Below are some tube evaluations and such that I've been collecting from Emery Sound customers. This is subjective stuff to be sure, please let me know what YOU find and I'll gladly add your 2 cents to the pile. Thanks much to those who have documented and shared their sonic discoveries! -Superbaby tube recipes- just like makin' tube soup...
Voicing Rectifier Output Preamp
60's marshall clean, loose 5R4, 5AR4 KT66, EL34 12AX7, 5751
70's marshall boost 5AR4 EL34, 6550 12AX7
hi watt boost 5AR4 KT66, 6550 12AU7
50's small tweed loose 5Y3 6V6 12AY7,12AX7
early 50's big tweed clean 5R4 6L6, 5881 12AT7, 12AX7
late 50's big tweed loose, boost 5R4, 5AR4 6L6, 5881 12AT7, 12AX7
60's 70's small Fender clean, boost 5Y3 6V6 12AU7,12AT7
60's 70's big Fender clean, boost 5AR4 6L6 12AU7,12AT7
small vox loose 5Y3 EL84 12AX7
- generalizations obviously, but good starting points nonetheless!
Every combination of tubes & Voicing switch setting has its own spectrum
of volume dependent tones, from clean to full saturation. Try as many as you can!
Emery Superbaby Amp, First Impression.....
I have had the amp for over a little over a week now and I gigged with it on this past Friday and Saturday nights. I ordered it with the 6L6 power tube and the 12" Weber alnico Blue Dog 15 watt speaker. This amp has two very convincing advantages; first, it is class "A" power, and second, it is the most flexible amp that I have ever used.
The amp is a single ended Class "A" affair. By nature, real class "A" amps are limited to about 10 watts or so (unlike faux class "A" amps such as a Vox AC30). I've owned and gigged with a class "A" amp since the mid 70's, my Fender Champ. However, the Champ is limited in power and by it's wimpy 8" speaker. I quit using the Champ when I started doing the solo thing, the 8" speaker just didn't cut it.
Tube impressions and their overall effect on the amps character.
* Power tubes:
I have a pair of old RCA 6L6 power tubes, and these are smoother than the modern Svetlana 6L6. I also tried a 6550 Tung Sol vintage tube that I pulled from my Sunn amp. This is the highest output tube that I tried. It provided more headroom before breaking up into singing distortion. I have also used a vintage Tung Sol 5881, a JJ Tesla 6L6 (this tube was fairly uninspiring in this amp), and a Electro Harmonix 6V6. I also bought an old Mullard EL34. The EL34 is pretty much different than all the other tubes as it changes from clean to overdriven much more gradually. I have discovered that I can control clean headroom with this amp by varying the power tubes.
* Preamp tubes:
In addition to the 12AX7 that came with the amp, I have a few others that I tried. I have found that the more powerful the preamp tube, the more grit that you get in power tube overdrive. So, I can use a 12AX7 tube and get a Strat or Tele into overdrive at equal levels with a P90 or humbucker pickup guitar when using a less powerful preamp tube like a 5751. The 6201 preamp tube provides a fairly clean preamp with this amp.
* Rectifier tubes:
The amp shipped with a Phillips 5Y3 tube. It is a low power rectifier tube that offers a lot of sag but lower headroom A 5AR4 rectifier tube is the most powerful you can use. It causes the amp to be snappy and have the maximum headroom. A 5R4 rectifer tube puts you somewhere in the middle.
Putting this all together...
My primary concern for my first gigs was to have enough headroom for my performance level. I don't want to gig the blues solo with a hard rock type sound.
For the first gig, I used a Mullard 5AR4 rectifier tube (most powerful providing the most headroom), a Tung Sol 6550 power tube (again, the most powerful tube that I have and again providing the most clean headroom) and the 5751 preamp tube (not high gain). I used a Hamer Newport Guitar with Duncan Phatcat pickups, (vintage voiced P90 pickups). I ended up with much more headroom than I needed, playing in a coffee shop to about 25 people, with another guitarist. There is a low/hi power toggle on the back, it softened the amp up a bit and worked for me.
For the second gig, I changed to the Svetlana 6L6 power tube (next down on the power chain) and the 5R4 rectifier tube (also down on the headroom chain). I liked the 5751 preamp tube, so kept it in. I played in a small restaurant to the same sized crowd, along with another guitarist and later also bass and harmonica. This was closer, but still to much headroom.
