Review: Eddie Current New 2a3/45 headphone and speaker amp
Apr 3, 2011 at 1:46 PM Thread Starter Post #1 of 55

jp11801

aka JP-nums or JP-numbers
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Last month Craig Uthus of Eddie Current debuted a new amp at a smallish gather of friends in NorCal. I've heard many amps by Craig including those under the old Moth banner as well as his current name Eddie Current and I've been impressed by his output,Under theEddie Current name he has helped define the high end space with amps like the BA and HD2 hitting it out of the park for me. I've owned a few of Craig's amps notably one of the original Moth 2a3s that was a visual masterpiece and sonically one of my all time favorites. To this day it is the one piece of gear that I regret selling. He's made better sounding amps like the HD 2 ( a one off that he built for me) and Balancing act since then but the marriage of industrial almost gothic design, old school innards like brass plugs for switching output impedance and wax cloth wires and  sound quality earned a special place for me.

Enter the new 2a3, Craig's had multiple iterations of the 2a3 design at Moth from an his first more expensive units, scaled down more entry level and finally his 2a3/45 SI ammo box units. This new amp can switch between 2a3 and 45 tubes with a toggle switch located in the rear. Users that try to run 45s in 2a3 mode will most likely learn quickly that 45 tubes do not like to be run in 2a3 mode (POP goes the NOS tube). So like all things a little care and knowledge goes a long way. The amp is a two box affair with a 5ar4 driven power supply with the amp hosting a pair of 2a3s (Craig supplied Sylvania tubes) but I'll also run my big bottle JJ's in there as well and a 6sn7 for the driver tube. I'll likely try and sub a 6fg8 with adapter in there at some point in the trial. There are three single ended inputs, a set of speaker taps, and both a 4 pin and 1/4 headphone plug out front.

I ran the amp with a pair of Alon Lotus SE speakers ( http://www.sonoris.c.../lotussemk2.htm ) , a pair of Audeze LCD2s, Audio Technica AD200s and the JH13s. As a source I've got the Metric Halo ULN 8 (badged as a Sonic Studio 305) and an Origin LIve Sovereign turntable with their encounter tonearm with either the ZYX Atmos cart or the Miyajima Shilable cart (still can't make up my mind about which to keep).

When I received the amp I  gave it a few listens with the Alon speakers, LCD 2 and JH13s and so far it is very favorable. This is an uber quiet amp with gobs and gobs of detail, glorious tone and drive. It really splits the difference well between pacing, detail/extension and the all elusive musical expression. Some amps do one or two of those but its tough to find an amp that has rhythmic drive, extension gobs of detail and great tone. as of this red hot moment the 2a3 is hitting all three equally well. I'l see over the course of my time with it how it fairs over the longer haul.
 
 
The speaker sound was fantastic, very detailed but also very musical but ultimately the Alons do need more power maybe like a 300b an 845 (which I already own). Where EC 2a3 bested the Fi X 2a3 and the Dared 845  micro detail, tone (oh that amazing natural and accurate tone!). At low levels the EC 2a3 shined but did run out of gas with dynamic peaks or recordings with full dynamic range. This is not a knock on the EC 2a3 just a fact of a 3 watt amp powering a three way passive crossover speaker. Hooked up to a pair of Cain and Cain Horns I bet would be a revelation.

I've always loved the AT AD2k and the EC really re-enforced my love. The common knock on the ATs are they are airy (what the heck does that even mean) and lack bass extension and power. This was totally mitigated by the EC 2a3 as the AT's shone like a light on the recordings that I threw at it. I downloaded the new Rolling Stone HD tracks 24/176 of Though The Past Darkly. Man of man it was like being in a studio control room listing to the masters. Little details jumped out. Ruby Tuesdays strings had stunning bow attack and Jagger's voice was so freaking papable. Jumping Jack Flash was a blast, Jagger takes a breath right before singing and I never really noticed it before " I was born in a crossfire hurricane" and it's like he's right there in front of you! This was one memorable listening session.

Switching to the LCD2s its a totally different perspective instruments are weightier bass is powerful and driving. Details are still there but its like going from a studio monitor to Maggies. Both are awesome but they just portray the music in a very different way.

I played some Beatles from the 24/44.1 usb stick that came out and same great results weighty detailed and musically involving. The EC 2a3 should be on any LCD 2 owners short list, particularly if they plan to power high efficiency speakers as well.
 
