Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by AppleheadMay, Nov 10, 2015.
Looks like changed from the unit that I have. The manual is correct. This should be easier.
That’s correct for me. I’ve made 2 sets of cables out of Neutrik NL2FX Speak-Ons, including one recently. I bought them from Amazon for convenience, but several sellers have them. https://www.amazon.com/Neutrik-NL2FX-2-Pole-speakON-Connector/dp/B00OVAXIBS.
Anybody have an occasion to ever try 2A3Ws? I'd not heard of this type before. From some googling they're a ruggedized version of the 2A3 produced for the military. They look like this:
The combination of Psvane ACME 2A3s with a NOS Ericsson 396A (from Brent Jessee) has brought my Af to new heights: delicate, detailed, smooth presentation that works so well with small ensemble modern jazz (my favorite genre) that I keep wondering when the spell will break (listening to JD Allen's superb 2019 release Barracoon). Pi2AES>Yggdrasil A2 soource; ZMF Verité open silkwood.
Rectifier is an RCA 5V4GA. I've got recommendations to upgrade that something like a Mullard 5AR4, but the prices are a bit silly, way more than driver and power tubes together...
did you get Acme pair from Grant Fidelity?
on ebay Mullard 5AR4 with date code f32 or f31 (fat base) can go for around $120 IIRC.
or are you looking for the metal base?
Do those fat base mullards fit in the AF? I was looking at an f32 but recalled reading somewhere that it might require a socket saver.
the fat base do require a socket saver. have been using one since Af Day 1. no issues.
Yes, ACME from Grant Fidelity. Regarding 5AR4, I hadn't got into the weeds yet regarding fat base vs metal base. More research needed
Can you recall any general changes to the bass (tone, tightness, impact) with these Psvane ACME tubes vs. the previous (unnamed?) 2A3s you had installed?
fully realizing you may need to change to a different genre of tunes to detect / recall bass deltas.
Going back and doing some tube rolling requires more time than I'll have for a while, unfortunately. The other tubes are RCA M-R 2A3 black plates, with some unknown length of previous use. I'd say bass is a bit tighter, better delineated. I'm not so focused on slam, more on getting a feeling of presence, solidity for bass, whether jazz double bass or bigger drums/tympani in jazz or classical. The rolling tympani in a recent issue of Bartók's Music for Strings, Percussion, and Celesta (Paavo Järvi, NHK Symphony) were especially satisfying.
Got @BillOhio 's Af a bit ago. So far pretty good time. Complements the Stellaris well which is what I wanted this amp for. Ygg also suits Af better than it suits Stellaris per my preferences. Will write out more thoughts about the Af later.
Tubes: I don't like tube rolling adventures, but:
I've read through the thread a bit before, but how big of a difference does the rectifier make in this amp? I can't tell for sure what 5AR4 is inside, looks like it may be a Mullard 7 notch (I see 7 notches on the plates and short black plastic base, will check base for hole tomorrow). I won't be getting the metal base Mullard 5AR4 due it being too expensive, but am wondering if a fat base Mullard (still pushing it with $) or maybe an old Amperex would be worth trying.
EDIT: 99% sure it's a Mullard 7 notch now. Shorter black plastic base, 7 notches in the plates, plates are copper lined, there is a hole in the base).
For 2A3, tried with included JJ 2A3 (modern prod) and what appears to be a matched pair of Sylvania 2A3 so far. One is Sylvania labeled, one is National Union labeled, construction appears slightly different in National Union. NU tube doesn't look like previous RCA or Raytheon tubes I've encountered, but I know construction methods changed many times over the years. Will also try with various RCA that I have, the included EH Gold with Af, and stock Shuguang 2A3 for Stellaris later. So far switching from JJ to Sylvania has produced a pretty (immediately) noticeable difference but it's not as drastic as I've heard on some other amps.
Have stuck with the included WE 396a so far (manual says 398a but per pins on the 398a I believe this is a typo). Will try rolling to Ericsson and the original 6N3P once power tubes and rectifier are sorted out.
Definitely a typo, 396a is correct. I'd say in terms magnitude of change, input >> output > rectifier for the Af. It does make an appreciable change swapping the rectifier but the lowest value for money change there.
For better or worse, Schiit DACs pair well with the Af due to the the strengths of one covering the weaknesses of the other and vice-versa.
@famish99 Sounds like most amps with a similar build/topology then.
Looking at compatible input tubes, the "best" I know of would probably be the WE 396a (even if objective best isn't always equal to subjective tube preference... but I've never had any instance of subjective tube preference not working well with WE 396a). Was going to get 1 or 2 more sets of 2A3 for Stellaris eventually so hopefully they work for Af too. Sounds like I only need 1 or 2 5AR4 at most (will have to research old Mullards and probably get a Holland made Amperex).
So... my tube rolling adventures got cut very short. @BillOhio did disclose the right socket is loose without noticeable impact on performance before he sold to me. However I want to know if I may have potentially messed something up:
I tried inserting 2 sets of RCA and the Shuguang 2A3 into the Af. None will go all the way down into the left socket (I could have pushed harder, but didn't want to break anything). More importantly, I don't think the right socket makes full contact with the tube pins. In each case, I inserted the matched pair with left sticking up by about 2-3mm and right all the way inserted. The amp would make the normal noise it makes when starting up and left tube would light up, but the right would not. In each case, when I noticed the right tube not lighting up, I immediately turned the amp off, within 10 seconds. And yes, I put the pins in with the correct orientation.
When using included JJ 2A3 and Sylvania, I have no problems. As a matter of fact, after all of the above, I put the Sylvanias back and and everything works as expected. As far as I can tell, no degradation of sound, no excessive heat, odd noises, or other "obvious signs" of trouble. Did I potentially damage something?
Lastly, does anyone have any socket recommendations for undermount 2A3 sockets that don't cost $$$$? I was going to use the same sockets as Stellaris but they're top mount and I don't want to modify the chassis of Af so...
If it helps:
Haven't taken apart to do measurements and I'd probably be kicking the tire here anyways (I don't know enough about vacuum tube amp design/analysis yet to know what values to expect when taking measurements at each node and if there are small parts in a tight space or on a PCB inside, I'm not 100% sure I could re-recreate the circuit diagram correctly by just looking at parts inside). I know in some topologies you can turn the circuit on briefly (<10 seconds) without tubes (or fully connected tubes) and nothing really bad happens (ex to check measurements briefly, etc.). In some topologies, you fry parts or tubes.
Haven't gotten the calipers out to check pin diameters and spacing yet, but the RCA and Shuguangs have been used in other amps w/o issue. Also, the JJ tubes fit and work fine in my Stellaris 2A3 sockets. No visible buildup/oxidization on any of the pins on any of the tubes. Regardless, to me it seems like the root cause of the issue is the socket, so screwing with the pins on my 2A3 tubes seems like the wrong solution anyways.
One of my sockets become loose, more accurately the female pin insert become loose.
You can easily fix a loose pin insert, or the whole socket itself, by opening up the back cover and using a needle nose to tighten the nut. Reference this image:
#1 to tighten loose pin insert, #2 to tighten socket base.
As far as tubes not going all the way down, at least on my Af, the phillips screws have mushroom heads that elevate the tube above the socket 1-2mm, reference image:
That's normal. If the tube is elevated above those screw heads, that's not normal.
Either way, opening up the back and checking, you should be able to see if anything might be impeding any pin inserts.
Oh, and you can't insert 2a3 backwards or anything, they have two large pins, two small, sized to the socket. So you don't have to worry about inserting them wrong.
Piggybacking off of @gridmaster excellent post, I had a loose socket as well @fp627. The metal bracket that holds the socket in place against the chassis was not able to grip the socket fully. This allowed movement of the socket inward when pushing a tube in, which may be similar to what you are describing.
I solved this by using small needle nose pliers and gently squeezing the brackets in at the arrows as I marked. I then used the pliers to hold the nut while tightening the screw on the top of the chassis.
I’m sure you don’t need to hear this, but please remember to be careful when touching metal instruments around charged capacitors etc. I always left the amp off for 24 hours prior to messing around.
Thanks for the great post @gridmaster . I'll open my amp up tomorrow and see. I have the same problem where it's just a loose female insert in the right socket. Hopefully it will also show why I can't insert any of my own tubes but all the included tubes work fine.
