View Full Version : 6C33C-B dual triode


NOSValves
05-02-2005, 08:01 PM
Nope, I regret that I didn't spend nearly enough time listening to that one and some others...

But yes, it's an interesting tube. Isn't it a low-mu high-current dual triode like the 6336, designed for use as a pass tube? I've heard several amps that use it, but mostly PP. I would guess that the OPT primary impedance doesn't need to be very high in any case.

It really was one heck of a nice sounding amp for the price of admission especially if SET is you cup of tea (If it is SET you have me wondering now). I'm not sure about the 6C33-B being a dual triode? I believe it was used in the Russian Migs as some type of Scope tube? The imformation on this tube is really slim out there on the net. It's funny you mentioned the 6336 my SET amp uses this tube one half per channel though very nice but way down in the power output compared to the 6C33-B the Almorro is rated at 18 watts but I'd be surprised if it really can do it. Heck if your right about the dual triode then maybe the Almorro is PP?

Craig

NOSValves
05-02-2005, 08:09 PM
Tubino,

Check out this schematic. I believe its a single Triode. They're claiming 30 watts on this design.

http://www.tubebuilder.com/images/schematics/singleended/6c33b_se1.gif


Craig

Billfort
05-02-2005, 09:30 PM
The 6C33C-B is a dual triode.

Here's a quote from meta-gizmo.com;

6C33B-3: This is a Russian manufactured dual triode voltage tube that has two triode tubes in one glass envelop. This tube which was no originally intended to be used an audio tube is gaining favor because of its very low output impedance, which is very desirable. This tube is also a great value in terms of cost. This tube doesn’t have the tonal refinement of the directly heated triodes, but is superior to pentodes. A number of American companies are now making amplifiers with this tube...but again, not at the level of refinement you can demand. Because there are two triode in every envelop if you are using a pair of tubes you are really using four triodes, which explains why you can get so much power from just a pair of tubes. You should also be aware that these tubes do not have a duty cycle life as long as the best audio tubes.

I wondered about the slight difference in numbers but I'm reading essentially the same description in an article about building a 15w SE amp using the 6C33C-B by Erno Borbely in an old Glass-Audio magazine.

NOSValves
05-02-2005, 09:36 PM
Billfort,

I was just looking at some more specs I found and actually it is a dual tirode but the plates/grids are internally connected so its not a traditional dual triode in that you have to run them together it looks to me like they share one common Cathode? This is all foreign to me. Kind of a real cool setup. My 6336 is a true dual triode tube with independant plates, grids and Cathodes

Here is the information I just found

http://www.mclink.it/com/audiomatica/tubes/6c33c.htm

Craig

Billfort
05-02-2005, 09:48 PM
From the Borberly article;

It has two filaments and two cathodes. You can connect the two 6.3V/3.3A fillaments in parallel or in series, consuming a total of 42w. Maximum anode dissipation is 45W with one cathode operating, and 60W with both.

This is mostly over my head Craig but it might explain the thing a little better for you.

NOSValves
05-02-2005, 09:56 PM
Well from what I can see the important part is the plates and Grids are connected so the tube has to run basically as a single tube. The filament information is to run it as a 6.3V or 12V I believe. New territory to learn always intrigues me. Now just find some time to actually play with it would be real cool. Trust me this is all new to me so were both lost ;) I'm a pentode man.


Thanks Craig

Billfort
05-02-2005, 10:10 PM
A friend of mine has a bunch of these things sitting in a box and a circuit layout ready to go, James makes some nice potted output trannies for them, the sockets are apparently the 'Achilles heel' here (these are major space heaters) but Yamamotto makes some nice ones...

Based on what I heard at AKfest, maybe a 6C33 amp should be on my DIY list :) .

NOSValves
05-02-2005, 10:48 PM
Sockets are no problem the "Tube Store" has them for $5 each and they look pretty darn nice. I think the power and filament transformers will be the real killer. These tubes suck up some serious current on the plates and the filaments.

Craig

tubino
05-03-2005, 05:49 AM
I think the power and filament transformers will be the real killer. These tubes suck up some serious current on the plates and the filaments.
Hey all, in a couple weeks I'm going to start downsizing on the serious IRON I've collected. I'm sure I could spare a 6.3vct @ 20A xformer, and have lots of good plate xformers too. But I wouldn't be surprised if you could use a 120=>240 with full wave bridge and cap input to get the relatively low B+ for that tube, and 500w-1000w xformers like that are not hard to find.

