[lukeap69]

Glenn 
 
What is the advantage of using four-6AS7's compared to two-6AS7's? More current? In my listening session comparing quad vs two Chatham 6AS7's on my OTL amp, the quad provides more impact/slam on my PM-2. I have never really liked any power tubes combo on my Darna using my PM-2 except this one (quad 6AS7) which is very enjoyable IMO. 

 

[2359glenn]

  Glenn 
 
What is the advantage of using four-6AS7's compared to two-6AS7's? More current? In my listening session comparing quad vs two Chatham 6AS7's on my OTL amp, the quad provides more impact/slam on my PM-2. I have never really liked any power tubes combo on my Darna using my PM-2 except this one (quad 6AS7) which is very enjoyable IMO. 

Four 6AS7s instead of two lowers the impedance supply's more current to the phones.
You can also try two 6336B tubes to do the same thing.

 

[2359glenn]

 

 
Yes I will be starting the EL3N amp have the transformers now.
Not sure when I will be finished maybe after I come back from Greece.
Probably will be finished before I leave so I would say a couple of weeks.

 
Enjoy your trip Glenn, and give our best regards to Stavros.  He doesn't come here anymore, but we still think about him.
 
If you want me to ear test this EL3N I'm ready and waiting.    We'll see if it's reputation for sounding like a 45 is exaggeration or not.

Tyrell I will tell Stavros you said Hi
 
The amp will be after I come back from Greece I want to play with it for a little while before I ship it to you.

 

[Xcalibur255]

Well the bad luck train came around to my stop again.
 
While in the middle of a listening session just now I heard a brief little "buzzzzz" then the music cut out.  I looked over at the amp and saw both current meters had dropped to zero and the plates on both rectifiers were glowing bright cherry red.  It wasn't a loud pop or anything, just a brief electrical buzz then nothing.  It was on and working normally for about 2 hours at this point.
 
I'm not going to try turning back on or doing anything with it tonight.  I'll check tomorrow after work and see if the fuse is blown.
 
Any thoughts on what could be going on Glenn?  Thanks.

 

[lukeap69]

Is your amp 300b like Tony's? It seems the problems reported lately are related to 300b amps only. Coincidence?

 

[TonyNewman]

Is your amp 300b like Tony's? It seems the problems reported lately are related to 300b amps only. Coincidence?

 
My issues were a mix of bad tubes and damage in transit, as best I can tell. The amp itself, after the repair, has been rock solid. Even the failed PY500 that took out my house circuit breaker and blew my DAC USB feed did not affect the amp.

 

[lukeap69]

My issues were a mix of bad tubes and damage in transit, as best I can tell. The amp itself, after the repair, has been rock solid. Even the failed PY500 that took out my house circuit breaker and blew my DAC USB feed did not affect the amp.

Nice to know Tony. Cheers.

 

[TonyNewman]

Nice to know Tony. Cheers.

 
No drama. I don't want folks to think that the 300B amp is fragile. Mine has had a blown a 300B and a PY500 since the repair. Only damage to the amp has been a blown fuse (a good thing).
 
If only my DAC had been as robust

 
I do recommend swapping out the fuses, as per an earlier discussion, to provide some extra protection for the amp.

 

[2359glenn]

  Well the bad luck train came around to my stop again.
 
While in the middle of a listening session just now I heard a brief little "buzzzzz" then the music cut out.  I looked over at the amp and saw both current meters had dropped to zero and the plates on both rectifiers were glowing bright cherry red.  It wasn't a loud pop or anything, just a brief electrical buzz then nothing.  It was on and working normally for about 2 hours at this point.
 
I'm not going to try turning back on or doing anything with it tonight.  I'll check tomorrow after work and see if the fuse is blown.
 
Any thoughts on what could be going on Glenn?  Thanks.

First I would change the rectifiers then see what happens.
It was not a output tube if the meters were on 0.
Could be also be a shorted filter capacitor but I doubt it use hi quality caps.
Most likely bad rectifier I will make you those SS rectifiers as soon as the tube bases get here.

 

[Xcalibur255]

 
First I would change the rectifiers then see what happens.
It was not a output tube if the meters were on 0.
Could be also be a shorted filter capacitor but I doubt it use hi quality caps.
Most likely bad rectifier I will make you those SS rectifiers as soon as the tube bases get here.

 
Okay, I'll put a different set of rectifiers in and assume these are bad.  Why would both of them get red hot at the same time though?  Something to do with how a full wave bridge works? 
 
The power transformer felt a lot warmer than usual too when I put my hand to it.
 
I checked the fuse and it was not blown if that info helps.

 

[gibosi]

I hope this will be an interesting respite from the problems some folks are having....
 
Received a pair of Telefunken C3g today and I am quite sure that these were actually manufactured by Telefunken. Upon close inspection, they do not look like rebranded Siemens to my eyes. What initially caught my eye was the Telefunken date code, "wr" (September, 1966).
 
Telefunken tubes link
 
I feel quite certain that as a general rule Telefunken did not put their date code on tubes procured elsewhere and relabeled. So my advice is look for this date code. If there is no date code, they are not most likely not genuine Telefunken.
 

 

 
So in terms of construction differences, how do they compare to the Siemens? First, while the cans are not flat-black and embossed like 1960's Siemens and Lorenz, they are not as shiny as the 1970's Siemens.
 
Compared to 1970's Siemens

 
Compared to 1960's Siemens

 
Since these tubes are enclosed in metal cans, the best and only place we can look for construction differences is the base. Note especially the area surrounding the base of the guide pin. The 1970's Siemens have a prominent escutcheon at the base, while the 1960's Siemens have no escutcheon. That area is almost perfectly flat with only a faint circle surrounding the guide pin. On the other hand, the 1960's Telefunkens have what looks like rays emanating out from the base of the guide pin.
 
Further, upon close inspection, there are also noticeable differences at the outer edges of the base where the metal cans are attached to the base.
 
1970's Siemens with prominent escutcheon

 
1960's Siemens with only a faint circle surrounding the guide pin

 
1960's Telefunken with emanating rays

 
Hope this is interesting and useful to those who roll C3g.
 
Cheers

 

[lukeap69]

How does the telefunken C3g sound vs the Siemens?

 

[gibosi]

  How does the telefunken C3g sound vs the Siemens?

 
I have only about an hour on them, just enough to verify that they are not defective. And further, they need to be thoroughly burned in before coming to any conclusions regarding their sound. So after they have settled in and I have some time, I will try to compare them. Until then...

 

[lukeap69]

   
I have only about an hour on them, just enough to verify that they are not defective. And further, they need to be thoroughly burned in before coming to any conclusions regarding their sound. So after they have settled in and I have some time, I will try to compare them. Until then...

 

 

[Khragon]

Please let us know.  I got Lorenz and Siemens, but stayed away from Telefunken because they are supposedly the same.