I borrowed an old friend's (i've know him a long time and he is old :wink: ) K1000s to see how they would perform with the EC 2a3 and they were sublime. The 2a3 to me rose to the top flight k1000 sessions I've heard with amps like the Moth 300b or first watt F1 being driven my an Eastern Electric pre amp . One of the knocks on the k1000s is they can get strident with the wrong amp and while some amps can power them they still don't sound good. The 2a3 provided a very balanced sound with nice bottom end (not the k1000s strong suit), speed like a possessed demon, PRat and tone.

Right now I'm using an RCA 5ar4 instead of the Chinese rectifier that was provided. I pulled the Sylvania 2a3s and popped in the JJs I had on hand and both are really good. The JJs have more bass and are overall thicker sounding where the Sylvania tubes are cleaner but have less bass weight and extension. I've got a few 6sn7 variants here but for now have stuck with the United Electronics that Craig sent. I do plan on popping in a 6f8g and maybe a 7n7 as well for kicks. I also plan on playing with the Bendix 6106 (?) and 5y3 I have here too. I'd go for NOS 2a3s if you can find then as they bettered the JJs and are normally only marginally more expensive and sometimes less.

While  not the TOTL experience that the BA is and the only comparison I did was in NorCal the 2a3 does not give up much. It's not a balanced input amp like the BA and the PS in the BA is arguably better but the 2a3 is dead nuts silent. The BA to 2a3 is a tough comparison as the BA's I've heard had either PX4/300b or AD1 tubes compared to the 2a3. Craig offeres the BA in  45/2a3 variation but most are being made with the PX4/300b option and from what I understand the AD1 version is no longer made.

The amp really responded to tube rolling and the change from the stock NU driver to one of my 6fg8 tubes (with adapter) improved tone and perceived headstage on both the AD2ks and the LCD2.
 
The amp can be made with either partial silver core or copper transformers. The partial silvers were in the amp I auditioned and I'd go that route as the copper provide slightly more gain but you lose the sonic benefits of the silver cores that according to Craig are speed and tone.
 
This amp really puts people in a spot that are looking at the BA as it comes close to BA quality, say a 9 out of the BA's 10 but that last bit of improvement is pretty large. I hate people that equate the percentage increase in cost to a value equation to improved sonics. First it's just not possible to truly measure improved subjective sound quality and secondly my 9 out of 10 might be someone else's 7 out of 10 depending on what their values are.
 
So in closing if you want to power just about all headphones (including the k1000s) and have a budget of around $3000 this amp is a slam dunk. You also can experiment with single driver high efficiency speakers while you are at it.
 
 
Here is a picture from Craig, as I failed to take a picture of it when I had it in house.
 

 
Lastly a financial disclosure, Craig paid for the amp to ship to me and I paid for the amp to ship back to him about $60.

 
 
Apr 3, 2011 at 2:09 PM Post #4 of 55
Could you pay another 60$ more ? so that others who are interested in the new BA will be able to
choose which platform to choose correctly.
Sorry for the mistake I made because I saw that you wrote about the 300B in the earlier part so I was not
sure whether you have heard the 300B from other amplifier or the new BA.
Thanks for your excellent review,  I have one new BA ordered in 300B  , but may be I will be interested in the
2A3 platform that can also drive the speaker,  What is the sensitivity of the speaker that the 2A3 BA can drive effectively?
 
Apr 3, 2011 at 2:19 PM Post #5 of 55
wow, Im not sure but I think you are asking me to have Craig send another amp to me and for me to apy $60 so you can better decide?? If so I'll have what you're drinking
beerchug.gif

 
The EC 2a3 will power speakers in the 94db and up range preferably those that are single driver as passive crossovers eat power. A perfect match for this amp would be Cain and Cain Abbeys or the old Moth Cicada's. There is a wealth of information on the web regarding single driver speakers
 
Congrats on the BA that is the true top of the EC line up and you should also be able to go PX4 as well
 
 
 
Apr 3, 2011 at 3:44 PM Post #6 of 55
wow, Im not sure but I think you are asking me to have Craig send another amp to me and for me to apy $60 so you can better decide?? If so I'll have what you're drinking  
 
beerchug.gif

Please do that and I can buy you some drinks and I'll pay via paypal
 
 
Kidding, but it's good to know that
 
my BA will use  the Tungsol BGRP and the new Royal Princess Sophia,  I am thinking of using the KR PX4 too.
 
Apr 5, 2011 at 6:40 PM Post #7 of 55
What I want to know is, how many people would listen to their headphones sitting up next to their speakers?  Besides already having two 45-based amps, for me one of the reasons I chose the 45/2a3 Balancing Act over this amp was that I would never listen to headphones near where I would place my speaker amp, as it would be too inconvient.  (Another reason was that I wanted the best sound-quality for my headphones.)
 
