Film-Tech Forum ARCHIVE: A little help in finding type 5693 tubes

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Posted by Luciano Brigite (Member # 1104) on 04-05-2004, 11:00 PM:

Hello,
I'm trying to find a few 5693 tubes for a project I'm planning to build but this tube is being a pain to find, it's one of the RCA "red tubes".it's listed as being a special version of the 6SJ7.specs seems to be the same, except this one is rated 10,000 hours life. I looked for it on a lot of sites that sells tubes but none had it in the listing.
The schematic came from a Japanese site and many amps shown there has this tube. The reason I'm looking for it is more (risking being silly) the look if it,as it differs from the usual black painting from the metal tubes.electrically it's about the same as the 6SJ7. from the look of things, seems that the Japanese took all of them away to them. I hope not
thanks!

Posted by Bruce McGee (Member # 131) on 04-06-2004, 07:08 AM:

Good luck finding them. The 5693 was used in alot of medical equipment back in the 1950's-'60's, too. I used to have dozens of these RCA red tubes laying around back in the 1970's. I TOSSED them after I decided that I had no use for them anymore!

In hindsight, I wish I had never tossed ANY tubes. For you tube enthusiasts, I tossed a box of used Western Electric 300B's in 1977 because I needed the space! Wish I had them now.

Posted by Jeff Stricker (Member # 224) on 04-06-2004, 07:10 AM:

Why not just use the 6SJ7 instead of the industrial number? You will perceive no difference and don't be too surprised if the original tubes will also achieve 10,000 hrs. [Wink]

Posted by Luciano Brigite (Member # 1104) on 04-06-2004, 02:46 PM:

[Eek!]

you tossed away WE300B's ??? arrrrrrg! [scream]

I'm looking for those too and will have to be kinda happy with either the Russian or Chinese current production [Frown]

the original we300B is being produced again but it's price is prohibitive for me. ( I listened to a few amps that were re-tubed with Russian tubes and they sounded very good,tubes being EL34'sfrom Electro Harmonix..maaaybe their 300B will perform ok?only getting them and testing to find out)

I'm considering using the 6SJ7 in place of the 5693..but a few minutes ago ,before posting here made a few phone calls to the last 3 dealers that still have some tubes and their prices for the 6SJ7 are reaching the sky [Frown]

and no discount for quantity [Frown]

I'll need 2 for each amp I'm planning to build and 4 more to another amp I have laying around for restoration ( a pair of Simplex AM1011) but with such prices.. their way is more headed to the junk

Posted by Bruce McGee (Member # 131) on 04-06-2004, 08:04 PM:

The 300B's are one of my biggest mistakes. I have an old mono tube amp that uses 4 of them. The 4 that I have are not matched, and only 3 are original WE. The 4th is a Shugang (?)

Have you tried www.tubesandmore.com ?

6SJ7 should be fairly easy to come by. I've got a couple of them, in both glass and metal shells. Gotta keep 'em, though, as I have a house-full of radios that use them.

Posted by Luciano Brigite (Member # 1104) on 04-06-2004, 08:21 PM:

I know that there are a few Chinese 300B's around but didn't know that Shuguang made those too. I know of the valveArt and one other I can't recall the name right now. The curious thing about it is that a few days ago while looking for reviews about the 300B's available nowadays, a Chinese tube was elected the better [Confused]

I'm waiting someone to call me back about some pricings I requested on Russian tubes (Sovtek/ElectroHarmonix, different names but same tube btw, since the factory is the same)including their 300B.
I looked for the 6SJ7 on tubesandmore.com this afternoon and their price is about half the price I was asked for, will contact them later about SH and maybe a discount for quantity. there are 2~3 other sites I might take a look later this evening .one place here wanted $40.00 for it !!
What makes me real mad is that I have lots of boxes full of tubes and most of them has no use in any circuit I get [Mad]

( well.. not really.. this last weeked while having nothing to do sorted a few tubes randomly and one,a dual triode intended for TV vertical oscilator and output turned out to be useful for a low watt dual SE amp ,going to give it a try someday, after I wind up the OPT for it; I have a feeling that it'll work, who knows [Smile]

)

Posted by Aaron Sisemore (Member # 145) on 04-07-2004, 12:16 AM:

Luciano:

Just about any tube out there if spec'ed correctly and run within parameters can be used in some sort of audio or radio/ham application...

TV damper diodes make great soft-starting power rectifiers, and TV sweep tubes can be made to perform sonic miracles in an audio ciurcuit... [Smile]

The only things I can think of that are literally useless in any audio duty are the HV regulator triodes such as the 6BK4 and 6EN4, and HV rectifiers such as 1B3GT, 3A3, 1AD2, etc.

Here is a site where some interesting things have been done with TV tubes and 'All-American Five' radios, as well as a few nifty audio circuits using other TV types... [Smile]

-Aaron

Posted by Phil Hill (Member # 371) on 04-07-2004, 12:49 AM:

Also, I don't understand the concern for the pricing... most places have 6SJ7 NOS for about 8 bux and the new stuff for about 12 USD.

Is it a shipping cost issue L?

>>> Phil

Posted by Paul G. Thompson (Member # 655) on 04-07-2004, 12:58 AM:

I think the only difference between an industrial tube and a home-entertainment tube is that the industrial tubes are a little more mechanically sturdy to handle the physical abuse due to cat shots from the old aircraft carriers that had aircraft that is filled with vacuum tubes in the avionics field as well as military electronics and old civilian aircraft avionics and other military electronics applications. Much of the high-end commercial and military electronics used that stuff before the advent of solid state devices.

The AN/APG-51, AN/APG-30, AN/APQ-50, AN/APA-127, and the AN/APS-20, ASB-1A, ASB-7, AN/APQ-72 and others immediately flash through my mind. There are tons of others thay were hybrid. The old G-51 had 210 vacuum tubes and 97 transistors. [Big Grin]

The military had certain specifications on all of their equipment, known as MIL Spec. Even ashtrays. The ashtrays of old in the US Navy were designed to break in 187 pieces when dropped, so I have been told...Mil Spec specified it will do that, or the military would not buy those ashtrays.

Same holds true for your 600 buck toilet seats....they have to meet Mil Spec.

By the way Luciano, I have a red one of the type you were looking for. It is sitting in my desk drawer at the radio station. Kind of beat up, and I never plugged it in to a tube tester to see if the damn thing is any good.....The only reason I have it is because it is cute. [Big Grin]

Posted by Phil Hill (Member # 371) on 04-07-2004, 02:22 AM:

So Paul... Bottom line is WTF cares? I didn't get the impression that L was going to take his amps flying or in a sub...

I'm the 1st to admit that I like "cute" tubes no matter on whatever (whoever)... I mean, I'm a sucker for a cool 833A for a paperweight or a 4CX5000A (or bigger) for a doorstop!

If the commercial and/or "consumer" tubes are available at a reasonable price... why NOT take advantage of it? I'm SURE that the rest of the OLD circuit DESIGNS will NOT outperform the stats or be hindered by NOS "cheap" tubes.

>>> Phil

Posted by Mark Gulbrandsen (Member # 72) on 04-07-2004, 05:00 AM:

I think the main difference that you guys would find is that the older tubes are pumped down to a much harder vacuum than the new stuff is. Older tubes with a harder vacuum generally last much longer than tubes made present day. The only exception would be the W.E. 300B's as they are being made on the original line with the original equipment. My RCA 621 post WW-2 television made in 1946 has most of its original 32 tubes including the original CRT! I had to install a new rectifier, and several I.F. tubes to get it running correctly after recapping it.

Mil Spec tubes are ruggedized meaning that the plates, and filament are usually a bit heavier made and may have more internal support than a standard consumer version.

