ECP Audio T4 Headphone Amplifier - Built and Sold by BeezarAudio
Feb 4, 2020 at 10:41 AM Thread Starter Post #1 of 103

adydula

Headphoneus Supremus
Joined
Dec 14, 2010
Posts
5,195
Likes
14,162
Ok I finally got thru several days of being sick and under the weather but we finally got time to listen with the T4 in great detail!

Tom Blanchard of Beezar Audio recently contacted me on Head-fi about some comments about his T3 torpedo para-feed headphone amp I made in a recent review. I got a note from him that explained how the issue had been corrected. In the conversation Tom asked me if I was interested in taking a listen to his new ECP Audio T4 para-feed headphone amplifier, this was back in December and here we are in Feb of 2020 and I just received the second prototype T4 which he uses as a loaner. Its pretty much the same amp electrically and has a few cosmetic changes, like smaller vacuum tube openings and logo. Sonically its the same as the production runs Tom has built and sold.

Until I met Jim Hagerman and his Tuba para-feed amp several months ago I really had no clue that there was another para-feed headphone amp out there. Tom has been involved with the Torpedo series headphone amps for quite sometime and it has gone through several “long” shaped iterations.(hence torpedo).

This amp, the T4 is the first amp that the shape has morphed into a more desktop rectangular shape with some nice looking walnut wooden sides. Toms opinion is the T4 is different than the T3, by quite a bit. “With the T3 he seemed to find a magical tube in the 12AZ7, even though it ran very hot in that amp (higher heater current). The T4 seems to prefer a regular 12AT7 tube best, with the best quality 12AT7 tube performing as advertised from audiophile tube sources. In that vain, the new JJ 12AT7 tubes are superior to the Electro Harmonix 12AT7 tubes,even though I’ve always thought Electo Harmonix tube construction was superior. (You will find JJ tubes varying by 1/4" or more in length!).” (this is from Tom directly).



WP_20200202_10_30_38_Pro
WP_20200202_10_30_38_Pro2672×1504 1.08 MB



My experience is with the T4 only, and not a comparison with the 3F which is a solid state amp designed for the Focal Clears to handle its undamped drivers. The T4 is a high voltage, low current amp, the 3F is a low voltage high current amp. And the T4 has a tubes in it
:slight_smile:
As stated in other comments, the T4 was designed to work with a wider range of headphones and impedance’s and utilizes some very special low DC resistance output transformers made by Lundahl. There is a Hi/Lo Z switch on the right front side.

From the Owners manual description:

" The T4 differential hybrid para-feed headphone amplifier amplifier , custom assembled by Beezar Audio was created by ECP Audio. The T4 continues in the tradition of its predecessor, the ECP Audio/Beezar Torpedo III. Its circuit and configuration are totally unique in the word of headphone audio. The T4 combines tubes with a fully differential solid-state-output feeding into custom-manufactured Lundahl output transformers for the finest in single-ended, zero feedback output from a headphone amplifier. The result is perhaps the finest tube amplifier available anywhere at this price point.

The tubes are configured in a long-tail pair that results in a fully differential output. From there a fully differential solid state buffer is used, terminating in output transformers configured into a para-feed arrangement, where the differential signal is combined back into a single ended connection at the headphone jack… Because of the fully differential circuit, common mode distortions is fully canceled out. At the same time, the solid state buffer output after the tubes results in more power than would be available from the tubes themselves. The output transformers assist with this, ensuring that ample current and voltage are available, regardless of the impedance of the load.

ECP audio designed this amp to utilize the ubiquitous 12A*7 audio tube family. Specifically designed for the 12AY7 or 12AT7, but others can be used that meet the general 12A(T,U,V,X,Y, Z)7 tube specifications. The Z switch is a 75or 300 ohm choice. Toroid transformer, ALPS Blue Velvet potentiometer, Special Visahy low-noise nickel chrome tube plate resistors, new thin film Vishay/Beyschlag resistors throughout. Finally a new advanced thermal bar heat rejection through casework.”

SPECS:



WP_20200203_11_53_09_Pro
WP_20200203_11_53_09_Pro2979×3700 1.98 MB



The overall look of the T4 is simple elegance, a large volume knob makes for easy articulation. Its smooth and stays put at all positions. I might state here that the amp is dead silent at any volume output, or impedance switch setting. There are no turn on or off thumps to startle you. The only other port on the front is the large 4pin XLR port. My focal Clears plugged into this with the balanced cable and works fine. If you have SE cans only you will need a special XLR to TRS adapter cable. Tom included one in the box and I used it to connect my HD600’s and it worked just great. I think the adapter is a $50 option.