I was going to use a 6V6 for my next gig, but decided to use a Mullard EL34 instead. The amp certainly aquired a decided British flavor! I was stunned. I had used the EL34 at home, but it's different when other musicians are supporting you!
I think that you can get the picture here of how flexible this amp can really be. I can control preamp gain/distortion with the preamp tube and even compensate for different pickup types (using a more powerful preamp tube for a guitar with weaker pickups like a Strat or Tele.)
I can control sag and headroom with the rectifier tube.
I can control power output with the power tube in conjunction with the rectifier tube.
Since the amp is cathode biased, there are no adjustments needed when I switch tubes. This means that I can do it on the fly at the gig!!!! I just need to shut the amp off, let the tubes cool a minute, then swap them out.
Also, the amp accepts a speaker within the 4-16 ohm range. The Weber Blue Dog is an 8 ohm speaker. I hooked the amp up to a Carvin cab with 2-8 ohm Celestions (4 ohm load), and the amp was amazingly loud, even more so than my 20 watt EL84 amps!!!!
There is also one more amazing feature with this amp. If you turn the tone control completely counter clockwise, it switches out the amp's tone circuits completely. I keep the tone circuit in the amp off all of the time. The increase in amp tone doing this is simply amazing!!!!!! It is as different as night and day. Nightwolf- plays the blues...
"I wanted to make you aware of a tube that is especially good in the Superbaby, probably the best power tube for it yet: a Mullard EL-84. I got a THD Yellow Jacket so I could use EL-84's. Being a Vox guy from WAY back, they account for the best and largest percentage of my collection of cool tubes: I have Mullards, RCA's, Telefunkens, Sylvanias, the whole Vox-fetishist works.
The Yellowjacket works brilliantly well in the Superbaby. I tried an RCA and then the Mullard. As will be no surprise to you, the full character of each tube came right through: The RCA was soft, warm, compressed, and even, the Mullard chimy, gritty, and upper-mid present, and the Sylvania was glassy, hard, and snarled savagely when pushed. This is great!
It is worth noting that this is the first tube with which I like a 12AX7 in the preamp slot. It's too much gain with most high-power tubes for my taste and I usually stop at a 12AT7, but with an EL84, well... the harder you hit them, the better it gets! This is great. I feel like a kid at Christmas. I found a particularly good tube combination: Telefunken EL84 / Brimar ECC83.
Here's another good combo: Penta Labs KT88 / Mullard ECC81-12AT7 / Brimar 5Z4GY
This is a gorgeous, gorgeous match. Through a Weber Blue Pup AlNiCo, it has a wonderful, robust, full-bodied sound that breaks up more than enough on full with the 12AT7 (a Mullard 12AX7 was not an improvement, somehow). Between about two-thirds and three quarters volume, it is "Peter Townshend at Leeds" Hiwatt -- what a GREAT tone. It cleans up just like Peter by backing off the guitar volume a bit, and when you hit hard, it's right there with whatever you want: compression, even-order harmonics, singing octave feedback that you can play whole songs on. It's so full and meaty, so BIG a sound. Truly a sound for a man. The best thing about it is how balanced it is... not like a Marshall, which can be a bit too upper-midrange biased. It's definitely the stuff you think of Hiwatts for -- headroom, weight, clarity, good-but-not-crazy distortion... a sound that's 20 feet tall. Alex Lifeson of Rush on "Farewell to Kings" comes to mind as a reference point. Astonishing to hear it coming out of a single 10. I notice that through a new Jensen 10, it gets back some of that extra bright, and loses a bit of the full-bodied midrange and upper bass. An interesting study of the differences between the speakers, actually. It was a nice apples-to-apples comparison. In the end, I prefered the Weber.
Dial it back to half, and it'd be a lot like a Bassman, except that it's more touch sensitive than I remember them being. A great Electric Blues sound to play an ES-335 through with a lot of authority."
I use a NOS RCA 6550, JAN 5R4, 12AX7EH- I like this set up a lot. I also like a N.O.S. TUNGSOL 6K6 on Lo power, WOW what a great sound, it's tone is fantastic! <TIBBY>
Fave tube combinations so far:
- That large 5R4WGB rectifier, the Svet. 6L6, and the stock 12AX7 - great distorted sounds w/ either my LP or PRS.
