Preamp Deal of the Century

Yes changing the fuse did solve the problem .
Thanks for asking.
Abill

So last night I was listening to some music and noticed my left speaker was making a hissing / spitting sound during quiet passages. After checking all the tubes in my monoblocks, I realized that the culprit was the EH 6SN7 in my Chardonnay. I was wondering how the tube could have gone bad so quickly as I just received the Chardonnay in March of this year. I run the 6SN7 in high gain mode. Could the Bendix 6106 I'm using as a rectifier have cause the EH 6SN7 to fail prematurely? I ask because I read somewhere in this thread that the 6106 runs a bit higher than the 5AR4 / GZ34 recommended for the Supratek. Or could it just be a faulty tube? Thanks.

Hi all, Regarding the Bendix 6106 ,Mick told me about someone that bought a ''dud'' 6106 ,it blew fuses,the guy persisted in using it .Finally it wrecked his pre...I guess that would apply to any rectifier not just the Bendix.A good thing would buy a decent tube tester ,learn how to use it and check the tubes you buy,or send them off to someone that will do this for you.

Kgturner,
The Bendix is a 5Y3GT (directly heated)and does not have the "soft start aka delayed start up time" feature that the 5AR4 has upon turn on. What it does is it wil strip your other tubes(cathode-stripping)because there is no electron cloud formed yet in the tubes before high voltage were applied(prematurely). The 5AR4 on the otherhand is a indirectly heated rectifier. They have different circuit characteristics. That is why some circuit design using the 5Y3GT has a filament heater first before applying the high voltage(delay). Here is a table of the typical "turn On" delay time (meaning full voltage appllied for maximum current)of some tubes:

5R4 5sec
5U4 6sec/6sec
5931 9s/7s/10s
GZ34 31s/33s/32s
PY88 40s
PY500A 45s/40s

Also, the 5AR4 has a lower voltage drop than a 5Y3, around 40 volts less than a 5Y3 at say 100mA current. So, replacing the 5AR4 with a 5Y3GT results in under voltage of other circuit stages that would shift all of the preamps operating parameters.

For me, it is on plain view that changing the 5AR4 with the 5Y3GT will change the characteristics of the preamp and of course its sound. That is why I stop believing that the 5Y3GT (6106) is the best rectifier for the Supratek because I think it is doing something that is not "healthy" on the preamps circuit masking as an improvement of sound. This can be proven very easily by measuring the rectified voltage (output) of the preamp PSU between two tubes.

This is the same reason why one of my previous post I commented that "the Supratek preamp parameters were voice/adjusted/calibrated to the tubes listed on the manual".

Again, all are my point of view/opinion. So take it with a grain of salt!

cheers

I thought the 6106 was indirectly heated. I remember someone telling me that I needed to wait at least a minute after turning the pre on to play music because the 6106 takes longer than most tubes to come up to full power.