I recently measured JJ EL84s in that application. Really nice but it was necessary to test a few samples to find the pick of the litter. Good ones show a beautifully monotonic decay of distortion harmonics falling quickly into noise, 'decent' samples fall quickly but retain a very long trail of low-level higher harmonic components. The good tubes sound terrific.
At the risk SY's cachet camp
one of the big suppliers recently had the 1940s RCA 9002 Navy-tested radar triodes on sale for little over $2 a pop and to my ear they sound fabulous as a CCS-loaded driver with a couple LEDs on the cathode. Measure terrifically in that app too.
At the risk SY's cachet camp
one of the big suppliers recently had the 1940s RCA 9002 Navy-tested radar triodes on sale for little over $2 a pop and to my ear they sound fabulous as a CCS-loaded driver with a couple LEDs on the cathode. Measure terrifically in that app too.
It's the 7-pin equivalent of the 955 acorn.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=80128&highlight=
That spectra as I recall was with a couple green LEDs for cathode bias so feedback reduced the third a little. Very quiet tube for hiss and in my application tapping it is audible as a low, well damped "tank" sound over 98 dB efficient speakers. I've read these tubes can be made significantly less susceptible with reduced filament voltage. Nice little unit.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=80128&highlight=
That spectra as I recall was with a couple green LEDs for cathode bias so feedback reduced the third a little. Very quiet tube for hiss and in my application tapping it is audible as a low, well damped "tank" sound over 98 dB efficient speakers. I've read these tubes can be made significantly less susceptible with reduced filament voltage. Nice little unit.
SY said:
I really love this forum.
I got some nos 5y3gt and 5v4 (mostly sylvannia) for my preamps and several 5u4gb, 5R4wgb for my tube amp.
I use 6SN7 mostly for my preamps, some are nos and some are russian new production...
http://www.filehigh.com/serve/13381/219458.jpg
Great info everyone,
I was thinking on trying a RCA 5y3 or a Bendix 6106 and for the el84's I'm not sure yet maybe JJ or some have said the new TAD el84's sound good. My input is a JJ ax7 and sounds pretty nice, I've only had my amp for 1.5 months now so this is all new to me. My amp came stock with a Sovtec 5y3, Sovtec el84's and a JJ ax7 and I love the sound but thought I'd see what some other good choices may be to try. Dave
I was thinking on trying a RCA 5y3 or a Bendix 6106 and for the el84's I'm not sure yet maybe JJ or some have said the new TAD el84's sound good. My input is a JJ ax7 and sounds pretty nice, I've only had my amp for 1.5 months now so this is all new to me. My amp came stock with a Sovtec 5y3, Sovtec el84's and a JJ ax7 and I love the sound but thought I'd see what some other good choices may be to try. Dave
I too like the JJ 'at7's over anything else that i have tried. I replaced a JAN phillips with one just for kicks one day, and the rest is history. i use their el84's as well, but i still prefer NOS RCA 7189-A...if that counts.
as far as 12ax7, I still like long plate Mullard or grey plate RCA, but as far as new manufacture, I am digging the JJ ecc803s lately.
i only have NOS 12au7, so I can't really comment on current manufacture, but I use them so rarely that i would have nothing to add anyway.
as far as 12ax7, I still like long plate Mullard or grey plate RCA, but as far as new manufacture, I am digging the JJ ecc803s lately.
i only have NOS 12au7, so I can't really comment on current manufacture, but I use them so rarely that i would have nothing to add anyway.
Nobody has so far mentioned the 6SL7. Personally, I prefer this tube to 12AX7/ECC83. It seems to do very well as a front end amplifier feeding a 6SN7 driver stage. I'm not aware of a subminiature (9-pin) high-mu double triode that can beat the 6SL7 for linearity; however, it isn't perfect.
6SL7 has high Miller capacitance, when used in the usual common cathode configuration. It needs to be fed from a low impedence, ideally 100k or less, to avoid roll-off of high audio frequencies.
6SL7 plate impedence and transcondunctace vary considerably with changing plate current. Used at the typical operating point with plate current less than 1 mA, its plate impedance is more like 60k than the 45k normally quoted in manufacturers' data sheets. For that reason, load resistance should usually be at least 180k, not forgetting that this will be shunted by the grid resistor of the next stage.
Oh, and if you want a particularly well-matched 6SL7, such as for a differential front end, you can use a 6SU7 (if you can find one).
6SL7 has high Miller capacitance, when used in the usual common cathode configuration. It needs to be fed from a low impedence, ideally 100k or less, to avoid roll-off of high audio frequencies.
6SL7 plate impedence and transcondunctace vary considerably with changing plate current. Used at the typical operating point with plate current less than 1 mA, its plate impedance is more like 60k than the 45k normally quoted in manufacturers' data sheets. For that reason, load resistance should usually be at least 180k, not forgetting that this will be shunted by the grid resistor of the next stage.
