[OctavianH]

Nothing newer on the Eastern Front. Just some light pr0n. Quite some lightning here today with these 6C5G clear glass (and some photo effects, of course).

And these Cossor 6C5G are quite nice, beautiful tubes:

 

[UntilThen]

Some more stuff today. Time for 6SL7GT, Brimar CV1985, a very neutral, clean and nice sounding tube.

Ah the 6SL7.... a tube I'm keenly interested in. I have 3 different types now. My supplier can get me another Brimar 6SL7 in red letters at the base which according to him is very nice. Also an Amperex 6SL7 which he say is the king of 6SL7 ...

Further tempt me with Philips Miniwatt double D getters brown base and metal base EL34. These are not going to be cheap. I'll have to defer buying these.

You have some very nice drivers there in the Cossor 6C5G. Congrats.

 

[UntilThen]

These Tung Sol 6550 arrived yesterday and they have incredible mid and bass. I can see how these differ from their British cousins GEC KT88.

My pair are grey plates with single O getter on top and 2 O getters on the sides. There are rarer TS 6550 in black plates with D and O getters. The earliest version from 1950 is the black plates with just a single O getter on top and these fetch a very high price now.

Don't stare too hard at my reflection in the tube because you will see Clarke Gable.

 

[OctavianH]

Don't stare too hard at my reflection in the tube because you will see Clarke Gable.

Nice hat!

 

[hpamdr]

Yes, 2.5mA is completely fine. Especially for the 6SL7

A variation of 6SL7 with same amplification (70) factor is the 6SC7 witch should bias a bit better in eternity...
If you want High amplification factor you can also use the triode part of 6AV6 / EBC91 but you will need an adapter to 6j5 (this is the input tube of standard Eternity)

 

[OctavianH]

A variation of 6SL7 with same amplification (70) factor is the 6SC7 witch should bias a bit better in eternity...
If you want High amplification factor you can also use the triode part of 6AV6 / EBC91 but you will need an adapter to 6j5 (this is the input tube of standard Eternity)

I do not see a real advantage for 6SL7 on 6SN7 or a pair of 6J5/6C5 soundwise. And since I keep my volume at half with Verite and at 60% with T1.2 I doubt high gain can provide me other advantage. I was curious, but I will not go further on the path of 6SL7. I will let others discover it. I wanted only to try one, I've tried it and now I'll stick to my path trying to explore more from 6J5 with my main outputs KT66/77/88.

By the way, I was quite disappointed by Langrex. I asked them to measure and provide some matched pairs since they had many items in stock, which they verbally agreed, but they have done nothing. I was quite lucky to have 4 pieces of what I ordered and matched them decently by myself, but I was expecting more from those guys. Judging by the fact that I have to pay 20% more for what I order from UK I'll buy from now on only previously tested tubes with good readings.

 

[OctavianH]

Regarding these Cossor 6C5G misterious tubes:

Thinking about a date code or manufacturer, I see an "N II" or "N 11" and another N near the logo.

 

[SonicTrance]

If you want High amplification factor you can also use the triode part of 6AV6 / EBC91 but you will need an adapter to 6j5 (this is the input tube of standard Eternity)

The 6AV6 is indeed the stock tube but yours and Octavians amps have been redesigned to use different tubes. So the 6AV6 can't be used as it's max plate dissipation is only 0.5W. You can however use the 12AX7 as that's a 1W tube and still mµ of 100. I'd run the 12AX7 at 2.5-3mA in Eternity.

 

[OctavianH]

The 6AV6 is indeed the stock tube but yours and Octavians amps have been redesigned to use different tubes. So the 6AV6 can't be used as it's max plate dissipation is only 0.5W. You can however use the 12AX7 as that's a 1W tube and still mµ of 100. I'd run the 12AX7 at 2.5-3mA in Eternity.

By the way Tomas, since you advise to use different tubes at different operating points in the same circuitry, it is not clear to me if the 3-5mA range is advised to have the tube in the "more linear" zone or if the circuit itself does not work at less that 3mA. For example, 6SL7 seems to work fine at 2.5-3mA and it seems 12AX7 is in the same situation.

 

[OctavianH]

A normal Saturday evening with Eternity. KT66 + L63. This evening on fixed bias because we relax.

 

[SonicTrance]

By the way Tomas, since you advise to use different tubes at different operating points in the same circuitry, it is not clear to me if the 3-5mA range is advised to have the tube in the "more linear" zone or if the circuit itself does not work at less that 3mA. For example, 6SL7 seems to work fine at 2.5-3mA and it seems 12AX7 is in the same situation.

The circuit works optimally at 4 and 20mA respectfully for input and output stages. That's where the current ranges comes from. The gyrators are most "happy" at 4 and 20mA. They do however still work at say 2.5mA and 25mA, just not optimally. Now, if you can hear that difference is another matter. Most likely not.

Regarding the 6SL7 and 12AX7 they need to run at slightly lower current as they're weaker tubes with a max anode dissipation of 1W. So, to not put too much stress on those tubes I recommend the lower current.

 

[OctavianH]

This evening is dedicated to Draconian. This swedish band is incredible, the last album made me listen on repeat several weeks on Elise and it seems it does the same on Eternity. This is not for everyone, but it is top class.



Eternity glows and sounds incredible.

 

[SonicTrance]

This evening is dedicated to Draconian. This swedish band is incredible, the last album made me listen on repeat several weeks on Elise and it seems it does the same on Eternity. This is not for everyone, but it is top class.

I usually don't listen to this kind of metal music but really liked this song actually. Another Swedish rock band I listen to sometimes is Sabaton!

 

[hpamdr]

I usually don't listen to this kind of metal music but really liked this song actually. Another Swedish rock band I listen to sometimes is Sabaton!

I prefer this swedish citizen

 

[OctavianH]

I usually don't listen to this kind of metal music but really liked this song actually. Another Swedish rock band I listen to sometimes is Sabaton!

Sabaton are ok, except those socialist symbols they always like to put on their covers. I do not listen to them but I've seen them live a few times and they do a nice show.

Edit: The Vintage Caravan are incredible. What they are doing with those guitars is some killer stuff. This is a song for KT66.