Which way to choose: Comparisons Chip/Class D/SE DHT ?

[WE91]

Hello all chip amp devotees!

As my alias here on DIY Audio indicates, I'm an old believer in the special magick of Single Ended Direct Heated Triodes, - and especially the WE91 SE 300B with pentode driver.

Well ... As the heading suggests, I've gotten into severe doubts about what gives the best sound quality.

I have been designing loudspeakers as a "hobby" for near 17 years now. One of my friends and co-designers have developed several amplifiers. One is a 50W Class A battery-powered monster, designed along L'Audiphile 20w Le Classe A principles. His recent design is a thoroughly modified Ice Power amp. The sound is better than anything Jeff Rowland has made with Ice Power. This last amplifier represents my current reference, together with SE DHT amps. The problem with SE DHT is low wattage, problems with driving loudspeakers, lethal supply voltage and extremely high building costs.

In my poor contry where I live, I know of no one that has ever heard a Chip-amp/Gain Clone/Gain Card, thus I know of no amp to borrow either, and no way for me to know how such an amp sounds.

I have been staying up late, getting too little sleep - and sneaking peaks on special sites on the internet during working hours, reading about ... Chip amps. I have understood that they have made quite a stir, even among die hard SET people. I have even read a review comparing the 47 labs Gain Card to the Audio Note Kondo Ongaku
What makes matters worse is the relative low cost of building them and ease of servicing and implementing changes and modifications.

So, to the BIG question:
Has anybody compared good Chip-amps to really good Ice Power (Jeff Rowland) or good SET (preferably 300B, 2A3 or 45) amps?

Because ... If they're as good as, or even bettering(!) the amps mentioned above, - then I really must build one!

My next question will then be, - what Chip amp to build?

Looking very much forward to your answers!

Regards
Aril

[WE91]

No replies to this post?!!

I guess my introduction may have been too long?

A more scary scenario is that no one actually has made good comparisons, and are in the dark as to how good a chip-amp actually is. I can't believe this to be true! Many of you guys do know. I guess there's many that's able to give me, - and certainly very many others, their impressions when comparing a chip amp to the best of the rest, namely Ice Power and DHT SE.

I am still looking forward to answers, as this may tell me, and others, if it is worthwile to go for a "non plus ultra" chip amp project.

Regards
Aril

[CLS]

Originally posted by WE91
... His recent design is a thoroughly modified Ice Power amp. The sound is better than anything Jeff Rowland has made with Ice Power. This last amplifier represents my current reference, together with SE DHT amps. ...

Since you got the chance to have both Ice Power & SE DHT, how about giving us a thorough & good comparison first?

After that, maybe someone will jump in with chip amp.

[WE91]

Thank you for answering CLS.

I hope you see the validity in my question?
If you design equipement, or have opinions concerning equipement, I hope you also have a feel for where you're at in comparison to the real thing (concerts and live music) and the competition your facing in technology (new or old). So then you can tell me about chip amps, can't you??

I am so lucky as having friends who are designers of amplifiers and friends that are agents for several High End brands of amplifiers. I have worked for many years as a "hobby" designer of loudspeakers my self, and as a High End Hi Fi salesman some 15 years ago. Through the environment I'm a part of I have the possibility to listen to quite a few designs using different tubes in different combinations. I also do give my good "amplifier- designer"- friend feedback through listening sessions on what he has accomplished with his modifications on the Ice Power modules.

As I allready have mentioned, I do not have a chance at listening to any Chip Amps. I know how well SE DHT amps sound and also how well good Ice Power sounds. I really do hope some designer or chip amp devotee also know this, and also know about how real music sounds!

What I'm asking about should be quite easy for a lot of you to answer!

I am curious about Chip Amps, and really want to know how they sound. You will have to compare against something when describing sound. I'm trying to get a notion of how well this technology stands against its "opposition".
Isn't this site about sharing not only designs, but also impressions, so that others may know if it is worth the effort and cost to go on with the process of builing their own?!

If there allready exist threads dealing with this kind of topic, pleas let me know!

Best Regards
Aril

[WE91]

Hi, CLS and others.

If I wind up making a Chip Amp, it will of course be tested up against all amps I can get hold of and in several different set ups.
All products I ever have made/been a part of making has allways been verified, measured and tested against all possible "adversaries" my friends and I can get hold of.
If it is of interest of users of this site, I will gladly write about my eventual evaluation in these pages.

The question is, - should I build a Chip Amp or am I better off choosing a known path, such as Ice Power?
I'm simply out to get an idea of what kind of contry I'm heading into if choosing Chip Amp.
You see, I do not live to construct/make amps, I live for listening to music, - and I want to know where Chip Amps stands!

Regards
Aril

[BWRX]

Aril,

Do you have or are able to make a power supply with +/-20 to 34VDC rails capable of at least a few amps (a standard transformer/rectifier/cap supply for instance)?

If so, I'd be willing to loan you a pair of my LM3875 based amps to audition and compare against others. All you'd need to do is wire up the power supply, input signal, and speaker connections to the terminal blocks. The assembled amps attached to the heatsink are roughly 11cm x 7cm x 7cm and don't weigh that much. They're capable of up to ~50W or until the chip's over current or over temperature protection kicks in

I'd be very interested in hearing your opinions on how the LM3875 amps sound, especially compared to the ICEpower modules.

[CLS]

There's already much praise to LM3875 on the net. I haven't heard any of them, but I'm not very curious though.

