yet another RM100 tube choice thread

[lolthrash]

Have read through 100 thousand million tube threads on here and am now even more confused than before I read them!
Basically, I need to replace the V1 preamp tube as it's gone microphonic as hell, and I also need to replace both tubes in my black stripe treadplate module. Am also considering changing the V3 (phase inverter) in the head to a different type, as people have mentioned good things about 12AT7's/5751's in this spot. Any suggestions about any tubes for ANY of those positions would be greatful.
Also, I currently have a quad of JJ 6L6GC's, playing through a randall 4x12 i loaded with GT12-75's and I'm thinking to try some different power tubes, probably two different ones to combine with the 6L6's. I play a lot of heavy metal stuff, metalcore/hardcore/thrash etc etc etc and I eventually want to get a salvation mamba (framus cobra clone) mod and also an SL+ or a Slodano mod. Any suggestions as to what would be good tubes to somehow accommodate all of that? I'm tossing up between a pair of JJE34L's, some kind of other EL34's, EH 6CA7's (really like the look of these but don't know enough about them), some 6550's of some form or some KT77's.
Help! :lol:

 

[Shinozoku]

Jan 5751 is a no brainer for the PI

Thinkin about getting another one for my V1 to clean up the front end some.

Tung Sols rule for most preamp tube applications in the modules, and you might even try the Mesa 12AX7's (their higher quality one in the module V1 and the regular in V2).

TAD or Winged =C= power tubes of any kind are fantastic, and I highly recommend the Winged =C= EL34's

 

[eyeball987]

I have a Jan GE5751 that I bought for the PI but I also just dropped 6550's in there. What are the advantages of using this in the PI with 6550's?

 

[kylendm]

^ That's what I've got going on. There isn't as much amp hiss from what I can tell. At the same time though it really doesn't lower the gain much from what my eyes tell me. Most of the modules have more than enough gain anyways.

 

[Shinozoku]

The 5751 in the PI just adds a lot of clarity IMO. more sizzle, clang, or chime depending on the module, etc.

 

[lolthrash]

Has anyone any experience with the electro harmonix 6CA7's? Particularly in a high gain amp like this? I seriously LOVE the look of them, am so tempted to just get some to try them out haha.

 

[lolthrash]

I might also add a bit of what I'm looking for I guess, although to be quite honest I'm not even that sure what I'm after! But I do love the sound of Soldano Slo 100s, a lot of the Marshall JCM800s (2203/2204), Framus Cobras, Bogner Uberschalls, Laney GH100ls etc etc. So maybe I'd be best to do a 2 and 2 mix of power tubes to create a nice mix of tones? I wonder how two 6CA7's would go in the middle of two of my JJ6L6's on the outsides?

 

[lolthrash]

Wellllll seeing as I am super impulsive, I just made a tubedepot order lol. Bought a matched pair of 6CA7EHs, a balanced JAN 5751, a tungsol 12ax7 to try in V1 and some JJEC83s for the treadplate. Will be interesting to see how it all goes and how the 6CA7s go with the 6L6s!

 

[Chak_wylde]

Hey. Can someone explain the V Positions for pre-amp tubes in the rm100. I know that for the power tubes v1 to v4 is basicaly left to right when looking at it from the back. Also where is the Phase inverter? Thanks.

 

[Shinozoku]

V1 is the tube closest to the amp input, V2 is the middle preamp tube, it's the effects loop buffer, V3 is the phase inverter, which is the tube closest to the power tubes and the last gain stage the signal goes through before hitting the power section. This last tube can be replaced with a lower gain tube like a 12AT7 or 5751 to clean up the signal and add clarity before it drives the power tubes.

 

[eyeball987]

The 5751 in the PI just adds a lot of clarity IMO. more sizzle, clang, or chime depending on the module, etc.

I was able to push a RM50 with 6550's this weekend after I dropped a 5751 into the PI. I tried it with a DLX, JF Brahma, Scary, and stock KH3. I am very impressed with the results.

