Long Plate verses Short Plate

[Structo]

Hey guys,

Over the last few years I have been trying to build up a stock of vintage preamp tubes.
Mostly all 12AX7's.

I like the old GE tubes and most of the time they can be had at fair prices.

The other day I picked up a couple 1959 Wurlitzer GE 12AX7's that have long plates.
It seems the consensus is, is that long plate 12AX7's are more prone to microphonics than the short plate versions, correct?

My question is, regarding Dumble ODS amps, which location is more suited for a long plate tube?
It seems that the V1 tube is a good place to put your "best" tube.
But does a long plate tube work well there?

So do you guys have preferences where a long plate tube can go and where they shouldn't go?

Is it true that the phase inverter tube is not prone to microphonics, therefore a long plate can go there with no problems?

Thanks!

[talbany]

For me in the PI and depending on the type of ODS sometimes in the OD spot..Hardly ever in V1 in high plate skyliner

Tony

[JazzGuitarGimp]

Hi Tom,

One thing to keep in mind is that each successive stage in a guitar amp adds a little gain (excluding CF's). So, using a microphonic tube is always going to be least noticeable in the PI position.

Cheers,
Lou

[Structo]

Thank you guys.

Do you have a favorite vintage brand?

Do you like the older black plates verses grey plates?

How about current production 12AX7's?

Any favorites that stand out?

[talbany]

Thank you guys.

Do you have a favorite vintage brand?

Do you like the older black plates verses grey plates?

How about current production 12AX7's?

Any favorites that stand out?

Depends
In OD spot my fave hands down are Amperex followed by Black plate RCA's
In PI ECC 803 Telefunkin or an Amperex close 2nd

BTW..I just scored some NOS never been used Mullard ECC 83's that sound great in V1..The only spot I might use current prod tubes might be in V1..Very subjective but I like the JJ's or TAD high grade 7025's (Shugang)

Tony

[Colossal]

Tom,

I know this is more about NOS, however, I've use short plate tubes in V1 through Vx as I most often dabble in high gain amps and have found them the most stable and least microphonic. I have come to really like the Sovtek 12AX7LPS (Long Plate, Spiral filament) in the PI position. They seem a little microphonic but I think this quality really works in the PI position. They are nicely balanced tubes as well but I think best suited for either low gain applications in the preamp or solely for PI duty (I give credit to Dr. Z for turning me on to these tubes).

As far as new production 12AX7s go, I've had very good results with JJ Gold Pin, Mullard reissue, Sino 12AX7B, and TungSol reissue. All of these tubes have quite different qualities so rolling is a must! I did a little rolling yesterday on my TWExpressPCB build and man, does the amp sound good now where before I was happy but not blown away.

[JazzGuitarGimp]

Maybe I just got lucky, but I bought some Mullard reissue 12AX7's for my Tonemaster and they sound absolutely incredible. I plan on buying more, as the need arrises, so we'll see if they are consistent. At this point, I am sold though.

[talbany]

Most here say they like the long plates but never state why...Here is my Why..
If I am looking at a 183 or 124 (amps with more low mid voiced in the OD channel) I roll through some long plates in V2 (if that's what I am after) These tend to have a slightly tighter punchier low mid response..On the opposite side though they don't seem to have that extended top end sparkle that the shorter plates have however this can be a good thing in the OD spot to help with a buzzy top end some can have (again componet choice)..
I like a little sparkle on my clean channel and since the high plate skyliner already has plenty of low end range on the clean channel I usually don't like to add more of it in my tube choice by going with a long plate there..
2nd generation amps love the RCA 7025's seem to be a perfect match for those amps however the OD channel (w/funky OD entrance) shaves quite a bit low mids so if say I want to fatten up the OD on my 2nd gen amp I will opt for a long plate there..
Long plates in the PI do the same, I don't like PI distortion especially on the low end so the long plates there keeps the low mids tigthter and again less of that grainy type top end, This is especially true on the hotter type PI's ie 10k tail 470 cathode and Marshall style presence..
Tube brands are highly subjective so this really just a guideline I use when choosing tube's for a certain ODS style amp..YMMV greatly!!

Tony

[CHIP]

Just the other day I decided to replace an Amperex 12ax7 and try an RCA blackplate in V2 of my 183 circuit amp. I was pleasantly surprised at the result, smoother and a little more harmonically rich OD. I have a GE 12ax7A in V1 and a telefunkin smooth plate in the PI.
I try to find recommended tubes and get the plate voltages close to clone values but sometimes it just pays to roll some tubes and use your ears.

[Chris333]

I don't have any RCAs, but a GE (short) in V1, Amperex in V2 and a Telefunken with long, ribbed plates in the PI is as good a combination as I've tried so far. But I've never been able to talk myself into paying for a good (Mullard or Bugle Boy) long plate, so I really don't know anything about those. I've tried GE, Sylvania, Raytheon and CBS-labeled long plates, and Telefunken and EI smooth plates, and I didn't like any of 'em very much in any position.

[212Mavguy]

This is a friggin' can of worms. I have collected a couple hundred 12ax7's of vintage types, nearly every kind that has been made. Also have a goodly amunt of 5751's and at's, including 6060's, CV 4024, and 6201's.

If you want yours to sound Fenderish in the clean channel, RCA 12ax7a shortplate or 7025 shortplate were the go to's in the blackface, blackline, and silverface days. For a more mid scooped clean and a more agro, gritty dirt, a sylvania long grayplate is nice, they have more gain than any other 12ax7 as a rule. They are ALL slightly microphonic or worse.

