[Whitigir]

That is a curse, to be able to tell the differences and not able to ignore it

 

[HiGHFLYiN9]

I noticed some sonic impressions have been posted by Mavin86

It's interesting that people prefer the DNA Stratus generally to other more-costly-to-build amplifiers. Mavin seems to prefer it to the 8900, with the 8900 having very premium amorphous core OPTs, whereas the Stratus seems to have low-cost Edcors . Like the Gain Card, sometimes simpler is better I suppose.

It looks like each heater has it's own choke and filter PCB which is a nice touch.

 

[JamieMcC]

It's interesting that people prefer the DNA Stratus generally to other more-costly-to-build amplifiers. Mavin seems to prefer it to the 8900, with the 8900 having very premium amorphous core OPTs, whereas the Stratus seems to have low-cost Edcors . Like the Gain Card, sometimes simpler is better I suppose.



It looks like each heater has it's own choke and filter PCB which is a nice touch.

The Stratus certainly has a lot of fans but after seeing its internals the cost of ownership seems at odds with the components inside.

Hopefully Mavin will get hold of some 300B tubes and post another update after three or four hundred hours of runtime. I think it's definitely beneficial to get the run time up on this amp.

Curiously 2A3 combined with no negative feedback would be my least preferred combination. With the choice of 2A3 or 300B with or without feedback at hand.

However I can honestly say listening with any of the combinations is very enjoyable and having that variety as there are considerable differences between them is a massive plus for switching between genres and enjoying what you want to listen to how you like to listen with both headphones or speakers.

PS @Maven86 thanks for sharing your thoughts on the amp I've enjoyed reading your write up on the build and sound impression having shared a many of those frustrations and elations along the way.

Definitely think you had a good handle on the overall sonics.

Cheers

 

[Maven86]

It's interesting that people prefer the DNA Stratus generally to other more-costly-to-build amplifiers. Mavin seems to prefer it to the 8900, with the 8900 having very premium amorphous core OPTs, whereas the Stratus seems to have low-cost Edcors . Like the Gain Card, sometimes simpler is better I suppose.



It looks like each heater has it's own choke and filter PCB which is a nice touch.

I think it's best that I clarify\elaborate a little more on what I meant in my comparisons. As far as the Stratus goes, I tend to like how Donald voices his amps (I briefly owned a sonnet before the stratus) and for most of the time I prefer that signature. If I had to choose between the Stratus, AF, and 8800, I'd probably go with the Stratus for the tone, but would still concede that it doesn't quite perform as well "technically" as the other 3 amps. Despite not being able to compare it in my current system, I've heard it more than a few times on much better systems (than mine), and didn't think it scaled too much.

Comparing it to the 8900 would a be a very different situation. I may still prefer the overall voicing of the Stratus but not by much, the 8900 is actually less "hifi" sounding than its predecessors, and the overall performance deficit is so large IMO, that I'd be more than willing to overlook the voicing in favor of the 8900. If I were to make a similar analogy in terms of TVs, it would be like choosing between a 720P plasma with near perfect color reproduction (e.g. Pioneer Kuro Elite), or a modern 4K OLED with excellent color reproduction.

Now if you throw in the current Stratus, and by extension the Stellaris with the new AudioNote OPTs, I'd wager things might be different...

Also, in all of my scrambling around, I JUST realized who you are. This is probably a good case for me needing a small vacation from work... Anyway, the resistor box I purchased from you a while back has been a godsend. Because of it, I've been able to take my Utopias and audition them with some very nice speaker amps over the course of the year. It's been very helpful for getting reference points and figuring what to do for my next amp project (in the works). Furthermore, I (greatly) prefer using the 8 ohm speaker outs with the box on my Elekit 8800, over the conventional headphone out. So thanks for that....and also...the new Shin Megami Tensei is pretty awesome .

 

[Maven86]

The Stratus certainly has a lot of fans but after seeing its internals the cost of ownership seems at odds with the components inside.

Hopefully Mavin will get hold of some 300B tubes and post another update after three or four hundred hours of runtime. I think it's definitely beneficial to get the run time up on this amp.

Curiously 2A3 combined with no negative feedback would be my least preferred combination. With the choice of 2A3 or 300B with or without feedback at hand.

However I can honestly say listening with any of the combinations is very enjoyable and having that variety as there are considerable differences between them is a massive plus for switching between genres and enjoying what you want to listen to how you like to listen with both headphones or speakers.

PS @Maven86 thanks for sharing your thoughts on the amp I've enjoyed reading your write up on the build and sound impression having shared a many of those frustrations and elations along the way.

Definitely think you had a good handle on the overall sonics.

Cheers

I appreciate the kind words Jamie. I saw you mention the 400 hour break in before and since then I've been paying closer attention to see if I notice differences. So far, if anything, it's been subtle after the 100 hour mark but perhaps it's because I'm using PIO caps instead of teflon.