Oh, and if you want a particularly well-matched 6SL7, such as for a differential front end, you can use a 6SU7 (if you can find one).
If you want a pin compaitibe alternative to the 12AU7 then a much better sounding one is the E80CC. It's not exactly the same, and takes more heater current, so check your equipment, but when I've put it in instead of 12AU7 e.g. in a CJ preamp the sound was clearly better. If you want some fun, use a ECC40 with rimlock socket - you can get some ceramic sockets that drop into a 9 pin socket chassis hole, but most don't - I was lucky to pick up a couple on ebay. The usual sockets are slightly bigger and have brown bases. But the ECC40 - what sound!! Makes mincemeat of the 12A*7 tubes.
jlsem said:
Currently, they're in my Red Light District power amp as the input tube and phase splitter. And my old preamp used them, but it's been replaced after 25 years of faithful service. For some time, I did a Stereo 70 mod that used them in a cross-coupled arrangement, where they worked very, very well.
On test, the JJs gave about 6dB less THD and dramatically reduced higher order harmonics. Many of the older versions (and the RCA is particularly poor in this respect) have a higher 5th than 3rd, and very noticeable 7th. Not good for sonics. The trick to getting these tubes to sing is to use much less current than is usually done. 1.8-2mA is the sweet spot, with a plate load greater than 100k.
It's to bad JJ doesn't make a 5y3, I'm using the 12ax7 ecc803s JJ signal tube and it sound's great to me, the extra gain is wellcome as I'm using a cdplayer direct to amp. Well it's looking like a good bet would be to replace my el84 Sovtecs with JJel84, has anyone tried the TAD 84's? Any advice on what to try for a 5y3? Dave
That's right at where I run mine and I find they vary widely from brand to brand. I've tried just about everything and they run the gamut from run-from-the-room unlistenable (Mullard) to sweet and life-like (RCAs).
I haven't tried JJs, however - too expensive and hard to get compared to $1 military o'scope pulls.
John
I like the Electro Harmonics tubes in the EL84 and the 12au7. Very balanced and so far no problems. I have a Eico HF81 that uses these tubes and it sounds wonderful. Although you didn't mention it, my favorite in this amp in the first section is the 12aY7. The amp is very dynamic with this tube but I was told to change the plate resistor to use this tube regularly and so far no time to do that. The JJs are strong sounding too but not as detailed in the high frequencies as the EHs. Of course every amp is going to sound different but if I had to buy one kind only I'd go with the EHs.
Steve
Steve
Hi all,
I use in vast majority NOS tube or second hand tubes (I am very short on money & my first sources are trashes & friends)
Personnaly speaking I tend to favor circuity in terms of sonic differences ! but...
microphonics exists (especially in recent production)
I thinks 60's tubes were the best ever made, I like philips-dario-mazda-amperex-mullard-telefunken (often "cross-factories" made (look at internal factory codes))
There were also cheap brands azdam (haha) & others... wich were not that good.
Pre-1945 european tubes were often not homogeneous in the same production, and must be used with caution.
I have tested sometimes 80's to now russian tubes that were bad on inter-electrodes isolations (a whole bunch of 6V6GT)!
I tend to prefer industrial or milatry grade (althought it won't change anything on sound)
Now I prefer 12AT7/ECC81 to 12AX7/ECC83 because of quiescent current to finaly achieve near the same voltage gain (with different values).
Hope this help
PS: I rarely saw a bad 5Y3 aside a OOO side
I use in vast majority NOS tube or second hand tubes (I am very short on money & my first sources are trashes & friends)
Personnaly speaking I tend to favor circuity in terms of sonic differences ! but...
microphonics exists (especially in recent production)
I thinks 60's tubes were the best ever made, I like philips-dario-mazda-amperex-mullard-telefunken (often "cross-factories" made (look at internal factory codes))
There were also cheap brands azdam (haha) & others... wich were not that good.
Pre-1945 european tubes were often not homogeneous in the same production, and must be used with caution.
I have tested sometimes 80's to now russian tubes that were bad on inter-electrodes isolations (a whole bunch of 6V6GT)!
I tend to prefer industrial or milatry grade (althought it won't change anything on sound)
Now I prefer 12AT7/ECC81 to 12AX7/ECC83 because of quiescent current to finaly achieve near the same voltage gain (with different values).
Hope this help
PS: I rarely saw a bad 5Y3 aside a OOO side
DaveCan said:...My amp came stock with a Sovtec 5y3, Sovtec el84's and a JJ ax7 and I love the sound but thought I'd see what some other good choices may be to try. Dave
Dave,
I built an EL84 SE amp using Sovtec tubes. Everyone who has heard it liked the sound. The tubes seem to perform well and are very reasonable in cost.
I tried JJ current production EL84s in the amp but I could not hear a difference. I am not in possession of any NOS EL84s or of any other brands so that is the limit of my experience with them.
Oh and Antique Electronic Supply has Sovteks on sale at $6 US right now.
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