Which brand of 45 tubes do you use?

I prefer NOS 45 tubes for my 45 SET mono blocks. I have a few pair of National Union tubes which always sound lovely. I also have a couple of pairs of Philcos that I haven't used.

I haven't tried EML or Sophia because the NOS tubes sound great, are still fairly available (bottles, not globes) and NOS is still relatively inexpensive if you shop around. I simply refuse to pay the prices asked for new triode power tubes. It's a hobby, not an addiction.

Give Andy at vintage tube services a ring. He listens to a bunch of nos 45s and has a healthy inventory. To me not a lot of difference between shoulder types that measure well. And they are not ridiculous expensive. The globes are certainly excellent but at a cost. I have not heard the new production 45 but not opposed. I’ve heard some really good new production like the Shuguang WE6SN7.

Look at the recent posting under chakster and you will see the answers to your question.
Some will depend on your amplifier but in general NOS are more musical under audiophile definition and much more economical.

Thanks for your comments.

I also use amps designed for 2A3 tubes. I have a few NOS, Shuguang and EMLs. In those amps in my system I prefer the EML 2A3s, mostly because they are the most transparent and balanced.

For my 45 amps I have several NOS and Sophia Electric. I'm trying to decided whether or not I should try EMLs. They are kind of expensive. I agree that good NOS 45 tubes are very close in SQ based on the small selection I have. I have no complaints about the NOS 45 tubes other than availability and reliability. They sound great to me. My overall preferred amp/tube combo in my system is my 45 tube mono amps using NOS 45s. 

@jmolsberg  I will give Andy at vintage tube services a call. Thanks for the contact. I guess a google search will find him?

@gwalt  Thanks, I will check out the recent posting under chakster.

^ certainly will. A call for sure he’s not email friendly. 

I never got to try genuine NOS tubes; at best, I could get my hands on old tubes that tested strong.  Most of the brands I heard, like the National Unions, sounded very good.  They also don't cost a fortune. 

I haven't tried EML 45's, but, I have owned their similar 2a3 tubes, both meshplate and solid plate and they are quite nice sounding tubes. The meshplates are quite different from any other 2a3's I've heard--more open, with the soundstage more enveloping, and a "dramatic" sound (I've heard this tube described as "technicolor."

Larry,   Now that you mention it, It's very possible that some of (or maybe all) the NOS tubes I bought aren't but just tested within new specs. They came in factory boxes with what appears to be period correct wrapping. I was told they were NOS. Who knows. Doesn't really matter, they sound great.

The EML 2A3 tubes I have are solid plates. I never tried the Mesh plate type. Did you prefer one over the other?

I liked the meshplate even though it was a bit over the top.  I liked the wide open soundstage, but, if someone said the tube sounded "phasey," I wouldn't disagree.  I used it in a parallel single-ended amp (Audio Note Kageki) and it had a reasonable life span, although not the kind of life that vintage 2a3s seem to have if run conservatively.

Just a point that may be of interest. Philco never made a tube but they did rebranding. So when br mentions Philcos these tubes were most likely made by Sylvania.

Our company has multiple matched pairs of old stock 45s and one of the owners has over 20 years experience selling old stock vacuum tubes.

National Union is one of our more popular brands. A customer in the know described them as a very nice cross between a Tung Sol and a RCA. FYI.

Larry,  Thanks for sharing your thoughts. I like a wide open soundstage, "phasey" not so much. I don't know if you can answer this but even a hunch will help. Is the "phasey" sound characteristic of mesh plate EML tubes or could something else be at play? 

I am looking into trying OTL amps as well. I have never heard our new speakers powered by OTLs. Could be a nice pairing.

audition_audio, I might be interested in adding another pair of NOS 45s to my stash. Can you share or PM contact info for your company? Thanks.

I don't know if any particular sound I heard is characteristic of meshplates, but, the sound of EML's solid plate 2a3 is much more like other 2a3's--very tight, dynamic, slightly lean and punchy sounding.  I own very dynamic sounding speakers so I didn't mind the less tight sound of the meshplate tube and I did like that wash of sound that evelopes the listener that I got with the meshplates.  I used the description "phasey" because the sound is a littlbe bit like when speakers are out of phase, but, instrument locations remain solid and correctly placed; in other words, it is a rough description.  As I said before, I like the meshplate tube in my Kageki amp.

I like very much the sound of several OTL amps I've heard.  The immediacy, and liveliness of good OTL's are something everyone should at least experience.  Speakers come alive with OTL's.  Like any type of amps, there are considerable variations in the sound, from different choice of tubes, components, design, voicing, etc.  Unfortunately, there are not that many commercial choices out there.  The amps I particularly like are custom-made ones that utilize a television sweep tube.   

Larry,  I believe I understand your description of  "phasey". My 45 amps are a simple SET using one 45 tube (1.5 watts) and silver hybrid transformers. Our speakers are very dynamic so the mesh plate EML might be a nice match

The only OTL amps I've owned were Joule Electra. The mid-range and upper mid-range was wonderful, bass not so much. I got them from a friend so I don't know their history but they turned out to be noisy, finicky and hot so they didn't last long in my room. I am interested in trying contemporary OTLs. 

I liked the Joule Electra OTL I heard.  It was a nice warm sounding amp that retained the explosive dynamics and immediacy of OTL's without sounding harsh or rough.  But, the particular amp I heard developed bad tube sockets that cause it to occasionally deliver extremely loud pops (a friend borrowed this amp from the dealer to use on his 105 db/w efficient system and he said the pop was as loud as discharging a shotgun indoors).  This problem was reported by others so it is something to be concerned about.

