1 also has a volume control on the input. If you use the DCB1 or the original B1 circuit, you can dispense with your current passive pre and use the volume on the B1 instead.

Siberia 10th February 2011 06:42 PM

Thank you for encouragements. I should have noted that I wish to replace (get rid of) my current volume controller (a very old PS AUDIO potentiometer) with a buffered pre OR a pre with some gain.

It looks like I'm going more for a buffered one, B1 or it's variations, like DCB1. Thanks for noticing me about it's existance too. That says, I should start investigating the treads about them immediately. Hope to find sources for parts as well. If anybody is up for posting quick links here, you're welcome! I'm looking for shipping to Eastern Europe.

Best regards.

ra7 10th February 2011 06:58 PM

I believe the original B1 boards are still available from

Look here for the DCB1 version:

The group buy is over, but there are always boards left over. You'll get all the help you need for both the B1 and DCB1. Search for threads in the Pass forum.

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