Mesa/Boogie Valve recommendations please

uncledick

I'm currently working with a band basically doing Indie (ish) stuff so probably need an AC30.  In the absence of that, I've dug out my Subway Rocket Reverb which has a twin EL84 output stage and can do a reasonable imitation of the Vox sound.  The amp is, however, getting on for 20 years old and is getting a bit hissy so I thought it would be a good time to swap out the valves.  Due to the fixed bias setup, I guess I'd better stick with Boogie valves for the output stage but I wondered if anyone had any recommendations for the rest, which are currently 12AX7s.

Bearing in mind I don't do metal and I'm looking for the cleaner/jangly end of the sound spectrum any input/advice gratefully received.  I'll be using my American Std Tele if that helps.

Drew_TNBD

No idea, but maybe @karltone can chip in.

ICBM

The Subway Rocket doesn't sound remotely like an AC30 unfortunately - it's nothing to do with the output valves. I have one here right now and it's one of the most middy, barky, aggressive-sounding amps I've ever heard… and that's just the clean channel . I used one in a band many years ago too and that's my main memory of it! Mid, mid, mid and more mid.

You can use any decent power valves, I would probably recommend JJs since they the most robust of the modern ones, and I think Mesa are using them now too. They're also using JJ preamp valves and I would definitely *not* recommend those because they are very harsh and middy, which will only make the amp more so. Tung-Sol, EH or TAD are all much clearer and brighter.

If you have more money to spend, replacing the extremely middy 'Vintage' speaker would help far more than a valve change. A Celestion Gold G10 would be the obvious choice but it costs about the same as a small car...

uncledick

ICBM said:

The Subway Rocket doesn't sound remotely like an AC30 unfortunately - it's nothing to do with the output valves. I have one here right now and it's one of the most middy, barky, aggressive-sounding amps I've ever heard… and that's just the clean channel . I used one in a band many years ago too and that's my main memory of it! Mid, mid, mid and more mid.

You can use any decent power valves, I would probably recommend JJs since they the most robust of the modern ones, and I think Mesa are using them now too. They're also using JJ preamp valves and I would definitely *not* recommend those because they are very harsh and middy, which will only make the amp more so. Tung-Sol, EH or TAD are all much clearer and brighter.

If you have more money to spend, replacing the extremely middy 'Vintage' speaker would help far more than a valve change. A Celestion Gold G10 would be the obvious choice but it costs about the same as a small car...

Thanks for the very thorough response.  As I'm currently laid up with a broken leg, I missed out on the Birmingham Guitar Show so the funds I might well have spent have now gone on a G10 Gold and some valves.  I'd been listening to some Celestion demos online at the weekend which is a complete waste of time with computer speakers so it's good to get a recommendation.  I'll report back in due course.

Maynehead

I have a subway rocket reverb too, and yes, I can confirm it's very middy, mainly due to the eminence 50 speaker it comes with. Playing it through my v30 2x12 cab opens up the sound to no end and greatly improves the tone on all channels.

As for valves, I'm using a Tungsol in v1 (the second valve in from the edge), EH in v2 and v3, and a JJ ECC803s in v4 as PI. As a rule of thumb you want to use the most treble heavy and mid light valves you can find to counteract the inherent middiness. Also don't worry about finding high gain valves as the amp has too much gain already. In fact some use a 12at7 in v1 to tame the gain (I don't as I find this adds even more mids!)

ICBM

They do have way too much gain, yes. I've just modded the one I have here, partly to fix a problem with it squealing due to valve microphonics when cranked - having tried many different ones and only been able to vary how bad it was rather than stop it completely.

I replaced the link wire which feeds the tone stack with a resistor, which has lowered the overall gain and reduced the mids a bit too. The link is roughly behind the treble control and runs front to back in the amp - I replaced it with a 470K resistor.

(On the non-reverb Rocket it appears to be a 100-ohm resistor rather than a link wire. No idea why since the value is too small to make any practical difference!)

Maynehead

@ICBM actually, since there seem to be 3 of us all with Rocket Reverbs, I might as well ask about something that has been bugging me.

On mine, on the crunch channel, the gain control will reduce the gain (and volume) as you turn it down until it gets to about 2, where the gain hits a minimum (but still not clean). Then as you keep turning it down to 1 and then 0, the gain actually increases slightly and stays at a slightly increased level all the way to 0. This means with the gain at 0, it will have more gain than with the gain at ~2.

On the clean channel it behaves as I expect - as you keep turning the gain down, it will get less and less gainy until you hit 0, when it practically cuts the volume off.

Is this normal or do I have a dodgy component somewhere?

uncledick

Maynehead said:

@ICBM actually, since there seem to be 3 of us all with Rocket Reverbs, I might as well ask about something that has been bugging me.

On mine, on the crunch channel, the gain control will reduce the gain (and volume) as you turn it down until it gets to about 2, where the gain hits a minimum (but still not clean). Then as you keep turning it down to 1 and then 0, the gain actually increases slightly and stays at a slightly increased level all the way to 0. This means with the gain at 0, it will have more gain than with the gain at ~2.

On the clean channel it behaves as I expect - as you keep turning the gain down, it will get less and less gainy until you hit 0, when it practically cuts the volume off.

Is this normal or do I have a dodgy component somewhere?

The gain on mine behaves pretty much the same on both channels.  Like some Fender amps it's a bit non-linear between 0 and 2 but not really a problem.  Overall, I've never found the amp to be too excessive with gain.  I tend to run the rhythm channel at around 6 and the lead at 3 or 4.  

ICBM

Maynehead said:

@ICBM actually, since there seem to be 3 of us all with Rocket Reverbs, I might as well ask about something that has been bugging me.

On mine, on the crunch channel, the gain control will reduce the gain (and volume) as you turn it down until it gets to about 2, where the gain hits a minimum (but still not clean). Then as you keep turning it down to 1 and then 0, the gain actually increases slightly and stays at a slightly increased level all the way to 0. This means with the gain at 0, it will have more gain than with the gain at ~2.

On the clean channel it behaves as I expect - as you keep turning the gain down, it will get less and less gainy until you hit 0, when it practically cuts the volume off.

Is this normal or do I have a dodgy component somewhere?

This one does that too, although the low position is at 1.

It will be caused by crosstalk in the V2 valve most likely - on the lead channel both halves of the valve are used, in series so they are out of phase with each other with the gain control in between, so if there's a little bit of leakage from the second stage back to the first the amount of cancellation will be greatest at a gain setting just above zero. In fact the tone at the low point is noticeable 'phasey', so I'm sure that's the cause. On the rhythm channel only one half of the valve is used.

Maynehead

Great info, much appreciated.