[knight_yyz]

Changed the title to a build thread instead of starting a new thread.


Hey guys, just wondering if anyone has done mixing and matching with pre amp tubes. For example, you have short gray plate, long gray plate, short and long black. They all have their own sonic qualities. If you mixed gray and black, would you get a little of each tube contributing it's "flavor"? Also, does the halo contribute to the sound?

I just scored a pair of NOS RFT EL-84 Funkwerks from E germany, 3 12ax7 From Raytheon short gray plates, and 2 Raytheon Black plate.

I was thinking I would put say 2 black and 1 gray or 2 gray and 1 black for a set of 3 preamp tubes when my Marshall clone is complete.

 

[Granny Gremlin]

Personally, I like to get away from having all of a preamp being 12AX series tubes. Granted this is not anywhere near as easy as subbing in another AXes, but to me the AX7 in particular is not a standout good sounding tube. Even a 6AV6, supposed to be the functional equivalent of half an AX7, sounds a LOT better. My heart truely belongs not to dual triodes, but the combo pentode/triode tubes like the 6AN8 and 6WJ8, but those won't work in a circuit designed for an AX.

I did come across something interesting, that I think I will explore further in the future, which is yellow-jacket style adapters for preamp tubes. I recently found available from shops online that I order other things from anyway, both tube bases (that I could wire up myself as adapters) as well as some premade adapters (e.g. 12AX7 to 6EU7, which I have never used/heard, but now am curious about). They are readily available (NOS and new production). Supposedly really low noise, but I dunno if they sound any good (not common, but apparently they have been used in guitar amps).

 

[knight_yyz]

I thought about buying the Russian Voskhod Rockets 6n2p, which is also a 9 pin dual triode but runs on 6.3v as opposed to the higher 12ax7 voltage They make adapters so you don't have to rewire your tube sockets, but at a buck a piece I'm not sure I trust them. But the 6n2p are all Nos Russian tubes at about 3 bucks a piece. And I've read they sound great.

 

[knight_yyz]

This came in the mail today.

 

[vadsy]

This came in the mail today.

Is it a juicer? Will it unlock the secret of the superfoods?

 

[sammyr]

the "halo" that your referring to is the getter. its heated and contains the stuff (barium?) that makes that chromey shiny looking coating to the top of the tube (getter flash). that itself doesn't really affect the sound but its part of the mix of differences that make certain 12ax7 tubes different from others.

Different tubes will impart some differences to the sound but it also depends on the amps circuit. typically v1 or your first stages of multichannel amps would be where people say most of the flavour comes from. as well the phase inverter can be a place to tinker with different lower gain 12a tubes to change the headroom ie a 12at7 or a 5751. in a circuit like a marshall your v2 is a cathode follower and this can be a stressful job so your main thing is to pick a tube thats rugged and will stand up to the potential abuse.

in terms of plate sizes and colours. black plates are typically earlier production and command higher prices. ditto for long places vs short plates. If microphonics are an issue you want to avoid the long plates. ultimately its up to you and your ears to decide what sounds best.

in terms of marshall specific they holy grail are mullards from england which came stock back in the day. its not uncommon for mullard tubes to be relabelled by other brands so there are often deals to be had on relabels. as well if you're looking for a budget mullard there are japanese tubes made on mullard tooling. again often can be had without spending an arm and a leg. as well later marshall like the jcms often came fitted with relabeled Ei tubes made in prewar yugoslavia. they look like similar to telefunkens with smooth plates. often labelled westinghouse.

 

[knight_yyz]

Definitely not a juicer. This is what I accomplished last night. Unfortunately a bag was missed and I did not get any resistors. I'm trying to figure out the heater wiring twist. Trinity 18 watt Plexi. My first amp build first turret board.

 

[knight_yyz]

Worked on the heater wiring for a bit today. Nothing soldered yet.

 

[knight_yyz]

Started adding the wires to the turret board. A few more to go.

 

[Granny Gremlin]

Don't you wanna lace up the turrets (e.g. ground bus) before you put the caps in?

 

[knight_yyz]

Nothing is soldered. Well, the wires on the backside of the turret board are. Still waiting for the missing bag of parts. And I don't have any bus wire so I'll grab some from work tonight.

 

[Granny Gremlin]

Ah.

 

[knight_yyz]

I'm hoping we have some at work. Might not though. Have to hit the electronics store otherwise

 

[Granny Gremlin]

Solder? Good luck - local I have only found 60/40 (for chumps; eutectic aka 63/37 is where it's at) so I have to order online.

 

[knight_yyz]

Bus wire. I was hoping I could find some at work but we don't use it. So I have to hit a few local electronic stores to see what they have in stock. I have tons of solder and liquid flux. I just haven't soldered anything because it's my first build and I don't want to have to undo things due to carelessness. I think I have the drawing memorized, I just need to read the manual a few times.

 

[Granny Gremlin]

For my pending build I figure I'd either grab some of the solid core copper out of the romex I got lying around (that's overkill though - I have a roll of thinner bare solid copper wire but not tinned so oxidized to snot; don't wanna have to clean it as thoroughly as I'd need to).

 

[knight_yyz]

I thought about using Romex but I don't feel like doing that much tinning. Plus I don't think it will look good if I tin a 12" long piece of copper by hand. Tons of stuff to do on the amp so no hurry for the bus wire.

 

[Granny Gremlin]

You don't have to tin it all just the bit at the turrets. Still, point taken.

I am hesitating just because of the huge guage ( bit of a pain to bend around a turret; I would only single lace it vs double).

I have to org my boxes of wire anyway; hopefully I'll find something better in there.

 

[knight_yyz]

I'd love to do the fancy bus bar hanging off the edge but maybe I'll save that for another build. I wish there was more info on the net but I can't find much about how to do the fancier bus bar. I ended up ordering 20 feet of 16 AWG pre-tinned bus wire. Since I had to pay for shipping I ordered some extras to make it worth the shipping price

 

[knight_yyz]

All the wires soldered to the turret board. Hope I haven't missed any.