Long Plate verses Short Plate

[alvarezh]

Tom, don't forget to roll some inside the D'Lator too! And please do let us know which plate length worked better for you in there also.

All the best.

[renshen1957]

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!

Hey,

You never know on tubes, NOS (when produced by the actual company as the silk screened logo and not an out sourced tube such as RCA logo/Mullard mfg) and New production as their can be quite a variance. We can speak in generalities about a specific tube and then find two samples from the same date of mfg (batch) to vary sonically very noticeably in the same tube position.

I have found that long plate 12AX7 tubes are fine (not microphonic) in heads, if the head isn't on top of the speaker cab.

My beloved tube integrated amp right channel went out last week I could still hear a faint distant sound of the music in the right channel with the balanced all the way over (eliminating the other channel) and the volume full up. A quick visual check didn't confirm anything wrong in the 7591 power tubes. Working from the power amp forward, brought out my Hickock 750 Tube tester to check all the power and preamp tubes, all 12AX7. I suspected the PI, (and prayed it wasn't something more serious) The Raytheon 12AX7 tested okay, however as my habit, I substituted a new tube (pre-tested) that was known to be good. An Electro Harmonic 12AX7.

Long story made, longer, after finding the cause (wasn't the PI tube), and being lazy, I left the EH tube in to listen to some music. I put on Tony Sheridan backed by the Beatles, and although not as quiet as the Raytheon tube, the detail extracted by the EH tube was revelatory. The Beatles singing back up and occasionally screaming in the far background in one cut jumped out of the speakers clearly like never before. Great detail.

As to Guitar amps, Tubes I've used, yes I have most of the usual suspects in NOS, especially tubes that were OEM for Electronic Organs (Hammond/mullards, Wurlitzer, Conn, etc) and for Hi-Fi companies as these are pre-screened, and quiet tubes.

A few new or NOS new tubes from Eastern Europe, I've tried. As to newer tubes, I found JJs (not the gold pins) to be of medium output similar to the old US tubes (and not high gain like some of the older Chinese tubes) and a good match for American amps. However, I use these to test a new amp before populating the tube sockets with NOS tubes in critical spots and catch as catch can by ear for the other.

I've used Sovtek LPS as a "test" tube that was sourced from a Hi-Fi source, NOS circa year 2000 that was as sweet as NOS to my ears, but I cannot state as to long term reliability as it is still only a "test" tube in new amps before population with NOS.

I look forward to testing TJ (Tianjin) Full Music 12AX7 box plates from China, heard some good comments in Hi-Fi's. I haven't been tempted by the Psvane (pronounced Pavane) a Shuguang tube that looks the same as their other cheap Chinese tubes they sell to Fender and Marshall. The Psvane is supposed to have better materials, metallurgy, and more experienced assemblers.

However, for the price the Chinese Hi-Fi 12ax7s fetch, I can buy NOS tubes on ebay on the Cheap, and test them myself. I purchased Siemens, Telefunken Smooth Long Plates, Telefunken Short plates, Mullards, Amperex, etc for a fraction of the going rate, if one is careful and does get caught up with auction fever. On the other hand being too thrifty I missed out on some Medical equipment 12AX7 tubes.

Best Regards and Happy Thanksgiving,

Steve,

PS I left the stock Chinese tubes in the Jolida Vacuum Tube CD player as they sounded pretty darn good. Been just to busy to tube role of late, but seriously tempted as I have more tubes than time. Replace the CD players preamp tubes with NOS and use the stock tubes in Guitar Amps.

PPS Part of the problem, a lot of the reviews for new production 12AX7 tubes are initially from merchants who only a year before oowed and awed over the TJFM tubes, but discontinued to sell the Psvanes.

Or you find a new tube with an old name (I call it the Rexall Syndrome, respected brand name on new products) with not much information about its pedigree.

The New production Northern Electric is a TJFM tube, but I can get the same tube for less than 1/2 (fringe benefits of marrying a Chinese Woman with connections).

PPPS I didn't start on 5751 or 12BZ7 not your usual Dumble tubes.

[sharkboy]

That was great, Steve.

