How to tighten up a tube combo amp? Preamp tubes?

[Number Of The Priest]

What can I do to tighten up the overall sound of my Mesa DC-2 combo amp? I like how warm and smooth it sounds for leads but it could really benefit from having a tighter defined sound and a little more "edge" for distorted rhythms. I won't hesitate to say that it's even a little bit muddy and flubby/loose.

Strangely enough, I got a wonderful, aggressive, tight/defined distorted tone from a Mesa F-30 combo I tried, and bought the DC-2 for a great used price since it was supposed to be the forerunner of the F-30.

I mainly play at quiet-to-light-jamming volumes, so keep this in mind.

Not sure what brand tubes are in it... they look like Mesa though. When it's stock, it's supposed to be two EL84s and six 12AX7s but I cannot confirm what's there in my own amp. Do the preamp tubes or poweramp tubes have a greater bearing on tone at lower volumes? Preamp is my guess... [img]/images/graemlins/scratchhead.gif[/img] If you suggest swapping them, what would you recommend? Post prices, links to vendors where I can buy them, a guide on how to replace tubes, etc. I'm a tube amp newb, sorry! [img]/images/graemlins/crazy.gif[/img]

Could it be that I'm just more accustomed to the Marshall-type tight defined crunch and searing leads? [img]/images/graemlins/scratchhead.gif[/img] I really did like the Mesa F-30 though.

[Cleveland Metal]

Re: How to tighten up a tube combo amp? Preamp tubes?

I'd have to say you could probably do a lot of tube crafting with it and probably tighten it up a bit. You'd really be needing to use a mix and match group of NOS tubes, and that is unlikely to find without months of ebay seeking.

I love old RCA 7025s for their loudness, upfront/bright and tight gain. Standout tubes for sure, one in the right socket might be enough... Might look on ebay and see if you could score one or two and move them around the sockets, you will be probably pleased.


[ QUOTE ]
Could it be that I'm just more accustomed to the Marshall-type tight defined crunch and searing leads?

[/ QUOTE ]

Could very well be... MESA have ALWAYS given me fits for their spongey, flubby sound. Definitely dark sounding compared to a Marshall. Yet, people like Loomis have amazed me at the tones they get. I can't seem to do it myself though.

[Number Of The Priest]

Re: How to tighten up a tube combo amp? Preamp tub

Damn, I don't have the patience to dick around with lots of tube combinations... that could take me an eternity! [img]/images/graemlins/laugh.gif[/img] [img]/images/graemlins/crazy.gif[/img]

What I need is an ultra low wattage 1x12" Marshall-type tube combo that has independent controls (including the all-important reverb) on two channels and be $500 or under. [img]/images/graemlins/laugh.gif[/img] [img]/images/graemlins/laugh.gif[/img] [img]/images/graemlins/laugh.gif[/img]

Actually, the Mesa F-30 would do, but I'm still waiting for a very inexpensive one to pop up on Ebay, and be located within the Canadian borders so that I don't have to pay customs. [img]/images/graemlins/laugh.gif[/img]

[Cleveland Metal]

Re: How to tighten up a tube combo amp? Preamp tub

Yeah. Can take time... Wish I had a couple RCA 7025s to send yas. I only have one and it's in the CAE.

Tube crafting in a good amp that recognizes them well, is the way to get the tone that is in your head. takes time, money and patience and is worth it all.

[Number Of The Priest]

Re: How to tighten up a tube combo amp? Preamp tub

RCA 7025 listings on Ebay:

http://search.ebay.com/rca-7025_W0QQfkrZ1QQfromZR8

[img]/images/graemlins/grin.gif[/img] Are these the ones you're talking about? [img]/images/graemlins/grin.gif[/img]

[screamindv]

Re: How to tighten up a tube combo amp? Preamp tub

At low volumes, the preamp tubes are supplying the crunch. I have gotten a nice tone using a groove tubes 12ax7M (Mullard reissue) in my triaxis. If your cabinet is sealed, try removing the back, that will give it a more defined sound. The type of speakes you have also makes a big difference.
Screamin'

[Number Of The Priest]

Re: How to tighten up a tube combo amp? Preamp tub

The speaker is a Vintage Black Shadow and the amp is an open-back design:



I thought a closed back had a more focused sound while an open back projects the sound in all directions. [img]/images/graemlins/scratchhead.gif[/img]

[Cleveland Metal]

Re: How to tighten up a tube combo amp? Preamp tub

Yeah, there are different vintages there, and I really don't know which one I have... As a rule of thumb, I'm told that generally, all of the NOS RCA 7025s are a tight, loud and bright tube.

Man, some nice ones there... Not too hip to the cheapies.

I like the guys that use the better Hickok tester and show the 115 or so rating. But the higher end ones are sweet ones. epecially he $165, wow... Way too much, but way cool...

Watch out of the newby sellers and the ones selling batches. Batches are often someone selling off low rating tubes they have amassed.

[Cleveland Metal]

Re: How to tighten up a tube combo amp? Preamp tub

[ QUOTE ]
I thought a closed back had a more focused sound

[/ QUOTE ]

My experience has been that sealed cabs are tighter, more focused and have better/tighter bass response and open back cabs.

[Number Of The Priest]

Re: How to tighten up a tube combo amp? Preamp tub

I just took a closer look at the back of my amp for the first time... I'm seeing the two Russian Sovtek EL84s and six Mesa 12AX7As. They're quite securely held in there by a big steel thing supporting them... wouldn't know the first thing about changing tubes... [img]/images/graemlins/laugh.gif[/img]

If I were to buy those RCAs, how many would I need? [img]/images/graemlins/laugh.gif[/img] I mean, I've got six 12AX7As in there right now, three per channel I believe, so does it really matter which ones get swapped and how many get swapped?

[img]/images/graemlins/crazy.gif[/img]

[screamindv]

Re: How to tighten up a tube combo amp? Preamp tub

I find that closed back cabinets have more bottom unless ypu put it against a wall.
Screamin'

[khabibissell]

Re: How to tighten up a tube combo amp? Preamp tub

Get an overdrive or eq pedal to boost it, then turn down the onboard gain.

Adding mids might help ya too.

[Number Of The Priest]

Re: How to tighten up a tube combo amp? Preamp tub

I actually don't use very much gain at all, and I actually LIKE a lot of mids! [img]/images/graemlins/laugh.gif[/img] Guess I'm screwed there. [img]/images/graemlins/laugh.gif[/img]

[Final Sacrifice]

Re: How to tighten up a tube combo amp? Preamp tub

Please forgive my tube ignorance, but what is it about the really nice old tubes that prevents them from being faithfully reproduced. I know they have repros of some but if they were good enough, no one would shell out the bucks for the old ones, while I'm sure a tiny part of that is bias and perception.

[Cleveland Metal]

Re: How to tighten up a tube combo amp? Preamp tub

Prolly not three per channel.

Pete would know for sure. In my xanax'd state lets see me say stupid things...

Prolly one tube is the main preamp drive tube, there are prolly tubes that are EQ, loop or reverb drivers. and a tube or two for clean and dirty channels, dirty channels will tendf o have several tubes, where the clean channels will have one. They do add up quick.

If you had one or two 7025s, I'd move them around and see where it makes the most difference.

Maybe someone will pop up with a tube diagram for that amp.

Just tubing it with new JJs might improve over the crappy tubes MESA uses a lot. I tried out 16 of the high end MESA SPAX?-12ax7s once to get a couple that weren't crappy. Most were extremely microphonic.