 
 
Apr 6, 2011 at 1:57 AM Post #8 of 55
Thanks, I saw this amp a couple of months ago on a thread. I talked with Craig and he had plans to try to go commercial with it at the end of February. I guess he has succeeded. My one concern is mixing the two tubes in a single amp. While the OPs can be adjusted, as you say, this is not enough to do justice to either tube, esp the 45. It really requires a different set of OPTs and PS from the 2A3. So, I wonder if Craig has not made some sacrifices to combine the two tubes. I also wonder about the power. If you have true 90dB efficient speakers and they are easy to drive and your room is small, then 3.5W ought to be "sort of" enough. You will hear more distortion, sure, in loud-soft-loud dynamic passages, but the amp shouldn't clip.Jazz, chamber music, acoustic, small stuff ought to be OK with a 3.5W 2A3. With the 45s, I'm less sure. What are the power-out ratings for the two tubes?
 
Apr 6, 2011 at 4:54 AM Post #9 of 55
first to bhd, many high end headphone amps also act as a high quality pre amp the Balancing Act is ne exception. So to answer your question while using your headphone amp as a speaker amp or a pre amp in a speaker system does not work for you it is a sought after feature for many that purchase high end headphone amps.
 
The 45 tube and 2a3 tube as similar enough to share a topology as many other ap manufactures combine them heck I have one in house right now, Don Garber's FI 2a3 X. The 45 tube is 2 watts and the 2a3 is about 3.5 watts but I've learned that an output rarting never tells the whole story. I called out that a 90db speaker is not really ideal for a 2a3 or 45 amp particularly one with a passive crossover. The speakers in question though were designed for SET amps and have a 14 ohm woofer that presents an easy load and actually requires a low dampning factor, a high dampning factor would produce an enemic sound.
 
Apr 11, 2011 at 1:14 AM Post #10 of 55


Quote:
The 45 tube and 2a3 tube as similar enough to share a topology as many other ap manufactures combine them heck I have one in house right now, Don Garber's FI 2a3 X. The 45 tube is 2 watts and the 2a3 is about 3.5 watts but I've learned that an output rarting never tells the whole story. I called out that a 90db speaker is not really ideal for a 2a3 or 45 amp particularly one with a passive crossover. The speakers in question though were designed for SET amps and have a 14 ohm woofer that presents an easy load and actually requires a low dampning factor, a high dampning factor would produce an enemic sound.



I talked with Don about this as I have a pair of Fi 2A3 monos on order. These amps will play either tube, but Don felt that they are not prefect substitutes in his amp without additional modifications.  Both tubes will play, but the 45 won't sound as good as it can in the 2A3 amp.
 
Apr 11, 2011 at 12:55 PM Post #11 of 55
The EC has a flip switch on the rear to allow you to toggle between 2a3 and 45. This indicates Craig set the amp up to work with both if you ran 45s in 2a3 mode you'd likely blow a tube and if you run 2a3s in 45 mode it would sound anemic.

Oddly having listened to the Fi last night with NU 45 tubes it sounds pretty spectacular. I also have RCA black plate 2a3 bi plates but really like the amp with the 45s
 
Apr 17, 2011 at 1:17 PM Post #12 of 55
I had a Fi X and rue the day it was sold. Accrued with it was a 15 yr supply of cunninghams, globes, and RCA 45s. Although Don indicated that the 45 would burn a little hotter and not see their full life expectancy, they became the tube of choice.
 
I know with the way you are using either amp, this is an apples/oranges question, but still. With either amp (EC, Fi) or any DHSET amps in general, are there any basically universal differences in sound signature between an OPT or OTL circuitry? 
 
Apr 24, 2011 at 2:34 AM Post #13 of 55


Quote:
I had a Fi X and rue the day it was sold. Accrued with it was a 15 yr supply of cunninghams, globes, and RCA 45s. Although Don indicated that the 45 would burn a little hotter and not see their full life expectancy, they became the tube of choice.
 
I know with the way you are using either amp, this is an apples/oranges question, but still. With either amp (EC, Fi) or any DHSET amps in general, are there any basically universal differences in sound signature between an OPT or OTL circuitry? 


Probably not.  The differences between amps will probably be as great as between typologies once you are talking both class A and DHT.  Keep in mind, however, that lower impedance headphones will generally do better with output transformers and that will create sonic differences if an OTL is not up to driving some cans.  In that case, it won't sound as good.
 
It's interesting you mention Fi.  The 2A3 monos make a great speaker amp, but the circuit Don Garber uses will not work at all well for headphones.
 
 

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