Which tubes to use?

[Tubes In a Hat]

I have an RM100 and I was just wondering about the 3 preamp tubes in the head and the tubes in the modules themselves.

Do any of these need to be current balanced or triode matched, or can I just buy 9 regular 12AX7 type tubes and be fine?

What type of tube should I try to increase clean headroom in my Blackface module? 12AU7?

Which brands and models are your favorites for these amps? Personally, I like the smoothness of JJs, but I also like the Sovtek 12AX7-LPS.

I'm thinking about using KT66s and KT88s for the power section... anyone have any experience with these?

Thanks

 

[speedemon]

ohhh man,

a few of us went gangbusters on this; do a search ("tubes", "12ax7", "5751" etc.) the threads are numerous. "Julia" , "Shinozuku" and "Mattfig" have a lot of great posts, and one thread lists a bunch of module/tube setups.

I personally have settled on running all NOS preamp tubes (I got a line on low cost USA ones), and the 12ay7 sounds great in a "Fender" module, but its a bit low on level.

Happy Hunting!

 

[byzon]

I have recently tried 12AU7's in my KH-1 and Clean modules to increase the headroom, which I could easily overload at 9 o'clock on the gain knob. It sort of works (now it breaks up at about 11 o'clock), but seems to rob a little of the sparkle and snap from the tone.

I've tried every combination of preamp gain, preamp volume, and Master volume adjustment to "clean" up my clean modules, to no avail. Even tried a compressor in the effects loop, and on the floor - doesn't help much at all. The only thing that helps is to turn down the volume on my guitars. It happens with both my active p'up and passive p'up guitars, incidentally.

I've written Randall/US Music on this, but still have not heard in over a week. I have asked them a few other questions in the meantime and heard back within 24 hours so I am thinking they have no answer.

BTW, I consider this to be a flaw of the MTS series - despite the descriptions on the website, the clean modules in general seem to have no headroom...

 

[Julia]

what pickups are you using? EMG or Duncan actives?

The Blackface, KH1, and Clean will break up with high output pickups like these. Sorry. It just does unless you run the gain at 9:00. And what's wrong with that? The gain doesn't have to be higher. The only thing that a 12AU7 will do is allow you to turn up the gain to noon, and I found it makes the module sound dead. So back to 12AX7s and I run the gain at 9:00 and I run the level at 3:00 with a rackmount dbx166xl gate/compressor/limiter in the effects loop.

Yet it still breaks up with my Alexi and the Duncan Blackouts unless I roll off the volume knob on the guitar or kick in a EQ as an input level reducer. The module will not break up with my SG Std bridge 498T.

 

[Tubes In a Hat]

my main axe is a PRS custom 24 with the stock pickups...

I guess I'm not so concerned about higher headroom on the clean module as I am concerned about whether any of the pre tubes need to be matched and balanced.

 

[Julia]

Pre tubes matched and balanced? no, they do not need to be. none of them.

 

[Mattfig]

Julia speaks the truth...Matching and balancing 12AX7s is a silly way for tube dealers to make a few extra bucks on each tube...Perhaps there are amps that are more responsive to such tubes but they ain't Randall or any I've ever owned...The only upgrade I do for tubes is to get a few setup for high gain...I personally feel Tung-Sols are the best sound and value in both preamp and power amp tubes...I've tried many and the difference is notable on certain modules and equally subtle to non-existant on others...But, as a general rule, a 12AX7 is a 12AX7...Playing around with 5751s (Jan GEs are great) and various lower gain tubes (for V1 on modules) can clean up tone a bit more...Sometimes a combo of a low gain in V1 coupled with a high gain in V2 can give some different tones...At the end of the day, it's a lot easier to buy a handful of various tubes and just play with placing them in different spots...It helps to keep a notepad handy to jot down your impressions...You'll eventally recognize which ones work best for you...If you don't hear much of a difference, you're not alone...The changes are not night and day...Even with expensive NOS tubes...
Good luck!

 

[Julia]

I will say this. The only place it makes a difference is in the recording studio and only if you've got top grade recording gear. For day to day use, I wouldn't waste my money. I run used UK made Mullards in my KH1 but I wouldn't if they hadn't come in a used amp I bought at one time. I took them out of the amp and sold the amp. I picked up a NOS Telefunken 12AX7 from a shop downtown that happened to have one in the box for $18 so I figured what the hell.

In the end no matter what you choose to use you will not change the character of your amp. The differences are very very small and I'd love to hear a blind test. From my own testing of stuff, I've ended up putting JJs back in pretty much everything else simply because I like a darker tone, and the tone is only slightly darker but I'm not using the "High Gain" rated ones, just normal (gain ratings probably run from 90 - 100, and the HG ones probably are more right around 100).

