RCA/Sylvania Tube Discovery

Hey all,

I've been reading through the abundance of great topics regarding vintage tubes and had an inspired thought.... I remembered I had an old radio up in the attic and thought it may have some usable tubes in it. So I crawled around until I found it and I think I struck gold. I'll know as soon as I get a chance to plug them in my Studio Pre or MKIVa. I've only used stock Mesa tubes, so I'm hoping I have found some quiet bottles with sweet tone and no microphonics.

The donor radio...


This is my first foray into understanding what tubes are available and why they are desirable.
I've basically been the content Boogie owner who had no idea the sun could shine brighter... :lol:

I believe these are two 1959 Sylvania JHS long grey plate 12AX7 with round halo getter's. I figured that much out from scouring the internet last night (learning terms like 'getter') and finding pictures of similar tubes. The colored text on these is basically dust held on by static cling. I rubbed some of it off by just touching it to remove them. I expect there will be nothing there pretty soon by just handling them.





Internet reference pics...




The other tube I found in there was (I believe an RCA) short grey plate 12AX7A with round halo getter.
There is just enough of the label left to identify it as the second tube in the pic below.



Internet reference pic...



After staring at these and smiling while I found threads holding them in high regard, I had another inspired thought. I had put an Ampeg V4 in the closet 10 or 15 years ago because it needed reconditioning and 7027a tubes were not readily available. So I went digging again. This time I had more of an idea what I was looking for/at and was very careful to not grab the bottles below the tip. What I discovered was (3) 12AX7A tubes. Two had nothing on them (except the etched label). The third had just a trace of what looks like Magnavox in red. I found some references to RCA's being rebranded by Magnavox. They look exactly like the RCA short grey plate 12AX7A with round halo getter that I found in the radio. They even have the flat edges on the mica discs.



Can someone help me to understand the term 'Triple Mica'. Is that referring to a layered section of the top and bottom insulates above/below the plates? The Sylvania's look like a single thin layer, but the RCA's are thicker and look like they are a sandwich of multiple layers. Is this what that is?

What do you guys think?
Did I strike gold?

Should I have any concerns plugging them in. I'll watch them close on power up to make sure they don't light up like a fireball... I was thinking the RCA short plate would be a good one to try in R1 and the Sylvania's on down the line, but I'm probably going to roll them all around and see how it sounds.

Mongo happy....

Wow..great score! Triple mica does refer to the wafer thin layers. None of these tubes have the third mica, which helps keep the tube quiet. Enjoy.

I did some more searching and found these pics of triple mica tubes.

All right Mongo! Keep up the good work and BTW, super cool pics! 8)

212Mavguy,

Thanks, coming from you that means a lot.
Am I pretty close on my understanding of what I have?

I opened up my Studio-Pre to see what was in it. It seemed to sound muddy after it warmed up. No definition, Flubby comes to mind.

This us what I found:

Studio Pre
1. Input
2. Rhy
3. Lead
4. Main/Rec Out
5. Rev

1.  MESA 12AX7-A 
     Russian 2     
     (Short Grey)

2.  JAN  12AX7WA 
     Philips  ECG  8726
     34167  USA  AGW
     (Tall Grey)

3.  JAN  12AX7WA
     Philips  ECG  8726
     34167  USA  AHG
     (Tall Grey)

4.  JAN  12AX7WA 
     Philips  ECG  8726
     34167  USA  AGW
     (Tall Grey)

5.  JAN  12AT7WC 
     Philips  ECG  8826
     34167  USA  AIN
     (Short Grey)

I'm thinking the Mesa Russian 2 in V1 might be the problem.

I'm planning on trying this:
V1. RCA 12AX7A Short Grey
V2. Sylvania 12AX7 Tall Grey
V3. Sylvania 12AX7 Tall Grey
V4. Philips 12AX7WA Tall Grey
V5. Philips 12AT7WC Short Grey

Any suggestions other than try everything and have fun... :lol:

I'd start with V1. Try all of your finds, one by one, until the best one sticks out. Then move on to to V2. Rinse and repeat.

AMEN!

Mongo,

If you find those tubes do not like Ibanez guitars, I may be able to take some off your hands.. 8)

Maybe you should buy a lottery ticket as well while you luck is good.

Peace

212Mavguy said:

AMEN!

Click to expand...

Awesome! Sounds like I have your blessing...

I never figured you a man of few words. I'm used to reading long informative posts from you. I'm practically a tube virgin. Am I correct on my understanding of the type/age? What about the character of them? Is the Mesa Russian 2 known to be muddy? Am I correct in thinking that the Magnavox is possibly a rebranded RCA?

