JamJar: an HPA-1-inspired power amp

The silver wire transformer Holo Springs probably not the one to go for. Level 2 would be a good choice if looking for possibly the best ladder dac. As with many DACs, people have found that a powerful PC to do DSP using HQ Player software can help a lot. Buying a top of the line PC just for use with a DAC adds a whole bunch to the cost, but some people don't seem to mind.

Regarding the silver wire, its that some people like to buy some bling with their audio gear.

Despite all the foregoing SD is probably the best way to go, especially if interested in using AK4499. That chip can make for a marvelous dac if well implemented. A moderate level DIY project would be to start with an AK4499 evaluation board ($600 US). Still quite a bit of work to do including things that taylor the ultimate sound. Much less of a project than starting from scratch.
 
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Pico,

I have not but a friend of mine who has ,proclaims it as one of the best. I have heard the Denafrips and it is very good, I am currently using a Chord Chordette and I am contemplating a Qutest.

But seriously I only use vinyl if I am voicing a design and only use a digital source on final test. Designing with a digital source tends to lead you down the wrong path, in my humble opinion. No flames please.

To be honest with you I only used vinyl and elecrostatic speakers to voice the HPA-1, headphones were used only towards the end.

Jam
 
Pico,

But seriously I only use vinyl if I am voicing a design and only use a digital source on final test. Designing with a digital source tends to lead you down the wrong path, in my humble opinion. No flames please.

Jam

If you’re in the business of selling audio equipment, then I agree, but if you’re into diy it probably should be designed to sound good with what you actually have. If one never listens to vinyl for whatever reason, then it’s not even going to possible to design that way.
I don’t have the financial resources to invest in both vinyl and digital, my mother threw out my vinyl collection when CD was introduced, thinking it must be an inferior way to listen to music. :headbash::headbash:
 
Pico,

I have to make my living by designing good sounding products and I find vinyl invaluable towards that goal.

My analogy about digital is like taking a prime steak converting it to mince meat for storage. Now before we throw it on the barbie trying to convert back to a steak............:eek:

Maybe a bit extreme, example wise, but I hope you see my point....granted digital is getting better but still no cigar.:)

Jam
 

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Pico,

I have to make my living by designing good sounding products and I find vinyl invaluable towards that goal.

My analogy about digital is like taking a prime steak converting it to mince meat for storage. Now before we throw it on the barbie trying to convert back to a steak............:eek:

Maybe a bit extreme, example wise, but I hope you see my point....granted digital is getting better but still no cigar.:)

Jam

I agree with that, I just know I will probably never get back to vinyl in this life time, so my attention is on the best sounding digital audio playback that fits within my budget.
 
Hmmm. There are audible defects in digital, and audible defects in vinyl. The defects are different, of course.

It may be easiest to design or voice on a very good system that one knows very well. In Jam's case, the best system that he knows well is the one that plays vinyl on electrostats.

I always thought the secret to his success was something else, the particular way he listens. That and some other things...

Just sayin' :)
 
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When I moved to Ireland it was going to cost a lot to ship my vinyl, and I was gradually gravitating towards CDs anyway (mainly to not have to hear the bump-da-bump-da-bump-da-bump after 20 minutes of music).

So I gave my vinyl away. Much as I rue that decision now, I'm not going back. Plus, Roon is the best thing since sliced Vegemite....
 
Pico,

I have heard the Denafrips and it is very good, I am currently using a Chord Chordette and I am contemplating a Qutest.

YouTube

Yeah it’s a toss up for me between those 2.

The holo audio dac by Kitsune looks good, I would love to have a chance to hear some of this gear first though.

Ladder dacs make the most sense to me, but the ears have the final say.
 
Jeff,

I am not saying that vinyl is perfect by by any means but...........

Music is an part emotional and part physical thing and the device/s that convey this is what I consider most important.

My primary system is electrostatic but I also use a box system as my secondary system. Equipment has to sound good on both but if you want to get into analyzing a component's characteristics electrostatic or planars (line sources) are best.

Probably something we should discuss at a later time.:)

Jam
 
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So I was helping a friend out with restoring his M22 and had to dig up a schematic. Lo and behold, it's the Hitachi topology with a BJT output stage. :)

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That's the simplified schematic. Being a Japanese amp from the 70's, the full schematic sports another 32 transistors and a couple hundred associated passives.

Here's the front-end, just to give you an idea:

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Good Star Grounding methodology. Input ground "3" is different from PSU bulk filter capacitor ground "23,24", which is different from PSU output ground "21", which is different from internal circuitry ground (schematic symbol ground).

Damned if I know why I/O terminal "1" at top left, is brought out to the outside world. It almost appears to be a logic gating signal that either runs the LTP at (36V/18K) = 2mA when pin I/O "1" is low, or else runs the LTP at (36V/168K) = 0.21mA when I/O "1" is high. Why is this good?
 
On other fronts, I played around a bit more with Pico's loading resistors for SixPack. I found a spot (4K7) where they deliver a nice even ramp of harmonics. (Without the loading the ramp is still monotonic, but not as even.)

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