#1
I recently purchased a Randall RG50TC tube amp & I'm loving it so far with my Jackson DKMGT w/ EMG 81/85 active pickups (I play mostly on the EMG 81 pickup). It's used mostly for hard rock/metal (Dan Donegan's tone from Disturbed).

It comes with everything stock (was bought used), though I was wondering if there would be any major difference if I upgrade certain parts. I'm still a bit new to tube amps, but I was thinking I'd give it a few months before I upgrade any parts so that I'd actually be able to tell the difference.

Here's what it comes with stock:
  • 1 X 12” Celestion Seventy 80
  • Four 12AX7EH Preamp Tubes
  • Two 5881 Power Tubes


Does anyone have any suggestions for a speaker, preamp tubes, and power tubes?
#2
Check out EV speakers.

You can never go wrong with JJ tubes.
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#4
Hey again.

I've decided on doing a speaker upgrade from the Celestion Seventy 80's to Celestion Vintage 30's. I've also decided on upgrading the (4) preamp tubes from 12AX7EH's to Tung-Sol 12AX7's, and the (2) power tubes from 5881's to either:

JJ 6L6's
JJ EL34's
Tung-Sol 6L6's

I have two questions:

Would an upgrade of preamp tubes (specifically the ones listed) really make a difference? Also, is anyone familiar with the two Randall RG50TC overdrive channels? I was wondering if I have, let's say, a JJ 6L6 power tube in slot 1, and a Tung-Sol 6L6 tube in slot 2. Would they be accessed separately through the two overdrive channels, or is it just best to have (2) of the same power tubes?

Excuse my ignorance but I am still a bit new to tube amplifiers, though I'm still looking through other threads (including the stickies).

Thanks for your time!
#5
Quote by keennay
Hey again.

I've decided on doing a speaker upgrade from the Celestion Seventy 80's to Celestion Vintage 30's. I've also decided on upgrading the (4) preamp tubes from 12AX7EH's to Tung-Sol 12AX7's, and the (2) power tubes from 5881's to either:

JJ 6L6's
JJ EL34's
Tung-Sol 6L6's

I have two questions:

Would an upgrade of preamp tubes (specifically the ones listed) really make a difference? Also, is anyone familiar with the two Randall RG50TC overdrive channels? I was wondering if I have, let's say, a JJ 6L6 power tube in slot 1, and a Tung-Sol 6L6 tube in slot 2. Would they be accessed separately through the two overdrive channels, or is it just best to have (2) of the same power tubes?

Excuse my ignorance but I am still a bit new to tube amplifiers, though I'm still looking through other threads (including the stickies).

Thanks for your time!

You can't put two different power tubes in each slot, they have to be matched or it can damage the amp.

The preamps will make the biggest difference in the tone of the amp in terms of tubes.

I doubt you'll be able to put EL-34s in that amp unless you mod it, stick with 6L6s.

The V30 would work well with, though I'd suggest you look into WareHouse speakers if you want a cheaper, arguably better, alternative.
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#6
Quote by MatrixClaw
I doubt you'll be able to put EL-34s in that amp unless you mod it, stick with 6L6s.


I've just opened up my amp and it actually has 2 Electro-Harmonix EL-34 power tubes installed.

I've just ordered some Tung-Sol 12AX7 preamp tubes, Tung-Sol 6L6GC-STR power tubes, and a Celestion Vintage 30 speaker. Another question, is there anything I should tweak on the amp before installing a new/different set of preamp and power tubes, or can I just simply pop them in?
#7
Umm,

Sorry to tell you this but if you're amp can only take EL34's, the 6L6's won't work.
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#8
Quote by keennay
I've just opened up my amp and it actually has 2 Electro-Harmonix EL-34 power tubes installed.

I've just ordered some Tung-Sol 12AX7 preamp tubes, Tung-Sol 6L6GC-STR power tubes, and a Celestion Vintage 30 speaker. Another question, is there anything I should tweak on the amp before installing a new/different set of preamp and power tubes, or can I just simply pop them in?

oh dear.

check your amp manual and see if your amp can run on 6l6's after a rebias. el34's and 6l6's fit in the same sockets, but they are absolutely different tubes.

you can really damage and ruin a major part of your amp if you neglect this.
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#9
Dammit, I read it wrong. 5881s are EL-34s, damn british tube names, numbers confuse me!!!

In that case, I doubt the 6L6s will work, but it *might* be possible with a rebias. Is it too late to cancel the order on those, or can you return them once you get them?
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#10
Quote by MatrixClaw
Dammit, I read it wrong. 5881s are EL-34s, damn british tube names, numbers confuse me!!! In that case, I doubt the 6L6s will work, but it *might* be possible with a rebias.

I keep reading elsewhere that 5881's are similar to 6L6's. It just happened that my amp came with EL-34's instead of the default 5881 power tubes. Please correct me if I'm wrong.

Quote by MatrixClaw
Is it too late to cancel the order on those, or can you return them once you get them?

I bought them off eBay, but it's no problem. I can just resell them and purchase the proper power tubes for my amp.

