[Zachik]

Remember the plate voltage for the 6SL7 should be lower than 200V which is not the case with 6SN7

Typical operation for 6SL7 is 250V according to datasheet. Max rating is 300V.

So... what's the practical implication? Do I need to change anything or add a note in my table?

 

[Zachik]

Hi rosgr63,
This is what the Radiomuseum says about the 7F7:
7F7 = VT-189 = CV893
Similar Tubes
Heater different:
14F7
Other base:
6SL7GT

And this is what it says about the 7AF7:
7AF7
Similar Tubes
Heater different:
14AF7
Predecessor Tubes 6AH7GT
Successor Tubes 12AU7

I have added VT-189 and CV893 to the table, along with more info at the note field.
Should I add 7AF7 as well? Is it GOTL approved?
If so - what is the difference between the 7F7 and 7AF7?

 

[Zachik]

Glenn made a point earlier in this thread about the 7AF7/14AF7 tubes. They do turn microphonic or become noisy. Out of all three that I have, they started off fine and then static or a very significant background noise kicked developed. 7N7s are good tubes though.

Interesting - I will add these to the table with appropriate note / warning...
Do 7AF7/14AF7 tubes use same adapter as 7N7 / 7F7 ?
is the difference higher gain? something else? (compared to 7F7 / 14F7 respectively)

 

[UntilThen]

Are these a replacement (i.e. no adapter) for 6SN7 ?
What is the difference (so I can add a note)? Different gain?

The Tung Sol 6SU7gty is a premier 6SL7.

The 6SL7 is a high gain low current tube whilst the 6SN7 is a lower gain and high current tube. 6SN7 has an amplification factor of 20 while the 6SL7 is 70.

 

[2359glenn]

My top ten drivers in no order of merit:-

ECC35
ECC33
ECC31
Sylvania 6sn7w metal base
Tung Sol 12SL7GT bgrp
RCA 5691
GEC B36
c3g
EL11
EL3N

I just loaded the 12SL7GT without changing the voltage to 12.6.

2 mins later I realise that and change it. This is waking up at 7:30am.

You brought all those tubes with you?

 

[UntilThen]

You brought all those tubes with you?

Except EL11 and EL3N.

All these tubes fit in a shoe box.

 

[2359glenn]

Except EL11 and EL3N.

All these tubes fit in a shoe box.

Cool you went for the long hall .

 

[stevenhertzberg]

Hi I was wondering about how long is the current wait for one of your amps

 

[2359glenn]

Hi I was wondering about how long is the current wait for one of your amps

End of the summer early fall

 

[Zachik]

12AU7 / 12AT7 / 12AX7 questions:
1. Currently, my table list both 12AU7 and 12AT7 (rows 26-27). Each has its own adapter (12AU7 -> 6SN7, and 12AT7 -> 6SN7). Are these adapters different? Isn't the only difference between those 2 tube types is amplification (gain) factor (60 for 12AT7 vs. 17 for 12AU7)?
2. What about 12AX7 (gain factor of 100)? Will it work? will gain factor of 100 cause it to be too noisy?? single adapter for all 3 tube types?

 

[gibosi]

The same adapter will work for all three 12A-7 tubes.

However, keep in mind that there are 12 volt adapters as well. That is, 12A-7 to 12SN7. And if you use one of these, it is necessary to set the GOTL to use 12 volt tubes.

 

[mordy]

At this stage I feel that I have a very good platform for the power tubes. Bass heft and punch from a pair of Raytheon (Bendix) 6080WB, mid bass warmth from a pair of RCA 6080.
Drivers are a pair of EL8 - can't put my finger on what they contribute to the sound, but they do. The net effect is a powerful bass and a crystalline quality to the sound with excellent instrument separation and clarity - you can hear very clearly what is going on in a recording and can concentrate on each instrument, even those in the background.
And then a single front driver in the 6SN7 slot; this driver changes the sound in a significant way. Every driver imparts its own sound signature to the total sound presentation.
Maybe this is the closest I have found in blending a musical with an analytic presentation.
Still experimenting with different single drivers. Here is a very nice combination:
The single driver is a Frankie 7N7:

Beautiful sound.....I wonder how close the Frankie sounds compared to a metal base Sylvania 6SN7W (which I don't have)....

 

[mordy]

12AU7 / 12AT7 / 12AX7 questions:
1. Currently, my table list both 12AU7 and 12AT7 (rows 26-27). Each has its own adapter (12AU7 -> 6SN7, and 12AT7 -> 6SN7). Are these adapters different? Isn't the only difference between those 2 tube types is amplification (gain) factor (60 for 12AT7 vs. 17 for 12AU7)?
2. What about 12AX7 (gain factor of 100)? Will it work? will gain factor of 100 cause it to be too noisy?? single adapter for all 3 tube types?

I think Glenn stated that the 12AX7 isn't suited for the GOTL - too much gain.

 

[mordy]

12AU7 / 12AT7 / 12AX7 questions:
1. Currently, my table list both 12AU7 and 12AT7 (rows 26-27). Each has its own adapter (12AU7 -> 6SN7, and 12AT7 -> 6SN7). Are these adapters different? Isn't the only difference between those 2 tube types is amplification (gain) factor (60 for 12AT7 vs. 17 for 12AU7)?
2. What about 12AX7 (gain factor of 100)? Will it work? will gain factor of 100 cause it to be too noisy?? single adapter for all 3 tube types?

Hi Zachik,
Here are more additions to your list:
You can add to the line 27: 12AZ7 and 12BH7
Line 29: 6F8G is the same as VT-99; 6C8G = VT-163
Line 31: L63/6J5 is also called CV1932
12V tubes add 12SX7 (no adapter needed)

 

[gibosi]

Decided to dig a little deeper into my cache of 4-volt rectifiers. Currently listening to a British Mazda UU8 with a Mullard ECC33 and clear-top 5998s. Using this rectifier might be something like marrying an ECC804 with an ECC33. Quite nice.

I think the blue highlights are from the GOTL power button....