The feedback thing has been interesting. A few more people came and listened over the last couple of weeks and 4\5 preferred NFB on, at least on my speaker setup. I gave it another go for a couple of days and still couldn't really jive with it. I guess I'll settle for being the odd man out in this case.

 

[Whitigir]

I appreciate the kind words Jamie. I saw you mention the 400 hour break in before and since then I've been paying closer attention to see if I notice differences. So far, if anything, it's been subtle after the 100 hour mark but perhaps it's because I'm using PIO caps instead of teflon. The feedback thing has been interesting. A few more people came and listened over the last couple of weeks and 4\5 preferred NFB on, at least on my speaker setup. I gave it another go for a couple of days and still couldn't really jive with it. I guess I'll settle for being the odd man out in this case.

I enjoy Non NFB rather than NFB. To me, it is kinda similar to Oversampling Vs NOS. The NFB yields better fidelity, extensions and details, but it compromises the realism, the tonal balances and the engaging feelings.

But when it comes down to nit and pick, NFB modes is better with 2A3 tubes where as the 300B is much better with Non NFB mode, and since I love WE300B. I am constantly on Non NFB

 

[Maven86]

I enjoy Non NFB rather than NFB. To me, it is kinda similar to Oversampling Vs NOS. The NFB yields better fidelity, extensions and details, but it compromises the realism, the tonal balances and the engaging feelings.

But when it comes down to not and pick, NFB modes is better with 2A3 tubes where as the 300B is much better with Non NFB mode, and since I love WE300B. I am constantly on Non NFB

100% agree with the NFB analogy. Couldn’t have said it better.

 

[JamieMcC]

I had a rough estimate of hours run so far and it's definitely now over 500hrs I work from home and most days the amp gets turned on between 7.30 & 8.00 am and stays on till 11 or 12pm. If I go out for more than three or four hours and there's no one home it goes off but if it's just for a hour it two I tend to leave it on.

Probably 200 hrs of that on the 2A3 and 300 hrs on the 300b.

Lot of the time I just listen to ripped cd or Tidal via Roon but also regularly play favourite cds (they just sound better than being streamed). Also vinyl but only if I can sit and enjoy listening so not for background tunes maybe one evening a week if I'm lucky.

I switched over to listening to 300b without nfb this morning then returned to nf this afternoon I really enjoy both but the loss in resolution and more relaxed bass control for the range of genres I typically switch between is very noticeable.

However if I'm listening to say smooth jazz or female vocal then those differences are pretty minimal and the extra presence and tone of Non nfb is a great combination.

On the other hand for such genres 2A3 is pretty spectacular with female vocal reproduction very beguiling it has I'm not sure how to describe it but maybe a crystalline clarity that sounds ethereal at times on good recordings. But male vocal like say Gregory Porter it's 300B all the way due to the gravitas and texture the 300b bass adds.

After 500hrs the only solid observation I have is there is definitely not one tube or nfb setting to rule them all.

I'm very tempted to try the Duelund capacitors or the WE 300b reissue but undecided which to do first. In the meantime some Duelund hook up wire has arrived and I'm going to rewire my speakers with it bypassing the banana plugs and soldering direct to the speaker tabs of the free range main drivers.

 

[HiGHFLYiN9]

The Stratus certainly has a lot of fans but after seeing its internals the cost of ownership seems at odds with the components inside.

Given it's hand-made in the U.S. it seems about normal, at least for this sector. I'd imagine the current pricing has much to do with supply vs. demand as well. While I don't have $4,300 in fun money to spare at the moment I can see how it would be worth the price of admission.

@Maven86 thanks very much for further clarification on your impressions. I tend to prefer tone over technical performance as I'm looking more for emotional connection with my music vs. e.g. "the most clear highs" (similar to how Whigir feels about NFB), so I overly simplified your post based on my own preferences. I like the TV analogy NFB I'm sure works better or worse depending on the whole systems voicing.

It would be an interesting test to drop a pair of higher end OPTs in the Stratus from Heyboer/Electraprint/Cinemag ... or even Lundahls. I've always avoided the bargain Edcors as I read they didn't measure well but maybe that's just what the doctor ordered for realism. Jupiter caps supposedly don't measure well but I've always liked those.

Glad you are enjoying the converter box I've got a new emblem for those. PM me your address if you'd like one.

I'm salty I didn't get the collectors edition of SMT, but I'll get over it eventually, lol Super glad a next gen one is out.

 

[Maven86]

Given it's hand-made in the U.S. it seems about normal, at least for this sector. I'd imagine the current pricing has much to do with supply vs. demand as well. While I don't have $4,300 in fun money to spare at the moment I can see how it would be worth the price of admission.

@Maven86 thanks very much for further clarification on your impressions. I tend to prefer tone over technical performance as I'm looking more for emotional connection with my music vs. e.g. "the most clear highs" (similar to how Whigir feels about NFB), so I overly simplified your post based on my own preferences. I like the TV analogy NFB I'm sure works better or worse depending on the whole systems voicing.

