Topic: TungSol 6550 "reissue" first impressions

[ducati]

I rolled in a matched quad of TS6550 "reissue" tubes  on Tuesday (old tubes were 6550EH that came from ARC).  After biasing them to the factory recommended bias, I sat down for a quick listen.  My first impressions were "wow!" the improvement in micro and macro dynamics was no subtle, nor was the entirely HUGE soundstage.  Lows were taut and tuneful, tighter than the EH's with maybe a tad less slam, but overall more enjoyable.  Mids were seriously improved--they became so smooth, not tubey lush at all but silky smooth and so transparent.  Highs seemed to go on forever and ever...  And so much air and ambience was being pulled from my recent 16/44 downsample of a 24/96 recording that I wondered if I was listening to full res again!

But here was the achilles heel.  Highs were somewhat spitty, and the overall tone was way bright for my tastes.

Over the next few days I let them settle and burn in a bit.  The highs smoothed out considerably but hot damn is it bright.  On one hand, I love the added air and detail.  On the other, I can't listen to 80% of my tunes like this 

I also have some new 12AX7's for my preamp (stock is 12AX7EH), so I rolled in a set of GT 12AX7 "Mullard Reissues."  The highs were immediately tamed, but the magic was gone.  Flat and boring my notes read.

So...  Initial impressions of the TS6550 is this tube has REAL promise.  At this point I wouldn't characterize them as a bright tube--the preamp tubes could certainly be to blame for this.  I will keep rolling, keep letting the TS6550's burn in, and report back soon.

Also, a friend of mine is going to send me a quad of the real deal TungSol's to try--I will eventually review the reissue vs. the originals as well.

Does anyone else here run a 6550 amp?  (I hope so!!)   

[Lil Kim Jong-Il]

My amp uses 6550s but I am currently running EI KT90s.  The 6550s I have are labeled Svetlana.


Edit:

you interested in swapping some tubes?

[ducati]

I'd like to try both of those.  The Svets (SED now) are supposed to be a little more lush and liquid than my 6550EH, and the KT90 works magic in some amps, supposedly.  It's an odd tube, based off an old TV sweep tube...  But I have heard good things if it's put in the right amp.

So many tubes to try, so little time and $$$   

I'll keep you posted--at $130/quad these aren't too terribly expensive, and they have great potential.

[Lil Kim Jong-Il]

I'm looking forward to your review after they settle.  I've been wanting to play around with some tube rolling and now that my other components are in place, it's time.  My system is very warm now and I could be happy with a little more sparkle at the top.

My preamp uses 6C4s but the manufacturer now ships the Mullard M8080, which is what the previous owner installed.  I think 6135 and ec90 will also work.  Any recommendations?

Let me know if you want to borrow one of the sets for a comparison against your new 6550s.

[Nick Culbreth]

Thanks for the review review, I'm glad some work actually went into making a nice copy instead of just branding any old Reflektor tube Tung Sol which was my first thought when I heard about them.  It sounds like you're going to have to do some searching for a better mate for the 6550s, maybe a tube like the RCA 5751 might be a good option for you.

[ducati]

I'd love to swap...

What amp are you running?  What pre?  I'll see what I have, and we'll work something out.

[Lil Kim Jong-Il]

CJ PV14L -> Premier 11A -> VR4Jrs + Vandy 2wq.
MI330Shotgun and Cardas 300B for component ICs.
MH750S2 to the speakers. 

[ducati]

Ha, very similar, I'd bet, to mine:
Moon Eclipse LE > ARC SP16 > ARC VS55 > ProAc D25
IC's are MIT MH330S2
Speaker Cables are MIT MH750Shotgun Biwire

I use 12AX7's in the pre, 6N1P and 6550 in the amp.  It looks like what we have in common are the 6550s (of course) and I have a trio of Sovtek 5751's to try in place of the 12AX7's in my pre.  Folks tell me the Sovtek 5751 is constructed very similarly to their 12AX7LPS which some regard as the best current-production 12AX7; but I am told the 5751 is even better (if my pre likes it).

Will you amp take EL34's?

I'd love to try your KT90's.  Do you want to try my 6550EH, or wait until I'm done burning in the TS6550 to try those?

