EC Aficionado (was: The Studio Jr.)

I've compared them both on a Stratus, the Acme 2A3 are far superior imo. Less air, but much more clarity and detail, with a slightly more natural timbre.

 

New Linlai E-2A3s on 2nd Af now. Supplier recommends 100h burn in. They did sound rough right out of the box. What's the recommended burn in process? Just 1) leave the amp on, or 2) play music? My very basic understanding of tubes suggests that 1) is enough, the point is to get the filament and other tube materials gas out and otherwise reach a thermochemical balance. But I could be easily missing something.

 

@earnmyturns looking forward to a comparison between the acme and linlai, I feel like trying something other than my solid plate EML.

 

I must say, this is the best way to burn in new tubes. Give to Jexby, wait, get tubes back.

(Thanks man!)

These do sound better than the stock Psvane I received. More stage, 3Dness, air. Plus other things and stuff I'm still figuring out. The last few hours have been quite enjoyable.

 

Do we Af owners want to orchestrate tube swaps between Friends so we can all taste the rainbow?
I suppose we could, in our own thread for those interested, post a sticky of what we each have and figure it out from there? Or is this best just worked out on an individual basis between Friends?

 

I'd be in favor of this or similar and can offer up a pair of ACMEs or Shuguang 2A3C-Ts. In my case I'd be trying the tubes in a Stratus but that shouldn't matter.

 

I have EML mesh, a couple of different pair of Sylvania black plates, JJ-2a3 40, EH Gold, probably some others to offer.
I've been hemming and hawing on buying a pair of Acme Globes. If an extra couple hundred bucks would get me the Jesus 2a3 tube of pure clarity and maximum staging then I'd rather do that. I just don't know what that is, if it's out there.

 

I'll have to remember to take one of the pairs to the other location, which may take a while. A quick impression now that the Linlais have been cooking for 18h is that they are sounding quite well defined already. Listening to Ahmad Jamal's Ballades, a good (mostly solo) piano recording. Attacks are maybe a bit still more rounded than I'd like them, but tone is excellent, different notes well layered, decays right. Double bass on one of tracks (So Rare) has very good tone and those fine-grained details from finger-string-wood interaction (there must be a technical term for this). Quite an improvement over yesterday's mush. For context: Mullard NOS 5AR4 (1962), WE 396A; Holo Spring 2 KTE DAC, 96/24 PCM; ZMF Verité closed (stabilized maple burl).

 

Current tube complement: Mullard 5AR4 short bottle, WE 396E, Linlai E-2A3 (50h burn-in). Maybe it's also the Holo Spring 2 KTE, maybe it's also the Verité closed stabilized maple burl, but I can't think of a better headphone jazz experience in staging, imaging, dynamics, instrumental detail. Attacks are less rounded than earlier, although not as punchy as, say, with Yggdrasil A2 and Psvane ACME 2A3 (could be just the DAC, though). Double bass and drum kit spatial placement and dynamic interplay are so right! (listening to a classic Van Gelder production, remastered: Black Fire with Andrew Hill, Joe Henderson, Richard Davis, and Roy Haines). Overall, superior immersion into the music, don't want to stop listening (but I must, early workday tomorrow). Gotta come back with more time, I never heard this recording with such presence.

 

This goes to show how little I understand tubes and tube amps... I upgraded Af #2 to the same kind of Mullard rectifier as #1, and new Linlai E-2A3 (mentioned above). After some burn-in, I was enjoying the results a lot, but I started noticing a very faint intermittent bzzz on the left channel when music stopped, as if there was some interference from a digital device. It did not depend on the Af's volume control. Looked at all the cable runs and noticed a suspect proximity between the Af umbilical and an Ethernet cable for the Pi2AES streamer. Changed that, I thought it was it, but later discovered it was not. Next, since I have a spare WE 396A, replaced the one on the Af in case it was something funky on the tube. No change. Next, rearranged all my audio rack to really separate digital and analog sides as much as possible. No benefit, although it looks neater. Finally, decided to swap left and right channel 2A3s to determine whether one was at fault. They are pretty tough to get out and put back in, I did it very slowly and carefully, making sure they were seated really well -- which I thought I had also done originally. Af stayed exactly the the same place, cables routed exactly the same way.