WP_20200202_10_49_22_Pro
WP_20200202_10_49_22_Pro4756×2365 1.41 MB


WP_20200202_10_50_06_Pro
WP_20200202_10_50_06_Pro5002×1280 975 KB



I have built many, many DIY amp, Amateur Radio gear and torn in to lots of retail products to look, see and modify stuff, and I can easily tell if something is well thought out, built well, etc…and the T4 is very well thought out and put together nicely. Its a simple laid out amp with high quality components, great soldering and tube sockets that are very well connected to the PCB. Even with this prototype inserting and removing tubes required a good amount of physical effort and you can be assured that your tubes have a great solid connection. In the T4 I received there are 2 yellow Auriacps XO, instead of the white caps in the pictures above…Tom tells me the Auricaps were a solid design choice for them and the photos will be updated to reflect the new Auricaps.



WP_20200203_10_57_02_Pro
WP_20200203_10_57_02_Pro3008×5344 3.35 MB



Tube changing requires removing the top lid via several small machine screws and using a small plastic tool to gently pry up the top and remove. Once inside tubes are easily accessible. Insert tubes, replace and screw top back and your good to go. Simple.



WP_20200203_10_56_34_Pro
WP_20200203_10_56_34_Pro1504×2672 1.04 MB



On the back side there is a power on/off/fuse unit to attach the power cord and on the opposite side a single set of RCA phono plugs for your source connection. I used simple Y-connectors off the back of my dac to run to two amps for fast comparisons.

Tom sent me two sets of 12AT7’s to play with, one set of CV4024 Mullards and a set of JJ 12AT7’s. More on that later.

First impressions are usually lasting ones. My first impression with the T4 was indeed a very, very good and lasting one. What impresses me most is of course how does it improve or make my listening experience better and secondly how well is it built. The pedigree of the T4 over the years speaks for itself and with the changes to lowering the DC resistance with those really special Lundahl transformers speaks volumes in the design of the amp and the the results are very apparent.

NOTE: All music was sourced via a new Schiit Bifrost2 True Multibit dac, via USB to a HP 27" AIO using the Schiit Unison Interface. Jriver MC 24 setup up for bitperfect playback was used, no weird stuff or plugins or eq’ing.

This is an amp that tells me “STOP thinking about specifications, power output, and just listen to the music “stupid””. From the first moment I turned it on and hit play, not even with my demo stuff, just some random stuff vial Jriver MC24 my jaw dropped and I was instantly mesmerized. OMG for the next two hours…not jumping around trying to find that tune that makes things sound good, it all sounded good…the tubes in the sockets for this first audition were the CV4024’s.

I started out the first night with just the Focal Clears, the second day I moved to the Senn 600’s. Low Z for the Clears, Hi Z for the Senns. I have never had an amp that paired with the Clears tonality characteristics as well as the T4. Matter of fact this has to be one of THE best pairings for the Clears period! Over and out!..



WP_20200203_09_28_59_Pro
WP_20200203_09_28_59_Pro5344×3008 3.8 MB



Day 3 I powered up the Bottlehead Mainline for a comparison, starting with the HD600’s level setting and making sure all the switches on the Mainline were set to HIGH impedance and UNBAL outputs, we started listening to Cowboy Junkies. Trinity Revisited, Dreaming My Dreams. The opening bass and male voice was delicious on the T4 and with a quick switch to the Mainline, the presentation was very similar! Both setups were delivering sound that was very close in comparison. The bass tightness on the T4 was slightly tighter or it seems to be at times but we are splitting hairs here.
The ambiance and background minutiae was present in about the same detail. But the T4 just eeks out the Mainline in clarity.

Second song was Eva Cassidy, Time After Time, I wish I was a Single Girl…her voice and strong guitar strumming here are in your face wonderful. The holographic depth the the sound-stage, hearing those studio reverberations are clearly heard. Tonality of the guitar strings are very well reproduced.

Third song was an old Eric Clapton, The Cream of Clapton, Badge, and this is a mediocre recording and it sounded equally mediocre on both amps! But popping on Eric Claptons 24 Nights and the Bad Love rendition…totally different story! Excellent recording and the T4 shine very, very well here! A live rock and roll session with Clapton at his best!!!

Fourth song was Michael Buble’s, Michael Buble, Fever! Wow this one the winner is decidedly the T4 here, but not by much. The difference in this recording compared to the others is this is a typical loud, brassy, fast sharp transients you hear from a Las Vegas nightclub band…BAM! in your face…The presentation with the T4 was just a little different in that it was more holographic and the tonality was just more to my liking…again either one is great, but we all have opinions. I would have to say the T4 is more accurate in being able to present all what in this recording, with no faults attributed to the amp, as the Mainline adds some smoothness to the overall sound…depending on the source materiel, time of day, your mood etc…this could change.

Alison Krauss, A Hundred Miles or More, A Collection, Jacobs Dream…Alisons beautiful voice and guitar strumming here are very, very well done, clear, and her high voice reverberate throughout the room…It was again pretty much a tie for both amps. the difference again with good recordings seems to be a slightly overall clarity and bass control of the T4 over the Mainline…

Switching over to the Focal Clears, Mainline set for Low impedance, and balanced output, quick level match…and up comes Rhythm Devils, the Apocalypse Now Sessions and Cave…what a weird strange recording, but it has lots of minutiae and minuscule sounds that actually make for interesting testing of stuff…Both amps did well.

Next up was an explosive Mino Cinelu, Mino Cinelu, Will O’the Wisp…WAHM!! the Both amps did very well…bass drum lines and bright distinct cymbal crashes with huge drum slams will surprise and shock you if your too loud…plus throw in a male voice…very busy recording excellent demo track.
Listening to Dave Brubeck – Time Out Classic…with the Clears…Simply the best I have ever heard…cleanly defined bass drum whacks that are so real…explosive…

Trying our a set of Beyerdynamic T90’s was a nice surprise on how well they worked in Hi Z mode with the T4. The ususal treble sparkle seemed to be tamed down just the right amount. The T90s are 250 ohms and they have enough power to be driven exceedingly well…From Special EFX , Slice of Life to Luiz Bonfa’s Non-Stop to Brazil. Keiko Matsui, Dragon Wings a holistic reproduction! Clean, crisp and articulate.

The Clears on the T4 have never sounded so tonally accurate and crisp…not over done just soo sooo right IMO. Again both amps are great, musically its hard to choose one over the other…but the T4 again edges out the Mainline with its slightly tighter overall control on the low end and overall clarity…like we are talking in the high 95% + area of getting to a perfect no faults, which doesnt exist in my book…

Lastly there is no complete test with out some LeaAnn Rimes country and western stuff!! LOL…Not my favorite genre but some of her recordings are so well done you can cut thru glass with them! LeAnn Rimes Unchained Melody" The Early Years…Sure Thing…This is CW Jukebox music and your gear if its any good should be able to handle this with aplomb! Both amps do well again, but this time the T4 just takes is away in handling everything, Fast transients, loud in your face piercing vocals with no sibilance. Some female voices can really grate on your ears, like Adele for me. but Rimes is like listening to a human glass cutter, amazing. the T4 handles this so well.

HD600’s attached with the XLR to TRS adapter cable:



WP_20200202_10_59_52_Pro
WP_20200202_10_59_52_Pro2672×1504 1.5 MB



This wasn’t meant to be a T4 vs Mainline shootout, but I wanted to see how two high end tube amps would fare against each other…and both do very well. Which one to pick? Well if you really want the best and can afford $2000 the T4 is the answer. If you like 12AT7 tubes…you can play to your hearts content, and no internally bias adjustments are required and you dont have to spend mega bucks on tubes, the CV 4024 are around $60 a pair…and worked so very well… With the Mainline the 6C45pi’s are pretty much it, not many other affordable options out there. The T4 only has the one Neutrik 4-pin XLR headphone jack , compatible with 4-pin XLR balanced headphone connections,so if your using balanced cables your set to go, There is no 1/4" phone plug, so for your SE cans you need to purchase an adapter to convert from 1/4" stereo to XLR. The one provided to me by Tom is an excellent TRS to ¼ cable, high quality and will stand the test of time.

