Tube newbie question on price differentials for "same" tubes

[sufioz]

Hi, I was looking at a pair of 12BH7 tubes and on this site  , it seems one pair is USD69 and the other pair is USD149. Both seem to be "sylvania tests NOS 12BH7A Gray Plate O Get matched pairs"  .  Here are the links, if any of the expert tube users could please explain the reason for the difference and if the more expensive one is worth it? 

 

https://www.vivatubes.com/tests-nos-matched-pair-sylvania-usa-12bh7a-grey-plate-o-get-tubes/

 

https://www.vivatubes.com/tests-nos-matched-pair-sylvania-us-12bh7a-grey-oval-plate-o-get-tubes/

Edited June 20, 2021 by sufioz

[muon*]

Different plate structure, one is oval one is not.

 

As far as the oval being worth the extra, maybe wait for @xlr8or our resident tube fanatic.

[xlr8or]

Oval anode plates were manufactured by GE. This is the reason for the higher cost. However, there are far superior sounding 12BH7's. The 1950’s AWV locally manufactured black plates with 90-degree square getters are legendary. Others that are worthy of consideration are very early 1950's CBS Hytron black plate 12BH7's with white print and 90-degree horseshoe or 45-degree rectangular getters. Brimar mid 1950's 12BH7's with black plates and 90-degree rectangular getters are also worth sourcing.

 

Edit: I would recommend acquiring singles to make up pairs.

Edited June 20, 2021 by xlr8or

[sufioz]

1 hour ago, xlr8or said:

Oval anode plates were manufactured by GE. This is the reason for the higher cost. However, there are far superior sounding 12BH7's. The 1950’s AWV locally manufactured black plates with 90-degree square getters are legendary. Others that are worthy of consideration are very early 1950's CBS Hytron black plate 12BH7's with white print and 90-degree horseshoe or 45-degree rectangular getters. Brimar mid 1950's 12BH7's with black plates and 90-degree rectangular getters are also worth sourcing.

 

Edit: I would recommend acquiring singles to make up pairs.

Thanks so much for the comprehensive guidance. Much appreciated.

[sufioz]

Hi @xlr8or, if I could tap into your knowledge again.....is 5687 a good replacement for 12bh7? I am dabbling in tube rolling and they seem a lot cheaper than the 12bh7s in the NOS land. 

[xlr8or]

12BH7's and 5687's are different tubes and not pin comptabile. Even with tube adapters they have different operating points.

[sufioz]

Thanks so much for clearing that up. 

[wavemechanic]

On 20/06/2021 at 8:20 PM, xlr8or said:

Oval anode plates were manufactured by GE. This is the reason for the higher cost. However, there are far superior sounding 12BH7's. The 1950’s AWV locally manufactured black plates with 90-degree square getters are legendary. Others that are worthy of consideration are very early 1950's CBS Hytron black plate 12BH7's with white print and 90-degree horseshoe or 45-degree rectangular getters. Brimar mid 1950's 12BH7's with black plates and 90-degree rectangular getters are also worth sourcing.

 

Edit: I would recommend acquiring singles to make up pairs.

How would the AWVs compare to the Electro Harmonix Gold?

[xlr8or]

2 hours ago, wavemechanic said:

How would the AWVs compare to the Electro Harmonix Gold?

 

The AWVs sound very different to the EH Golds. I don't think the 2 can be compared. One is a modern production type and the other is a vintage type. The AWVs offer far more fullness and body. They also have more realism, accuracy, positioning and soundstage. The EH Golds sound brash in comparison in all these areas. Also, the AWVs sound far more stout with less of the smearing that is associated with the modern production equivalents. Vintage tubes were engineered to much higher standards with distinct internal construction techniques and the use of more unique materials that is uncompromised in comparison to new production equivalents. I'm biased towards vintage tubes based on my tube rolling experience over the past 20+ years. Once you've locked yourself into the vintage sound camp you can't really go back to modern production types.

[wavemechanic]

9 hours ago, xlr8or said:

 

The AWVs sound very different to the EH Golds. I don't think the 2 can be compared. One is a modern production type and the other is a vintage type. The AWVs offer far more fullness and body. They also have more realism, accuracy, positioning and soundstage. The EH Golds sound brash in comparison in all these areas. Also, the AWVs sound far more stout with less of the smearing that is associated with the modern production equivalents. Vintage tubes were engineered to much higher standards with distinct internal construction techniques and the use of more unique materials that is uncompromised in comparison to new production equivalents. I'm biased towards vintage tubes based on my tube rolling experience over the past 20+ years. Once you've locked yourself into the vintage sound camp you can't really go back to modern production types.

Interesting. I have a Consonance Linear845 with Golds in at the moment, I'm happy with the soundstage but it just isn't as quick as my Quad 520F (which in comparison has no soundstage at all!). Transients seem muted in comparison, both forceful drum hits and small cymbal taps for example.  Would AWVs help in this area? Would better 845s help?

[xlr8or]

8 hours ago, wavemechanic said:

Interesting. I have a Consonance Linear845 with Golds in at the moment, I'm happy with the soundstage but it just isn't as quick as my Quad 520F (which in comparison has no soundstage at all!). Transients seem muted in comparison, both forceful drum hits and small cymbal taps for example.  Would AWVs help in this area? Would better 845s help?

 

What's the tube type that feeds the first input stage? I see there is reference to 5687 and 12AX7 tubes in use for the Linear but that's for the most recent version.

[wavemechanic]

On 27/07/2023 at 4:34 PM, xlr8or said:

 

What's the tube type that feeds the first input stage? I see there is reference to 5687 and 12AX7 tubes in use for the Linear but that's for the most recent version.

There are 2x 12BH7s and a 12AT7 that sits between them. These tube types are screen printed onto the chassis adjacent to the sockets, and are different to those on the website, which are 1 x ECC83, 2 x 5687.
http://www.opera-consonance.com/products/amplifier/Linear845.html
The 25th. anniversary edition is the one I have, unsure if there are any others. I've bought some AWV 12BH7s to try, will report back. I expect there's a burn-in period?

[xlr8or]

8 minutes ago, wavemechanic said:

I've bought some AWV 12BH7s to try, will report back. I expect there's a burn-in period?

 

Yes, 150+ hours for thermal conditioning. 90+ minutes in for assessing the tonal characteristics.

[Klipscher]

I can recommend the early 12BH7a RCA long black plate with dimple getter. Them and the 1950-1952 Hytrons. I have a couple of the red tip Hytrons that sound excellent.

 

 

[Gremrock]

NOS baby tubes in the linear 845 definitely will improve things if you’re running stock.

linlai Elite 845s are also very good as are the WE replica.

the WE probably have a better midrange and balance overall to the linlai in my opinion but the linlai have better top and bottom end. 
 

This said I’ve now gone back to 300bs for the midrange magic they produce and have the linear up for sale, but only because I can’t afford to keep it for a future system.

 

to the OP, don’t get too excited by “bargains” on eBay etc too, any monkey can write “NOS, tests as new” on anything. There are a couple of guys around here (plasmod3/stevenvalve for example) who have extensive knowledge and collections of these things.

www.nostubes.com.au -plasmods tube site.

pay the extra for reliable offerings and honest help, and if you can buy within this forum you are likely to get both.