- Same configuration, only with a 5881 power tube - this may be my favorite combination yet...(the harmonic structure & chunk of the rhythm chords are amazing!)
WOW, do I notice a difference with the tube rectifiers!
- The 5AR4 recto. / Svet. 6L6 / 12AX7 - the fast attack of this recto. with clean sounds on my PRS are great! Anthony A.
As to modeling amps, you left the only factor that matters to me unbulleted, whether they nail (and I mean NAIL) the tone. For that matter, they'd better nail the smell, too. (Nothing like hot tubes in the morning...) Music is magic, and while the ol' back ain't what it used to be, I'll carry whatever I have to to sound the way I want. I'm not bullheaded, I'd buy one if the sound were exact. But you have a LOOOOONG way to go to convince me of that. Features? Who needs 'em, anyway? Give me a few tubes and a volume control. Best amp I have is an Emery Superbaby, with one Power tube socket, one for the Preamp tube, and one for the Recto tube. Pretty much accepts any type for each, and that's how you change the sound. It has Volume and Tone controls, and you can flip a switch to take the tone stack out of the circuit altogether, which I do. 6L6, 6V6, 6550, KT66, KT88, EL34, they all sound different in there, and you really really hear the differences. Same with 12AX7s, AU7s, AY7s, AT7s. And I found I prefer a 5V4 rectifier to a GZ34 or a 5Y3. But they all sound good sometimes, depending on my mood. "Features"? "Built in effects"??? Keep 'em. I'm having too much fun to bother with 'em. Hector
Amp continues to be a source of joy. Recently bought a Paul Reed Smith McCarty model for my birthday. Boy, does that guitar with the 5Y3, KT66, and 12AX7 or 12AT7 belt out the "tone"! Bill Tant
Got an NOS Amperex 6CA7/EL34 that they say was made by Mullard. Very expensive, but it sounds Marshally and rich with the 5Y3 GT and the EH 12AX7. Also have an Amperex 5R4 and have been trying that with different output tubes; a Tung Sol 5881, a NOS National EL34 from Germany, and an RCA black plate 6L6. The only EL84 I have here is a Sovtek, but it sounded pretty cool too. Last night a Ruby EL34 sounded fine. Howard Starr
My most recent prized acquisition was a GEC KT77 (an EL34 kinkless triode). I got it cheap @ $110 every other one I have seen has been around the $400 mark absurd! It has this surreal 3D soundstage that sounds like reverb and angelic sustained decaying harmonics. Weird and wonderful.
Good Lord! What a tube. I'm running it with a Mullard 12AT7 and Mullard GZ34. It is the most articulate tube I have heard. Absolutely pristine and crystalline. Rob Worrall
The GE 6550 is my favorite tube in the Superbaby. I've tried the Valve Art KT88 and I thought it sounded so flat compared to the GE. I'm using an Amerex GZ34 with an RCA blackplate 12AX7 and it sounds awesome. Mark B.
My favorite tube combo is a Genelex KT66, a Genelex CV378 rectifier, and Amperex bugle boy, old German made GE or Mazda 12AX7's or a Brimar CV455 (12AT7). It kicks ass! Very warm, buttery and not too bright. Mark D.
I got out the tube chest, and did a little experimenting with my Emery Superbaby, which can take any of these tubes as well. NOTE that your mileage will vary widely, because every 6L6 is different from every other 6L6, and this is true for all types of tubes. Also, for the sake of full disclosure, the preamp was a Mullard 12AX7, and the rectifier a Mullard 5AR4. That said, I offer the following gross generalizations:
The 6L6(1) gave a full-bodied sound, big in the bass region if a little flabby sometimes, solid in the mid, and with a good ring on top. It certainly didn't 'jangle', but there was a nice bell-like top end. Pushed through grit to raunch, which took some pushing, since there was a lot of headroom, it made a good Boston-like roar, to pull a comparison out of the air.