EDIT: Forgot to ask, do other owners have a quiet 60Hz hum? The hum is stable and steady - touching stuff or changing volume, etc doesn't change hum. I'm hearing it even with HD6xx and Auteur (i.e. not super sensitive headphones). Noise is slightly louder with one of the WE396a than the other, but barely noticeable difference. Also more noticeable with mentioned Sylvanias/NU tubes than JJ tubes, but still there with JJ. Haven't tried a rectifier swap yet. Other Af I have heard and the same amp in the past did not have a hum so my educated guess is a component (most likely a cap?) or two may need to be replaced. Anyone know off the top of their heads which components are most likely culprits here?
@Gaspasser - Thanks for warning. If not for me, then for casual browsers. Yes, I have spare resistors that I will use to discharge caps before I play around with stuff. Had a surprise once in college (luckily very minor / trivial) combined with expensive equipment that I'm not familiar with, I definitely err on the side of caution.
Lastly, for reference, I measured the large and small pin diameters on the RCAs in my Stellaris right now against the National Union/Sylvania tubes that came with Af - the diameters of all pins don't vary by more than 0.0x mm. Also measured the distance between pins (outside edge to outside edge, basically including pin diameters in measurement) - doesn't vary by more than 0.1mm except when measuring between large pin and small pin on all tubes - this varied by 0.2mm at most. However, knowing that the socket itself has significantly more play than 0.2mm, I haven't figured out why I can't get the tubes into the Af yet.
Pictures for reference:
In the first picture, I can get the RCA tube down so that it floats above the screw by that much. This is after using more force (more than I've used in any other socket period... but again fragile parts and objects, so I didn't go nuts). In the 2nd picture, I can get the same RCA tube down that far BEFORE applying more force. If I use more, it will go all the way down like the NU tube in the first picture. Lastly, when inserting in both sockets, it feels like the small pins are the ones getting stuck, not the large pins. I didn't try to turn the amp on this time given what happened above with only 1 tube lighting up. And lastly, yes, I did do the obvious and look down into the socket - no debris/etc.
Some casual thoughts on Stellaris and Af. Casual A/B, approximate volume matching by ear, listen to 3 or 4 songs on one then the other. Done over the course of several days, intermittent days. May edit with further impressions later after more comparisons.
Mostly in comparison format b/c there is already so much in this thread talking about how the Af sounds. However b/c EC just closed up shop, I feel that some previous potential EC customers will now be looking at DNA amps.
Tubes on Stellaris: RCA 2A3, RCA rectifier, some specialty 6N1P from m17xr2b.
Tubes on Af: Sylvania/NU tubes mentioned above, swapped between 2 different WE396a, Mullard 5AR4 mentioned above
DAC: Both fed by Ygg, Af via balanced, Stellaris via SE (I didn't opt for XLR inputs on Stellaris given the difference in most DACs isn't THAT much and it doesn't matter on the Stellaris side anyways if I'm not mistaken).
Note I do change tubes on Stellaris from time to time but generally revert back to the above.
- I can hear a quiet 60hz hum on Af and not Stellaris. (see above).
- Both 2A3 in Af are intermittently microphonic if NU branded tube is used on left channel / Sylvania branded on right. Odd that nothing happens when swapped. The WE396a also need further examining - one will give a slightly quieter background and less 60Hz hum than the other. Have not tried said 2A3 tubes in Stellaris yet to see if intermittent microphony or any noise follows. Both amps are plugged into the same surge protector so it's probably not a power issue.
General Af comments first:
- I was a little worried about sibilance or treble peaks given the drier sound of Af, it's energetic sound, clear treble, etc, even after I decided that I want the amp. Even after listening to songs I use to test for sibilance many times and switching to silver cables, etc etc, no problems. However, some amps get rid of sibilance by mucking things up or messing up the treble. Af does not do this.
- No glaring faults. However, like any other amp, it still has it's own signature and it isn't going to match everyone's sonic preferences.
- Things left out are b/c mentioned in thread already or b/c they can be assumed already competent and don't really need to be explicitly mentioned
- Bass is more on Af, but when there is a swing (i.e. when the bass drops or comes on), Stellaris brings more and maybe goes a little deeper (more likely "deeper" is really just limited by my headphones). Oddly enough, Af still feels like it has more heft/umph or I guess it feels like it hits harder. Also a tiny bit more texture in bass. Both go down low enough for Auteur/Clear/HD6xx. I don't like unmodded (or modded) HE6se on Stellaris and don't like unmodded HE6se on Af (modded it's not bad, but you can still hear the "underfed planar" sound a little) so no comments there.
