LU1014 differential amplifier

[Babowana]

I'll keep you guys posted.

Please . . . interested . . .


Seasons greetings,

 

[carpenter]

Happy holidays, guys. Now, where'd I put that ice-berg

Water cooling anybody?

 

[carpenter]

Interesting things to do with your spare transformers:

 

[carpenter]

Here's the best part: It drives a one ohm load.

Notice that those specs are in thousands of watts:

 

[carpenter]

Getting real...



Me, get real? You gotta be kidding.

Anyway, I fabbed an aleph style front end (used the single-ended input version), and I also tossed together my version of the PLH front end (for use as a signal splitter). I used ZVP3310As in the differential front end and used the ZVN3310 in the signal splitter version.

The Aleph front end combination gives very clean sounding tones (not too warm, but sparkling with a solid punch--think very lean steak).

The PLH splitter (adjusted to give fairly even opposing sine waves) sounds like butterscotch pudding taste. Ummm... so sweet. I've been spooning the input straight out of the CD player. The problem is there's no gain to speak of. That means another gain stage. No free lunch, it seems.

I like both front ends for their own unique qualities. I'm working up a jfet differential. I'll write back with the results.

Thanks for the time...

 

[carpenter]

Happy New Year, everyone!

I've been simulating and bread boarding this amplifier. I've learned a lot about the power curve probe in SIMetrix:

Power mosfets want a lot of current. I implemented the design mods to flesh out a reasonable looking power sine-wave and discovered why Class A amplifiers are so inefficient.

But, when adding the extra current, I don't necessarily get more power to the driver. Instead, it gets gobbled up by the transistor!

The end results are astounding. I've never fabricated such a nice sounding amplifier. It has that plush, cozy sound in addition to crisp, delicate highs.

Man... Thanks so very much, Nelson, for turning me on to sims. It has helped me immeasurably!

 

[Nelson Pass]

But, when adding the extra current, I don't necessarily get more power to the driver. Instead, it gets gobbled up by the transistor!

And a well-fed Mosfet is a happy Mosfet.

 

[carpenter]

And a well-fed Mosfet is a happy Mosfet.

...and even happier ears!

 

[metalman]

Carpenter,

This is the most interesting and innovative bit of work by someone other than Nelson to be posted here in quite some time. Kudos for coming up with a new idea and having the hutzpah to jump in and get your hands dirty making it work. I've been watching with keen interest.

Cheers, Terry

 

[Tyimo]

Carpenter!

Which version did you built??
Could you post a schematic??

Tyimo

 

[carpenter]

Thanks for the interest, guys. I'll get something posted.

 

[carpenter]

Here it is:

 

[Tyimo]

Thanks!

Unfortunately there is no LU1014 inside anymore and it is far from your original idea.....

Tyimo

 

[Tea-Bag]

Thanks!

Unfortunately there is no LU1014 inside anymore and it is far from your original idea.....

Tyimo

Maybe Q3 and Q4.

 

[carpenter]

Thanks!

Unfortunately there is no LU1014 inside anymore and it is far from your original idea.....

Tyimo

Good point!

Replace the power mosfets with LU1014D jfets.

But, in the end:

You'll discover that the IRFP044N sounds significantly better. Less strained. And you won't have to listen with your fingers crossed.

 

[carpenter]

Here's my latest creation. It's all jfet and has beautiful power curves on all transistors. I show eight jfets in the power output, but you could have sixteen if you want to really keep the wattage on each device standard. Currently, as depicted, there is about twenty watts on each device.

 

[carpenter]

Here's the graph:

 

[carpenter]

Power curves:

 

[carpenter]

More power curves:

 

[carpenter]

and the power supply: