Build This MoFo!

[vdi_nenna]

Isn't the point of a follower to not add a sound signature of its own?
How does global feedback hurt things?

 

[xrk971]

Update on the Aksa Lender preamp, I had a software glitch that was causing some anomalous 5th and 9th harmonic to show up. Here are new measurements.

Driving 20v p-p into 25kohm load:

Now decrease load impedance to 3.4kohm and 20v p-p:

Still quite good. This preamp is essentally zero distortion at usual drive levels, for example, here is 4v p-p into 3.4kohms:

So, this should be a great pre for the MoFo or other unity gain power amp.

More info here:
AKSA's Lender Preamp with 40Vpp Output

 

[meanman1964]

Can I use a 176mH/3A/RDC : 0,5 OHM Choke for this amp ?

 

[Ralph G]

Can I use a 176mH/3A/RDC : 0,5 OHM Choke for this amp ?

Sounds like a perfect choke. High inductance, high current en low resistance.

 

[Nelson Pass]

Isn't the point of a follower to not add a sound signature of its own?
How does global feedback hurt things?

Sours the cow's milk. Get the pitchforks and torches and gather some villagers!

 

[vdi_nenna]

Sours the cow's milk. Get the pitchforks and torches and gather some villagers!

Umm. I'm getting vision of Young Frankenstein.

 

[PRR]

My first electronics book had a class A amp in it with an inductor for a current source. I thought it was ancient at the time.

Here's one.

 

[vdi_nenna]

Just remembered the book- Electronics the Easy Way, 1988 by Rex Miller.

Barron's Electronics The Easy Way by Rex Miller

 

[dantwomey]

Any PCBs yet?

 

[Michael Rothacher]

Soon. They have to be bagged-up, labeled, etc.

 

[JPS64]

Here my first one, again, thank you Mr. Rothacher.

JP

 

[Michael Rothacher]

Looking good.

Family coming in for Thanksgiving next week. Good chance to put them to work bagging circuit boards.

 

[konst]

Here my first one, again, thank you Mr. Rothacher.

JP

Love the space invader pattern

 

[xrk971]

Here my first one, again, thank you Mr. Rothacher.

JP

Did your Preamp and CLC come in yet?

 

[JPS64]

@xrk971

will be ordered (some small modifications pending: R//L) this weekend with B1 KORG Clone and my 1AD4 Headphone Amplifier (before PCB companies close for Christmas).

Will inform in time.

JP

 

[briansz]

Interested in a pair of PCBs as well.......

 

[Zen Mod]

Ya Happydodo ......... nutz almost as Picododo

 

[xrk971]

While waiting for the inductors to show up, I built a MoFo with a pair of 25w 8ohm power resistors in parallel for 4ohm load. I really wanted to test out my new Aksa Lender preamp so hooked that up and running on my XKi W5-2143 speaker now. Power is 24v SMPS and running 1.95amp bias at moment. Sounds very nice

Here is measurement of Aksa Lender preamp driving a 7kohm load 4vpp:

Basically about as good as it gets, and can drive up to 40vpp cleanly, when needed. No shortage of volume control with this preamp that's for sure.

A great combo, looking forward to getting the Hammonds.

I did a quick measurement of the amp and distortion seems a bit high for 2.83vrms into 8ohms (1.95amp bias):

Am I doing something wrong or this is what is to be expected with a resistive load as a "CCS"?

 

[Michael Rothacher]

Starting to bag boards for the store. The first fifty pairs get a spiffy sticker.

 

[Michael Rothacher]

Am I doing something wrong or this is what is to be expected with a resistive load as a "CCS"?

The inductor load is not a CCS. If you simply substitute a a resistor or CCS, it's a different amp, so the comparison is apples to oranges.

Looking good by the way.