My expereince with OTL amplifiers and 6AS7's indicated that some of the Russian and Chineese tubes are quite good sounding but are generally VERY poorly made. I have heard that some of the Svetlana broadcast tubes are VERY good and will sometimes outlast some of the Eimac or Varian equivelents. The 6C33CB is a very well made tube and just about indestructable for use in an OTL amp.

Here is a link to a place that stocks then at 19.95 each. Sonno what brand they are though...
http://store.yahoo.com/thetubestore/nos-5693.html

Mark

Posted by Jeff Stricker (Member # 224) on 04-07-2004, 06:57 AM:

I have been using a pair of "Sovtek" (Russian) 6L6GC's in one of my McIntosh Mc 40's for 6+ years now and they still test as new. I don't know what the "Sovtek" trademark changed to after the colapse of the USSR. Svetlana maybe?

Posted by Jon Miller (Member # 163) on 04-07-2004, 09:23 AM:

Sovtek is still very much alive and well today (they made great 6922s, an audiophile favorite). Svetlana is just another Russian-made brand of tubes, not related to the Sovtek folks.

Posted by Aaron Sisemore (Member # 145) on 04-07-2004, 11:36 AM:

Actually 'Sovtek' and 'Electro-Harmonix' are brand names owned by US-founded and based New Sensor Corporation for tubes manufatured by several Russian factories (there is no 'Sovtek factory' in Russia, the bulk of New Sensor's 'Sovtek' tubes are made by the Reflektor factory) Also as of last year, New Sensor bought the rights to the 'Svetlana' trademark, but not the manufacturing plant or Svetlana patents: The tubes made in St. Petersburg that were formerly called 'Svetlana' are now known as 'SED' tubes and they have gone back to using the original 'flying C' logo...

-Aaron

Posted by Luciano Brigite (Member # 1104) on 04-07-2004, 11:40 AM:

a small multy reply this time [Smile]

Aaron: I have seen some diy otl amps using EL519's in it,it takes about a dozen of them for each channel,well designed, it looks very nice. I have one circuit I want to try using a vertical sweep tube, it's a 6BL7GTA (dual triode) both sections has the same specs and looks just the same,from all the tube math I did (following it from a RCA tube book) with 250 on the plates a load of 3600K it'll put out about a watt in class A SE. only reason I still didn't try it is the output xformer,already have the math for the coils, the wire and iron for it but since I have to wound the coils by hand and my average turns per hour is about 160, it'll take one day for each xformer to get done
[Big Grin]

Phil: Shipping cost to where? and no.. I'm not gonna take my amps inna plane or anything..but it just gave me the idea of having tube amps in my car and NOS means New Old Stock [Smile]

(so new tubes)don't know of any recent production of 6SJ7 for a while.

Paul: It's the red 5693 I was looking for,mostly because the same reason you keep one in your desk, it looks neat [Smile]

Mark: The last Russian tubes I have seen (from Sovtek) looks very well made ,at least their 6L6WXT+ and the EL34,Bought a pair of each last week ,the construction on both is very good. seems that they stopped using the light bulb-style for the stem (?) and went to a real tube stem. going to test the 6L6's in a few hours.
I've heard that OTL amps have a very nice sound, however the lack of the opt makes me afraid of them, instantly think of some HV running tru the speaker wires mrrrf! the 6C33 also seems to give a nice dual SE class A amp or a single PP amp.

Jeff and Jon: from what I know about the Sovtek and Svetlana:
the Sovtek (and Electro Harmonix) tubes are made at the Xpo-Pul factory (AKA Reflector) and the Svetlana (prior to 2003) in another factory in St Petesburg (theSvetlana factory)
Because of some problem with the company that had the rights of the Svetlana brand, it changed ownership and now the same group that owns the Sovtek/EH brand also owns the Svetlana brand. However the real Svetlana tubes are still in production and are being sold under the "winged C" brand.
That's the info I read on a tube site how accurate it is, I don't know .