It would be an interesting test to drop a pair of higher end OPTs in the Stratus from Heyboer/Electraprint/Cinemag ... or even Lundahls. I've always avoided the bargain Edcors as I read they didn't measure well but maybe that's just what the doctor ordered for realism. Jupiter caps supposedly don't measure well but I've always liked those.

Glad you are enjoying the converter box I've got a new emblem for those. PM me your address if you'd like one.

I'm salty I didn't get the collectors edition of SMT, but I'll get over it eventually, lol Super glad a next gen one is out.

I think in essence we agree. I'd take a much cheaper, emotionally engaging amp over a sterile 5 figure one with XYZ fancy transformers any day. I guess what I was trying to say in all my ranting is that I find my 8900 more emotionally engaging than my old stratus. It just does it in a different way.

As for NFB, like almost everything else, system synergy plays a significant role. FWIW, I preferred the Elekit 8600 & 8800 over the the AF. Both had NFB, the AF didn't... Implementation and circuit matter, I've learned that very few things are black and white in this hobby.

Interesting experience with the Edcors. I recently sold a pair of 45 monoblocks that had some old 1960 Tamura transformers pulled out of a Sony tape deck. According to some guys at DIYaudio, they were probably the worst measuring transformers of any tube amp I've probably owned so far.... It wasn't the most resolving, or the fastest amp I've heard but it had one of the most beautiful sounding tones of any I've heard so far (and I've heard a lot). It was so engaging, that it compelled me to start up another project. FME, I feel that after a certain acceptable threshold, measurements don't say much about whether or not you'll like the sound of something.

You and I are two in a very large crowd of salty people, it was pretty much impossible to get that special edition. However... My brother managed to pull a miracle and snag one before the scalpers so I guess prayers get answered lol.

@JamieMcC I vote for the Duelunds but not because I have any sort of selfish curiosity for how they compare to the V-caps .

 

[Whitigir]

It's interesting that people prefer the DNA Stratus generally to other more-costly-to-build amplifiers. Mavin seems to prefer it to the 8900, with the 8900 having very premium amorphous core OPTs, whereas the Stratus seems to have low-cost Edcors . Like the Gain Card, sometimes simpler is better I suppose.



It looks like each heater has it's own choke and filter PCB which is a nice touch.

Well, it have come to the point that these components (OTs, Capacitors, resistors…etc… ) are not always the case of better specs, more expensive to automatically translated into a better performances machine. This have come from since whenever people have discovered the reproduction of music !!!

That is why it is called “Acoustic tuning”. I think one of the reason why people love tubes and rolling it is because personally, they can tune it to voice the way they desire the most from their stuff.

Back to the 8900!!! I love this amp!! It always leaves me speechless with it vast soundstage, depth, width and it even creates a further out projected soundscape for HD800/S/820 all alike. Musical, warmth, and yet at high fidelity, there is no question it.

I love it so much that I don’t think I would need to change up anything else. It is lovely the way it is. The discussion of the output resistors and so on, did get to me a bit, but whenever I turn on the amp, all my doubt is gone away.

 

[JamieMcC]

First piece of what looks like it's going to be a in depth review with tube rolling impression on this Japanese site. It auto translated for me.

https://tubeaudio.exblog.jp/30655505/

 

[Whitigir]

First piece of what looks like it's going to be a in depth review with tube rolling impression on this Japanese site. It auto translated for me.

https://tubeaudio.exblog.jp/30655505/

Thanks!

This is significant for measurements for Non NFB, very wide bandwidth to begin with



Also the DC that uses to feed the detection and bias circuits were measured to be in the mV range! That is pretty amazing. Then again, with OTs, there should be no DC that is coupled into the output. This explains why I love this amp so much! Very powerful, and yet so clean, even for headphones

 

[Maven86]

First piece of what looks like it's going to be a in depth review with tube rolling impression on this Japanese site. It auto translated for me.

https://tubeaudio.exblog.jp/30655505/

Nice find, those are some high profile tubes. The Takatsuki 300Bs cost more than the amp itself... I'm wondering if this build is with the stock OPTs, not sure if Elekit Japan also offers Lundahl?

 

[petewebb]

Hi All,

I'm currently building my 8900 and thinking of replacing some of the stock resistors with Texas Components TX2575 Naked metal foils. I used the TX2575's in a few places on my Bottlehead mainline, and they added a bit more detail/smoothness that I was impressed by.

I'm still in the early stage of learning to read and understand circuit diagrams/architecture in general, but I was wondering if anyone had suggestions on which resistors in the signal path 8900 have the most impact on sound quality? Metal foils are pretty expensive, so I'd rather not have to replace a ton of the stock resistors if I don't have to. I'd likely be using the headphone out more than the speaker output if that makes a difference.

Any suggestions would be much appreciated!