The EL34(2) lost a little of the full bottom, but there was a good spike in the upper midrange. You may or may not prefer this, or it may depend on your mood, but it was noticeably different. There was something like jangle when it was run clean. Pushed, it took less to get through crunch to filth, because there was less headroom. All the way, the sound was more compressed, more 'crunchy' and spanky; with its upper mid spike, you could almost call it snotty, but in a good way, if you know what I mean. And less boomy. I guess you could say it was more of a quintessentially 'Marshall' sound than the 6L6, whatever that means. It reminded me of that 70s band Sweet, remember them? I started playing "Ballroom Blitz."
The 6550 (3) came in in the middle in terms of balance, which I guess means it was the most balanced of the 3. It was more bassy than the EL34, less than the 6L6, which in the case of the bassy, was an improvement, I thought. It had a little less of a certain flabbiness a 6L6 can have in the lower mid. The upper mid spike was not there, but there was good mid clarity, and the top was very hard and bell-like It was almost a hi-fi sound, with lots of everything there, and all balanced and tight. There was more headroom (lots more), and it took a lot to get it to saturate. I never did get full raunch out of it, but the grind was very nice. It made me think of a Hiwatt all the way: Clear, solid in every way, a brick wall of sound.
If you have an amp on which you can experiment, for God's sake, experiment. You never know what you might like, and there's only one way to find out.
1. The 6L6 was an RCA 6L6GC short bottle. I also tried a Philips 7581A,
which was similar, less boomy by just a little, and had a bit more
headroom before it gritted up.
2. The EL34 was a GE-branded Mullard dual getter. I also tried a Svetlana, and
it was a little more brittle and a little thinner in the low mid. For all
that, it wasn't half bad, either, but you can't beat a Mullard EL34.
3. The 6550s were a TungSol (branded IBM), and a Penta Labs. There was
surprisingly little difference between the two, actually. Maybe the TungSol
was a little shinier at the very top. Maybe I was imagining it. They were
both very, very good. Lars O.
-Microbaby tube recipes-
Excellent choice of power tubes with the RCA 6G6, it seems really quite close to the blackplate RCA 6V6 but a bit more compressed and of course you can never go wrong with the coke bottle look. With the 12BZ7 preamp tube the Microbaby is really getting a full, round tone with extra saturation at full bore, maybe more tweed bassman as opposed to tweed champ with the 12AX7. My rectifier tube preference, after a few back and forths, is the 5852 right now. The 5852 seems a bit crisper and the 6X5 a bit darker and saggier if that's a word. I prefer a 5AR4 over 5Y3 in my big amps for much the same reason.
Thanks again, it's a great amp,
The Microbaby is a great platform for experimentation with tubes. I've already installed some of the treasures from my precious stash of NOS bottles. This amp seems especially fond of a Mullard 6BQ5 (incorporated into the circuit via the Yellow Jacket socket converter that you sent me), and I swear, Curt, you would not believe what happens when a Brimar 12AX7WA slams the signal into a Tung-Sol 6K6GT on "lo power"! Magic! I am bereft of superlatives....
For some reason, the Microbaby really accentuates the sonic difference between a EL84/6BQ5 and all the octal tubes that I've tried in that amp (6G6, 6K6, 6V6). The Microbaby, more than any other amp through which I have played, also seems to bring out the uniqueness of the individual EL84/6BQ5 tubes, even within matched sets. By now it will not surprise you to learn that I have a theory that might account for this very interesting phenomenon. I enjoy trying to conceptualize tone in language almost as much as I enjoy playing guitar!
In the "Micro", each tube in a closely-matched pair of Brimar 6BQ5 tubes sounds radically different from its mate. On my "Maxi-Matcher" tube tester the tubes register as a nearly perfect match; incorporated into the circuit of the Microbaby, however, they sound worlds apart. My guess is that when an output tube stands alone, as it were, in a single ended amp, more of its specific and unique sonic characteristics become audible, whereas these properties fade into the "mix" that is created by the sonic synergy of tubes in pairs or quartets. To put it in terms of a proverbial metaphor: a matched pair or quartet is the forest; the individual tubes in a pair or quartet are its trees; and the sonic whole is greater that the sum of its parts. In an amplifier that's built around a single output tube, however, the tree IS the forest; and the sonic whole is identical to its singular part. The other elements within the circuit of course come into play, but the simplicity of the Microbaby's circuit probably accentuates the sonic effect of singularity. In any event, it certainly allows an extraordinary degree of fine-tuning, tone-wise.