Hey beans: I can't seem to find any info anywhere else on the current draw for those particular 6SL7's (pic shown in post #94). According to a guy who sells NOS tubes at a well-known website, the spec for all 6SL7's is around 0.3A.
Where did you find out that the current draw for those particular tubes are 0.6A?
You can download the RCA datasheet here. The 5691 is not quite a true spec 6SL7.
Yeah RCA goes up to 20 man!:
The legendary OP-6 all pentode portable amplifier.(Ribbon Mic Pre AMP)
Tubes are 3 RCA 1620/6j7 JAN Steel envelope, grid cap octal + GZ34
Rectifier. http://www.r-type.org/exhib/aaa1072.htm
Depending upon what the tube is to do for us, often more mu (amplification factor) is not what we want. Especially, early in an audio chain, to our ears, several tubes in series, each adding low mu, sound a whole lot more musical than a lesser number of tubes with high gain.
Mathematically, I understand that the above makes no sense.
Some of the very sturdy tubes, those with massive internal bracing and double mica separators (easily visible) also sound "sturdy" and less fun than some of the lighter built tubes. I am ignorant as to why this is true. I've seen no difference in the longevity of "light" tubes when the gear is designed for them.
Some of the very sturdy tubes, those with massive internal bracing and double mica separators (easily visible) also sound "sturdy" and less fun than some of the lighter built tubes. I am ignorant as to why this is true. I've seen no difference in the longevity of "light" tubes when the gear is designed for them.
Hmmm......as Arte Johnson used to say on R&M's Laugh-In, "Verrrry interesting!"
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"Too much of a good thing.......can be wonderful!" - Mae West
FWIW, I dig the 5691's. Just got another pair of NOS. They're so cute and sturdy looking.
More NOS I picked up over the last couple of weeks. A couple more 5691's as well as some different RCA's (clear and gray glass) which also sound great.
The first 5691 I got is lovely and I've kept it in the first position of my preamp. The NOS Tung Sol next to it was bad (heater to cathode leakage) but TC refunded my $.
The two reissue Tung Sol's were nice and quiet but seem to lack a bit of gain/heft compared to all the NOS stuff. Not bad though and bumping up the gain a notch seems to compensate.
Hey beans: I can't seem to find any info anywhere else on the current draw for those particular 6SL7's (pic shown in post #94). According to a guy who sells NOS tubes at a well-known website, the spec for all 6SL7's is around 0.3A.
Where did you find out that the current draw for those particular tubes are 0.6A?
Further to what Charlie posted, here is some more info on vintage RCA premium tubes. If there is room in your amp, you could install a separate heater transformer with the current capacity to handle the 5691.
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Last edited by beans-on-toast : 11-16-2012 at 08:50 PM.
Does anyone here on TB happen to know the current draw for the Tung-Sol 6SU7GTY which is supposedly a rarer industrial version of the 6SL7? Is it 0.3A?
EDIT: never mind. I found a site that says the 6SU7GTY draws 0.3A.
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"Too much of a good thing.......can be wonderful!" - Mae West
Last edited by SactoBass : 11-19-2012 at 09:57 PM.
Bumping this thread because I just had work done on my B-15N and got it back with a couple new Sovtek 6SL7GT's and the Sylvania 6SL7 I got last year. And unlike most of you bogarts, I made recordings of them being swapped out in V1 Also recorded the REDDI just because it's a constant that I'm used to for comparing to the B-15, and it has a Sovtek 6N1P inside:
Bass was an 09 AmStd Precision with 62 Original and D'addario XL's almost new (black/black/maple, the most manly of Precision colors). When I used the B-15, it was speaker DI'd into my Fast Track C400 with a Countryman Type 85. I used channel 1 normal input, both tone knobs at noon. The REDDI, of course, went right to the Fast Track. Nothing else was done to the tracks, though Soundcloud normalized them. And yes, I used a dummy load...you kids out there, NEVER use a tube amp without a speaker or dummy load! The DI does not take the place of a speaker load.