I have wanted to ry the TJFM tubes and also the PSVANE tubes. TJFM's factory is up north and PSVANE's is near Shenzhen, and is not the Shuguang factory, as I understand. Both make "treasures" types of tubes.

A lot of tube sniffers really like both of the brands for audio. They might not be the kinds of tubes that we would want to torture in something like a guitar amp, but if we don't try, we'll never know. Both of those companies have people with stron tube pedigrees, so at least it sounds like it could be interesting.

I also have started using LPS tubes and like the sound very much. I think I'd put them ahead of the TS reissue 12AX7, which is a good tube, but haven't used them enough to have road confidence. I'm a little less worried about that, though, as I'm not even getting a lot of time to practice these days.

-Markg

[Roe]

I've always heard that longplates are more prone to microphonics. hence I avoid longplates in v1. but longplates tend to sound more punchy in the PI. also I often like longplates in cathode followers

[cbass]

I like Tung-sol 12ax7 the original not russian.In almost everyamp I have Ecpecialy fender types.Long plates definatly more prone to micros so I have to go through a few to find ones that will work in V1 for higher gain amps.I think slightly Microphonic tubes sound better sometimes if you c an keep them under control

[Structo]

I have not heard of TJFM tubes and PSVANE tubes.

A quick Google didn't show anything.

Do they have a website or are they for sale anywhere?

[ToneMerc]

I have not heard of TJFM tubes and PSVANE tubes.

A quick Google didn't show anything.

Do they have a website or are they for sale anywhere?

http://diyhifisupply.com/catalog/43

http://www.diygene.com/store/index.php? ... ry&path=75



TM

[bluesfendermanblues]

I have not heard of TJFM tubes and PSVANE tubes.

A quick Google didn't show anything.

Do they have a website or are they for sale anywhere?

http://psvanetube.com/wordpress/who-is-psvane/

[Structo]

Wow, those are expensive!

I guess I will just stick with vintage, slightly used tubes or ANOS.

[renshen1957]

Wow, those are expensive!

I guess I will just stick with vintage, slightly used tubes or ANOS.

Hi Structo,

I use primarily NOS, occasionally ANOS, in the important tube position and for non critcial areas of the Amp (tube buffer, tubes in NFB loops, Reverb) new production, even Chinese Tubes (TAD 7025, Ruby, or Ruskie/JJ). In a Tweed, Blackface (Fender Electric Instrument Company era), or silver face for a working musician, I recommend short plate tubes.

For the post 1980 Fender PCB circuit amps owner who is a full time working musician, I recommend buying another amp, something else that will last.

Long plates have a reputation of being microphonic, somewhat deserved, but a tube combo Guitar amp is the worst tube environment. At home a Long Plate tube for your own pleasure is fine, or in a Hi Fi great, too.

As to economics of tubes:

The price TJFM on Ebay runs $62.50 for 2 tubes, about half that for a single tube which isn't bad price for Hi-Fi, almost the same as New Sensors Gold Lion Re-issue.

Northern Electrics reissues from thetubestore.com run about $58.00 per tube (I've read these are TJFM tubes.) So about double for Hi-Fi.

Compared to a single NOS Telefunken from partsconnexion.com on sale $99.99, regularly $150.00, http://tubedepot.com/nos-12ax7-mullard.html prices a Military Mullard NOS late production CV492 12AX7 at $179 per tube. And if you have to ask the price for a 10M Mullard, you wouldn't believe it or afford it.

Hi-Fi and Audiophile tube rollers have driven up the prices. Not only for preamp tubes but on tubes that a musician wouldn't have given a 2nd look 3 years ago (or even now). 6L6B tubes now go for a premium, as these were "discovered," the same way that original Tung Sol 6550 were discovered, etc. Speaking of Tung Sol, everyone know to get that SRV sound you must have a 3 mica 5751 Tung Sol. The 7581 Tube was discovered as a replacement for 6L6GC's.

So it isn't only the domain of Golden Eared amp tweakers who purchase Silver foil and Wax Paper and Oil caps at prices that make me cringe.

As it is Thanksgiving, we can give thanks that our amps don't use four 300B power tubes.

The new production aren't as expensive as one would think.

