EC Studio Junior (not AF)

If I gently hold the driver tube with 2 fingers and shake the hand the tube does wobble a bit. It makes a slight rattling noise. But it doesn't rattle when tapping with one finger. Could this be the issue? I'll try bending the pins.

 

Update: I bent driver pins until it no longer wobbles. No SQ changes.

 

The way you described the amp does sound like modern EC tho, very AF, v Studio B, etc…

As has been said before, you can tube roll for a slightly wetter sound, but the genetics of the amp will still be the same, or you can cut your losses and sell if you don’t like the tonality.

 

Oh well. Worth a try!

 

Missed this when I responded yesterday, but this is probably normal.
In most tube amps power is not regulated the voltage into B+ is controlled by the resistance of the PSU, into what's "assumed" a constant current draw from the amp.
When you test the PSU disconnected with a meter, the load is 1M+ Ohms and so draws a very small current, resulting in a small drop in voltage from the original rectified DC voltage.
The amp however is going to draw 40-100mA/channel, so the voltage drop across the internal resistance is MUCH larger.
And can be easily 100+V.

 

Yes that voltage difference is not necessarily abnormal. But then it is not possible to have 300V plate voltage Marv mentioned for Studio B. Did he mean B+ is 300V? Caps in the PSU are rated for 400V, so it was designed for this idle voltage. The idle voltage is likely correct.

Most of the diff in 387 idle vs 283 full amp comes from rectifier output. Rectifier voltage drop on full amp in 90V more. This is also normal according to tube charts. I hoped maybe the CLCLC in good amps does some magic and reduces that drop.

@purr1n Can you take a look pls?

 

Wondering if anyone tried Aficionado/Studio Jr/Studio B with solid state rectifier. It should have minimal voltage drop. Then amp should have close to 400V B+ and ~300V plate voltage.

 

I have a new production JJ and old stock Sylvania. Sylvania has less voltage drop by 0.5%. Comparing them sonically, Initially I thought Sylvania gives a bit better dynamics. But after seeing the voltages I think it was placebo.

I asked Craig a month ago if he can do a paid repair. He didn't reply.

Here you say Studio B has 300V plate.

Can you confirm if this is plate or B+ ?

 

Thanks!

I believe it is B+, and all the numbers are correct. For these reasons:

1. Rectifier voltage drop matches the specs.
2. Aficionado has the same PSU and was primarily made for 2A3. 235V plate that I'm getting is close to optimal operating characteristics of 2A3. 300V plate would push it to maximum allowed or beyond.

All other voltages inside the amp look good. Drive heater is 5.8V instead of standard 6.3. But this is within tolerance. According to all internet discussions, very unlikely to be the problem. Heater is regulated to 6V, the diff is the loss through umbilical chord. All by design.

Turns out the amp is ok. This is how it is supposed to sound. Genuinely surprised how can people like it for this price. I do prefer Lyr+ instead of Studio Jr with both ZMF Eikon and TH-X00.

Will provide more detailed impressions later.

 

I am curious... Does the Studio Jr sound very different than the Balancing Act?

 

This is hardly going to be very useful since I only got to spend an afternoon with @Taguro 's Studio Jr. at a mutual friend's place with my HD600s some time ago out of an unfamiliar DAC (the original AKM Modius— I do use a Modi 3+ at home so there's likely shared DNA at least), but I can at the very least concur that the amp nixed my expectations in the sense that it actually lived up to the "studio" moniker and wasn't a particularly euphonic experience; "dry" fits, as it was remarkably precise-sounding on top of being resolving as all get-out.

The SE out sounded really plodding and boring, and I was serious when I said that I actually preferred the Magni Piety on high gain to the SE out of the SJ with my Senns; XLR outs were a wholly different story, and that's where I realised how high the resolution ceiling on the Senns actually was (taking into account the AKM DAC-- think it was feeding SE into the amp since that's all it takes?).

If measurements are within spec, I feel it's fully possible that the amp just isn't to your tastes. Just because something is expensive doesn't necessarily mean you'll like it more.

 

Shhhhhhh.

 

I think Marv had to hammer home the point that Craig named this amp w intentionality… it is exactly what is says it is.

the moment when you realize your 600s finally have become the weak link in the chain…

 

Allow me to chime in with my SJR experience (I'm guessing this is also same for Studio B as they are basically the same amp). Upon first listen, I was surprised by the solid state characteristics of the amp. No added warmth or euphony that we would normally associate with tubes. The most tubey thing about it is the spatial presentation, with great depth and width. The Utopia normally gets associated with a small headstage, but with the SJR, I didn't really mind or found anything lacking. Exceptional layering and pinpoint imaging, if a bit dry.

Where the amp really excelled was pushing the Utopia's strengths to the forefront. Rather than smoothing things over with extra warmth, it accentuated things that the Utopia was already known for, namely the slam, dynamics, speed, tactility and incredible resolution. I'm normally a transducer-first kind of guy, but the difference between the SJR and say, a Violectric or Ferrum solid state amp was levels above, at least for dynamic driver headphones I've tested (HD650, HD800, Clear Pro, Utopia).

However, I could see why people looking for a more traditional tube sound would look elsewhere. It can sound kind of dry, and requires matching with a wetter DAC (if you don't love the dryness). I love the SJR for what it brings though and it's a definite keeper. Ever since getting it last January, I have been using it for 90% of the time with the Utopias. I don't really find myself looking for another component for my main listening rig. Sure, I've bought other stuff like the RAALs, but those were out of curiosity and novelty. For my general listening time, I'm extremely happy with my chain (thanks @purr1n for the reco).

(For the record, I listen mostly to anisong, aka anime songs, where dynamics and slam are more important than say, timbre or soundstage so my preferences may not necessarily align with most people. It's the reason why I stick with the Focals and why the SJR is my favorite amp right now. It gets me closer to that live concert slam)

 

Interesting because the Balancing Act that I listened to wasn’t warm at all, I think it did a balancing act (lol) between neutral sound and euphoric sound very very well.

I want to chase this kind of sound but not sure if getting a different EC amp will work...

 

Surprising experience. Dynamics and slam is precisely what I'm not getting. I'm listening primarily to rock/metal and a bit of classical. Without slam, headphones just fall out of my ears.

I get transparency/subtle tonal transitions/soundstage. But not dynamics. Can't say if it is just bass or all frequencies, but I tend to believe dynamics is lacking in general. My tubes are EH and Gold lion. With Gold lion it sounds a bit warmer/richer, a bit longer decays, but macrodynamics could a be a bit weaker. So I'm not decided which is better.

 

That's surprising. I didn't try balanced out. Did you get more dynamics out of it or more microdetails?