DCAudioDIY.com

Hi All,

New to the DC diy community. I've built a few speakers before, but nothing of my design (only proven design by others).

I have a request which I am hoping a fellow DCAudioDIY member may be willing to assist with.

I have a Don Allen tub pre-amplifier. I really like the way it sounds. I use it with my Plinius SA-100 MKIII amplifier and my Wayne P. Pi3 Speakers. Pursuant to Wayne's recommendation, I want to add "flanking subs" to my system.

In order for me to incorporate stereo subs to my system, I would need a pre-amplifier with dual outputs (one to my main amp, and one to my subwoofer amp). Unfortunately, the aforementioned pre-amp only has one set of outputs.

Is there anyone here that may be willing to help with installing another set of pre-outs to my preamplifier?

There's a bunch of us who can help with that.... Where are you located?

Roscoe

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I can explain it to you, but I can’t understand it for you.

You can also use a Y adapter.

Depending on the output impedance of the preamp, a little FET buffer for the subs might be beneficial. Two low impedance (I assume) SS amps might be quite a load for a tube line stage, if it doesn't already have a low impedance output. But I don't know the equipment being used.

Stuart,

My current system consists of the following:

Computer with Lynx Sound Card --> Music Hall DAC 25.2 --> Don Allen tube pre-amp --> Plinius SA-100 MKIII amplifier --> Pi3 speakers.

I'm plan on building flanking subs - will likely use Eminence Lab12 drivers (one on each side).

I was planning on using a pro-amplifier for sub duty, specially like a Behringer EP2500 (or may a QSC PLX3402).

I don't have any knowledge about the Don Allen pre, but can take pictures and upload.

Thanks,
Dhar

Look for a used QSC USA400, two if you need more power. Cheap, linear power supply, no fans...

Roscoe

_________________
I can explain it to you, but I can’t understand it for you.

Roscoe,

The reason why I was contemplating using the Behringer EP2500 and the PLX3402 is because I have both on have, and both have been modified with a quite fan mod.

Do you have a schematic for the preamp? If not, do you know its output configuration and/or impedance?

Input impedances for the power amps?

Do the power amps have level controls?

Input Z on the Plinius is a remarkable 100k.

Roscoe,

I do not have schematics of the pre-amp. I'll atleast try to upload pictures.

Please find specs below for my Plinius:
*INPUT SENSITIVITY: 0.8V RMS for rated output at 1kHz.
*INPUT IMPEDANCE: 47kΩ.

Please find specs below for Behinger EP2500:
*INPUT SENSITIVITY (V RMS @ 8Ω): 1.23V (+4.0 dBu)
*INPUT IMPEDANCE: 10kΩ unbalanced and 20kΩ balanced.

Please find specs below for QSC PLX3402:
*INPUT SENSITIVITY (V RMS @ 8Ω): 1.9V (+7.7 dBu)
*INPUT SENSITIVITY (V RMS @ 4Ω): 1.7V (+6.6 dBu)
*INPUT IMPEDANCE: 6kΩ unbalanced and 12kΩ balanced.

All of the aforementioned ampls have Blanaced inputs, but the pre-amp does not have balance pre-outs.

Both pro-amps (i.e., the Behringer and QSC), have level control on the front.