Added lots of clarity and the gain knob is usable much higher now but I find myself actually keeping it lower now. About noon on the Scary and KH3 and up to about 3:00 on the Brahma with the gain boost off. I am going to buy another 5751 to keep on hand.

 

[Chak_wylde]

Many thanks Shinozoku. Thats helped alot. I think i'm gona have to get me a 5751 tube by the sounds of it. Seems to do wonders! Oh and btw thanks for replying to my other thread. Your a great help dude!

 

[lolthrash]

ok so i've had some time to put a few of them in and see how things go etc, but mostly at louder bedroom volumes, haven't really cranked the hell out of it yet.
but i have put the JAN 5751 in the PI spot, and unless my ears are trying to deceive me with some placebo effect tomfoolery, it seems to have made my tone much nicer and clearer, definitely a very nice improvement.
I've also found out that I am really quite fond of these TUNG SOL 12AX7s, they're doing everything I want them to do and more. I put the new one I bought in V1 of my amp and it loves that spot and my amp loves it being there. Also changed out the microphonic JJEC83s in my XTC module for one of the older (but apparently still good condition) tung sols in V1 and a brand new JJEC83 in V2. These new tubes have allowed me to realise just how versatile the XTC module really is (and how **** nice a clean sound I can get from it with the gained rolled all the way back).
I did the same with the treadplate module too, put a tung sol i had in V1 and a brand new JJEC83 in V2, same as the XTC, sounds great!
I must say buying new tubes has really driven my faith in/happiness with the amp a whooooole bunch.
Can't wait to try these two EH6CA7s in the middle pair of my power section and see how that goes. Will also try them on the outside with the 6L6s in the middle, and will also try a combination of the 6CA7s with an older pair of EHEL34s I have, trying them in both positions.
Awesome!

 

[Shinozoku]

I found when I first got my EL34's that I loved them in the middle position with my Sovtek 5881's on the outside, but after mods and trying the 5881's on the inside again, I prefer them that way. Just sounds more open, clear, and punchy to me. You may come up with different results though

 

[lolthrash]

So I spent a little bit of time with just the 6CA7s in earlier tonight (pulled the outside two and just ran the 6CA7s in the middle pair) and it sounded awesome! I need to spend more time with it loud tomorrow, and I'm going to try the JJ6L6GCs on the outside and then swap them. But I'm curious about biasing, I read one of Julia's posts and it mentions that the EL34/6ca7 family have a higher power rating than the 6L6 family, so the bias range is slightly higher, yet the RM100 manual says the exact opposite? :?
So how do I know which is which, and what difference is being in Australia (240V line voltage) going to make? And is it true you need to run the two pairs at the middle of their ranges? ALSO. Julia mentioned that 6CA7s will have a range up to 33mV, and the rm100 manual says up to 38mV.. but on the boxes the tubes came in from tubedepot, it says "Bias Point 43", so what does that mean??
So confusing..

 

[lolthrash]

6CA7EH in the middle pair - about 43mV each
JJ6L6GC in the outside pair - about 35mV each
That's what I just had them running at and WOW it sounds so good.......
On my TREADPLATE module it is so tight, lots of bottom end, nice mids and sparkling highs, a lot of clarity (and this is all with my dinky tuned down to drop B, my les paul in standard will sound ridiculously cool), heaps of creamy sustain, just everything is so cool.. And then on the XTC, roll back the gain to about 1.5-2 just enough to engage a full signal into the module but no distortion, and the clean tone is AMAZING.
I'm actually so excited hahaha. Cannot wait at all to get some pete/anthony modded mods and run them through this setup, awesome.

However, I'd still love someone to fill me in on the proper biasing. Should those 6L6s be running harder than 35mV? It does sound really **** good now though, maybe time to apply the "if it ain't broke.." theory. Can't wait to really turn it up tomorrow

 

[Shinozoku]

Actually I don't go over the bias ranges in the Randall manual :lol:

Running two JJ 6L6GC's in the middle at 31mV and two SED Winged =C= EL34's on the outside at 33mV. Even more clear and punchy than with the 5881's with plenty of harmonic content and meat to spare

Keep in mind though, those 5881's were Sovtek :lol: