Oh Sh#7! Eddie Current Studio B

@Josh Schor

How difficult was the Khozmo to install? I'm no stranger to a soldering iron, but I'm also terrified to tamper with an amp that is far harder to repair or obtain a replacement than the Crack builds I usually play with.

 

Glad for @rhythmdevils to find the GLs working for him. And they’re not too expensive too. IIRC Craig uses/used GLs, even for the power unit.

I don’t know about the “dryness” in the SB (I started out with GLs and didn’t feel compelled to upgrade—except the power tube), but the amp is not geared toward “wetness” which I guess would be a boon for cheaper tubes rolling.

Maybe time to try Shuguangs and TJs?

 

I had a freind who can solder install it, its very easy 6 wires, 3 to r and 3 to left , fits in the predrilled hole well. I am a noob and luckily have a friend who is good at this stuff.

 

Not sure which Bendix you have but i wouldnt have described the jan 2c51 i have as lush, it reminds me of the stock jan GE but way better detail and holographics, and improvements in most other categories. I do know the 6xxx whatever number is said to be a bit warmer. I have a WE 396a coming to compare and that is supposedly more lush.

Parched is kind of a good word. I am happy with the bass and highs but the mids feel weak. Not a lot of meat on the bone and it needs help. Overdriven rock guitars felt like they lacked power. So much so that my lcd2.2pf felt like it's special mojo was taken away, the hd600 was still very much its characteristic self despite this.

Most of this i am sure are the transformers, but i do wonder if a cap swap can help, i have been fond of audionote caps in the past would love to see if that would add a little "romance" to the mids. Tubewise @rhythmdevils stay away from psvane acmes, they felt V shaped and very cold, flat, and thin in the mids. I found the WEs to help a lot, but at times gave the impression of colored glass in front of the same white light. Just not the same as the something actually with an amber glow. The GLs were also recommended to me so that is a next step, i will probably post a WTB once your WTB is fulfilled.

Rectifiers help as well, the mullard gz34s are expensive but being a lot to the table. Next tryout is an RCA 5u4g which should give it a looser feel. The stock sventlana i was given sucked.

Ill also note that this amp tends to need about 30 minutes minimal to warm up, and it has taken positive steps with break in. I am at about 25-30 hours.

 

It’s funny because I think the “unicorn” LCD2.2pf Marv measured on here a few years ago was Craig’s. Since Craig likes the GL’s maybe the GL’s are the secret sauce there…

FWIW if anything mids are more pronounced on the 800 with the SB (Mullard fat base, Cossor Linlais, non-JAN Bendix) than I’ve heard out of them with any other amp. Then again, I’m a detail/soundstage/air/treble extension whore, so mids are not much of a priority for me in my sonic preferences.

I’m refurbing my old 600’s (and likely going to JAR them) before I try them out in the SB but I’ll comment on that at some point.

 

Perhaps. The PFs were good on the taboo as it leaned into what they did so well but didnt improve its weaknesses. The Shiny Eyes i tried was the best, the amp was built for an AB1266TC but it felt less heavy hand flavored than the taboo but still had mid romance, and just flowed better, extended more and played with ease and air.

The Studio B takes it further but the mids lean a little too lean. But it does things so well, better micro than the other two, more sparkle and texture, that i feel it is worth investing in closing the last 15% of the gap.

 

Oh no.

I have a bunch of 5AR4 rectifiers and wanted to try them out again to see if I could get more "wetness" than the Mullard fat base. It seems that despite the center pin guide, you an insert these in the wrong orientation. I have never seen that before in a tube, the center pin guide always keeps it oriented the right way. But I put one in oriented wrong, and now the turned it on that way, and now the amp won't turn on at all.



I'm having very bad luck with amplifiers lately!

Can anyone give me any advice for what probably happened and how to fix it? I'll have to be careful and line the center pin up by eye from now on instead of just turning until it goes in, like you can do with 6SN7 tubes.

 

It won't turn on at all? I had it happen once after a rectifier swap (I wasn't paying attention). Maybe check the fuse? It's tucked back under a little cap where the power cord is in the power supply. If you're lucky it blew out and everything will be fine once replaced. At least it was for me.

 

If you plugged it in backwards you could have connected the cathode to the high voltage winding and the plates to the filament winding. This is unlikely to have damaged the tube but possibly blew the fuse (if the pilot light is off, it definitely blew the fuse). Check the fuse and replace it if blown and try again. If the fuse blows again with the tube oriented correctly the amp will need servicing. If the amp does not turn on and the fuse is good then the filament in the rectifier has shorted and you will need a new one.

 

The same thing happened to me with a rectifier swap last month. Craig (EC) got back to me quickly, guessed it was just a blown fuse and told me to look for "5X20mm 2.5A slow blow", which I mention in case someone else with the same problem finds this thread! (https://www.amazon.com/dp/B08FDPQ6JY worked for me). Not sure what happened in my case, but bad tube, or a still-charged cap were other ideas suggested to me. Anyway, from now on I'll align pin guides by sight as well as feel, and leave the amp unplugged for a while before rolling tubes!

 

I had a chance to spend time with @keemniloc ’s recently resuscitated toy today. I still think you had an “operation” moment with a still-charged cap

It’s no wonder why the Studio B is well regarded in the community, and often at the top of summit-Fi gear lists. I used an Yggdrasil OG A2, HD600, GS1000e, and Dan Clark Stealth, which more or less covers my “zone”. Synergy was really good with everything - the HD600 scale as one would expect, the GS1000e get to show off their spaciousness, and the Dan Clark Stealth do what they do best, which is get themselves out of the way. Yggdrasil shines through the Studio B. I really felt the chain disappeared and was happily left with only the music. Very cool.

This toy is a beast and quite possibly endgame for a lot of folks. Two things stand out to me: (1) the blackground is remarkable. There’s just nothing there. Really, really quiet. (2) The music, left to right, is incredibly clear, very well separated, defined and detailed. It has a crazy natural, realistic tone. The image I came up with (because I truly am without words here) is a blank page, flat, with nothing in it, and then music precisely typeset on on it without caveats. Everything in its right place. Dry.

Because of the other amps I enjoy frequently, there is a flat quality to the Studio B that stood out to me. I don’t mean to pass this as a negative, it’s just not very (or perhaps not at all) deep. It’s left to right, on plane, with good height. No “hall sound”. Orchestra right in front, I guess. Def Leppard tracks with wall of sound were almost too much - I need my depth to breathe!

Respect!

 

My stock Tungsol rectifier blew after a couple of months, and Craig seemed keen at wanting to know which rectifier it shipped with at the time. Swapped to Wathen rectifier and driver about a year ago based on longevity outlooks. My WE396 blew after about 4-5 months as well fwiw.

 

Any impressions on the Wathen rectifier? I had rolled rectifiers a bit when I first got my Studio Jr, and also blew the fuse from a bad rectifier. Since then, I've just stuck with a new production Gold Lion 5AR4. Missed out on a metal base Mullard 5AR4 deal recently, but I'm never sure how much that will actually make a difference for the exorbitant price. The Wathen tubes have received high praise from what I've read, but they're also not cheap necessarily.

 

I liked my fat base Mullard 5AR4 in both my Aficianado and Studio B the best of a bunch of rectifiers I tried, basically all the ones I could find. Worth the price. They won't fit in some EC amps though because the tube socket is recessed, so you need to get a socket saver to raise up the tube.

 

The mullard is a favorite here too. Best ive heard in the 300B amps ive tried it in.

 

Mainly a smoother presentation if I had to say, but pretty subtle and doubt I could pick in a blind test. Much easier to note 300b and driver differences on the SB for me. Mainly got the Wathens for their purported longevity, especially since both my rectifier and WE396 blew so quickly. Peace of mind mostly.

Fwiw-and it may be worth very little-the Wathens VISUALLY look more stable, if that makes sense or means anything objectively speaking. And by that I mean their actual glow/filiments appear extremely stable compared to any other tubes I've ever seen. Not that other tubes flickered or anything, but more like the glow almost seemed to vary off and on, whereas the Wathen are extremely...uniform at all times, visually. Might sound silly and might mean nothing...but is obvious to me, and hopefully speaks to their potential longevity. Time will tell, but they certainly give me more peace of mind so far.

My .02

 

I get what you mean re: filament glow. First Mullard fat base I got on fleaBay had unbalanced sections and measured only ok, sent it back. Second measured NOS level with balanced sections and was noticeably brighter than the previous. Both f31 Blackburn but different years (‘61 vs. ‘59).

It is true though that filament glow isn’t a very reliable indicator of tube life or strength, from what I understand. Still, helps with the nervosa when you’re throwing a lot of money at a tube.

 

300B’s are funny to me in that way, too. Can’t even tell they’re on half the time unless you’re looking down into them to peer between the plates. Some variation there with manufacturer, though, and obviously different if you’re running mesh. Still, coming from other non-DHT amps it’s kind of a trip.

 

Turn the lights off, youll see tons of cool colors in there.

 

Oh yeah for sure, they’re cool in the dark.