The Atmasphere OTL's are also nice sounding units, though a bit too lean sounding for my particular taste.  With high efficiency speakers they often are a bit noisy-buzz/hum.  Still, they are a must listen to amp because they might fit your taste and they certainly deliver the OTL goods.  I've heard other commercial OTL's from the past, and I liked the sound, but, they seemed to be often in need of repair. 

There is the unique Berning circuit amps, which are the subject of debate whether they are OTL's or not.  I've heard both the Berning models and the Linear Tube Audio models.  For my particular taste, they are a bit too lean sounding.

The Joule Electra OTLs were very nice sounding amps but too finicky for the showroom. Maybe the set we had needed repair. The biasing system was not consistent. I never experienced loud pops from faulty tube sockets but had read about it. The contact between the pins and sockets were, in most cases, very loose.

Yes, the Atmasphere OTL S-30 is on the top of my list to try. Our speakers have powered woofers. The main towers have a sensitivity of 105 dB and the high pass is 120 Hz. They are a very easy load for most amps. As long as the S-30 is quiet enough it should work well.

I have read about the Berning amps but have never heard them. I had a chance to speak with David Berning at the CAF 2018 show. Very interesting design but beyond my price point. I prefer to not demo our speakers with amps that cost more than three times their cost. I wouldn't mind trying them though. 

If you are interested in Berning amps then contact Linear Tube Audio. They manufacture amps based on the Berning ZOTL technology. Their ZOTL10 should work very well with your speakers and the price is just a tad over $3k.

I have owned both the Atma-Sphere S-30 and M60s. I know you don't need the power, but in my opinion the differentiation dictates that the M60 is the one to get. For reference I also have Music Reference and Futterman OTLs.

As for tubes, it's EML or bust for us for new production and RCA/Cunningham for NOS. Also, the recommendation to use Andy at VTS is a good one. He is my go to guy for NOS tubes I otherwise can't get my hands on.

The S-30 is quite a nice amp and compact so it's a space savor. At a minimum I would get the power supply boost if you were to purchase one. You may also consider modifying it so the feedback loop is disconnected, even though Ralph uses an extremely low amount of feedback, or no feedback in his designs.

As for differences, I just find the M60 provides a more realistic sound stage with better imaging and separation of instruments, as well as more dynamics. The sound in the lower frequencies is where I hear the main difference with the M60 providing more of a good thing there. I think those who pan the bass in Atma-Sphere amps or consider it lean are mistaken. In addition, this whole thing about "tight" bass that I hear thrown around like ketchup on a burger is a misnomer to me. To me "tight" bass as I have heard it defined is a coloration and not something I want in my system. I find the M60 to provide a very natural presentation in the bass area.

Any Atma-Sphere amp, as well as any well designed OTL is going to give you transparency and detail the likes you have not heard before, assuming they are a good match for your speakers. The Music Reference OTL-1 is no different, although Roger and Ralph differ on their preferred platform for circuit design, Futterman vs. Circlotron, as well as use of feedback.

The OTL-1 was designed for high efficiency speakers or those who prefer low level listening. I've used mine on speakers of lower efficiency with good results as long as you keep the volume within reason. It is direct coupled with no output capacitor and a servo manages DC offset. The main thing I enjoy about the amp is it's flexibility. Four taps employ an autoformer that allows the amp to put out 10 watts into a 2, 4, 8, or 16 ohm load. Feedback can be taken from the same tap your speaker is connected to, or any other tap to adjust gain and damping (versus Atma-Sphere the OTL-1 has much lower output impedance). There is also a direct tap that bypasses the autoformer. In this case you get 1.7 watts into 4 ohms, 3.5 into 8 ohms, 7 into 16 ohms and 14 into 32 ohms.

clio09,  Thanks for your detailed description of the subject OTLs.

The OTL amp(s) will be used to power just our towers which play down to 120 Hz. The speakers have powered woofers. Do you think the "better low frequencies" of the M60 fall below that range? I personally don't like overblown bass. Good definition matters. If the recording has lots of bass, so be it. If not, a system shouldn't add or overemphasize what's there.

My understanding is that the Music Reference OTL-1 is no longer available and that few were made.

Even if the cut off is 120 Hz I would still opt for the M60. I crossed my ESL57 at 100 Hz and while the S30 was fine, the M60 just gave me more.

A revival of the OTL-1 and a new Music Reference OTL are on the drawing board. Progress is somewhat at a standstill right now though for obvious reasons.

i prefer EML 45 solid plate to National Union NOS ST 45 on my Jeff Korneff amp. The NOS is very nice but EML is even better. 

KR makes a 45 that they ship with their P-135 Preamp. Most KR tubes are designed so that although output is consistent with the spec for the tube, the plate dissipation is higher than spec allowing you to drive the tube harder to get more out of it without sacrificing tube life.

I have retail pricing on this tube at $850 a matched pair but don’t have the spec’s or data sheet. I reached out to Eunice and Marek to get it. I ought to have the data sheets on Monday. They are usually super responsive.

An interesting amp to try with your speakers might be the Art Audio PX25.  It is 5w amp and obviously uses the PX25 tube.  The PX25 is between a 300B and 2A3 in terms of sound profile where it has a midrange that is lush but not as lush as a 300B and it offers more detail than a 300B but not quite what you would get from a 2A3.  It sounds closer to a 300B than a 2A3.  Pricing depends on a few variable but it is an interesting amp.  

I think Art Audio may have been mentioned to you by a mutual friend. PM Me if you want more info on the tube or amps.

I have 4x EML mesh plate bottle 45 tubes running in my triode labs parallel integrated.  Best sound I’ve heard.  Yes the EML’s are pretty expensive.  Nothing comes close to this amp in accurate musical reproduction.  
Omega super alnico monitors running very high efficiency helps create the immediacy.  A small sub was a perfect addition.  
Not sure if the mesh plate Sophia ´s would sound better.  I haven’t heard them.