Orange Rocker 30 - Pre-amp tube replacement

[Johnnyseven]

Hi there, i'm new to the forum and I apologise if this has been brought up before.

I've just bought a 2nd hand Orange Rocker 30 and I have been advised that the power tubes are self biasing so no need to pay a tech to re-bias the amp when replacing them. However i'm not sure if the pre-amp tubes are also self biasing. The previous owner replaced the stock power amp tubes with JJ EL34's but not the pre-amp tubes, which after I opened the amp up and had a look seem to be stock still. How do people rate the stock tubes, is it worth replacing them with JJ ECC83S tubes and do I need to get someone to bias for me?

Any comments would be appreciated.

[the_blue_bomber]

Preamp tubes never need biasing. You can just put the amp on standby or turn it off and switch them yourself. Just gently tug on them and rock them back and forth a bit and they'll come right out.

There is nothing wrong with the stock tubes unless they're starting to sound dull or microphonic. (i.e. bad) If they sound okay to you, they are okay. Generally, preamp tubes don't need to be replaced as often as power tubes.

If you're not sure if your amp would benefit from new preamp tubes, you could try some. I find that opinions vary greatly when it comes to what sounds good, so focus on trying to find out what you like. I've tried coveted vintage Telefunken and Amperex tubes and was less than amazed. Honestly, I like the preamp tubes that came in my Oranges, but I recently picked up some Tung-Sols and plan on extensively comparing them to the stock tubes. The differences I've heard so far are pretty subtle.

I say pick up some preamp tubes and try them out. If you prefer the stock ones, keep the ones you bought as spares. If you prefer the ones you bought, keep the stock ones as spares.

[Johnnyseven]

Thanks very much, that's really helpful information.

I also have a 1969 Carlsbro 50 Top and I fitted a set of JJ E34L's and ECC83S's and I really love the sound. I'm thinking of getting the same valves for my Rocker 30 to see what they sound like, although i'm sure it won't make the amp sound like the 50 Top. I like your suggestion that if I like the sound of the stock tubes over the replacement ones them keep theam as a spare set, that way I don't feel like if spent money uneccessarily on tubes that i'm not using.

It's also good to know that I can replace both the power amp and pre-amp tubes in my Rocker 30 without having to worry about paying someone to bias for me.

[ronnes]

Thanks very much, that's really helpful information.

I also have a 1969 Carlsbro 50 Top and I fitted a set of JJ E34L's and ECC83S's and I really love the sound. I'm thinking of getting the same valves for my Rocker 30 to see what they sound like, although i'm sure it won't make the amp sound like the 50 Top. I like your suggestion that if I like the sound of the stock tubes over the replacement ones them keep theam as a spare set, that way I don't feel like if spent money uneccessarily on tubes that i'm not using.

It's also good to know that I can replace both the power amp and pre-amp tubes in my Rocker 30 without having to worry about paying someone to bias for me.

i think your rocker 30 is delivered with JJ el34 tubes stock, what did the previous owner change them to? they say that the stock JJ tubes sound good(generally). do you know if the previous owner still has them and if you could get them?

[Johnnyseven]

The tubes that are in the amp are JJ EL34's, I presumed the previous owner had replaced them himself as the pre-amp tubes are not JJ tubes but some tubes with no name stamp on them other than saying ECC83. I would have thought that if the power tubes were JJ from new then the pre-tubes would have been as well.

As I was going to buy some pre-amp tubes anyway I thought I would get a pair of JJ E34L's at the same time, the glory of this amp is that I can take the power tubes in and out without having to worry about biasing - this way I can see which ones I like the best and keep the other set as a backup.

In the end I went for a set of Tung Sol 12AX7's as I was recommended them, does anyone have any comments on these particular tubes in this amp?

[a.hun]

Don't assume that the amp will run ALL EL34 type power valves in range without a bias check. Most will be fine but cathode biasing isn't quite fully self biasing, only having a limited range of self bias which fortunately should cover most modern production valves.

Still worth getting a matched pair from a food specialist supplier and specifying to them which amp they are for. Then you should be fine.

BTW more recent R.30s have come with EH 6CA7 valves. I like them fine in my R.30C. JJs are of course decent too.


Andy.

[blackorangegaz]

Hey, I too am a newby and was going to ask something similar regarding my Rocker 30, I emailed Hotrox and was recommended JJ ecc83's and E34L's, do the E34L's need biasing? are they the same as EL34's? I was told that EL34's do need a bias check. Sorry if this is a dumb question!
Cheers

[chazmusicman]

Actually I just received my new Rocker 30 combo in January and from the factory stock
it came with Ruby EL34s I thought it would come with JJs. The 12AX7s have no label on them so they could be JJs or something else.

I love the JJs though I put those in my Tiny Terror WOW

[Randy Bass]

...Still worth getting a matched pair from a food specialist supplier and specifying to them which amp they are for. Then you should be fine...

Do food specialist suppliers use tubes for convection ovens or something ? (Sorry, I know that typos happem all the tine)

Hey, I too am a newby and was going to ask something similar regarding my Rocker 30, I emailed Hotrox and was recommended JJ ecc83's and E34L's, do the E34L's need biasing? are they the same as EL34's? I was told that EL34's do need a bias check. Sorry if this is a dumb question!
Cheers

They probably told you that EL34s need a bias check because the vast majority of EL34-powered amps run in Class AB (instead of cathode-bias or Class A), and they assumed that you had one of those. The (power) tube type does not determine whether biasing a particular amp is necessary, as the process is actually biasing the amp to the tubes. The Rocker 30 uses a cathode bias resistor to set the bias from the factory. This value is suitable for MOST new tubes, so you should be OK to install a new pair of quality EL34s without any trouble. The E34L from JJ is a slightly different spec designed to produce more power and may not be OK to install without a check by an amp tech to make sure the amp is built to handle it properly. Don't be afraid to use Google to learn more about the E34L.

[blackorangegaz]

Cheers for that, think I'm going to play it safe and get it done by a tech, it shouldn't cost much if I'm supplying the valves right?

[Randy Bass]

Cheers for that, think I'm going to play it safe and get it done by a tech, it shouldn't cost much if I'm supplying the valves right?

It shouldn't cost much, but I wouldn't rule out getting the valves from the tech if they have a particular type or supplier that they have had good experience with. They don't usually charge much more for the valves than you would pay buying them yourself since they make their money from the labor.

[adamskiuk]

sometimes i've found that a tech can get the tubes cheaper than i could even online. The best i ever got in my rocker 30C was Harma EL34 retro's and Harma ECC83/7025 drive tested DR250. I got them from watford valves and they put the rocker in a different league! lots of smooth gain and a sparkling clean channel i found the JJ's sounded brilliant in my house but were too dark to cut through the mix live and in rehearsal. I'm really gutted that Orange has moved away from this rocker as the el34 power and 3 preamp tubes, for me was the nearest to a superlead i'll ever need and more!

[minty]

Can't comment on the tesla's but i'm sure they're fantastic too. i've found that the stock JJ's in the power section with tung sol 12ax7's in the preamp my rocker really opens up the sound, theres less of that muffled/boxy sound with waaaay over the top mids, now theres more dimension (ie. makes my 1x12 sound more 2x12...if that makes sense) and upper end definition with no major loss of bottom end, overall the sound seems more balanced with glorious harmonics. So for a few dollars spent on relatively inexpensive preamp valves i've got the sound i've been searching for.

[Johnnyseven]

I have to agree with you. I put Tung Sol 12AX7's in mine with JJ E34L's and played it for a while but didn't really like it, but then I decided to put the stock JJ EL34's back in and I was really surprised how good it sounded. My band has been on hiatus for a few weeks while various members are on holiday and I can't wait to get it to practice again and crank it up!

[TESLA_EL34]

seems like the tung-sols are a great match for the rocker 30?
on a german forum a guy reported the same with the tung-sols.
he said it's like someone has removed the invisible carpet before the amp...
sounds cool. well the tung sols are brighter as some other 12ax7's.

i experimented with different 12ax7's in v2 and v3 and i think the
shuguang 12ax7 (mine came with them stock) are just fine.
i like the gain they deliver and they don't sound bad!

i never like the tung-sol 12ax7 in my other amps but maybe with the R30 i give it a try.
for v1, i found the EH12AX7 to be a good match. adds more
highs to the clean channel!

i'll replace the JJ EL34's with some original Tesla EL34's and i
will report if it's worth it...got them really cheap from a tubedealer