Hi, tube folks!
Based on your experience, how would you rate Shuguang 6L6GCR and 6550, in terms of sonic performance, reliability, and life time? Are they really comparable to EH, SED, WingedC or Russian NOS like 6P3S-E?
If possible, please mention your audio setup settings.
Many thanks in advance
and of course
Marry Christmas and happy New Year !
Based on your experience, how would you rate Shuguang 6L6GCR and 6550, in terms of sonic performance, reliability, and life time? Are they really comparable to EH, SED, WingedC or Russian NOS like 6P3S-E?
If possible, please mention your audio setup settings.
Many thanks in advance
and of course
Marry Christmas and happy New Year !
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The 6L6GCR's sounds pretty alright to me,but I haven't listened to many 6L6's yet. I do know that they are fairly tough,and can take higher voltages well,IME.I've run them at 600+V in UL mode.
I've only used them in a guitar amp, but the Shuguang 6L6GC perform well and are as tough as nails!
Jim
Jim
I've run the 6L6's at 450V 50mA on the plates and screens in UL for about 10 hours and they were totally fine.
I bought 2 MQ 6L6GCR, but in one quartet was one tube gassy. :-(
I've run them at 470V 30mA on the plates in Mesa Boogie Fifty-Fifty, about 200 hours yet, and no problem. Ask later....
I've run them at 470V 30mA on the plates in Mesa Boogie Fifty-Fifty, about 200 hours yet, and no problem. Ask later....
LinuksGuru,
Just be careful; I hope you realise that these tubes are quite different, and not intended for simply 'rolling!'
Firstly the 6550 draws almost double the heater current of a 6L6 (1,6A vs. 0,9A), and a power transformer will certainly not like going from 6L6 to 6550, especially in p.p. Secondly the bias needs to be quite higher for 6L6, and thirdly the transconductance of a 6550 is double that of a 6L6. In my opinion they should not only sound slightly different (I have not much experience of the 6550), but the 6L6GC max. ratings will be quite exceeded when plugging straight into a 6550 socket. V.v, the 6550 would not perform optimally - all this depending on the circuit.
Just be careful; I hope you realise that these tubes are quite different, and not intended for simply 'rolling!'
Firstly the 6550 draws almost double the heater current of a 6L6 (1,6A vs. 0,9A), and a power transformer will certainly not like going from 6L6 to 6550, especially in p.p. Secondly the bias needs to be quite higher for 6L6, and thirdly the transconductance of a 6550 is double that of a 6L6. In my opinion they should not only sound slightly different (I have not much experience of the 6550), but the 6L6GC max. ratings will be quite exceeded when plugging straight into a 6550 socket. V.v, the 6550 would not perform optimally - all this depending on the circuit.
Thanks for warning, Johan. My custom R-core power transformer has 6.3V winding rated at 15A. As for output transformer, it will be also built-to-order 60W or so with 5K primary impedance. The original schematic uses 6L6GC at 485V, I would like to try to push it with 6550 (or KT88 may be) at 580V B+ voltage.
Off topic - regarding high current transformer windings: Best to wind that with several thinner gauges wire - either bifilar or separate parallelled windings. Better 'space factor' that way than winding with a 'hauser'.
I did not made this transformer myself - I ordered it from factory. One small R-core (160VA) for Pioneer SM-83 (original 22V power transformer developed a short), and another big for 6L6GC push-pull project (weights over 5 kg). From what I can see, 15A winding is made with so thick wire so I have no idea have they wind it on bobbin. Originally I have ordered 3 x 6.3V/5A instead of 1 x 6.3V/15A, but engineer from the factory reported they cannot make so much secondary windings. As the result, I've got this R-core unit:
Primary 220V 50Hz
Secondaries, output voltage (loaded)
1 – 206v 500mA
2 – 206v 500mA
3 – 50V 100mA
4 – 6.3V 15A
5 – 2.5V 15A
BTW, when running unloaded (I have not installed it yet), this transformer (unlike another small 160VA R-core) is quite noisy. I suspect this noise comes from vibrating thick wires which cannot be wired in the tight layers as thin ones.
Primary 220V 50Hz
Secondaries, output voltage (loaded)
1 – 206v 500mA
2 – 206v 500mA
3 – 50V 100mA
4 – 6.3V 15A
5 – 2.5V 15A
BTW, when running unloaded (I have not installed it yet), this transformer (unlike another small 160VA R-core) is quite noisy. I suspect this noise comes from vibrating thick wires which cannot be wired in the tight layers as thin ones.
Again off-topic, but as the author supports (and since it is Christmas time: That's what is nice about this forum - one learns almost more off-topic than on ...!)
'They could not make so many secondaries??' 😕
That second one is rather a brute (550VA). In my (almost identical) case I specified 6,3V 4A twice, 6,3V 3A (and 680V 800mA!).
But LinuksGuru,
When running unloaded there is no current through (secondary) windings, thus no force generated by them and no vibration can be caused by them. That I fear is only because of poor core assembly and no proper varnish/whatever impregnation afterwards. Man, can that be a problem! If unvarnished, do your own thing: Probe, push in slivers between core and bobbin, whatever. I had such problems. My heart bleeds for you. (Over here one can return a local over-noisy new transformer to some manufacturers for betterment/recoring.)
'They could not make so many secondaries??' 😕
That second one is rather a brute (550VA). In my (almost identical) case I specified 6,3V 4A twice, 6,3V 3A (and 680V 800mA!).
But LinuksGuru,
When running unloaded there is no current through (secondary) windings, thus no force generated by them and no vibration can be caused by them. That I fear is only because of poor core assembly and no proper varnish/whatever impregnation afterwards. Man, can that be a problem! If unvarnished, do your own thing: Probe, push in slivers between core and bobbin, whatever. I had such problems. My heart bleeds for you. (Over here one can return a local over-noisy new transformer to some manufacturers for betterment/recoring.)
Hi, Johan,
Thanks for help and suggestions!
Its vacuum varnished/impregnated, and built like a tank. In fact, its less noisy, then other conventional 800VA EI-core I have, but still not as silent as another 160VA R-core. I like transformers which can be heard ONLY if one put ears just few centimeters next to them, otherwise, I consider them noisy.
R-core has 2 relatively small bobbins, which is why they can be very problematic to have many high-voltage windings. I think to reduce noise the best choice would be epoxy potted toroid. Toroids are usually emit more noise then R-core, but potting would eliminate it almost completely.
Looks like it was my mistake to order R-core with 5 secondary windings, 2 of which are high-voltage. I realized it only when engineer from the factory reported me that they cannot build R-core with 8 secondary windings, and asked to reduce them as much as I can.
Thanks for help and suggestions!
Its vacuum varnished/impregnated, and built like a tank. In fact, its less noisy, then other conventional 800VA EI-core I have, but still not as silent as another 160VA R-core. I like transformers which can be heard ONLY if one put ears just few centimeters next to them, otherwise, I consider them noisy.
R-core has 2 relatively small bobbins, which is why they can be very problematic to have many high-voltage windings. I think to reduce noise the best choice would be epoxy potted toroid. Toroids are usually emit more noise then R-core, but potting would eliminate it almost completely.
Looks like it was my mistake to order R-core with 5 secondary windings, 2 of which are high-voltage. I realized it only when engineer from the factory reported me that they cannot build R-core with 8 secondary windings, and asked to reduce them as much as I can.
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