Which brand of 45 tubes do you use?

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.