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In Reply to: Sylvania 5751 3 mica gray plate (different varieties?) posted by posbwp55@msn.com on April 19, 2007 at 14:53:13:
I have several iterations as you call them. Yes there are some that have square getters like the black plate. This tube in every case I have is a lush sounding tube. In fact the bass should be dominant and richly toned. I have many different versions the Gold brand Double Micas. I have the steel pin triples, I have USAF JHS triples (early) I have the early gold brand triple mica etc. etc... You may not have the real Sylvania 5751.
Follow Ups:
Hi Mechans,Thanks for the response. I think they are real Sylvania 5751's. They are green label JHS Sylvania 5751W1 JAN (Joint Army Navy).
It is funny how initially when a tube provides something lacking (high end detail)in a different tube's pesentation, you think it sounds better. Then after a while the deficiencies are apparent.
Anyway, I am now going thru some of my favorite 12AX7's that I had long given up on since discovering the Sylvania 5751 blackplate triple mica square getter. So far the jury is still out. Give me a little more info on the Sylvania 5751's you have (grayplate) and their sonic characteristics. I understand now that the one Joe reviewed is probably the square getter triple mica grayplate you have described as lush. How is the detail on that tube? Particularly the high end detail? I am now auditioning the Raytheon 12AX7 blackplate square getter (very good tube). It is possibly just a bit strident (only shortcoming). Next up, Mazda 12AX7 silverplate 4 bar. These are all tubes I have not listened to in a while that are getting a listen after juggling my 12AU7 slot extensively. The E80CC is best here (Tungsram or pinched waist Philips/Holland). The 6922 pinched waist is top dog in that position (either the Holland or US version, Holland slightly better). That's enough to chew on for now. All relevant posts are welcomed. Bart
You have to understand that the Jan tubes came into prominence decades later and are supposedly a low cost version of the 5751. I still like them but it is not a fair to compare them to the older tubes.I am being truthful when I say the true triple mica 1950-very early 60s Sylvania grey are all full,lush and sweet sounding tubes. The negatives are that any 5751 may not sound their best or even function in certain circuits because they are by a lower gain tube. If you use them when the circuit may need a 12AX7 clearly it will not sound good. Thus if you are trying to use them as phase splitters or followers or in a gain position of a marginally powerful phono stage they don't work out, 12AX7 are more versatile. The other negative I can tell you about,in particular the older Sylvamia greys are that they are not the cleanest 5751 you can get and can get loose on you.
You ask about their treble. It is not a firecracker sparkling star but very musical and pleasant. The treble is more overwhelmed than absent and therefore a small step back compared to the mids and lower. The detail is there but a tad recessed, since you seem to want a sweeter sounding tube the grey plates are a good choice. They are less edgy than all but the older GEs. If you really want a hyperdetailed sounding tube definitley try the Raytheons and see if you can get a well preserved, strong TMBP RCA they are both very clean with excellent definition and range . The holy grail Sylvania triple Mica Black Plate with square getters, which is the only way they made them, has the clean sound and definition but IMHO they hose the competition by having the best tone and controlled low end extension in addition to the quiet musical sound that is elusive in tubes. BTW the I forgot to tell you the RCAs are frequently superb stagers.
If you want a less intense quieter tube type the 5751 is likely to please you. They seem like they give me the imaging of a great 12AU7 while not letting all that current shoot by.
Thanks for the posts Steve and Mechans. I ended up thinking the Sylvania 5751 TMBPSG were better than ALL 12AX7's (Mechans description of this tube matches what I hear). Then, I tried a little something. I took the Raytheon 12AX7 (ultra detailed with lots of high end energy) and put it in the input position of my CAT JL2. I followed it (buffer stage) with the Philips (Holland) E80CC
(very tubey sounding tube with severely rolled highs and a sluggish overall presentation). Talk about synergy! This is one case where two wrongs make perfection. I think the Sylvania 5751 TMBPSG in the
JL2 is some kind of mismatch in this circuit. It doesn't do anything wrong but the Raytheon 12AX7 just opens the soundstage (depth and incredible presence) unbelievably. I still use the Sylvania 5751 TMBPSG in the CAT Ult MK2 pre. The articulation of this tube outclasses all 12AX7's. I have so many different varieties of the 6DJ8, 12AX7 and 12AU7 families that finding this magic through the process of trying these in different positions would have literally taken a lifetime. It took understanding the strengths and weaknesses of the Raytheon 12AX7 and the Philips E80CC
presentations to surmise that they may compliment each other perfectly. CAT JL2/JL3 owners really need to hear this combo.
This may be just a hearing or preference difference thing, maybe not a technical tube issue. Try to lay your hands on some Raytheon and/or RCA TMBP 5751. They don't sound at all like the 12AX7, but perhaps you will take more of a fancy to them. These 3 are often thought of as the most musical buy guitar players. I will also add that the current production Sovtek 5751 is a honey of a tube for the price in my equipment.
nt
Hi Frihed89,I came full circle back to the Sylvania 5751 TMBPSG. It is still more coherent than any of my large assortment of 12AX7's. While some tubes may best it in one area, they fall short in all the others.
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