Craig, if you want to make a trip to Toledo later this month, I'll lay out a big spread of transformers for you to pick from, with very reasonable prices. I've got to make space!

Jack G
05-03-2005, 06:59 AM
FWIW, the Almarrow A318 is on the dark side of reality. The treble is a bit rolled offf. Its a very forgiving amp though.
Jack

NOSValves
05-03-2005, 08:57 AM
Hey all, in a couple weeks I'm going to start downsizing on the serious IRON I've collected. I'm sure I could spare a 6.3vct @ 20A xformer, and have lots of good plate xformers too. But I wouldn't be surprised if you could use a 120=>240 with full wave bridge and cap input to get the relatively low B+ for that tube, and 500w-1000w xformers like that are not hard to find.

Craig, if you want to make a trip to Toledo later this month, I'll lay out a big spread of transformers for you to pick from, with very reasonable prices. I've got to make space!


Tubino,

Man that is a great offer but in reality I'm so darn busy for the rest of this month even a day trip is going to be impossible. I have my yearly vacation coming up the end of the month and have to get some what caught up from the AKfest before I yet again get behind further.

If you could just snap some shots I would be interested in some transformers that would be fitting for a tube like the 6C33-B the tube just plain intrigues me.

Craig

Thatch_Ear
05-03-2005, 09:01 AM
I split the thread leaving the 845 biasing on it's own, just can't get the title changed where it shows up in the forum.

I think John Day made a stereo SET with a 6336 that we were calling Big Blue. I'll see if I can hunt it up.

As far as the Almarro goes in the environment that I heard it in it was impossible to say if it was on the dark side of tube amp soundstaging or not. With the Almarro speakers it was hooked to it certainly sounded much better than the paralled 6550s that I am taking for granted were triode strapped. The 6550 amp was causing the woofer to over excurt almost to the point of bottoming out on the back stroke while the 6C33 sounded like a great match up. The darkness Jack was getting might have been from the speakers used or it was just so nice to listen to an amp/speaker matchup that sounded right I just missed it.

NOSValves
05-03-2005, 09:06 AM
I split the thread leaving the 845 biasing on it's own, just can't get the title changed where it shows up in the forum.

I think John Day made a stereo SET with a 6336 that we were calling Big Blue. I'll see if I can hunt it up.

As far as the Almarro goes in the environment that I heard it in it was impossible to say if it was on the dark side of tube amp soundstaging or not. With the Almarro speakers it was hooked to it certainly sounded much better than the paralled 6550s that I am taking for granted were triode strapped. The 6550 amp was causing the woofer to over excurt almost to the point of bottoming out on the back stroke while the 6C33 sounded like a great match up. The darkness Jack was getting might have been from the speakers used or it was just so nice to listen to an amp/speaker matchup that sounded right I just missed it.

Thatch no need to find John Days 6336 amplifier I own it LOL !!!

Craig

Thatch_Ear
05-03-2005, 09:13 AM
And here is the thread with the pics from when I saw/heard it. Nice amp ain't it?

http://audiokarma.org/forums/showthread.php?t=15587&highlight=Big+Blue

Thatch_Ear
05-03-2005, 09:13 AM
Wanna sell it?

Jack G
05-03-2005, 09:48 AM
The A318 would work if your system was a little on the bright side. I tried multiple sources, speakers , tubes, everything short of rebuilding the amp, it just didn't gel for me. The highs were noticably rolled off. Biasing was a PITA, and it took forever to stabilize (not sure it ever did).
I don't mean to sound so negative, it isn't bad for the price.
BTW, there is a review of it at enjoy the music.
Jack

Thatch_Ear
05-03-2005, 09:52 AM
Have a URL for that?

Jack G
05-03-2005, 09:57 AM
http://www.enjoythemusic.com/magazine/archives/

go to equipement reviews, then to amplifiers, then click on:
Lucky Find! The Almarro A318A Integrated

Jack

NOSValves
05-03-2005, 10:00 AM
Tatch,

I have over $650 in it after I bought it from Luther I had to have custom wound output transformers made for it because one didn't survive shipping severe channel imbalance. I talked to John about the specifications that the transformer should be wound at so its a perfect match. I mounted these up top. The originals were PP transformers chicago transformer EL84 types. Within its range its the darn nicest sounding SET amplifier I've heard. Very full, Detialed, rich and creamy! Nice balance ! Your wlecome to make me a offer. I have the boxing that Luther used which was extreme to say the least. But this beast is heavy. I also bought some spare tubes for it drivers and a 6336. I like the amp enough that losing much of my investment would lead me to just keep it. I hook it up every now and then because it adds a nice flavor to the mix. If I could get this sound with 30 watts for something near reasonable in cost I would be in heaven at least some of the time:)

Craig

NOSValves
05-03-2005, 10:03 AM
Thatch

I think were talking about 2 different amps John Built, mine is a mad scientist project he did before the blue beast.

reyneman
05-03-2005, 11:26 AM
That's why I love this hobby- different people listening to the same item come away with totally different perceptions!

During the time I listened to the Almarro 318 at AKFest, I had the opposite of Jack G's experience. Rather than rolled off on the top, I found it to add sparkle and clarity to the laid back AN/Js it was driving. Of course, I doubt I hear much above 10 - 12K now anyway :sigh:

I currently have the use of a 318, and when circumstances allow I will give it a much closer eval and post what I hear in my system(s).

Thatch_Ear
05-03-2005, 03:48 PM
You heard it in LV too.

Billfort
05-03-2005, 03:59 PM
Yes, at AKfest, I heard the same thing as you Ray. Maybe it was just that system and in that comparison we tried?

Thatch_Ear
05-03-2005, 09:18 PM
Well I liked it the short amount of time I got to listen. Custom OPTs from Bill's friend might do the trick. Your weight in WE wire Bill?

DanTana
05-03-2005, 10:33 PM
Rick, If you have a couple nice OPT's I wouldn't mind buying them off you.

tubino
05-03-2005, 10:44 PM
Probably worth pointing out that the 6336 is in many ways just a bigger version of the common 6080 or 6AS7. PP and SE amps using that tube are easy to find, and they can sound good!

Check out this page (http://www-personal.umich.edu/~monk/rig.html) for a 6AS7 amp (scroll down). I've heard this guy's setup a number of times, and it's really quite nice. It's how I got sold on Tannoys.

Thatch_Ear
05-03-2005, 11:19 PM
6080s are cheap but I have only seen them in scopes with 6DJ8s (a good place for most 6DJ8s). The Blue Magoo was like listening to a stereo 300B, maybe not 8 watts but close enough and I think John used all Hammond steel, so it wasn't real expensive. Hernia maker though.

Thatch_Ear
05-03-2005, 11:27 PM
I looked at the amp and just don't get it. I think I was looking at 3 6080s per ch which would mean 6 sides. I guess paralleling 3 sides twice in each amp? Weirder things have happened but it is a bit out of the norm. I guess I have just seen multiple triodes paralled in 2s and 4s, thinking next would be 8.

Billfort
05-04-2005, 07:20 AM
There is a lot I don't get now - maybe I'm wrong but I don't think the 6080 is anything like the 6C33C-B - they look like different animals to me.

tubino
05-04-2005, 08:30 AM
I looked at the amp and just don't get it. I think I was looking at 3 6080s per ch which would mean 6 sides. I guess paralleling 3 sides twice in each amp? Weirder things have happened but it is a bit out of the norm. I guess I have just seen multiple triodes paralled in 2s and 4s, thinking next would be 8.
The Golden Tube SE-40 runs 3 EL-34s per side for SE. No reason you couldn't use 3 triodes (halves) per side of a PP amp either... Just more current, lower primary impedance...

But people who know tell me that matching sides of 6AS7s or 6080 is NOT so simple. They are typically way off from each other.

tubino
05-04-2005, 08:42 AM
There is a lot I don't get now - maybe I'm wrong but I don't think the 6080 is anything like the 6C33C-B - they look like different animals to me.
That may very well be... I don't know squat about the 6C33, but I was just saying that a 6336 (that's the US tube, not the Russian one with the little horns) is just a 6080, but doubled (in plate current, plate dissipation, filament current).

At least that's what I remember from back when I looked at tube data regularly. I first came across a couple 6336 years ago in a really large voltage-regulated power supply from a chemistry lab. It was one of those industrial-design pieces that reminded me that even decent home audio gear from the 50s and 60s can't hold a candle in build quality to industrial tube gear from the era. But if you look at what a Tektronix o'scope COST back then, it's not hard to understand the difference.

NOSValves
05-04-2005, 09:08 AM
The 6336 is really nothing like the 6C33-B the only common internal connection on the 6336 is the heaters for both triodes. The 6C33-B I'm guessing is more like two triode halves running together to give it more power and lower impedance ? From what I can see there nothing alike. The 6336 the two halves can be run independantly I don't see how this could be done with the 6C33-B.