A slightly microphonic long plate tube adds some sustain and swell in the PI spot, faves are telefunken ribbed plate, and the US long blackplates from raytheon and Sylvania. I much prefer 'funken ribbed plate brighter top end than the smooth, both types do a very nice compressed violin like sustain in V2... The siemens longplate has never been surpassed in my c-lator... They are more bright and detailed on top than the longplate Amperex or Mullard. Also less spendy by about half. Harmonic monsters, those are...and often too microphonic for a V1.

Telefunken ecc803s are stupid spendy today. For the 10,000 hour rated euro trash I prefer the tones from the siemens e83cc. The tesla e83cc and ecc803s are the same tube made on the same tooling as the earlier produced telefunken ecc803s, a frame grid design, although the jj looks similar,there are some significant construction differences and they are not nearly as sweet as their tesla daddies are. The teslas make great V1's and spectacular v2's.

My C-tone SSS is pretty bright, so I like a slightly darker tube in V1, I love the sound of a vintage Tungsol 12ax7, for some reason they toss out more odd order harmonics than most other 12ax7 to my ears, but they are ALL at least slightly microphonic. A couple layers of one inch black heatshrink over the bottle sides helps after the glass gets hot.

Raytheon 12ax7 long blackplates are insanely good in PI, and v2. The Sylvania long blackplate is very similar in tone. The rare sylvania short blackplate is one of the tonally girthiest 12ax7's ever produced, a good choice to fatten up some lower output single coils. They never seem to match between triodes, though.

I like to hear a lot of vowels in the voice of my moderately gained OD channel. Philips was the parent euro company that owned Mullard, Amperex, Philips, Miniwatt, Siemens, Electrohome, Valvo shortplate and longplate 12ax7's. I dislike the long "U" vowel, that to me is a sign of too much mids, so for me two of those Philips family sshortplates is a v1 and V2 no no. I like to have a euro tube follow an american one or vice versa, there is a lot more vowel variety that can be had with the pick attack. I like the "ah's" and the "oh's" from the mixed combos of US and euro...

For some reason I have seen a lot of GE shortplate 12ax7 in HAD's amps as original equipment. Their tone set works very well with his circuits, apparently. They are more affordable, and resist microphonics well as a rule.

[sharkboy]

I do not go full volume and would carry short plates with me if I did. But I tend to use long plates for everything I can. I know, I'm kinda nutty that way.

I find that much of the "magic" of one tube over another is how lively it is- how close to the edge it is. Some is how much full frequency detail is available through it. In this way, a Telefunken or Ei long plate tend to be the go-to tubes for me in almost any amp. I'll use a Brimar CV4004 if I need to tame it a little.

V1 has the greatest opportunity for defining the tone of the amp. I like an explosive pentode or a long plate there. Granted, I stay away from amps like SLOs.

[212Mavguy]

My ears do prefer the telefunken smooth and ribbed plate greatly over the EI smooth plate, the harmonics in the EI are rather strident when overdriven compared to the telefunkens pushed into similarly dirty situations. I have never liked the EI's in a D- circuit, but they do sound great in a Mesa Boogie Heartbreaker that they were original equipment in. I think there is some real similarity when clean, but pushed into the dirt is definitely another story on the EI vs Telefunken thang.

Definitely a personal taste situation, to me. I have some Brimar CV 4004's, what a sweet sounding clean those have! BTW, the Tungsram 12ax7's, either earlier Brit or Hungarian sound wonderful clean, the fat mullard mids and bottom with a really sweet, sparkly top end, they are difficult if not impossible to locate with matched triodes, and the sustain in the dirt is less than Mullard shortplates in my experiences. speaking of brightness in top end, this is how my ears rate the philips family shortplates from brightest to darkest...
Matsushits 45degree getter flashing is brightest, next Amperex/Electrohome/Valvo (Heerlen), then Siemens e83cc/ecc83, with Mullard and Matsushita level flashing being darkest. Other ears will beg to differ from mine, and that's just fine with me...

I was as lost as a babe in the woods until I got a copy of the 12ax7 shootout article in Vacuum Tube Valley magazine, bTW. Never found a better vintage 12ax7 tube primer than what is found in those pages. Worth the 15 bucks it costs for a back issue. Then I started buying and rolling to get my own impressions, don't rely on words of others. Strongly disagree with their opinions on M8137 Mullards and cv4004's, for instance.

Still feel that way, please don't take what I write as gospel, ever. Test for self. Ears are unique to their owner.

BTW, the pics of the GE 12ax7's in this thread are of two different types, the second is the shortplate often found in pics as original equipment in the HAD amps. The shortplate is very durable, long lasting, and relatively free from microphonics when new. There is another style of longplate GE made as well. Have seen GE gray plates in Raytheon bottles too. And the semi unobtanium Ray 7729 is in a GE bottle...go figure.

[ER]

I think you just need to roll till you find what you like.

I tried RCA, Sylvania, Matsushita, Mazda, Old Boogie 7025s most likely sovtek, Tungsram, GE, 3M (look like sylvanias), Amprex bugle boys, and finally settled on a fisher labeled long smooth telefunken for V1, old short mullard 12ax7 for V2 and a mullard 12at7 for PI.

If any garage members in Sonoma County area of Nor-cal wants to try rolling some various vintage 12ax7 tubes in their amp before spending the bucks send me a PM.

-Erik

[Structo]

Wow, thanks a lot guys that does help.

Yeah, the two tubes pictured are simply to show the long plate and short plate style GE tubes I have.

Looks like I need to roll through some of my stock to find what I like.
It's a bit of a chore due to the way my amp is set up.
Because I need to have the D'lator and pedals connected to have a real world test.

Thanks!