Donald North Audio — Owners Thread

No! Many have used them to bypass the ODAMs with good results in different amps. Maybe would be worth trying on their own here but they are quite expensive.

 

Horses for courses, but in my EC Af my cap rolling went like this: stock russian PIO, Miflex KPCU, ODAM, CuTF, Duelund CAST PIO Cu/Ag hybrid. Best value for money would be the Miflex KPCUs; I kinda wish I'd stopped there, but I'm an idiot.

 

How did you like the CuTF and Duelund CAST PIO? I bypassed my ODAMs with small value copper Dueland caps in my Mainline and really enjoyed them.

 

Duelund hybrid: It's not worth the money, but it's worth it, LOL. You're probably getting most of the benefit just bypassing some big copper caps with a little siver. In all seriousness, they're like moving from 94% good to 96 or 97% good. And to temper proclivities/align preferences, I tend to be a bit of a silver wire/foil whore. I could wander off into more specifics, but that'd probably be better in the general cap rolling thread (if I can find it...).

 

Oh no… I got the feeling that the old EC house sound is one of a kind. So not even the more neutral latest versions of DNA amps can emulate a bit of that kind of sound...

Are there things that the DNA house sound do better than old EC in your opinion?

 

What causes some rectifier tubes to whine (physically from the tube itself, not through the headphones) in the Stellaris? I got a few GEC U52 tubes and they all have a whine that is loud enough to be very annoying since you can't just turn these tube amps on and off all the time.

But I've had other NOS 5U4G tubes develop a whine too. Which makes me think it is damage to the tube of some sort.

 

Something related to power, apparently. I have an Elrog, actually two of them which does this mechanical whine. That was the explanation Thomas Mayer provided me when I asked why that tube did it. None of my other rectifiers have this whine.

 

Here's what the tube sounds like, it's not really a whine, it's more of a clanging hiss. As recorded by my iPhone which is not entirely accurate

https://www.dropbox.com/t/z6xyNqeIJVbOVtJf

 

The primary component in this recording is 120 Hz. This would infer a power issue.

Suggested power issues to investigate:
1) AC mains voltage too high with respect to DNA amp target operating voltage
2) AC mains voltage too low with respect to DNA amp target operating voltage
3) AC mains has a distorted waveform from the expected sinusoid

My EC Studio B power supply has mechanical hum / noise when AC mains is above 115 VAC. I use a Staco 3PN1010B Variac to reduce 120 VAC down to 115 VAC and the PS noise ceased.

 

I live a couple of miles from @rhythmdevils, same city, AC never seen it below 122 V, right now 124 V where I have my own Stellaris. No whine from the EML rectifier I'm using, though, nor from the RCA NOS rectifier I've used before (now on my other Stellaris, different location). However, I had a bad whine from another RCA, so bad I sent it back. As for your hypothesis 3), bad waveform, I don't know. But I do know I have DC offset, given the transformer hum on my May, now blocked by an Emotiva CMX-2. I had the same issue on a different house in the neighborhood, so this may be a common issue in this town.

 

On my Stratus, also in CA but not close to either of you (I'm in LA), I have never been above 120v, usually 116-119v. Rolled many tubes but never experienced that sound. Not sure if that helps in any way, but yeah.

Deoxit or 99% iso?

 

Question for Stratus owners...

I've heard the amps get continually "drier" the higher the version (with v4 being the driest). Is this accurate? And is there a version of the Stratus that is as "wet" as the Starlet?

 

thank you @atomicbob ! Yes there is something very wrong with the power in this house but it is very complicated, I have been trying to troubleshoot it for over a year and it makes music feel like troubleshooting tech which is just awful. I've slowly eliminated every source of noise though except the mains itself, coming from the pole at the street, and I tried calling the city but they had no idea what I was talking about and didn't care. Like "do your lights turn on? ok buh-bye".

When my health improves enough I'd like to make a blog here describing all my troubleshooting efforts with noise. I have a thread on my Discord.

I have no DC on my line. It is consistently 120V

But I have tried the following power devices, all very expensive to try to resolve the issues and none of them have done anything:

• PS Audio Perfect Wave Power Regenerator (so either it's not the waveform here or the PS audio device doesn't work)
• ebay power isolation transformer
• Equi=Core power isolation transformer (2400 model!)
• iFI noise cancelling power strip
• Puritan PSM156 (currently using because it sounds better than the Equi=Core and the company doesn't seem like BS but it doesn't really "clean" the power)
• Emotiva CMX-2
• iFI DC blockers and Ground Defenders
• Zero Surge surge protector power strip (the less is more option for the "plug it into the wall folks)

I have my amp plugged into a dedicated line, which has a power cable that was laid by a sound professional far away from any other power lines all th way to a dedicated panel. With a Purtain Ground Defender connected to it.

At the end, it's really a phantom. I'm very frustrated because I love the sound of this rectifier but the amp sits right next to me I can't stand the rattling noise.

Does anyone make a tube socket adapter thing that goes between the tube and socket that fixes this problem? Seems like something @iFi audio should make.

 

I was wondering if the problem could be not in AC power but something else in the local EM environment that couples with those rectifiers, but I looked at a spectrum for your recording, and of course I should just have believed what @atomicbob observed, those peaks at 60 and 120 Hz. I know that the amp is on a dedicated line, but is there some nasty load on the same circuit? The 120 Hz peak suggests something with a rectifier, like an electronic ballast.

 

Man, time to just take your audio chain off the grid. Set up a big battery bank or something.

 

Stromtank?

 

https://www.superbestaudiofriends.o...s-power-station-comparison.13589/#post-412351

@rhythmdevils, I'm not sure If it's possible to borrow something like this, or purchase to try, but it's worth a shot to see if it helps.

 

I could never invest that much money into a power generator, but it would sure be interesting to see if it helps my noise issues.

 

I'm finding the Stellaris to be, well a bit underwhelming and troublesome in some ways. I want so badly to love it, but there's something missing and some things that seem just plain tuned wrong.

It's very bright and harsh for one thing, with neutral tubes it has a ton of treble and elevated upper mids that are quite harsh. eg EML 5U4G,Elrog. + Linai Global Elite + whatever driver tube. OUCH sooo much treble and upper mids.

I've managed to get rid of this pretty much with all NOS tubes.

But it also is missing a certain "looseness" that good tube amps have. The Stellaris is very solid state in its presentation. SS amps tend to only let you hear the front 1 dimension of notes, but with good tube amps, there's this magic thing that happens where you can hear around the edges of and even behind notes and not only does this incredible dimensionality appear, but you can hear all the detail/plankton/villi that is all around the sides of and even behind a note. And the placement of notes around in space, and all the sounds in between all the other sounds, its' all very magical, it goes from a "very good sounding amp" to something that mimics real life.

And one of the qualities I look for in an amp is that it is transparent not in the neutral sense, but the feeling that there is air inside of notes, as if you could reach out and put your hand through a note, there is that much space and air and dimension in every note.

But the Stellaris tries really hard to be flat and not have these qualities and I've been fighting with NOS tubes to try to bring it out in the amp, and I've gotten it much better but I'm not there yet. It's still too flat and sterile and dry.

I think I've found the wettest, best rectifier for my tastes in the GEC (pm me if you want the specific GEC I have, I won't say publicly)

Does anyone have any recommendations for 2a3 tubes that are very wet and well, I guess some people would say "tubey" though I don't like that word because it implies coloration/artifacts, when really what I'm looking for sounds more like real life.

I think I have all of the 6BQ7 and 6CG7 tubes out there, even weird ones like "Rad-Tel" and different versions of Raytheons and I prefer the 6BQ7's by far. For 6BQ7's I have all the usual suspects that you'd think would give this amp this quality and not be bright, but this amp is so bright it overtakes most of them.

Mullard
Brimar
Mazda
RCA
Brimar CV4xxxx whatever on an adapter
Raytheon (to my surprise0

Are there any other tube types I can use on an adapter and some really wet juicy 3D driver tubes I could still try?

Maybe the Stratus is just more to my preference, I haven't hooked it up yet I've been too sick and I'm also obsessed with bending the Stellaris to my will. I'm a total resolution whore and I want to make this amp work for me. Which is probably not wise, better to start with an amp that sounds the way you want instead of fundamentally chaining it with tubes, but I can't help but think that the tightly wound internals of this amp combined with tubes that give it that "looseness" might be really magical.

You can send me a pm if you don't want to share your favorite tubes publicly. I'm going to create a Pyrate only tube recommendation thread when I have the energy and time..

Oh, and it's the latest version of the Stellaris if there are versions, I got it from someone who just received it recently.

Cheers Baby Blue Heads!

 

Trying to change the fundamental nature of an amp with tubes... I made that mistake with the EC 445.