The normalization doesn't let me demonstrate the lower gain level with the Sovtek...it's not much but it's noticeable. But it did level the field for comparison purposes. And I have to say that for me the Sovtek pulled off an upset. Through the B-15 cab, the Sylvania sounded way bigger and badder. Turns out it was a trick of the volume. I don't think the Sovtek sounds any less big or bad, just brighter. It's not quite as bright as the REDDI IMHO, but that might be blamed on the Countryman's own rolloff past 10k. To me the Sovtek in the B-15 brings it more in line with the REDDI as opposed to the darker Sylvania.
Never thought in a million years the Sovtek would be the one I prefer, but I think I prefer it. I can always turn up the volume if I need more, but adding treble that's not there is a tougher trick. Always interested in second opinions, though. And I reserve the right to change my mind tomorrow after some sleep
Charlie, accidentally made the REDDI and B-15 Sovtek tracks the same track, but I fixed it now. Probably won't make a difference in your opinion, though.
Charlie, accidentally made the REDDI and B-15 Sovtek tracks the same track, but I fixed it now. Probably won't make a difference in your opinion, though.
I thought the other two sounded pretty danged close...
This kind of comparison is always a bit tough for me to interpolate to my fretless-only, active-only (yadda yadda) world. As usual, all your clips sound really good though Jimmy.
Thanks mang! I think it's time I change my riffs for stuff like this, though I totally get why you would like the Sylvania. That pre you made with the EUB there sounds amazing (the fingers work great, too), and the Sylvania sounds way more up your alley. I tend to go for darker sounds as well but it's nice to know I can slice heads off if I need to,
Thx Foz! Is it because of the excess brightness you guys prefer the Sylvania or is it something else you're hearing that I'm not?
Just seems the most pleasingly balanced of the three to me, but it could be that my Sony cans (MDR-V6) don't play as nicely with the brighter clips -- they are "revealing" to a fault. Your clip still made me want to try a Sovtek in my new build though, for sure.
Thanks for the clips Jimmy, it's always fun!
I'd say the Sovtek has a fatter bottom that makes for a more immediately pleasant sound, and more p-bassy too.
The Sylvania is more balanced, and more precise and detailed in the mids and highs, but sounds a little weak and harsh compared side to side with the Sovtek. Maybe you could dial the same sound you get with the Sovtek, with the Sylvania, but with a more precise sound all around.
The Sovtek seems to me "pre EQed" and ear friendly, but to the cost of some mud hidden behind the low mid bump.
The Reddi track is great sounding, maybe what you could get with the Sylvania if you boosted the lows. Weight, character, clarity and precision.
My 2 cents
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The Sovtek B15 sounds clearly the best to me. The REDDI sounds a bit thin on the higher strings and the Sylvania seems to lack some lows that are present with the Sovtek.
I've been using reissue Tung Sols in my prototype DIY preamp and now I am GASsing for some other tubes! The reissues sound good and I have been "voicing" the amp with them, getting nice results, but I love what I hear from some of these other tubes. Want me some o' dat!
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My fEARful build:talkbass.com/wiki/index.php/Oobly
So far, I've tried red base 5691, clear glass, and smoked glass RCA's - they all sound very similar though I may slightly prefer the 5691's. Also tried the new Tung Sol's which were OK, but a little bland - they seem to have a bit less gain than my NOS stuff.
Oh hell no... that **** is downtown - I have never owned a unit I was less inclined to tube roll ['cept for the Avalon 737 = doesn't really count cause its all about optical grade clarity - toobey mojo aint part of the thrill]. My personal preamp builder hand selected those tubes from a stack of thousands of post-war production units built by the greatest generation - so don't you be looking at em - or thinking about em - or ever putting your grubby mitts near em - or calling me Francis - or I'll kill ya.
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Jimmeh!
The low EQ differences are trivial to me - I could bridge the difference with finger technique or the most gentle tweak of a tone knob [and so could any other hack I reckon]. In stark terms I think I prefer the way the toob compression decays with the Sylvanias - listen at 40 sec. in your high end turn around- the Sylvania blooms up all toobey [as they all do] but clamps the note decay with a sweet clean end... the articulate toob compression of the Sylvania makes grace notes and soft runs stand out more - those subtle touches you add come out more refined and elegant by standing a bit apart from the toob bloom of the following notes. My $0.02
Also recorded the REDDI just because it's a constant that I'm used to for comparing to the B-15, and it has a Sovtek 6N1P inside:
