The Reference 6J5 Thread (L63, 6C5, 12J5, 6P5, etc.)

[L0rdGwyn]

Great list and nice comparisons! It just goes to show how much of a difference amps, tube synergy, and ears can make in tube rankings. Personally STC 6J5G are quite possibly my all time favorite in the Bottlehead Crack w/ SB with the Chatham 6AS7G, with Visseaux 6J5G being one of my least favorite. Completely agree it’s all relative and all of the tubes in this family are enjoyable to listen to, some just more magical and better power tube synergies than others.

Oh yeah for sure! The STC 6J5G was one of the first I listened to during the day and wasn't part of my tube rolling blitz, I'll give it another listen today and see if it gets bumped up a notch.

 

[whirlwind]

I did some rapid fire tube rolling to get some first impressions of how each 6J5 fits with the 6528 in this amplifier. None of these tubes sound bad, differences are quite subtle, but they can be heard. Going with my gut first impressions on this one, I don't have time to do extensive comparisons, critical listening is a chore!!!

RFT 6J5 - these are quite good, well-balanced top to bottom, maybe a little more lean than the Mullard 6C5G, but very detailed, satisfying treble without stridency, great bass resolution. A top 6J5 for me.



STC 6C5G - the only one I really did not like. I found vocals to sound slightly harsh and unnatural on the tracks I was listening to, which pretty much made it a no go. This was probably the 6C5G I remembered not liking, not the Mullard.



Visseaux 6J5G - I've always liked these tubes, this pair is slightly noisy, but once they settle down they are very resolving, airy, and smooth. Up there for me with the best.



Sicte 6J5GT - pretty uncommon tube, they are pretty good, similar character to Fivre tubes, slightly warm leaning and smooth. I like them, very easy listening, but not the last word in resolution. Above average, I think I prefer them over the gray plate Fivre 6J5GT.



Ken-Rad 6J5GT - these are quite good, excellent body, warm leaning, good bass heft, and smooth upper midrange. Very easy to listen to and quite detailed.



Tung-Sol 6J5G - these used to be one of my favorites, but not quite as impressive as I remember them being. Maybe they are getting old? I felt the midrange was a little uneven, but a nice full low end. I would put the middle of the pack in this circuit.



Sylvania 6J5GT - I have thought highly of these in the past, still do now, they are nicely balanced, nice full low end, sparkly highs, but not harsh, and good resolution. They don't seem to do anything "wrong", but perhaps don't separate themselves from the rest to be called top tier, but above average.



Nippon Electric 6J5GT - one thing I have found about Japanese tubes, they all seem to be exceptionally quiet. These are no different. Another middle of the pack tube I would say, midrange could be a tad smoother, but a nice low end, detailed highs.



Right now my personal tier list goes something like this.

S - MOV L63, Fivre 6C5G, Mullard 6C5G, Visseaux 6J5G, RFT 6J5
A - Ken-Rad 6J5GT, Sylvania 6J5GT, Sicte 6J5GT, STC 6J5G
B - Tung-Sol 6J5G, Nippon Electric 6J5GT, Fivre 6J5GT
C - STC 6C5G

That's right, my scale only goes to C, every tube gets a passing grade. Cs get degrees!

I know I have more 6J5 somewhere, but that's what's in the drawer next to me lol maybe I'll update the list as time goes on.

I have some Fivre 6C5G and I like them a lot.

I don't have the Fivre 6J5GT. What is the biggest difference between those ? I understand different amps and circuits, but just between what you are hearing between the tubes ?

 

[L0rdGwyn]

I have some Fivre 6C5G and I like them a lot.

I don't have the Fivre 6J5GT. What is the biggest difference between those ? I understand different amps and circuits, but just between what you are hearing between the tubes ?

To me, I am getting a little bit more resolution and air with the Fivre 6C5G over the 6J5GT, it's pretty subtle however. I would say you are good shape if you already have the 6C5G, plus it seems the 6J5GT are pretty hard to come by nowadays.

 

[whirlwind]

To me, I am getting a little bit more resolution and air with the Fivre 6C5G over the 6J5GT, it's pretty subtle however. I would say you are good shape if you already have the 6C5G, plus it seems the 6J5GT are pretty hard to come by nowadays.