- Stellaris is much wetter and a somewhat fuller sound. It's also more musical. Af is more lean, can be slightly thin in sound (although not necessarily in a bad way, this is actually one reason I wanted Af) due to the drier sound, but it's more energetic and "sparkles" more.
- Mids and highs presented differently, but I'm happy with both. Af could have slightly more mids per my preference, Stellaris maybe a tiny pinch less. Again, still happy. Both are relatively even / neutral across audible spectrum though if we only talk FR.
- DNA amps overall sound slightly more natural. Both very good regardless.
- Staging in all respects is a little better on Stellaris. Still very sufficient on Af, no complaints or oddities. I actually like the way Af presents staging of small ensemble slightly better.
- Separation - this is tricky to describe. Better on Stellaris but everything is slightly more blobbed/bloomy just due to the wetter and fuller sound (not a fault, just inherent nature). I guess Stellaris is like taking a very fine tip marker, putting a dot on paper, and then the paper gets wet and the edges bleed out faintly but you can still see the original fine dot. With Af it's more like someone took a normal size marker and put a dot on paper. Much better than other stuff I've heard where it's just a giant blob or stamp on paper - i.e. you can only tell the general area.
- Both can keep up very with busy music in all respects. I listen to a lot of busy music, so this is important for me. However, on a few songs, with the right/wrong tube combo, Stellaris can bloom a little too much here and Af with JJ tubes can sound a tiny bit compressed.
- Stellaris has more resolution and detail overall. Not surprising given 2x cost when new and pictures I've seen of insides of both. I don't feel like I'm hitting the limits of my gear or recordings with Af. Even after having the Stellaris for 9 months, I still very often feel like "good not great" recordings are almost getting torn apart at the seams and my headphones are the limiting factor, not the amp. Based on memory from almost a year ago, I would say Af is about on par with Stratus which were both much closer in cost.
- Dynamics, micro and macro are better on Stellaris. However, both are very good. Compared to Stratus and Starlett on memory, Af is better at macro dynamics, I can't remember for micro.
- Af slight dryness lets you hear the texture in sound easier and at lower volumes. i.e. it jumps out more vs other traits. However, relating to better micro, you will ultimately be able to hear "more texture" on Stellaris if you turn volume up, but it will be mixed in with a lot of other traits/things going on.
- Aside from a slightly thinner sound at times and the Ygg stage 5 sound both kind of messing with tonality and timbre a little bit here and there, Af lets the tonality and timbre of the headphone shine through a little more. Stellaris injects a tiny bit of it's own tone and timbre (which is fine b/c the Stellaris is very good here, one of my favorite things about it.)
- On all 3 headphones, Af will get a bit odd if I listen loud (to me) after a while, like there are just random things that will jump out at random as too much. Stellaris if I listen loud comes across as a much more even handed big wall/wave of sound.
Current summary, may change:
- So far I like about 65% of my music better on Stellaris, 35% better on Af. This is not genre or headphone specific. However, if we take an album filled with similar songs, I will like maybe 8/10 or 9/10 of the songs better on one amp vs other. Even different albums from the same artist/band may not be the same amp preference though. Also, based on memory, if I had to choose between Af and Stratus or Starlett, it'd probably be Af for 75-80% of my music instead of 65/35 in favor of Stellaris due to my slight preference for EC vs DNA house sound (Cavalli still my favorite, even if it's unique and per some standards not quite "full audiophile"), not any shortcoming of either mfg. DNA amps are very well designed down to a lot of fine nuances and thought out though. They're also even less holy grail tube dependent (which is pretty genius IMO).
- Exception to above would be anything like hard dubstep or very electronic - 95% to Af over Stellaris. May not be relevant though b/c HE6se + proper amp would beat Clear/HD6xx/Auteur with either amp anyways.
- Both are very good and I'm very happy that they complement each other so well per my preferences. edit: In short, it comes down to house sound preference and I guess how much do you want to spend or maybe if you already have tubes or not.
I know nothing about changing components. Most of the discussions in this thread, concerning hum, were on pages 20 - 24.
However, the above quote from @famish99 is the closest to my hum issue. I'm driving some DefTech speakers, with big-honking-magnets. It was less of a side-by-side issue and more just moving the power supply away from electrical fields that caused the hum.
Yeah, make sure the power supply part of the Af is a good distance away from other electrical sources, especially DACs.
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