What about these Jan Philips? They look very similar in construction to the Sylvanias. I know every tube is unique and I'll definitely listen to them all, but I guess I'm trying to catagorize what I have.

Please forgive me in advance if I'm asking things that have been asked to death. I've been scouring searches learning as much as I can.

I'm planning on doing exactly what y'all recommend.
Starting with V1, rinse and repeat... ;~)

I remember hearing that you should wipe any finger oils off the tubes because it may create hot spots on the glass. Is this true? If so, I can kiss any colored text goodby on these vintage tubes...

Is there any concern with using a Sharpie to re-label them once the original text is gone (or should I be able to know what they are by looking at them???)

I know, I ask a bazillizn questions.

Having just changed tubes in two amps, I asked the tech a tube depot about touching the tubes. He said they are not like mercury xenon bulbs, that get so hot they blister up from skin oil. He said I could install them with a cotton sock over my fingers if I wanted to, but don't drop them. He also said don't wiggle them much or squeeze in the middle. I am a tube rookie so I asked many questions.

I also had some MESA 12AX7-A tubes that had Russian 2 printed on them, as well as some Sovtek 12AX's and 6L6 power tubes in my old REC. They told me the Russian 2's are preferred by some customers over the current MESA 12's. Looking at them the Russians have thicker mica plates. Maybe quieter? The old Fender I have has Groove Tube 12's in it, they are triple mica and look a little like the triple mica tube in your pic.

I am going to have to do some swapping about to see what is best.

Keep us posted on your sonic adventures

Mongo1 said:

212Mavguy said:

AMEN!

Click to expand...

Awesome! Sounds like I have your blessing...

I never figured you a man of few words. I'm used to reading long informative posts from you. I'm practically a tube virgin. Am I correct on my understanding of the type/age? What about the character of them? Is the Mesa Russian 2 known to be muddy? Am I correct in thinking that the Magnavox is possibly a rebranded RCA?

What about these Jan Philips? They look very similar in construction to the Sylvanias. I know every tube is unique and I'll definitely listen to them all, but I guess I'm trying to catagorize what I have.

Please forgive me in advance if I'm asking things that have been asked to death. I've been scouring searches learning as much as I can.

I'm planning on doing exactly what y'all recommend.
Starting with V1, rinse and repeat... ;~)

Click to expand...

Yep, sometimes I get pretty bong-preachy. :shock: Waidaminnit, **** near all the time! AAAUUUUGH! :wink:

Your Maggie 12ax7 looks like an RCA shortplate. You are also correct about your JAN Philips 12ax7's having Sylvania roots. You are on the right track about your dates. Try to find an article named "12ax7 Shootout" in Vacuum Tube Valley magazine, they are available on back order, like 12-15 bucks per issue, and worth every penny, you get a real good description of the vintage tubes. That one article started me on collecting vintage tubes.

One caveat: what sounds the best in one amp might not sound the best in another...or exactly as described in the article. They used a Fender, I think...

One of my amps, a Siegmund Midnight Blues Breaker head, has a bias knob for the 12__7 in V1, you can change the basic tone of your preamp by a small adjustment of that knob! Can go fat and warm, or bright and detailed with the same tube in front of all the others. That is a GOD amp, BTW.

As far as changing them out, I just use my bare fingers or a piece of old car tire inner tube for a better grip. Cotton sock slips more than rubber and you have to squeeze much harder.

Dunno anything about Russian 2's, I don't buy new production tubes. I don't worry about squeezing the middle, and I use a circular rocking motion to take them out of a tight socket.

Looks like one of your pics shows a few Raytheon red print military type triple mica black plate 12at7's, those are very nice sounding to my ears.

My experience with Sovtek 12ax7's is that they are resistant to microphonics, but they sound pretty thin and nasty compared to the vintage stuff. I like the sound of EH 12ax7's more.

I use sharpie type markers to mark test results. The kind that schoolteachers use for whiteboarding or overhead transparencies are water soluble, so a damp rag will wipe the bottle clean.

Do some looking back a page or two for links to Timbre Wolf's tables of tone impressions of 12ax7's and 12at7's, he is a class act. Or simply read all his posts, they are informative and fascinating. There are others not mentioned here who really know their stuff too! Keep digging, read their posts, and don't take anyone's word for gospel, roll your own,your tones will reward you!

****, another long post...again! :mrgreen:

Peace.

Well, I spent several hours rolling tubes and WOW!!!

I initially had the Studio-Pre through a mixer with a small shelf monitor. It really sounded bad... So, I decided it really needed to be at playing volume and plugged it into the loop return on my MKIVa. OMG! This thing is a whole different animal through 6L6's then direct.