[Lil Kim Jong-Il]

I'll loan you the Ei KT90s and then wait until you get settled in with TS6550s.  You can loan me back which ever you think I might most enjoy.  It's probably better that way so you can swap back and forth during your comparison.  I have the Svetlanas to run in the mean time.  PM me an address and I'll pack these this weekend.

For the smaller tubes, I am running RCA 5751 and RCA 6FQ7.  I don't know how to identify these as anything other than RCAs.  I suppose there are different grades?  I've got two pair of the RCA 5751s but I don't know if they are different or one pair is old.  I've no access to a tester.

The OEM tubes are GE 5751 and National 6FQ7.  Have not run those yet. 

I need to crack this preamp and see if the mullards are really in there.


edit:
no this amp won't take EL34s.  I had an MV50 that used EL34s but I needed more power.  That amp was very sweet and tubey and I miss it.  The Premier 11A is not warm like the MV50.  Don't know if that is due to the 6550s or the general design.
 

[ducati]

Thanks for the review review, I'm glad some work actually went into making a nice copy instead of just branding any old Reflektor tube Tung Sol which was my first thought when I heard about them.  It sounds like you're going to have to do some searching for a better mate for the 6550s, maybe a tube like the RCA 5751 might be a good option for you.

Just a note of clarification...  I don't think these tubes are actually meant as a "copy" of the originals, per se.  I believe they are a new tube, perhaps preserving some general similarities with the original TungSol 6550, and using a similar shaped envelope; but not direct copies, per se.  The TungSol 6550 is the most famous 6550 power tube ever, no wonder someone would like a new (perhaps sonically similar) tube in their lineup.

That being said, I think these new tubes should be evaluated like any other--as a standalone, unique offering.  Although it just so happens I will have a beautiful quad of original TungSol 6550's in house this week to do a head-to-head 

El Barto, PM sent to hammer out the details of the KT90 loan.

[Lil Kim Jong-Il]

Since changing back to the Svets, I'm noticing the sparkle is back to the extent that I had to mute the ambience driver in the JRs.  There is less punch than with the KT90s but it's not like the bass is gone, just a bit subdued in comparison.

[ducati]

Interesting.  I might have to try them with my 12AX7EH's in the pre, which I now know were too bright for the TS6550's.  The 12AX7EH is an excellent tube that I'm having trouble finding an equal of in a less-bright version!

As I recall, the KT90s are noted for their bass, and also noted to decrease brightness in some components.  Both reasons why I want to give them a whirl

[ducati]

I just wanted to post a quick update.  I've rolled the following tubes through my preamp:
1. 12AX7EH
2. GrooveTube 12AX7M "Mullard Reissue"
3. Ei Elite 12AX7
4. Sovtek 5751
5. A trio of Telefunkens a friend loaned to me

I have determined that the TS6550 "reissue" power tubes are not to blame for the brightness.  If anything, they are a very neutral tube--they show changes in anything upstream VERY well.  They can soundstage well if fed properly, and seem to take on the characteristics of the preamp tubes feeding them more so than my 6550EH.  To me, this means they are a fairly transparent tube. 

This is a good quality, and for folks with tube preamps you can use the pre tubes (much cheaper) as tone controls of sort.  However, folks without tubes upstream who want the tubey sound might want to try these tubes before buying them--they are a neutral, modern sounding tube, and some folks may not like that.

I haven't formed an opinion one way or the other yet.  The best matchups I've found so far are Ei 12AX7/TS6550 and Telefunken/TS6550.  The first pairing is very liquid, smooth, and a bit laid back.  Putting the Teles in adds a bit of sparkle and midrange tube magic, at the expense of some soundstage focus and air on top.  I've only had the Teles in one day, so this is a bit premature... 

I have some other pre tubes to try, too; some 12AX7 Mullards and some 12AX7 Mullard Gold Pins.  I am also ordering a few more new-production tubes, and may have a trio of NOS TungSol 12AX7's to try soon as well.  I'll keep everyone posted, but I doubt my impressions of the TS6550 will change too much.  I'll post final impressions, as well as a verdict, in another thread.