Szekeres with IRF3205?

[kuroguy]

I searched and could only find info on using the IRF3205 in a power supply.

I happen to have salvaged a few IRF3205 Mosfets. I am interested in using them as a current amplifier in a szekeres stage. Is the IRF 3205 suitable for use in a szekeres amp? just a matter of substituting the IRF3205 in the standard szekeres circuit?

Thanks for the help.

Kuroguy

 

[h_a]

You make it a little hard to help you, don't you?

At least a schematic would be nice. If you mean the Szekeres headphone amp, then just go for it, as it's just a simple source follower that has nearly no specific requirements for the fet.

Have fun, Hannes

http://headwize.com/projects/showfile.php?file=szeke1_prj.htm

 

[kuroguy]

Thanks for the link Hannas. Sounds like I can reuse the mosfets I found.

I thought I said I was interested in using the mosfets for a szekeres stage in my previous post. If I wasn't clear enough, I apologize.

Yes, I want to use them in a szekeres headphone stage as part of a line preamp I'm building. Has anyone used this particular mosfet for a szekeres stage? I guess I'll just breadboard a couple channels up and see for myself.

Thanks again.

Kuroguy

By the way, I salvaged a bunch of parts from an old APC UPS. Had several useful transformers (one that I think is going to be part of an active crossover, another one that will be used as part of a power supply (heavy transformer), mosfets (with insulators and mounting hardware), many capacitors, diodes, etc....

A great place to salvage parts.

 

[h_a]

szekeres stage

See, I think the misunderstanding comes from calling a source follower (or common drain configuration if you want) a Szekeres stage (and not putting up a schematic). This thing is absolutely nothing special and I really don't see a reason to assign that a new name.

Here something similar
http://www.diyaudio.com/forums/showthread.php?s=&threadid=95841&highlight=

Is that a GRollins stage then

Have fun and enjoy your amp, Hannes

 

[kuroguy]

I am having fun. That is the point, isn't it? The amp is about half done now and construction is on hold while I breadboard up the source follower and wait for more funding (damn this economy). Since I need to order some parts, I may just order a few IRF510 MOSFETS. After all, they only cost about a buck each. My plan was to use a split rail power supply and I already have a couple of power supplies for the job. Any opinions whether the IRF510 or the IRF3205 will sound better?

In the meantime, I think I'm going to start writing the code for the microcontroller that is going to control the whole thing.

Thanks for the suggestions.

Kuroguy

 

[paulb]

Any opinions whether the IRF510 or the IRF3205 will sound better?

I'm hoping we'll find out from you.

 

[kuroguy]

eventually you will. It might be a few weeks though. It has taken me almost a year to get this far (top panel machined, wood frame built, rear panel about 50% machined, DAC installed, LCD display mounted, heat sinks mounted, Relay/controller board about 70% complete)

I still need to build the usb to digital audio converter, the relay driven stepped attenuator, program the microcontroller, build the headphone amp. I figure a few more months 'til completion of the entire preamp.

 

[h_a]

Sure, enjoy

BTW you can use nearly every mosfet you want.

Have fun, Hannes

 

[kuroguy]

This worked great. I finished up the buffer board for my amp and powered it up for an evening of testing it before installing the next stage of my project. Had some spare resistors in my box. a couple of 39K input resistors, 470 ohm gate resistors and I had 9 330 ohm 1/2 watt resistors that I wired up as three 110 ohm, 1.5 watt resistors. Scavenged the irf3205 (3 of them), mounting and insulating hardware from an old UPS. Salvaged a couple of 12 volt switchers and wired them as -12v, 0, 12v power supply.

The entire thing was salvage parts.

 

[kuroguy]

There's the source follower i threw together on the right. the relay/controller board gets mounted above the source follower board. The power supply for the sourc follower is at the bottom left, a couple of switchers i had lying around.

 

[h_a]

Scavenging is fun