Laney AOR50 series II power tube swap...bias pot?

[Animal]

I've been considering gettin' some JJ 34L's for my Laney AOR head and I've read that you should bias your amp hotter with these type of tubes. Although I would assume that an amp like the Laney AOR (hotrodded JCM800 clone) would have a bias pot, I want to make sure that it actually has one before I order new tubes.

Also can anyone vouch for JJ EL34L's in such an amp? I want to decrease the top end harshness, increase sweeter mids, and tighten up the low end. Are 6CA7's worthy of consideration?

It's sounding a bit flubby and fizzy. Mainly on the AOR channel, which I'm pretty sure uses op-amp clipping. I've been advised to get my caps checked out as the amp is almost 20 years old. Any further suggestions?

 

[wixedmords]

Re: Laney AOR50 series II power tube swap...bias pot?

It is hard to miss the bias pot on that one HJ. Being an older amp, a cap change is a good thing. I have heard that changing the caps will also make it more crisp. I went to an AT7 in P2 & P3 in mine. You are gonna have to play with preamp tubes to get a sound you like.

For what you describe, the E34L isn't the tube you want, you are looking for JJ's standard EL34. (Notice the difference in model number) The E34L is meant to bridge the gap from EL34 to 6L6, having more headroom/bass and being a bit less middy.

 

[Animal]

Re: Laney AOR50 series II power tube swap...bias pot?

I went to an AT7 in P2 & P3 in mine. You are gonna have to play with preamp tubes to get a sound you like.

Yeh I'm rather overwhelmed with the amount of pre-amp tube possibilities. I've put a full set of Sovtek LPS in it and didn't really notice much difference from the unbranded stock tubes that were originally in there. I put a JJ ECC83S in the first position and it warmed it up a lil' bit. The GT12AX7c seems to get a good rep round here so today I bought one on ebay. I'm also interested in trying out a RFT ECC83. NOS Mullards and Sylvanias look appealing but I find it hard to justify spending so much coin on a pre-amp tube that might not work out too great anyway.

For what you describe, the E34L isn't the tube you want, you are looking for JJ's standard EL34. (Notice the difference in model number) The E34L is meant to bridge the gap from EL34 to 6L6, having more headroom/bass and being a bit less middy.

Hmmm, actually I think have enough mids. My EQ settings are rather hilarious. The bass, middle, treble and presence knobs are almost always turned down to somewhere near ZERO! The treble is especially fizzy. The mids are alright however can make the amp sound boxy/grainy when pushed and I would like them to sound "sweeter" if that makes any sense. Bass response is pretty loose and undefined when incrreased. I pull the bass knob out to engage it's "deep" function and keep it on 0. In hignsight, I would actually like to able to use my EQ without having nasty frequencies poke out.

I still have the Sovtek WXT's that came with the amp. I think they were installed right before I got the amp second hand about 10 months ago. I'm considering the EL34L's or 6CA7's to see what kind of different flavour they can give this amp. From what I've read, JJ EL34L's seem to be the ticket for giving EL34 amps extra balls for heavy and tight playing. Some dude on the Vintage Amps Bulletin Board was raving about how awesome an AOR's series II he had with Sylvania 6CA7's and then how lost it's mojo when he switched over to Sovteks.

So many options...

 

[Pierre]

Re: Laney AOR50 series II power tube swap...bias pot?

I have the same problems on my own AOR. It needs a recap but no one can do it for me. I put JJs in mine (6V6s and 12AX7S) and they improved the condition a little but the caps must be shot to death now. There definitely is a bias pot.
For V1 and 2, I'd advise a mid gain, silent tube, such as the EH standard ECC83, I quite like it. For the driver and PI, whichever decent tube would do.

 

[Animal]

Re: Laney AOR50 series II power tube swap...bias pot?

It needs a recap but no one can do it for me.

No well known amp techs in Scotland or Netherlands than can recap an amp?

