Buffer for Plate amp

[johnf]

I have a tube preamp with a 5K output impedance. I want to use my sub plate amp which seems to be 10K. The pre has 2 parallel outputs. I want to use my GetSetGo full range or maybe put a 4700pf cap on the input to roll off the bottom end around 80Hz. I am thinking a unity gain buffer between the preamp and sub amp is the best option here. Does anyone have a view or recommend a buffer circuit to do this. Would the Firstwatt B1 work? Something on a small PCB would also be a consideration.

thanks
John

[Geek]

Hmmm, 5K output impedance means it should drive something 10x that for minimum distortion, like a 50K volume pot (RCA Tube Handbooks rule-of-thumb).

You didn't specify tube or SS buffer, so I'll assume tube. Check out a white cathode follower with ECC 88 tubes. That can make a buffer that drives nails. Shannon's Budgie Line Stage can also drive pretty hard by nature of the 12B4's low Rp.

Cheers!

[johnf]

I was thinking of a simple-as-possible solid state buffer between the tube preamp and the sub plate amp to deal with the impedance mismatch.

[Geek]

Ok, I'd go with a follower made from a simple TL072

[johnf]

Thanks. Can you point me at a circuit?

[Geek]

Here's a nice source of info:
http://sound.westhost.com/dwopa.htm#buffers

More info can also be had from the manufacturers datasheet.

Cheers!

[johnf]

Many thanks. I built a simple TL072 dual buffer into a small 4"x2" box with a 9v plug-in. This now sits between the preamp and subwoofer plate amp and solves the impedance mismatch problem for small change.

Schematic at: (http://www.generalguitargadgets.com/pdf ... buf_sc.pdf)

Vero layout at: (http://i1236.photobucket.com/albums/ff4 ... obasic.png)

[Geek]

Great news!