Donald North Audio — Owners Thread

@Donald North can you verify the above list?

Then I'll ask the mods to copy paste it into the first post of this thread so it can be referenced by us and new owners to make for less repetitive questions (like I asked )

 

Also, @Donald North, I have read conflicting information for compatibility of 5U4GB with Starlett. Is it okay to use? Thanks and Happy New Year!

 

@rhythmdevils I have used the 5U4GB and 5AS4 in my Stellaris and Donald confirmed they would work with me before I tried.

For me, with whatever tube compliments (plural) I tried the above input tubes with at the time, the 5U4GB and 5AS4 were both slightly less resolving, but were better in some other ways to me. Both of these were more I guess linear sounding and in short, sounded much more like a 5AR4 instead of a 5U4G (extrapolation based on how various 5AR4 based amps have sounded vs various 5U4G have sounded to me). Standard 5U4G IMO has some slight issues with deadened dynamics as well as something I can't quite place my finger on or can't remember anymore just being "off" with the sound.

Very roughly this diagram is both about how linear they sounded with 5AR4 being the most and also how similar or not they sound to each other - meaning 5U4G and 5AR4 are the most different. Not to scale because I don't remember anymore, but I vaguely recall drawing a much more to scale version of this before. I do recall the 5U4GB and 5AS4 being closer to each other in sound vs 5U4G and 5AR4.

5U4G -------- 5U4GB --- 5AS4 --------- 5AR4

I've since switched to running modern production 5U4G (and also currently selling/sold some 5U4G, 5U4GB, 5AS4 tubes I own) which also has it's own issues IMO, but between vintage, modern, or other rectifiers, the issues w/ modern prod 5U4G bug me the least for my personal preferences. Conversely I could see some people liking 5U4GB and 5AS4 more than either modern or vintage 5U4G.

 

5U4G ( equivalent U52, VT-244, CV575 ) is the rectifier for the Stratus \ Stellaris. Of these the GEC U52 has worked the best for me.

That said the 422A is my preferred rectifier on the Stratus/Stellaris which (per Donald) works fine but not 'optimally' without rewiring the socket. My SSpecial is built with a switch to rewire the socket for the 422A, and guess what? Sounds better when still configured the for directly heated rectifier ! Go figure.

Mullard GZ34 (5AR4 variant) works as well but sharpens / speeds up the sound considerably. Interesting not something I visit regularly.

 

After further research and testing with the Supernaut (which uses a directly heated rectifier powering indirectly heated signal tubes), it should be fine to try a 5U4G and GB in the Starlett. The voltages aren’t high enough to damage their cathodes. And the 5V rectifier winding can handle the 3A filament current of the G/GB.

 

Are the 6BS8 and 6B7Z the same tubes as the 6BQ7A and ok to use?

 

They aren’t identical but look OK to use

 

Has anyone tried 6BQ7A tubes in a Starlett? @Donald North told me he had never tried it but thought it should be ok. But that makes me a bit uncomfortable, I'd rather not be the first one to try it.

With the Stratus and Stellaris, the 6CG7 sounds much more diffuse and less resolving than the 6BQ7A so I imagine the same would be true with the Starlett.

 

The TAD 5U4G was bothering me, a bit hazy, out of focus. Put the EML mesh back, everything is more in focus, finer details are back. TAD went too far in the dark chocolate cake direction.

 

I did a comparison with my favorite three 2a3 tubes in the Stratus with my RD-4.

Linlai Cossor/Global Elite
Much flatter presentation than the others, more sterile, less lifelike, less resolving and transparent sounding. A real step down in realism IMO

Psvane Acme Globe
Much more spacious, realism goes up quite a bit as the sound isn't flattened, but expands back with depth, more resolving, small nuances to notes come alive, also more dynamic

Psvane WE275
The best, in 2 different sessions comparing these tubes. The most spacious, the most realism to notes and their timbre and tone, the most resolving, the best layering.

Linlai Cossor/Gloabal Elite >> Psvane Acme Globe > Psvane WE275

I thought I'd post this because I haven't seen much talk off the Psvane WE275. I now want t hear the Psvane WR2a3 and it's supposedly being discontinued...

I'd love to hear the Tatsukis and KR Audio 2a3's again now that I've realized the Stratus sounds so much better with my RD-4 than the Stellaris. And I need to force myself to listen to some of the cheaper 2a3's I've bought before selling them, like the gray glass Psvane 2a3-TII.

The Stratus has some special magic with my RD-4. I'm comparing it to my Cavallli Liquid Crimson right now, which should be a wonderful pairing giving its current output, but the Stratus so far wins in sheer realism, soundstage and tone. And probably resolution too. The Crimson sounds faster though and has more delicate, nuanced treble. But I have done a lot of tube rolling with the Stratus, currently using some special kind of Mullard 6BQ7A that I could never find again, but not much with the Crimson. I'm going to have to pay up for some premium 6922 singles and see which one wins. For sure, the Crimson will win with the 4z and X and lower impedance Audeze's, which don't sound good at all on the Stratus. But the LCD-4 is 200ohms which seems just enough to work well with the Stratus. .

 

It's pretty interesting that the Stellaris sounds so bad with Audeze's. They are totally flat and lifeless and lack resolution even compared to the Stratus. I prefer the Liquid Gold X to the Stellaris with Audeze's. i talked to Donald about it and the Stratus and Stellaris are the same circuit, just with different parts and output transformers. Just goes to show how much the parts chosen for an amp matter, and not just the topology and circuit design.