Quote by UnsignedRecords
oh dear.

check your amp manual and see if your amp can run on 6l6's after a rebias. el34's and 6l6's fit in the same sockets, but they are absolutely different tubes.

you can really damage and ruin a major part of your amp if you neglect this.

The manual is not very helpful, though I have created a thread over at the Randall Amplifiers Forum. Thanks though!
#11
I also have a randall RG50tc. I bought mine used, and 1 of the power tubes was dead. I put in new JJ power tubes. Most people i talked to told me not to bother replacing pre amp tubes, as i will not notice the difference.

The amp sounds pretty good now, but i am also considering installing a new speaker. I think the vintage 30 is a good choice. I'd love to know how it sounds, you should make a post with the new speaker in, as i'd be interested in the difference it makes.

Good luck
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#12
Quote by e32lover
I also have a randall RG50tc. I bought mine used, and 1 of the power tubes was dead. I put in new JJ power tubes. Most people i talked to told me not to bother replacing pre amp tubes, as i will not notice the difference.

What I will do first is replace the preamp tubes and try the amp for a while to see if I notice the difference (maybe for a day or week). Then, I'll change the power tubes. Lastly, I'll change the speaker. I'll let you know if it's worth it to do a preamp tube change (assuming yours came with the stock 12AX7EH's).

Quote by e32lover
The amp sounds pretty good now, but i am also considering installing a new speaker. I think the vintage 30 is a good choice. I'd love to know how it sounds, you should make a post with the new speaker in, as i'd be interested in the difference it makes.

Good luck

I sure will!
#13
Sorry to bump, but my tubes have arrived and was wondering if anyone had an answer to the question from Post #10.
#14
Hmm 5881s are 6L6s, I dunno what I was talking about in my last post, but online all the ones I see for sale show it as coming with EL-34s. Sorry about that, I must seem like I'm contradicting myself all over the place

I really doubt you'll be able to bias it for the 6L6s as they run on much different voltages. If you have the proper biasing tools, I'm sure you can figure out if it can use them quite easily, but chances are it will have to be modded to use them.
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#15
If they have EL34's in there now it wont take 6L6's unless you get the amp modded by a tech.
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#16
Thanks! I pretty much have an idea of what I'm going to do at this point (just resell the Tung-Sol 6L6GC-STR power tubes and go for some sort of EL-34's), but I have one last question, if I am allowed to post it in this thread.

Would it be worth it to get a technician to rebias the amp to accept the 6L6's (I don't mind the cost of hiring a technician), or would I barely be able to tell the difference between the two types of power tubes and should I just stick with EL-34's? If so, which EL-34's would you say could compare to Tung-Sol 6L6GC-STR power tubes?

I'm not too sure if JJ's may be something I would want (I've heard they were a tad dark), but feel free to guide me in the right direction.

I appreciate all of the help I have received so far!
Last edited by keennay at Dec 2, 2008,
#17
either way you're going to have to get your amp biased to work with a new set of tubes.

we're not sure if your amp could handle 6L6's at all. but if it did, it would also need to be rebiased because 1) it's a new set of tubes and 2) they're biased at a much different voltage than el34's.
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#18
Yeah, it's not just be biasing, you have to get your circuit changed. Not really worth it.
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#19
Hey again,

My preamp and power tubes have arrived! I now have JJ EL-34 power tubes, instead of the Tung-Sol 6L6GC-STR's.

I have two questions now:

* Can I just simply replace the preamp tubes (Electro-Harmonix 12AX7EH's to Tung-Sol 12AX7's)?
* Since my old power tubes are Electro-Harmonix EL-34's, can I just install the JJ EL-34's or do I still need a rebias?

Thanks

P.S. The amp sounds awesome with the Celestion Vintage 30 speaker!
#20
yeah, you can just replace the preamp tubes, but you should get your amp rebiased for the different powertubes.

chances are nothing majorly bad will happen, since the amp is most likely biased a little cold. but if you want the most out of those tubes, get it rebiased.
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#21
yea but i wouldnt put in the powertubes without a bias anyways.. if someone knew how these amps are biased from the factory and we knew what rating the tubes he bought were then we could say for sure. but dont do it if you dont bias, you risk the chance of them redplating, its unlikely yea, but do you want to throw away $40.

also, the biggest difference for the speaker would be just to get a closed back cab. single v30s dont really sound that good, especially in open back things like a combo. and open back is definitely not that good for metal. i can do it with my mark iv combo but it really needs a cab for good rhythm work.
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#22
Just here to say the power tubes have been installed and biased by a technician and all upgrades have been completed on this amp!

Upgrades:
-- Preamp Tubes: (4) Tung-Sol 12AX7
-- Power Tubes: (2) JJ EL-34
-- Speaker: Celestion Vintage 30

The technician even gave me a record on what was done, stating he "adjusted the bias to 70% MPD @ 465v idle" (I have no idea what that means)!

Thank you everyone for the help! All that is needed now is an ISP Decimator & maybe an MXR 10-Band...
Last edited by keennay at Dec 17, 2008,