Otherwise you are buying this product

 

[crankyrayhanky]

I agree with Julia on this one...I read people saying good/bad about 12ax7 brands, and I'm thinking my ears are cooked because I can't hear a big difference between EH, JJ, Tung Sol, etc
No if you get a bad tube, that would be a valid reason to not like something

However, I am interested in getting some hi gain chinese 12ax7s to see if they bring out the chainsaw in a few of my mods

 

[Shinozoku]

All the advice so far is pretty good. The hubub about balanced tubes only applies to high grade tube hifi systems, which we aren't working with.

If you want a cleaner Blackface, throw a 5751 in it (NOS only). Try both positions and see which one works best for you.

If you want a bit more headroom, cleaner cleans, and grittier, clearer high gain tones, throw that same 5751 in the third preamp tube position int he head (This is the PI, it's closest to the power tubes).

I highly recommend getting 3 or 4 5751's to try in various places of your amp. The second preamp tube in the head doesn't matter much, as it's the FX loop buffer. However, if you crank your FX Level knob for a fuller tone, it may sound better with a decent quality tube in it, but it doesn't need to be anything special.

Just make sure you don't use Sovteks and you should be fine.*

*There are a few exceptions but they escape me right now.

 

[kylendm]

Julia speaks the truth...Matching and balancing 12AX7s is a silly way for tube dealers to make a few extra bucks on each tube...Perhaps there are amps that are more responsive to such tubes but they ain't Randall or any I've ever owned...The only upgrade I do for tubes is to get a few setup for high gain...I personally feel Tung-Sols are the best sound and value in both preamp and power amp tubes...I've tried many and the difference is notable on certain modules and equally subtle to non-existant on others...But, as a general rule, a 12AX7 is a 12AX7...Playing around with 5751s (Jan GEs are great) and various lower gain tubes (for V1 on modules) can clean up tone a bit more...Sometimes a combo of a low gain in V1 coupled with a high gain in V2 can give some different tones...At the end of the day, it's a lot easier to buy a handful of various tubes and just play with placing them in different spots...It helps to keep a notepad handy to jot down your impressions...You'll eventally recognize which ones work best for you...If you don't hear much of a difference, you're not alone...The changes are not night and day...Even with expensive NOS tubes...
Good luck!

The only kinds of things that need balanced are MAYBE Hi-FI stereos

 

[BigBrewtus]

I can tell a difference! The EH are great! JJs are darn good but maybe a little harsh. Depends on what your goin for. I have a good time using the original 12AX7 I robbed from my Chandler Tube Driver!

 

[pipedwho]

+1 to what's been said so far. I've been using new production stock for the last few years which are IMO far better value than NOS.

I've been ultra impressed with the Tung Sol RI 12AX7 tubes. When these were released a few years back, I was pleasantly surprised at how good they sounded. These are my go to tube. (For some really high gain stuff I leave the Sovteks in as they seem to have more 'edge'. Shuguang also works better in ultra high gain IMO.)

 

[Julia]

I found the Chinese HG 12AX7s bring out the fizz.

The chainsaw from the old Marshall amps is due to power tube distortion.

The RECORDED chainsaw is a Sonic Maximizer.

I've recorded Mr. Scary and believe me it is a chainsaw and it sounds nothing like it does live. Live it's a lot smoother. The key to a recorded chainsaw is not to use as much gain as you do live.

 

[Mattfig]

I always hated JJs as they were too dark sounding for me...But I gotta say, JJs KILL in V1 of the Mamba....That module was the most difficult to tube as it has so much gain on tap and a ton of great harmonics...JJ in V1 and a high gain Tung Sol in V2...Killer combo....

 

[I am Legion]

A JJ in V1 and a Tung-Sol in V2 has quickly become a starting & finishing point for me with any high gain module too.

After that I start A/B-ing with NOS Mullard's, Marconi's (which are f**king excellent in Randall modules) & Brimar's.

 

[speedemon]

Yeah,

I like the NOS tubes in it also. where are you getting the Mullard and Brimars?

Getting your module clean. A 5751 should drop your gain to clean the module, if not a 12ay7 def should. I have a gray plate GE you can have on the cheaps; sounds great in my Tweed module, I just liked the RCA black plate an @$$hair better.

Good luck!

 

[speedemon]

Also worth mentioning,

I read everywhere about deplorable QC on modern production tubes. I took a batch of 12ax7s to be tested, and lo and behold, the one that tested "weaker" really sounded like *** in my amps (at least in V1 in my Splawn, and V1 of the Randall modules). V2 in the Randall module didn't seem to make much difference to me so I have left the chinese 12ax7s there.

as Hank mentioned, a weak tube sounds like crap regardless of brand, so order them and get them "tested" in whatever way is available to you.

 

[Mattfig]

Great points....I had a bad loop tube in one of my RM4s and it was a brand new, tested, and expensive tube...I blamed the problem first on cables, then grounding issues, then a bad compressor...I think if you stick with the reputable sellers already mentioned, you're cool...Stepping outside that box is not worth saving 2 bucks a tube like my cheapass did!!!! I test my own tubes now anyway so I won't have that problem again, or so I hope...

 

[I am Legion]

Double post