 

[Pierre]

Re: Laney AOR50 series II power tube swap...bias pot?

Yep... but that'd mean getting my amp to the shop, wait a Tuesday for the tech to pick it up and bring it to his, him tell me what's wrong, me deciding how much I can fix... All the while the shops are NOT authorising me to talk directly to him, which I'd quite like, so I could know what he'd want to do to my amp. I decided I'd talk to every type of tech before giving them any jobs, and up in Edinburgh it's totally impossible

 

[devastone]

Re: Laney AOR50 series II power tube swap...bias pot?

I've been considering gettin' some JJ 34L's for my Laney AOR head and I've read that you should bias your amp hotter with these type of tubes. Although I would assume that an amp like the Laney AOR (hotrodded JCM800 clone) would have a bias pot, I want to make sure that it actually has one before I order new tubes.

The AORs are very "Marshall-esque" in the power section and do have a bias pot. If it was a fixed bias amp, you could still try the JJs in it, they just may not be running at their optimum. I also have to say, if you are asking if the amp has a bias adjustment, unless the amp has an external bias measurement point, you probably want to have a tech do it for you. As has been said 1000s of times, tube amps run at very high voltage (although the bias is a very low negative voltage) and can kill or maim you, or at least hurt really bad and maybe make you wet your pants. To measure the bias, you have to get very close to that high voltage.

 

[wixedmords]

Re: Laney AOR50 series II power tube swap...bias pot?

fixed bias - an amp you usually need to adjust the bias
cathode biased - an amp that adjusts itself within a range
The tube is called E 34 L.

I think where many go wrong with this process in the fizzy AOR's is to put in dark tubes thinking they can tame the gain. I find that just muffles the sound, the old blanket over the speaker. You may want to think about adjusting your approach and look for something that will reduce the gain and cut through.

When you play with tube amps, you gotta have many preamp tubes to pick from. Switching them around is the only way to come up with the combination that fits your own ear. There is no short way around.


Edited because it seems like I was being too fresh.

 

[Animal]

Re: Laney AOR50 series II power tube swap...bias pot?

T As has been said 1000s of times, tube amps run at very high voltage (although the bias is a very low negative voltage) and can kill or maim you, or at least hurt really bad and maybe make you wet your pants. To measure the bias, you have to get very close to that high voltage.

Yep I'd be planning on taking it to a tech.

 

[Animal]

Re: Laney AOR50 series II power tube swap...bias pot?

. I went to an AT7 in P2 & P3 in mine. You are gonna have to play with preamp tubes to get a sound you like.

I'm curious as to what type of AT7's you put in those positions. There's a pair of JJ 12AT7's on ebay atm I'm considering snapping up for trying out this configuration. Also, what have you got in your V1 and PI position? I've heard 12AT7's also good for the PI slot.

Oh and thanks for pointing out the whole E 34 L confusion thingy. For so long I thought they were EL34's but just a bit different.

Thanks.

 

[wixedmords]

Re: Laney AOR50 series II power tube swap...bias pot?

Hey HJ. I put (2) Jan 12AT7 in P2 & P3. I put a JJ ECC803S in the PI slot. Tube suggestions are really a matter of personal preference, and speakers need to figure into the equation somewhere. (The ECC803S and ECC83S tubes are different tubes also.The most common JJ 12AX7 is the ECC83S.)

Even with the (2) 12AT7's anything noon on the dial and before is very Angus Young and anything above that gets into high gain. It made the gain more usable for me.

The 2x12 I am running this head through currently has a Emi Wizard, and a V30. Both speakers allow that treble grit through that I am trying to tame a bit. So I am looking to change out the V30 which also muffles the bass a bit too much, making the bottom end flabby, which I don't hear in the Wizard.

It has been an amp that takes more work than some to find the right tube combination because of that gritty annoying top end that mine has. But, I'm not done yet. Not satisfied yet.

It really is like a high-gain JCM 800. It is alot different than my GH100L.