I was too young at the time to remember exactly what my Dad paid for a 12ax7 tube at Thrifty Drugs (I "helped" him test tubes in their emission testors), I recall around $1.50 for 12AX7 tubes in the early 1960's. If adjusted for inflation the NOS when it was New New Stock cost $11.19 in today's dollar. Mind you $1.10 per hour was the minimum wage, about $8.21 in today's money.

However, the buying power of the today's dollar is different. I could buy a hamburger for 15 cents in 1964 at a fast food joint. A burger not on special runs $2.00 today. That would be 27 cents, so the buying power in today's money when adjusted back to 1964 buying power could be thought of as about half. A 2012 comic book runs $2.49, but for a comic book in 1964, I paid between 10 to 12 cents for in '64 would cost adjusted is 33 cents. So the purchasing power varies from 1/2 for fast food and 1/3 for a non durable item such as a vacuum tube.

In the 1960's we can consider the amount of tubes manufactured, Canada alone had consumption of 20 million tubes annually and the US to the south consumption I don't have figures) the intense competition, and US military support of the electronic industry in purchasing great quantities from tube manufacturers the price of tubes are harder to provide comparable values.

Since we are discussing todays' low production non food product (compared to the world 50 years ago) that 11.19 adjusted for decreased buying tube price would be roughly about $35.00, about the price of the Ebay TJFM tube.

Best regards,

Steve

PS: I went into an Electronics store to purchase a Midi cable a few years back for my musician son, I found the price was significantly less than the quote at the local store (no guitar center in town). The clerk said that there is a low price for DIY, a higher price for consumer electronics, a higher price for consumer electronics, and then there is Audiophile prices that are through the roof. All but the last category came from the same factory in China.

[Structo]

Interesting perspective thanks.

I too remember going to the grocery store with dad and a brown paper bag full of TV tubes trying to find which one was bad.
Then you opened the cabinet and picked a new one out to buy.
Don't remember the prices but you are probably right on.

[212Mavguy]

@renshen

Very nice, thoughtful, posts from obviously a large inventory of experience! Your ebay experiences parallell mine...Right on!

Would like to see a pic of that short plate telefunken, unless it is the ecc803s build. I have seen RFT 12ax7's in Telefunken labels, does your short plate tube have the diamond between the pins?

RE 10m Mullard, not worth the stupid money they go for. Same tones are in a Philips labeled Mullard Blackburn 12ax7a/7025 label with Philips in big white easy to rub off print. Interestingly, both the Philips and the 10m, after repeated on/off cycles, exhibit a purplish colored filament flash deposit on the inside of the bottom of the bottle, a different color than the brownish garden variety (still awesome!) Blackburn stuff. I have both types, not a large sample size of either. That particular Philips has about doubled on ebay in the last three years. My fave 10k hour 12ax7 hands down is the Siemens e83cc.

I share your opinion about the RI Fender amps...

peace.

[roberto]

I think slightly Microphonic tubes sound better sometimes if you c an keep them under control

Absolutely. They keep the amp on the egde.

Yugoslavian EI 12ax7 were my must-have, but they ended the production few years ago.

[Structo]

I think slightly Microphonic tubes sound better sometimes if you c an keep them under control

Absolutely. They keep the amp on the egde.

Yugoslavian EI 12ax7 were my must-have, but they ended the production few years ago.

I too got back into tubes after EI were affected by the war and production ceased.
Or at least the export of them ceased.
However, I have read that EI tubes were not too consistant in quality.

I was given a few organ pulls that were Sylvania and Raytheon that got me wanting more vintage 12ax7's.

[sharkboy]

I've had a few EI 12ax7s that had a weak triode.

Some of my EI 12ax7s probably would have been microphonic in a high gain combo. That said, I don't usually play extremely high volume and tend to only use heads and cabs, and these things have performed extraordinarily well. The other thing is that unless they are severely tortured, preamp tubes last a long time.

I have a few Telefunken 12ax7 long plate pulls that were on their last legs 10 years ago and they are still good, Though I have stopped using one of them for the moment.

Microphonic tubes are reported to get worse if they keep getting sent into that mode (this makes sense to me, but I am pretty careful about avoiding it). I have used dissimilar dampening materials for EF86 amps in addition to the feet (a very non-scientific approach to deaden different frequencies).