I thought it was sounding awesome and wondered if there was a need to swap tubes, but my better sense had me start the process. As I began rolling on V1 it was quickly apparant the different characteristics of each tube.

Here's what I discovered:
* V1 sounded great with all of the JAN Philips, two of the RCA's and all of my Mesa 7025 STR 12AX7A/ECC83's, but, the Sylvania 12AX7 is pure magic! It added a clarity and sparkle that was full of rich overtones. Strong, clean and quiet.

* V2 responded well on Rhy to the JAN's, the Mesa 7025's were a bit hot there, but two of the RCA's brought it to life. I had a hard time picking the best one of the two. I'll be marking the other as a V2 spare.

* V3 liked the other Sylvania, but I still have to go back through V3 again since it's too late to run the lead channel at volume tonight. I plan on rolling them all through again to recheck.

* V4 was a real learning experience. It's listed as the tube for the outputs, so I initially thought it would be fairly benign and of little consequence. Was I ever wrong. By this time I had identified some tubes that sounded pretty muddy and dead. When I rolled them through V4, all the great tone I had dialed in was gone. I found that any of the JAN's really work great in V4.

I'm not sure what my options are for V5. It's spec'd for a 12AT7 and that's what's in it (JAN), so should I bother rolling 12AX7's through it?

Here's my results for the various tubes.
* Sylvania 12AX7 (tall grey):
Clean, clear, crisp and has a resonant quality that just sparkles. It lets notes ring and draws out harmonic qualities that makes me sound like a better player. In short, amazing!

* RCA 12AX7A (short grey):
Nice warm tube with a fair amount of grit when pushed. It seems to respond differently depending on where it's placed. Has a chameleon quality. A good one sounds good in most spots. In contrast, I do have one that can make any channel sound like a sock is stuck in the speaker...

* Mesa 7025 STR 12AX7A/ECC83:
Hotter then all my other tubes. A bit noisy, probably because of the gain. Sounds good in V1 but doesn't breathe as much as the Sylvanias.

* Mesa 'Russian 2' 12AX7A:
Boxy sounding with very little harmonic overtones. This may be because they are new. They didn't rise to the top at all in this company.

* JAN Philips 12AX7WA:
Beautiful sounding tube with clean crisp definition. Just a hair less open then the Sylvanias. I loved it in every slot, but others shined just a bit more.


I'll be spending some more time tomorrow on V3 and V5 if there is a reason to. I can't wait to repeat this process with my MKIVa. It's running factory Mesa tubes and I expect a revelation awaits me...

A HUGE thank you to everyone for your expertise and encouragement. This forum is GREAT!

Welcome to the faith brother Mongo!

I just got done playing again (headphones with the Mrs sleeping). Not the same as cranking the 6L6's, but oh soooo nice! I guess a 50/50 is definitely in my future.

I can't wait to post build pics of this rack when I'm done. I'm reconditioning a JC-120H, I wonder if it will push my theiles like the 6L6's?

For your v5 thang, if it's spec'd for at's use at's. 5751's or ax7's might distort with no benefit and no cleans. GE 6201's are inexpensive, articulate, lots of detail in upper mids and top. Bulletproof for microphonics. In contrast, Mullard cv4024's are warm, fat, almost syrupy smooth. Siemens ecc81/at7 are very much worth having, f-ing gorgeous. The aforementioned Ray red print BP 3xmica are smooth, warm, and musical, telefunken at7's have a gorgeous dirty tone besides the clean.

Keepin' it short this time... Dassall!

peace.

Since V5 is for the Rev, will it make that much of a difference?

Hypothetically, not a lot of difference. Reality demands that you roll another one just like the other one... :wink:

Thanks for the AT7 recomendations. I'll look them up. I think I have an AT7 in my MKIV. I may be confusing it with an SPAX7. I'll roll it and see what I hear. So far the JAN's have been strong contenders. This is so much fun.

I just got done playing at church. Two services and we rocked it pretty hard. My fingers are talking to me after all the hours I played last night. Well... There in for another few hours when I get home.

Anyone have a 50/50 they are thinking of selling?
I know this thread is about tubes, but I figure I can hijack my own topic.

This is a really good thread. I will be getting some ax7's and 6l6's from a guy in the not too distant future. Old ones.. I don't know how many but I will try to get as many as possible!! I have been looking for old tubes for a few weeks now and it is a struggle to find them anywhere but the Internet ... So I just sent out an email to a bunch of people in my address book asking if any of them had tubes or old electronics or knew someone who did and I got a couple of bites. So that is something to try.
Also it would be nice to know what type of electronics that these tubes we all look for can be salvaged from. I may start a thread on that.