I think both amps were likely tuned with electrodynamics in mind, Donald told me to try an HD650 or R10 out of the Stellaris, but I won't like it no matter what so that's a waste of time. But I am sure that those of you who love the Stllaris ar using headphones that work better with parts used. I'm guessing the Stratus synergy with the LCD-4 is just a happy accident.

The LCD-4 goes from really mediocre with the Stellaris to shining with the Stratus. Really curious about the Supernaut now!

 

Well my RD-4 is my favorite full size headphone, and I've tried a lot of tube amps and solid state amps. And so far, the Stratus is the best they have sounded, barring the possibility of a tube preamp -> First Watt F4. I'm going to be playing around with that later. But at a recent meet, multiple experienced members here preferred @loadexfa 's Stratus over my Minimax pre -> First Watt F4. I have a Moreplay preamp to try though which may offer more voltage and sound better with the F4.

I don’t think the Stratus is likely a good ortho amp in general, but it really shines with my RD-4. And I'm happy having a specialist amp for this headphone as it is my favorite and I think my best work. I think the synergy with my RD-4 and Stratus may be unique to a lot of orthos because the LCD-4 is 200ohms like a lot of electrodynamics. Lower impedance and the Stratus does not work, and it also is not going to work at all for The Abyss 1266 or Susvara. But I have little interest in either of those.

So given that, interest in the Supernaut makes sense. Not as an amp for orthos in general, but for my RD-4, given that it does not have the huge output transformers of the Stellaris and seems likely to be more similar to the Stratus but with KT66 tubes. it's hard to know what orthos like best given that almost all amps were tuned for the HD650 so there is very little to go by.

I'm definitely keeping my Stratus v3 for now!

the only other amps I can even think of trying for my RD-4 are custom amps. I've gone through all the commercial tube amps I can think of and for my RD-4, the Stratus is on top. But I do have some cool custom amps in the works...

 

@rhythmdevils
I think you should try special tube amps that have design consideration to drive planars.

In the same price as Stellaris there is Feliks Envy, I haven't tried Stellaris but specific for planars I would pick Envy over the Stratus. A lot more control in the bass frequencies and more open sound and airier stage. Also since it's 300B based you have access to Elrog tubes which are super smooth and detailed.

If you are willing to spend more there is the Woo WA33, this is also an excellent amp and it seems to be tuned in SS direction speaking generally, a bit drier but high resolution and textured. Tons of impact. Maybe more Eddie Current-ish? I suggest get the base version since the "upgraded" version is like the KTE levels in Holo products, fancier parts but not critical.

There is also the Riviera AIC10, this one is the warmest compare to Envy and WA33 but it's also very fast and liquid and can drive small speakers. This one is a hybrid design and I feel that it sounds the most SS compare to the Woo and Feliks. Get the single ended version because I think the balance one does not worth the extra cost.

All these 3 amps I feel play around the same level depending on your sound preference and can drive any planar on the planet. My main headphone is Susvara and for my personal taste I like Riviera the best.

 

I'm thinking of using the Stellaris funds to try an Envy or WA33. But I don’t have any orthos that are that hard to drive and don't know when I would in the future. Audeze is committed to low impedance, easy to drive orthos. I don't think I'd like the Susvara or 1266. But there's always future orthos. And maybe the WA33 or Envy would grip the LCD-4 drivers better than the Stratus. But you'd be surprised how good it sounds. Like I said, at a recent meet, multiple experienced SBAF'ers well known here preferred my RD-4 with the Stratus over my Minimax tube pre -> First Watt F4 speaker amp.

I wish I could hear these 2 without buying them first, so expensive. I think it's a misconception that orthos all need a million gigawatts of power just because the Susvara and 1266 do. And I guess the new Tungsten does as well.

I recently had an Aegis here which has way more power than the Stratus and you'd think it would be a better match for my RD-4, but it sounded pretty bad. So it's not always about power. Audeze's in particular I have found have pretty confounding amplifier synergy.

But I'd still like to hear all 3 of them and see.

 

Have you ever tried a Sylvania 6BK7B? I have a few spares that I just got, let me know if you'd like to try.

 

Thanks Fernando! Yeah I actually have like 7 of them or something and I have no idea how. Let me know if you want some more!

 

Driver tubes in the Stratus and Stellaris

I've found that all 6BQ7A are basically the same technically in the Stratus and Stellaris, they just have different frequency responses ie balances of bass and treble mostly, and you have to choose the right one for your 2a3 tubes and rectifier. But I don't notice the Mullard 6BQ7A sounding more revolving or more liquid or anything like that compare to even the Raytheon 6BQ7A. I have a set of like 7 of them and one usually works to get the FR right for any given 2a3 tube.

I find the 6BK7B tubes to all be too bright, I've never gotten the Sylvanias to work with any tube arrangement. Just my experience.

I find all 6CG7 tubes to sound inferior to the 6BQ7A in every way. They sound muffled and diffused, less focused, less resolving, less dynamic.

I wouldn't spend a lot on driver tubes for your Stratus or Stellaris, my recommendation would be to get a few 6BQ7A tubes until you get the FR you want and then just use them.

A list of my favorite 6BQ7A tubes that has so far got my Stratus/Stellaris FR the way I want it with every 2a3 tube on the market:

Mullard
Brimar (these vary a lot! You may need to get some from some different sources, I have one that is ridiculously bright and one that is well balanced)
RCA
GE gray label and red label and clear top with ring top getter (they're all different sounding)
Raytheon
I think 2 more but I forget right now.