According to the simplified circuit diagram on the datasheet, we can see a typical solid amp circuit. Nothing too special except the same npn type on both (+/-) sides of driver & output stages (, as opposed to the conventional push-pull npn-pnp pair).

I guess this might be chosen by either performance-wise or manufacturing-process-wise.

This construction can also be seen on other discrete designs (Kinergetics for example) which are claimed to have better linearity --- performance-wise.

On the IC manufacturing process, under the same conditions, npn has better hfe than pnp. Or, in other words, it's very difficult to have good enough hfe on the pnp to match npn.

Or maybe we can consider them as one thing. (I guess this might have already been discussed here somewhere, I'm not sure.)

Under the same degree of efforts on the power supplies & overall execution, I think the sound quality of an amp is mostly determined by the linearity of the active devices, which, we all know that the triodes are the best.

As to class D, that's another story.

[WE91]

Hello again.

Thank you for your very kind offer, BWRX, and thank you for your explanation on topology, CLS!
CLS: So you think a SET might be a better choice? The problems I see with tubes are, in addition to what I have mentioned before, the necessary evil of an output transformer, a much longer signal-path than a Chip Amp, very high sensitivity to PSU-regulation/quality and noice from high voltage supplies. I thought a Chip Amp might better the SET with regards to this and get a good head start.
When it comes to Ice Power. My evaluation of the sound of a non modified unit, is that it completely looses against a good class A solid state amp (such as Hiraga 20w Le Classe A) in the upper mids and highs. It is grainy and "coarse" in direct comparison. But in the bass, nothing really comes close, allthough huge Krell's and Dynamic Precision's are very near. Considering price, nothing even comes close to Ice-Power in the bass (from, say, mid-bass and down; 3 - 200Hz down). If you have different preferences, a very well made SE triode-amp can have a bit better "tunefullness" and character in the mid-bass/upper bass, than a Ice Power, and all solid state. If one modifies the Ice Power modules (sorry, I really can't give this away, as this is to become a commercial product), it blows all competition to pieces with its extremely smooth way of rendering the music, - like music just "happening" out of total blackness and with an absolute precision, without ever sounding harsh or edgy. The level of detailing and absence of vail is breathtaking on good recordings. This is it's manner all the way, - from bass to highs. In the start one might think it is "soft" or even "dark" - sounding. Putting on music with bite and energy soon let you forget about that notion. The thing I think (this is a very subjective observation) that the best SE DHT amps (pentode driver), does better is in the "fleshing out" of the musicians and stage. It seems to me to be more three-dimensional with these small low watt "babies (30kg or so a piece). The detailing also seems to be on par with modified Ice Power, but the in the bass from 2 - 300 Hz down, nothing touches Ice Power. The modified Ice Power may resemble a very well made SE 845 or 211 amp in its three-dimenionality and ease of playing, but is, as said, hugely bettering these in the bass.

What I seem to have learnt from reading tests about Chip Amps, is that they have the "tunefullness" of the SE DHT in the bass, but with more control. That they have the midrange reproduction of SE DHT and the ability to "flesh out" the musical scene as a SE DHT. Considering the price of realizing the best SE DHT amp's, a Chip Amp is a real bargain and may seem to me to blow much of it's competition away ... Well, it's here that I really need input.
It's here that my map says stop, and that dragons and huge octopussy lurks ... Are Chip Amps dragons?

The cost of building a Chip Amp is not huge. I really appreciate BWRX offer, but I might just build my own. I'm actually out to try and explore as much of this "unknown" territory as I can, before embarking on my own journey into Chip Amp-land. I really want all you can give me of input on which Chip Amp to build.

I work as a teacher, and at this time we're in the middle of final exams. I will not be able to begin my journey before, at the soonest, early this fall. I'm also finishing some prototype loudspeakers now, and all my funds and spare-time are consumed by this at the moment. So, please be a little patient with my testing/findig out about Chip Amps. I guess several of you guys have a lot more to say about comparing Chip Amps to "the best of the rest".

Looking very much forward to even more info.!

Best Regards
Aril

[WE91]

Yippeeekayeee ...

Right before my nose there was a thread giving me lots of info, with links to other places. This thread quite expressively deals with much of what I'm asking about, and between the lines - and through links, there may be new layers of info. (it's an old thread, and some links do not function).
Great fun!
Here's the thread: Tube with Power IC Output Stage - JLTi
Regards
Aril

[CLS]

I guess the liveliness of the sound is very much replied on the feedback mechanism.

And the feedback is there for the non-linearity of active devices. (So, I enclose a loop here... )

This is just where the SE DHT & class D shine.

As to the (output) transformers, it's a highly controversial topic. Considering the back EMF by the speaker driver, they are not all that evil. By contrast, I think they are very good in dealing with conventional electomotive driver.

I myself love irons. In my system, there are 3 irons in the signal chain (outputs of DAC, pre amp, & power amp). To my ears, they preserve the signal quite well.

The poor power rejection performance of the SE DHT amp is caused by the SE construction, not the tubes themselves. This can be resolved by regulated supply (like JC Verdier), or make them class A push-pull to get real constant current draw in both AC & DC (like Amity by Lynn Olson).

As far as I can see, the circuit of a chip amp is more or less a conventional, traditional discrete solid stage. So I suppose the sound quality & characteristics should also more or less the same. The key points of these chip amps should be the package and all the following conveniences.