Hamptone - 1 stage or 2?

E-money · Jun 30, 2005

I've been lurking this board for a few weeks now, and I've decided to try the Hamptone jfet preamp as my first project (I was intrigued when the article first ran in TapeOp).

The original article suggests chaining together 2 stages of the Jfet Preamp for a mic preamp, but I've seen some complaints that the signal is too distorted with this setup. I'm curious what people here have done for their Hamtone builds? I'm thinking of building 2 stages that could be used as 2 seperate channels, or linked together for extra gain.
Does anybody know if Scott's kit has 2 stages of preamp, or just 1?

Thanks in advance.

Milkmansound · Jun 30, 2005

I'm pretty sure its 2 - the preamp is exactly as described in the TO article.

chrissugar · Jun 30, 2005

You need two modules because one amp module has aprox 26-29dB gain.
Of course the modules are not for recording classical orchestra. They are coloured, but in a very good way. Also it is not exactly simple to make the modules because you have to sort the FETs and the output transistors or they will distort like hell and/or they produce more heat than is normal.

Here is a thread about the modules I built:
http://www.groupdiy.com/index.php?topic=1184&start=0

And the preamp based on these modules but with different transformers (Lundahl or OEP) and some aditional features.
http://www.groupdiy.com/index.php?topic=4737

Some soundengineer friends who used them for a while think it is the most versatile preamp, even compared with API and N*ve.

chrissugar

E-money · Jun 30, 2005

Chrissugar, your modules look awesome, and so do the RED BOXES!

I'm leaning towards using your layout, can you list the actual dimensions of the board so I can resize and print for pcb transfer?

It looks like your layout/design is a versatile way of building these, it would allow me try out the various applications listed int he article.

chrissugar · Jun 30, 2005

I'm glad you like my modules.

dimensions are 2.2inch x 1.3inch
or in milimeters 55.9mm x 33mm

chrissugar

Scodiddly · Jun 30, 2005

I think the number of stages would depend on your mics and applications. If you were recording orchestras you'd want two stages. Screaming vocals on a condensor mic would probably do better with much less gain, probably just one stage.