Craig

Compare

http://hereford.ampr.org/cgi-bin/tube?tube=6336A

http://www.mclink.it/com/audiomatica/tubes/6c33c.htm

tubino
05-04-2005, 10:01 AM
Rick, If you have a couple nice OPT's I wouldn't mind buying them off you.
I'm sure I will be downsizing there too. Interested in old PP from Scott and Heath? Or just SE? Send me a PM with wants and I'll contact you first with whatever surfaces in the next few weeks.

tubino
05-04-2005, 10:08 AM
The 6336 is really nothing like the 6C33-B
True about the connections. I assumed there was a family resemblance as both have massive plate structure, use a LOT of filament current, are designed for relatively high current (600ma for the 6C33-B!) and relatively low max plate voltage, with relatively low plate resistance (200 ohms for the 6336!)-- all because they are designed as voltage reg pass tubes.

I believe I'm on solid ground about the 6AS7/6080/6336 on that, but I'm not sure on the Russian tube. What I know for sure is that it looks very cool. What's not to like about a squat beefy tube with horns?

NOSValves
05-04-2005, 11:06 AM
True about the connections. I assumed there was a family resemblance as both have massive plate structure, use a LOT of filament current, are designed for relatively high current (600ma for the 6C33-B!) and relatively low max plate voltage, with relatively low plate resistance (200 ohms for the 6336!)-- all because they are designed as voltage reg pass tubes.

I believe I'm on solid ground about the 6AS7/6080/6336 on that, but I'm not sure on the Russian tube. What I know for sure is that it looks very cool. What's not to like about a squat beefy tube with horns?

Tubino,

There is nothing not to love about the "squat beefy tube with horns" I love that line ;)

Your absolutely right about the 6336 it is a dual 6AS7/6080 basically.

Craig

Thatch_Ear
05-06-2005, 09:59 AM
Just curious, has anybody listened to 6C33s in anything other than the Almarro? I know I haven't.

tubino
05-06-2005, 10:12 AM
Just curious, has anybody listened to 6C33s in anything other than the Almarro? I know I haven't.
John Wolff uses them in his OTL Atma-Sphere amps, I think. In fact he had that at AK Fest last month, and used it for the low end, with the deHavilland Aries for the top end when bi-amping. (That cool-looking amp he had in the bathroom -- what tubes did it use?)

I've heard a Russian amp that used them too, but am blanking on the name -- began with a G I think. The tube has been around in the US for awhile, with a number of DIY projects based on it.

Thatch_Ear
05-06-2005, 10:43 AM
The one with horns in an OTL?

Billfort
05-06-2005, 10:50 AM
Actually, most of the amps I've seen or read about that use the 6C33C-B where OTL's.

Thatch_Ear
05-06-2005, 10:56 AM
I have only seen/listened to an early Atmosphere and it was using tubes that looked more like the 6080 type.

ilimzn
05-06-2005, 12:30 PM
The first 6C33C I've seen i found (believe it or not) on a dump that used to get the ocasional decomissioned MIG21. It is a very curious dual triode that has all it's elements connected in parallel, except the heaters. This curiosity probably stems from it's military use, providing redundant heaters in case of heater failure. In stationary use, both heaters can be used but you only get about 50% more plate dissipation capability and even that comes with a warning about lower endurance. This tube was designed as a series regulator which makes it the beloved tube for OTL designs due to a plate resistance of only about 80 ohms.

As a point of curiosity, the MIG21 aircraft electronics used to be entirely tube based, using aluminium encased tubes (many upgrades were made to it during the years). It was constructed out of aluminium blocks that were close to 8" per side cubes, forged using a process that made the aluminium have the consistency of foam - so much so the blocks would float on water. They were very light yet incredibly sturdy and impact resistant. Unfortunately, whenever an aircraft was decomissioned, it would be literally plasma cut to pieces and the cockpit would be destroyed (as in flattened by a bulldozer) so little of the electronics survived. Funnily enough, though, often spare parts boxes associated with the aircraft would be thrown away with the tubes still in original boxes with printed characteristics! I only wish i had the presence of mind to hoard up some tubes then, it would have made for a nice collection...

tubino
05-06-2005, 02:39 PM
I have only seen/listened to an early Atmosphere and it was using tubes that looked more like the 6080 type.
Yes, as has been pointed out, both the 6AS7/6080/6336 family and the 6C33 have the very low plate resistance you want in an OTL, and were designed as high current-low resistance tubes for use as series regulators. However, linearity is not nearly as good as with some other triodes. They certainly were not designed for Class A audio use -- though properly used, they can sure sound good.

Very cool stories about the MIG electronics!!!