EC Studio Junior (not AF)

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by purr1n, Mar 2, 2019.

  1. purr1n

    purr1n Finding his inner redneck

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    I have the EC Studio Junior pre-production in the house to help Craig troubleshoot some issues. This amp is configured with 300B tubes and uses feedback from the tertiary winding of the output transformers. The most significant difference from the AF is the output transformer. The SJR transformer is a custom deal, not the Cinemag used in the AF. It was based on a pre-existing transformer (quite pricey). This original transformer was taken apart, disassembled, and dissected to discover the secrets of its core laminations. The tertiary winding (based on an old McIntosh design back in the day) was then put into this transformer. I've heard both the original and tweaked with tertiary winding version and I can say that have the same or similar sound. The experiment was a success.

    The AF transformer is slightly drier. The SJR transformer is slightly wetter and richer. A most important change with the SJR transformer is the availability of 4-ohm and 8-ohm taps. The headphone out uses the 8-ohm tap only. The output impedance from the 8-ohm tap is probably 2-3 ohms, and the 4-ohm probably just a little over 1-ohm. Don't quote me on this. These are just predictions. The speaker outputs are Neutrik Speakon (the best thing ever - used by pros - screw you audiophiles with your lame gigantic lugs and banana plugs that tend to break shit more than offer better sound). Pin 1 +/- are the 8-ohm taps and pin 2 +/- are the 4-ohm taps. The reason this transformer has a 4-ohm tap is because of the JBL 4698Bs which Craig owned for a while: the woofers are 4-ohms. Necessity was the mother of invention.

    The SJR can be ordered with 2A3 tubes instead of 300B. Standard, the SJR comes with 300B and feedback. Those who prefer a bassier, thicker, and heftier sound a la Amp&Sound will want to order it without feedback. The SJR never gets quite as thick and rolled sounding as the Amp&Sound stuff with or without feedback. I like the transformer in that it doesn't have overblown mid or upper bass, but it packs a ton of punch just below the mid-bass and is full-bodied in the mids. This effect is exaggerated in the non-feedback version. The non-feedback version has quite a punch! The downsides are less controlled and articulate bass and slight high-end roll-off. It's a 300B after all and this is how 300Bs sound. The good thing is that the sound isn't soft. The AF 2A3 is a little softer and less punchy, feedback or non-feedback.

    The feedback version of the 300B is what I would recommend. This approach tones down the 300B sound and results in what I would like to say as "the best of the 300B without the worse of the 300B". The resultant sound is very stately, controlled, perfectly damped. In comparison, the mids and highs of the non-feedback AF 2A3 tended to be a bit jumpy and overly lively (this is more of a transformer issue than feedback issue). Nothing is for free of course. The feedback does constraint the soundstage and immediacy factor by a tiny bit, but with the 300B, I find that the positives outweigh the negatives - this keeping in mind that I am not exactly a 300B fan.

    I am uncertain if balanced inputs (iso transformers in the chassis) will be offered. I'll check the metal work next time I am in the lab.
     
    Last edited: Mar 2, 2019
  2. EagleWings

    EagleWings Friend

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    @purr1n , does SJR's wiring allow for a FB/NFB switch like what @JK47 did for his AF? If yes, would Craig be willing to do it.

     
  3. purr1n

    purr1n Finding his inner redneck

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    Since the SJR comes standard with feedback and the design was never to have the tertiary outputs used for an SE line out like on the AF, there are no holes in the back plate that can be repurposed for a switch. I can check the back plate to see, but I am not aware of Craig wanting to offer such an option.

    The AF feedback thing drove Craig nuts. Not my fault. His own doing by saying certain things to the wrong person, who in turn blabbed to the public about certain things Craig said to him in confidence (implied, but young customers can be impetuous and dumb). You know, that comzee guy who berated me of "intentionally nerfing the AF because the Jupiter caps and feedback mod were not publicly available options". What happens is that Craig wants to be a nice guy, but then bitches to me about non-original owners (or even original owners) wanting him to do mods. I believe that consumers should NOT be given options for a product - that those different configurations should be entirely different products altogether. The reason is that EC, or even Schiit for that matter is not Dell or Audi, with sophisticated just-in-time supply and manufacturing chains.

    I would hope that the SJR 300B just comes in one package: with feedback. Of course, now that I say this, people will now call and ask for the non-feedback mod. I'm hoping Craig will have now learned this lesson and just tell people "no" to no-feedback, or "buy Woo".
     
    Last edited: Mar 2, 2019
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  4. allegro

    allegro Friend

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    @purr1n which 300B tubes were you using? Are the lower cost new tubes like Genalex Gold Lion PX300B satisfactory?
     
  5. purr1n

    purr1n Finding his inner redneck

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    Yes, get cheap shit. I was and am using EH 300B cheapo specials. Sounds damn good. I like the JJ 300Bs quite a bit too, they are smoother (maybe a wee bit) but more lively. Great tube amps will sound great with decent tubes. There is no need to buy $2800/pair Albacore Tataki or $1600/pair WE Retcon tubes. This is why I love Craig's (and also Donald's) amps. They just sound good with whatever stuff you plug into them.

    I do immensely dislike the TJ Full Music tubes though. Their construction is shit, the metal creaks and pings when the tube is heating up, and the sound is way too bloomy and romantic, but hey, people love that stuff. The fake metal mesh Chinese tubes also sound like ass, like ass caked with dry shit.

    You can't go wrong with JJ, EH, Genalex, etc. The EMLs are very nice, focused and rich, but have gone up hundreds of dollars in a few years. FWIW, I have no intention of spending more than what JJs or Genalex cost. So sick of listening to tubes. I listen to music now and don't GAF about tubes.

    BTW, gain on the two triodes on the driver tubes will be important for channel balance. Less an issue with 300B since gain is low on 300B. The driver tubes are for the gain. The 396A is fairly high gain, so easy for stuff to be off.
     
    Last edited: Mar 14, 2019
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  6. Thenewerguy009

    Thenewerguy009 Friend

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    I always wanted to ask, but can't the RCA inputs just be removed & replaced with balanced inputs if you just want one set of XLR inputs & no RCA?
     
  7. purr1n

    purr1n Finding his inner redneck

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    Just confirmed with Craig on the phone. It will come with only unbalanced inputs x2.

    The amp is still being worked on. Final tweaks to eliminate some intermittent noise which seems dependent upon the state of the power lines. The metal is in.
     
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  8. fp627

    fp627 Friend

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    Sounds like the amps are "largely" the same but roll transformers?

    2 other questions:
    - @purr1n Given your distaste for config/customization options, is there any way to have both feedback and no feedback via a switch or something similar? Ex flip switch to connect or bypass resistor from output circuit path? On the flip side I can also totally see how this can go very wrong via user error.
    - Similarly, while I'm not a fan of excessively chasing components/tubes/etc, I'm still curious if different caps and other components will make a "significant enough" difference in this new amp (lets say more than switching between copper only and silver coated copper RCA cables that are otherwise similar)? If so, are components something that can be spec'd at time of build/order? (Excuse me if this 2nd question sounds dense after mentioning "AF feedback", but that isn't one I'm familiar with, if it was just a case of a bad customer or something much more of a headache.)
     
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  9. purr1n

    purr1n Finding his inner redneck

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    Yes. I believe a few users installed a switch or had one installed by Craig. It's more than just bypassing the two feedback resistors. Without feedback, there is the addition of a cap and resistor paralleled for the cathode bypass of the driver tube. So it's kind of a PIA for Craig. He's done the mod for his customers but will not do it for people who did not buy the amp from him.

    The interstage cap is worth playing with but which one is a matter of preference. With the feedback, I think the interstage cap differences are less. Audiophiles are strange creatures and once the cap rolling option is available, then cap rolling suddenly makes "massive" changes. What makes big changes is the output transformer.

    The other caps, cathode bypass on the power tubes. Other people have rolled different ones and values, for the worse. I'd stick with what Craig did here.
     
    Last edited: Mar 16, 2019
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  10. songmic

    songmic Gear cycler East Asia edition

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    Has anyone bought and listened to the Studio Jr (preferably, the default feedback version)? It's been quite a while since it was announced but I'm surprised no one has written a review or impression of it. Or is it still being built and the first batch has not even been shipped out?
     
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  11. songmic

    songmic Gear cycler East Asia edition

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    Just confirmed from Craig that the output impedance of the balanced headphone out is 3 ohms.
    Gain is 12 dB and 18 dB for SE and balanced outputs, respectively.

    Spec-wise, this amp should be able to drive very low impedance (as low as 25 ohms) and low sensitivity headphones (perhaps with the exception of K1000/HE-6/Susvara) without issues.
     
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  12. Vtory

    Vtory Illogical Spock

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    Pasted from GS 2019 thread (to keep that thread clean)

    @songmic Did you become to own SJr? Was very curious about this amp but no owner's impression has popped up so far. I almost assumed Craig decided not to make it for some reasons.

    If possible, could you elaborate a little more details about your new amp?
     
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  13. songmic

    songmic Gear cycler East Asia edition

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    I’m currently working on a thorough review. Craig is accepting orders alright, but I’m also baffled as to why no one has yet to review a production unit. This amp has been out for several months now. Maybe because a lot of people are still under the wrong impression that Af = SJ?

    IME it usually takes months for an EC amp to be completed upon order, but for me it only took 2 weeks since I was the first in line. I’m not sure how long the introductory price of $3300 is going to last.

    To give you an idea of how SJ sounds:

    In my review of Studio, I aptly called it uber-Jotunheim. People who heard both will understand where I’m coming from. I’m guessing Af is uber-Valhalla 2, not as ruthlessly revealing as Studio but still somewhat dry sounding (even without feedback). In the same vein, I would say SJ is uber-Asgard 3, at least the 300B version with feedback. In general, headphones that sound good on my Asgard 3 also sound good on SJ.

    Having been an owner of ZDS and Studio, I had hoped for an amp that lies somewhere between: not overly euphonic like ZDS but not stringent like Studio, while throwing that massive soundstage they are known for. Craig nailed it with SJ, which has become my favorite EC amp by far.

    I had initially gotten the SJ for my Verite, but I found it to be a better pairing with the more neutral sounding Code-X.

    Stay tuned for more.
     
    Last edited: Dec 4, 2019
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  14. songmic

    songmic Gear cycler East Asia edition

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    Some follow-up impressions (thanks to @ext1 for lending me his JAR 600 and HD800):

    1. The SJ is the best amp I've heard with HD800, period.
    - Note that the HD800 is modded, I'd never listen to it in stock form regardless of whatever magical amp I pair it with.
    - I have yet to listen to the Stellaris, which is probably even better.
    - SJ is a league or two above ZDS, Stratus and L-2 (which I'd considered the best HD800 amps with different strokes).
    - Studio is technically superior to SJ but Studio/HD800 is bright as fuck and unlistenable for more than 5 minutes.
    - Interestingly, the SJ reveals the HD800's inherent shortcomings in comparison to true TOTL headphones such as Utopia, and I'm not talking about its peaky treble. I'd thought that the HD800 was, for all its tonal flaws, still the champion when it comes to technicalities (transparency, imaging, resolution, soundstage, etc.). Well, almost. While the HD800 excels in most departments, for the first time I noticed how it sounded less transparent, and less clean, than Utopia and even Code-X. I'm not sure if this is what people refer to as the Sennheiser veil, though I'm familiar with this veil in their 580/600/650 line of headphones.
    - Nevertheless, if you're looking for a sub-$4K amp for HD800, get this and look no further. I don't even think the no-feedback option is necessary, I could listen to my feedback SJ/HD800 with brightly mastered K-pop without fatigue.

    2. The SJ is a step behind the Studio when it comes to technicalities.
    - This was evident when using it with JAR 600 (which is the best iteration of 580/600/650 I've heard so far). As mentioned above, the 580/600/650 line of headphones have this Sennheiser veil, regardless of their excellent resolution and scalability, and JAR 600 was no exception. Very few amps were capable of piercing through this veil, namely Jotunheim and Studio (though the former had a somewhat flat soundstage and was overall uninvolving). I was hoping the SJ could too, but it couldn't.

    So far my favorite headphone for the SJ is Code-X, but I still feel that Code-X benefits more from powerful and slightly warm amps such as LG or Pro iCAN (in tube/tube+ modes). I have a feeling that Utopia will be an incredible pairing. Will report back after spending some time with LCD-4 and Utopia.
     
    Last edited: Dec 9, 2019
  15. Carlos CPA

    Carlos CPA Almost "Made"

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    Thanks for the review, @songmic. I’m very much looking forward to your thoughts on how the Utopia pairs with this amp.

    Can you please post pictures of your amp? I’m particularly interested in seeing what the back of the amp looks like. I’d love to see what inputs and outputs are available.
     
  16. songmic

    songmic Gear cycler East Asia edition

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    Utopia will hopefully arrive by this weekend.

    I plan to take better photos later, but here is a crappy one I shot in the dark.

    [​IMG]

    As for the back of the amp, here is the official photo from Eddie Current. 2 pairs of RCA inputs, a pair of balanced preamp outputs (NOT bypass line outputs, the amp needs to be powered on for them to be active), and a pair of SpeakON outputs.

    [​IMG]
     
    Last edited: Dec 16, 2019
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  17. songmic

    songmic Gear cycler East Asia edition

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    The SJ/LCD-4 combo was, thankfully, not too dark as I had feared. The LCD-4 is slightly warmer than neutral, but nowhere as warm as LCD-2C. Overall, I preferred SJ/LCD-4 to SJ/Code-X, not only due to LCD-4's superior technicalities but also that it's more efficient.

    However, and I don't mean to derail the thread, but I found that even the LCD-4, which is a relatively efficient planar with high impedance that makes it more suitable for tube amps, is still is a planar and is best driven by a headamp or speaker amp with high output power. The SJ/LCD-4 was excellent sounding, but I had to crank up the volume to reach sufficient SPL. When driven by my Pro iCAN or EX-M1, the headphone really opened up to a whole new level with deep soundstage that not even my 300B SJ could throw. While I believe the Studio would be an even better amp, I doubt that Studio/LCD-4 could reach that level.

    Moral of the story: if you own planars, don't bother with pure tube amps. OTL amps are just bad in general when it comes to driving planars, and even if you're looking at TOTL OPT amps with lots of power (Stratus/Stellaris, SJ/Studio, etc.), in most cases they still don't have what it takes to take them to their fullest potential. The best planar headphones I've heard, including Susvara, Code-X and LCD-4, all sounded best from a solid-state, hybrid or speaker amp with gobs of power. The Pro iCAN is a possible exception because it can be switched between SS and tube modes, both of which are quite powerful. Although discontinued, I would look for Cavalli amps to pop up.

    Alternatively speaking, if you own TOTL DHT SET amps, stick to TOTL traditional driver headphones (Focal, Sennheiser, ZMF) for optimal performance.

    On a side note, the LCD-4 is another legitimately TOTL headphone when driven to its fullest. Some people say LCD-2C is close to LCD-4 in performance, but having heard both, LCD-4 is at least 2 tiers above LCD-2C (with Code-X between them). It's also surprisingly comfortable for its weight. iCAN/LCD-4 vs SJ/Utopia should be an interesting comparison.
     
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  18. bozebuttons

    bozebuttons Friend

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    I use a Lampizator big 7 with a 3volt output feeding either my Studio
    or Passlabs XA25 speaker amp
    both drive the Susvara equally as well
    Volume knob on the Studio between 10:30-!1;00 .I listen loud.
    Using a source with a higher out put level helps driving PLanars.
     
  19. songmic

    songmic Gear cycler East Asia edition

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    The XA25 is not particularly a powerful amp in the grand scheme of things. Both the Pro iCAN and EX-M1 are much more powerful. I would use at least a 60W speaker amp (or its equivalent headamp) to drive something like the Susvara or K1000.

    Yes, using a more powerful source can help, but most SET amps only have SE inputs (with SE DACs outputting 2V RMS from their SE outputs). Even the ones that have balanced inputs (e.g. Studio, balanced Stellaris) convert balanced to SE since they are essentially single-ended topology.
     
  20. purr1n

    purr1n Finding his inner redneck

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    LCD-4 is Utopia level. I might actually prefer it's darker signature. I remember when Tyll did a Utopia vs LCD-4 comparison where all mastering engineers preferred the LCD-4. After listening to an LCD-4, I'd agree. It does depend upon the amp though. A neutral amp does the Utopia no favors.

    LCD2C is clean, but nothing near LCD4 in terms of resolution and transient response.

    Can you roll EML or KR 2A3s for a more solid state kind of sound. The JJs are very very good with a sound that is close to the original WE300B.
     

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