The Reference 6SN7 Thread

[Renexx]

I haven't gotten them, but I am thinking right now the possibilities seem to be a different tube than labelled, or wrongly tested

Being a fake ecc802s is one thing, but not being a 12au7 compatible tube is even more scarier

Tester might be not calibrated or has faulty electrical parts or wrong testing method.

The Siemens labeled ecc802s might be a cherry picked Siemens with closely balanced sections. But it's not a ecc802s build quality tube.

 

[dimapro]

Hi All!

If you're also bored by slight ugliness of adapters, I have made a small guide on how to re-wire the socket to 6F8G:

 

[Galapac]

Hi All!

If you're also bored by slight ugliness of adapters, I have made a small guide on how to re-wire the socket to 6F8G:

Your second post and you offer this? Keep ‘em coming! This is great!

 

[bcowen]

I haven't gotten them, but I am thinking right now the possibilities seem to be a different tube than labelled, or wrongly tested

Being a fake ecc802s is one thing, but not being a 12au7 compatible tube is even more scarier

For readings to be over 2x the bogey (average NOS) value is very suspicious. As @Galapac noted it could be the tester being badly out of calibration or not being operated correctly, but I'm more inclined to go with your suspicion that they aren't really 12AU7's. I get "over bogey" readings on tubes I test somewhat frequently, but that excess is more like 10% - 15% over, not 100% or more like these.

 

[TLO]

For readings to be over 2x the bogey (average NOS) value is very suspicious. As @Galapac noted it could be the tester being badly out of calibration or not being operated correctly, but I'm more inclined to go with your suspicion that they aren't really 12AU7's. I get "over bogey" readings on tubes I test somewhat frequently, but that excess is more like 10% - 15% over, not 100% or more like these.

...or they are not tested at the correct typical parameter. Those test results sure seem very suspicious.

 

[DropTekRoon]

Deleted

 

[triod750]

JAN explanations for those who never knew or have forgotten: https://www.radiomuseum.org/tubes/tube_jan-.html

 

[magiccabbage]

Hi guys.

I haven't posted here for an age. I have a woo audio wa5. I use 6f8gs with adapters ... Got em 2nd hand a few years back. Unfortunately they are staring to get a bit noisey and I'm wondering if they are starting to fade. I have no access to a tube tester so should I bin them and err on the side of caution? Do you think they could damage the amp if they fail while plugged in?

Paddy

 

[jonathan c]

For readings to be over 2x the bogey (average NOS) value is very suspicious. As @Galapac noted it could be the tester being badly out of calibration or not being operated correctly, but I'm more inclined to go with your suspicion that they aren't really 12AU7's. I get "over bogey" readings on tubes*** I test somewhat frequently, but that excess is more like 10% - 15% over, not 100% or more like these.

*** incidentally, bcowen’s golf scorecards are riddled with ‘over bogey readings’ !! … … handicap padding …

 

[ColSaulTigh]

Hi guys.

I haven't posted here for an age. I have a woo audio wa5. I use 6f8gs with adapters ... Got em 2nd hand a few years back. Unfortunately they are staring to get a bit noisey and I'm wondering if they are starting to fade. I have no access to a tube tester so should I bin them and err on the side of caution? Do you think they could damage the amp if they fail while plugged in?

Paddy

A fine choice of amp and tubes!

I'd try resoldering the pins and hat first - noise tends to come from the solder starting to break down over time. I've fixed many a noisy tube with a simple resolder of the pins...

 

[magiccabbage]

A fine choice of amp and tubes!

I'd try resoldering the pins and hat first - noise tends to come from the solder starting to break down over time. I've fixed many a noisy tube with a simple resolder of the pins...

Cheers. They sound amazing I also love the Ken rads ... Maybe more actually. Thanks for the advice on the tube pins. I have actually found a guy here in Ireland who can test 6sn7 for me.... But the 6f8g can that be tested in the same slot or does it need a different device?

I also asked if he could test 300b and he isn't familiar with those (because he mostly tests guitar amp tubes) so he asked me check if there is another name for 300b and he can check if he has a tester for that. Anyone know if 300b is also called by a different name?

Thanks

Paddy

 

[ColSaulTigh]

Cheers. They sound amazing I also love the Ken rads ... Maybe more actually. Thanks for the advice on the tube pins. I have actually found a guy here in Ireland who can test 6sn7 for me.... But the 6f8g can that be tested in the same slot or does it need a different device?

I also asked if he could test 300b and he isn't familiar with those (because he mostly tests guitar amp tubes) so he asked me check if there is another name for 300b and he can check if he has a tester for that. Anyone know if 300b is also called by a different name?

Thanks

Paddy

The 6F8G can test in a 6SN7 tester IF the tester uses a heater wire (which it should). You can also send along your adapater and he should be able to use that and test as a 6SN7 that way. I will defer to others with more experience with testers than me to confirm.

As for the 300B - that's a classification of tubes, just like 6F8G or 6SN7. It's a design that dates back to the late 1920's, early 1930's, and was developed by AT&T (Bell Telephone & Telegraph at the time, I think) to be used to allow Trans-Atlantic communication over wire. It is only known by the 300B nomenclature (that I'm aware of).

 

[LobalWarming]

The 6F8G can test in a 6SN7 tester IF the tester uses a heater wire (which it should). You can also send along your adapater and he should be able to use that and test as a 6SN7 that way. I will defer to others with more experience with testers than me to confirm.

As for the 300B - that's a classification of tubes, just like 6F8G or 6SN7. It's a design that dates back to the late 1920's, early 1930's, and was developed by AT&T (Bell Telephone & Telegraph at the time, I think) to be used to allow Trans-Atlantic communication over wire. It is only known by the 300B nomenclature (that I'm aware of).

The 6SN7 is a 6F8G without the spiffy looking top hat. The 6F8G was a double section version of the 6J5. All tubes are derivatives of other tubes (almost).

 

[g0ldl10n]

Just wanted to share my latest creation - a dual adapter made for strapping pentodes and hexodes (6J7G, CV1581, 6U7G, 6K8G among many others) -> 6SN7

I have not seen much in the way of wooden adapters, but it sure does look nice so thought I would share.

Also, I wanted to express my gratitude to everyone on here that has been so willing to share so much valuable information in regards to the vast world of tubes - you have all done wonders for the learning curve involved. Without that, I am sure I wouldn't have made it even close to this point yet.

Here it is running a pair of RCA 6J7G tubes

And here it is running a pair of Mullard CV1581 tubes

Amp is a Eufonika H5M for anyone wondering.

 

[magiccabbage]

wow