Posted by Mark Gulbrandsen (Member # 72) on 04-07-2004, 08:24 PM:

Luciano, Never had any problem with the 6AS7's and blowing out speakers. each tube was fused with a fast blow fuse if things went shorted internally.

The sound of an OTL is quite good but nothing comes close to the Pass Labs single ended MOSFET Class A stuff I've been building. The Pass is far better sounding than any tube amplifier I've listened to or owned and as one would expect they run as hot or hotter than a tube amp of comparable size.

Jeff S.
The reason your Sovteks last so long is because all McIntosh amps output stages are biased for Class B operation... including the solid state stuff. Take them to high bias class AB or Class A and you'd get a few months life span at best.

Here is a typical OTL power amp that could use 6AS7's or the 6C33CB. Both are actually voltage regulator tubes.

Mark

Posted by Luciano Brigite (Member # 1104) on 04-07-2004, 11:38 PM:

Aaron beat me by 4 minutes with his post about the Sovtek and Svetlana tubes [Smile]

.
Now that I think about it,who's the manufacturer for those "National" branded tubes? about 2 years ago I bought 6 of their 6L6GC's and they're worth [bs]

they do work but it takes nothing for them to glow red even with a bias cranked up to full (nearly 58V) and 380V+/- on the plates running on class AB-UL.
If it's true what Mark said ,that those tubes won't put out more htan a few months in a or AB class then I'll get kinda displeased with them because among the amps I plan to build someday are a few class A PP ones..hte others are class A SE/SE-UL class AB PP/PP-UL and A/AB PPP .
I'm starting to think I'm a kind of diehard DIY dude because I wanna do most of the stuff including the xformers. right now I'm at 51% of the primary winding for a 5000 ohm SE OPT. it's being wound by hand with an average of 181 turns per hour, the total turns acording to my math is 2557 for primary and 102 for secondary,1"x1"GNO iron stack with gap.

The OTL circuit Mark posted resembles (??) a transistor amp schematic [Smile]

It also seems kinda easy to build,the PSU however may be not because of all the voltages needed .
Something in that circuit that left me thinking is why two phase inverters? unless I'm making a mistake here, the arrangemet with the V2 and the other with the 1/2 V3 are phase inverters ( damm my head that keeps forgetting names of those arrangements)
Since the tubes mentioned are voltage regulators,maybe the 6336A's will have some use in such circuits? I saw a few of those tossed around,NIB, inna junk/surplus depot. if they're not costing a few bodyparts maybe I'll get them for a try

Posted by Aaron Sisemore (Member # 145) on 04-08-2004, 11:35 AM:

quote:
Now that I think about it,who's the manufacturer for those "National" branded tubes?

the 'National' brand (red and white box) along with the 'Amperex', 'Bugle Boy', 'Mullard', and 'Cetron' brands are trademarks owned by Richardson Electronics .

It's ironic that Richardson is one of the last US companies that still manufactures tubes here in the US, yet almost all of its receiving and low-power transmitting tubes are rebranded Russian and Chinese garbage (I would assume that your glowing 6L6's were probably Chinese)...

They have the tooling (most likely the Philips/Amperex equipment) to manufacture 'common' audio types, but I guess the market isnt out there for mass-produced quality tubes anymore. [Frown]

-Aaron

Posted by Luciano Brigite (Member # 1104) on 04-08-2004, 03:32 PM:

The National 6L6CG's I got are russian. tried to take a pic. of it but the webcam is being crappy lately, anyway here it is..

Sovtek as 2 kinds of 6L6's, the ones I bought two weeks ago ate the WXT+ and doesn't looks any close to the National. I couldn't find a pic of their other 6L6. the National still has the lightbulb stem in it.

and for the 5693, I'll go for it's equivalent, the 6SJ7,it's a lot cheaper and can be found easy for a while.