I was expecting the mystery bzzzz to show up the right channel. I got no bzzzz on either. No idea what magic happened.

 

For anyone this may help (and I realize this may belong in the tube rolling thread), I was able to get a good deal on some Shuguang Treasure 2a3s and they are NOT warmpoo. They're nice, sound smooth but not enough stage. This is specifically with the Aficionado. With the 800S they work because the 800/S is basically a cheat code to good staging, but with VC the sound is good but the stage is nothing special. I guess it's hard to top the stage of the EML mesh though.

 

I just ordered a pair of Psvane ACME 2A3, and the seller asked me if I wanted to specify a particular plate current? I looked at the RCA 2a3 spec sheet, and although I see that plate current is mentioned, I'm at a loss at how to answer.

My RCA tubes from Brent Jessee have plate current of around 280 mA with plate voltage of 250 V.

Is there supposed to be an optimal plate current (assuming new tubes should have higher current than used tubes)? Marvey said that Aficionado has autobias, so presumably not an issue?

Thanks in advance.

 

280mA? Lol no, that will burn it out in 5 minutes.

Typical 2A3 is 60mA in the datasheet for SE class A which with the standard 250V makes 15W, the maximum allowed.

People usually aim for 70-90% of the maximum dissipation and this can be done by tweaking either the current or the voltage. For example a lower bias for 2A3 I'll use is 40mA and 240V, this makes 9.6W and should provide a nice long life and I don't need the full swing for headphone use even with Susvara.

In any case the bias is set when the amp is designed and you shouldn't care or know what it is unless fixed bias or DC coupling is employed, not the case for EC, DNA or Woo. The tube is required to fully function up to the 15W dissipation without issues. It's really weird someone would ask for a specific plate current unless you may ask for a lower value which a B grade tube would satisfy. Ask for 60mA and 15W dissipation, the industry standard.

 

Thank you so much. That makes sense with what I saw in the RCA 2A3 spec sheet. Just for my education, any idea what Brent Jessee is referring to in the label (attached)?

 

That's quite unusual, while somehow makes sense for the curves even if it goes beyond the graph, you'd never use it at that operating point, that 70W.

For testing purposes -20V and 250V can work as an impulse test only I guess, if it can do that crazy current it's pretty strong and will work on anything. Never seen or heard about this type of testing plus for a tube vendor I'd expect not just plate current but gm value as well, with both values one can know the heath of the tube, just current doesn't show the full picture.

Bottom line that 280mA current doesn't represent a true picture at normal operating conditions for tube amp use and has the potential to hide iffy tubes by not being able to compare against the datasheet.

 

I don't remember the details + process but I do remember talking to Brent Jessee about 2 or 3 years ago and the tester only shoots up to a high level very briefly (<1 or 5 seconds I think??, high level in this case being ~250+ mA). I can't remember the reason right now - I only recall that it made sense to me at the time as I had been reading more about tubes, tube operation, testing and the graphs/curves, etc. at the time.

 

Oh well... Yes, it's there on the right channel, maybe fainter, I'd just missed it, as I don't always listen to the Af. The chain goes Pi2AES > Holo Spring 2 > Goldpoint > { DSHA-3F | Af }. Everything is dead quiet on DSHA-3F. Af is also, except for the very, very faint occasional sweep "mmmwhaaaa" on the right channel that's only audible on silent periods. I'm inclined to suspect the Linlai 2A3 tube, as I was hearing the same sound when the 2A3s were swapped.

Any ideas on whether this is "normal"? It's not a big issue, but...

 

Thanks! What makes me think it's one of the Linlai 2A3s is that the slight noise moved from left to right when I swapped them around, after trying everything else you suggested. I've swapped them back, so if the noise now appears on the left again that will be quite indicative. It does take a while to come up after the amp is on.