Preamp Tubes? - Who, What, When, Where, Why, and How?

[Sg-ocaster]

Thats the beauty of tubes. You can taylor your amp to your style with differant tubes in each slot. One tube might make certain things you play better and others worse its finding the right combo that makes what you play work. Key is to find what you like and stock up.

 

[Sg-ocaster]

Yes ecc823 into V1....V1B is the Ultra channel all the other stages are shared. The ecc823 is 1/2 12ax7 1/2 12au7. The 12au7 half would fall into V1B reducing the ultra channels gain while keeping the green channel unchanged.
Its an option some say works well. I have not tried it myself I modded the V1B stage on mine.
And yea this came from the DSL40c thread. LOL

 

[Dogs of Doom]

yes... just so we're all on the same page.

V = valve (tube)
V1 = 1st valve V2 = 2nd, V3 = 3rd, etc.

Each pre-amp valve is a dual triode valve. This means that there's 2 halves of the tube. In tube amp's, they utilize each ½ of the tube. In this case, in V1, they use one ½ for one channel, & the other ½ for another channel.

So, the ECC823, is a mixed dual triode tube. one ½ is an ECC82, & the other is ECC83. There's also a reverse tube the ECC832. The ½'s are flipped, so, it would do the opposite, keep the opposite channel full power & lower the other...

So, when SG says V1A, vs V1B, he's talking about the 2 triodes. V1A is used for 1 channel, & V1B is used for the other. The ECC823 will lower the side of the tube that corresponds w/ the channel you are trying to lower...

https://www.jj-electronic.com/images/stories/product/preamplifying_tubes/pdf/ecc832.pdf

832, has 83 (A) & 82 (B)
823, has 82 (A) & 83 (B)

 

[Pete Farrington]

V1A, vs V1B

To further complicate matters, valve manufacturers refer to the pins678 triode as A or 1, 123 as the B or 2 triode, see https://tubedata.altanatubes.com.br/sheets/049/1/12AX7A.pdf
Whereas following Fender’s typical practice in this as in so much else, amp manufactures refer to the 123 triode as the A triode, 678 as the B triode https://el34world.com/charts/Schema...45w_mstrvol_pullsw_super_pro_bmstr_rev_2_.pdf

https://el34world.com/charts/Schematics/files/Marshall/Marshall_jcm2000_100w_dsl100.pdf

Some valve info notes that the 678 triode ‘is more favourable in respect of hum’, eg https://tubedata.altanatubes.com.br/sheets/010/e/ECC83.pdf

 

[RiverRatt]

I think you chose the right action. No voltage problems whatsoever. I would not try to use the ECC823. A 12AU7 will effectively neuter the amp. Save those for an amp that was designed for them.

As for Mr. Underwood’s statement, you obviously haven’t read this entire thread. If you had, you would know that a good many ears were exposed to a particular tube and the descriptions were virtually identical.

 

[mickeydg5]

And yet 99% of people see red as red and blue as blue................but no one hears the same.

 

[Bownse]

And those of use who see some reds as grey and some greens as lighter grey.

 

[mickeydg5]

And those of use who see some reds as grey and some greens as lighter grey.

You are the other 1%.

Like that @Pete Farrington.

 

[C-Grin]

Might as well Bump, I mean why not?

 

[Pete Farrington]

Amongst those of Northern European descent, up to 8% of males are red green colourblind https://en.m.wikipedia.org/wiki/Color_blindness
Fortunately I’m not, though I’ve known EEs that are.

 

[mickeydg5]

Ok, ok!
I stand corrected. It is 92%.

 

[Dogs of Doom]

like the guys at Fender, who call their blue guitars green & their green guitars blue...

 

[RiverRatt]

I love this thread. So many rabbit holes. It’s always felt like a bunch of friends sitting around talking. You never know what direction a conversation will go in. I grew up in a big family and Sunday afternoon BS sessions were a ritual.

 

[mickeydg5]

like the guys at Fender, who call their blue guitars green & their green guitars blue...

I wonder how they see aqua?


Still, if I hear the red, I see red again.

 

[RiverRatt]

If anyone is still interested in preamp tubes, I found an oddball. I bought a Raytheon JRP-12AX7 off eBay recently. When I got it, it had long gray plates. By all accounts, it is a USA made tube. I’ve never seen a Raytheon 12AX7 with gray plates though that wasn’t Japanese. It’s a pretty safe bet that the military wouldn’t accept a foreign substitute, and the exhaust tip has that Classic Raytheon pipette look, so I’m calling it USA. I would add pictures but I don’t want to. Maybe later.

 

[mickeydg5]

If anyone is still interested in preamp tubes, I found an oddball. I bought a Raytheon JRP-12AX7 off eBay recently. When I got it, it had long gray plates. By all accounts, it is a USA made tube. I’ve never seen a Raytheon 12AX7 with gray plates though that wasn’t Japanese. It’s a pretty safe bet that the military wouldn’t accept a foreign substitute, and the exhaust tip has that Classic Raytheon pipette look, so I’m calling it USA. I would add pictures but I don’t want to. Maybe later.

You have to show.
I have seen some before and may even have some in some box somewhere.

I know I have those ladder long plates in gray and am pretty sure I have some in black too.

 

[RiverRatt]

Here it is Micky. All this time and I still can’t take a decent tube pic.

 

[mickeydg5]

Here it is Micky. All this time and I still can’t take a decent tube pic.

Looks ok. Maybe try not so close up and do the finger on the sight thing if using one of them smart phones.

I am sure I have seen RCA black and gray plate like that.

 

[RiverRatt]

A lot of companiies used that plate design, I just didn’t ever remember Raytheon using a long gray plate in a USA 12AX7. I am always glad to learn something new

 

[RiverRatt]

Now my question is, when was this tube made? Was it just before the black plates or just before Japan?