So in closing, if you have a set of Focal Clears and want one of the best amps for them the 3F is out there if you can catch one, but its designed again for these cans…while the T4 will play the Clears so much nicer than many other amps AND if you want to use your HD800’s and other high impedance headphones, well the T4 can do that as well!! The T4 is a no-brainer choice IMO.

I want to thank Tom Blanchard for allowing me to listen to this marvelous amp, its a real winner and whoever winds up with one will have a piece of gear that will provide thousands of hours of enjoyment. I really hate to send this one back! Its really world class!

Maybe someday!!

Alex

UPDATE: Tom has posted a very detailed thread of the recent T4 builds: https://forum.headphones.com/t/t4-headphone-amplifier-by-ecp-audio-official-thread/5090/82
 
Last edited:
Feb 26, 2020 at 9:05 AM Post #7 of 103
I've started on a new production run of T4 headphone amplifiers that should be ready by late March. I'll update the thread with some progress photos and details between now and then.
 
Feb 27, 2020 at 9:14 AM Post #10 of 103
The 3F is a solid state amp, while the T4 is a Parafeed Tube amp...
The 3F from what I understand was designed to specifically work with the Focal Clears, due to the way the drivers are mounted etc...
The T4 is designed for more than just the Focal Clears...

There may be more technical design traits that Tom might help explain...

Alex
 
Feb 27, 2020 at 10:31 AM Post #11 of 103
Iif you search through much of what Dsavitsk has stated, the 3F was specifically designed for super-low-output-impedance, mainly in response to Focal headphones such as the Utopia and Clear. The new driver design that Focal uses in those headphones (and others, like the Elear) is extremely undamped. In some cases, you can actually see the driver move back and forth simply from the motion of walking with the headphones in your hands. So, an amplifier with as high a damping factor as possible is probably recommended.

That may not be the best scenario for higher impedance headphones, or even relatively low impedance phones that have higher inherent damping. For instance, Grado headphones (typically 32 ohms) prefer a bit higher output impedance to cut down on the harshness. It's why many people prefer Grados with tube-transformer amps such as an ECP Audio tube-parafeed design (like the T4), Bottlehead Mainline, or a Mapletree headphone amplifier.

In that respect, the T4 is a more all-around traditional output transformer amplifier (albeit unique tube-parafeed-differential hybrid), with two transformer output windings optimized for 32 or 300 ohms (switchable with the Z switch).

There are some who would claim that super-low-output impedance is preferred in any case, be it low or high impedance headphones. That is subject to debate and everyone is going to have their opinion - I've stated mine. :wink:
 
Feb 27, 2020 at 10:40 AM Post #12 of 103
I might add, that even despite the T4 having output transformers (usually considered higher in output impedance), Dsavitsk went to great effort with Lundahl to wind completely unique, custom output transformers. At low impedances, the DC resistance of the output winding begins to override other effects on output impedance (at least as I understand how Dsavitsk has explained it to me). The effort Dsavitsk went through (with a couple of unsuccessful attempts by Cinemag) was to lower the DC resistance of the output transformer windings. The custom, ECP Audio-Lundahl output transformers in the T4 are the result. There is probably not another headphone output transformer available with lower DC resistance on the output windings.

What does that mean? It means that in comparing another output-transformer equipped headphone amplifier with the T4, the T4 is most likely going to have a lower output impedance. So, it is probably going to do much better at powering Focal headphones compared to another tube, output-transformer amplifier design.
 
Feb 27, 2020 at 11:24 AM Post #13 of 103
Tom,

Thanks for that input, I dont put much stock on this from just a viewpoint, they are pretty narrow minded folks IMO. They have many interesting discussions and viewpoints but the tolerance for other stuff is limited as far as my experience goes....

From the 12 amps + I have here and having several parafeed tube amps, I can say with the Focal Clears specifically it doesnt get much better than the T4.

And it worked very well with several other headphones....

I think both amps are stellar...and would be happy with either one....SS or tube? Your choice....

But to state one amp is the unequivocal best for ALL headphones, I think not.

Alex
 
Mar 25, 2020 at 8:40 PM Post #15 of 103
Nice review!

Have a question for Tom. Can the low setting on the amp be changed? My two cans are an Ether-2 and Abyss Diana. They have 16 ohm and 40 ohm loads accordingly. The Diana is a pretty tough load, but sounds great with the right amp.
 

Users who are viewing this thread

Back
Top