Thanks, I was kind of hoping you would say that...they seem to be quite pricey, if that was not the case I would grab a pair.

 

[L0rdGwyn]

Yeah the more rare 6J5 seem to be harder to come by than they used to be, I've been out of the loop for a while lol but still a good supply of more common types. I am hitching my cart to this OTL for the long haul, so we'll see if I end up picking up some more pairs. Will need some backup 6528 as well.

I am back on the STC 6J5G.

 

[Velozity]

I've been enjoying this roll with the Tung Sols for some time. Wish they weren't so hard to find.

 

[therremans]

I've been enjoying this roll with the Tung Sols for some time. Wish they weren't so hard to find.

I have a decent number of tested Tung-Sol VT-94a matched pairs, NOS/NIB that I will consider selling or for trade. In my experience, they sound superior to the non-military version. The build is slightly different. Send PM if interested

 

[therremans]

Okay, so only 4 pairs left and I would prefer to keep 1-2 pairs for myself. I’ll reply to the PMs shortly as I am not completely sure what they’re worth.. as I never see them come up for sale anymore.

 

[Velozity]

Okay, so only 4 pairs left and I would prefer to keep 1-2 pairs for myself. I’ll reply to the PMs shortly as I am not completely sure what they’re worth.. as I never see them come up for sale anymore.

The "PMs" plural?? Somebody better not snipe me, lol. These look great. If the price is right I'll take a pair. Thanks.

 

[bcowen]

Okay, so only 4 pairs left and I would prefer to keep 1-2 pairs for myself. I’ll reply to the PMs shortly as I am not completely sure what they’re worth.. as I never see them come up for sale anymore.

I think they’re going for $9.99/pair on EBay right now.

 

[pravous]

I have been running the Tung Sol VT-76 in the Airmid for the last week and I really like them. Pair very well with the 5998.

They share a lot of the same construction characteristics with the Tung Sol VT 37 as well.

 

[mordy]

Received an unknown tube today - except what you see in the picture (6C5G Made in England) there are no other markings.

The screen grid is unique in that the holes are larger than in other tubes and the flanges are protruding like a grating iron.
Tried to identify the tube on the internet. One source (LordGwyn) thinks they are made by Mullard (although that pair had GEC labels) and another site said that BRIMAR made them (Haltron rebrand). They are supposedly very early production which would place them in the second half of the 30's.
I think that GEC made them because I have only seen such "Swiss Cheese" holes on GEC tubes.

What do you think?

 

[pravous]

Received an unknown tube today - except what you see in the picture (6C5G Made in England) there are no other markings.

The screen grid is unique in that the holes are larger than in other tubes and the flanges are protruding like a grating iron.
Tried to identify the tube on the internet. One source (LordGwyn) thinks they are made by Mullard (although that pair had GEC labels) and another site said that BRIMAR made them (Haltron rebrand). They are supposedly very early production which would place them in the second half of the 30's.
I think that GEC made them because I have only seen such "Swiss Cheese" holes on GEC tubes.

What do you think?

Not sure who made those. I have two pairs of the Brimar that have the finer mesh shield.

One of my favorite input tubes. A little on the warm side but amazing with live music. I like these a little better with the GEC 6as7g than the 5998.

 

[mordy]

Not sure who made those. I have two pairs of the Brimar that have the finer mesh shield.

One of my favorite input tubes. A little on the warm side but amazing with live music. I like these a little better with the GEC 6as7g than the 5998.

I do want to point out that even though a lot of people call the perforated/stamped shields mesh shields, they really aren’t mesh but perforated metal shields with different size and shaped holes.
Real mesh is a weave of metal threads. Some people claim that such mesh results in better sound, but you usually only find it in very old tubes, and I personally don’t have any experience with mesh tubes to be able to compare.

 

[pravous]

Philco mesh plate 37. While they sound great they are microphonic and seem to pick up just about any interference you can imagine. Furnace kicks on, buzzing, dishwasher cycles humming. They only work when I have the house to myself and nothing else is using power.