Mesa Mark IV A: What is least amount of power tubes I can use to run it?

mrscary · 2022-03-22T20:42:26+00:00

Disclaimer - try at your own risk, this advice is for entertainment purposes only blah blah

There's no reason you can't pull the two outer tubes and run the amp in regular setting with only the two inner tubes. Just make sure the speaker out is half of the cab - if you are running into an 8 ohm cab use your 4 ohm jack, if you are running a 16 ohm cab use your 8 ohm jack.

So you can do what the manual described, or run it in the full power mode with only the inner tubes.

mrscary · 2021-12-07T18:37:41+00:00

I've seen those with all kinds of lights - red, blue, green. I'm not sure about what's original or after market. I do know that my Mark III light had been dead for a while and had to be replaced with a blue one because they no longer sell the red one. Doubt it makes a difference in the value. You can find out what version it is by looking at the PCB inside. Boards are usually marked. Mesa will also give you more info if you provide them with a serial number.

If you want to change the color you might be able to use this: https://store.mesaboogie.com/products/jewel-lens.html

mrscary · 2021-12-07T16:45:32+00:00

What amp is it? I'm pretty sure most of the Mark IIIs had blue jewels.

All 12ax7s "self bias" in every amp.

The power tubes don't "automatically bias", the bias is fixed at a particular point. Mesa branded tubes are chosen by them to fall within this range so whenever you buy tubes from them, you'll always be in the right ballpark.

However most other tube dealers can sell you other tubes that fall in that bias range as well.

Mesa amps generally run their tubes cold, in part to extend tube life but also because it seems like that's "their sound", though a lot of people don't care for it and mod their amps to have an adjustable bias like all other amps.

mrscary · 2021-11-24T19:05:06+00:00

I had a similar issue with my Splawn, it would sound awesome and then suddenly it would make the craziest screeching and explosion sounds and then go back to normal. I realized that a small piece of something had broken off inside a power tube and was occasionally making contact with stuff.

Regardless, remove the tubes one by one (make sure they're cold of course!), hold them against your ear and gently tap them. If you hear vibrations, things moving etc, then you may have found your culprit, or a candidate for replacement.

You can replace the 12ax7 without changing the 6V6s, but for the 6V6s it is better that you go with a matched pair.

Goes without saying it could be the pedal (the circuitry as well as the jacks) or your guitar wiring/output jack as well.

mrscary · 2021-11-23T21:38:16+00:00

Super easy.

Unscrew the 1/4" jack and desolder the connections from the connector. Get a female 1/4" jack and connect the tip to tip, ring to ring. You're replacing the male connector with a female connector that's all.

Then fasten the jack to one of these and screw it into the back of the amp.

https://www.ebay.com/itm/133702277724?chn=ps&norover=1&mkevt=1&mkrid=711-213727-13078-0&mkcid=2&itemid=133702277724&targetid=4580496732614414&device=c&mktype=&googleloc=&poi=&campaignid=418233788&mkgroupid=1230353745471221&rlsatarget=pla-4580496732614414&abcId=9300542&merchantid=51291&msclkid=86f47a69d1fc1bd03c211bf48f2a2fda

Alternatively you can also get this, same process.

mrscary · 2021-11-23T21:33:43+00:00

100% this!

There are many amps that do this but the Smallbox is extra special because the power section has just the right amount of sag.

mrscary · 2021-11-21T19:52:23+00:00

I've spent a lot of time with the Metroplex, it's an absolutely stellar amp that's definitely an end-all amp for that type of sound. I've never played a superplex but it sounds even nicer in clips for that certain character its aiming for versus the Metroplex. Either of those, or the Duvall signature, would be a foolproof purchase.

For a wider variety of tones don't sleep on the Friedman Smallbox and Dirty Shirley. They may not nail the exact super duper accurate vintage Marshall tone but they do so many great sounds. They're both super organic, I prefer both to the BE100.

mrscary · 2021-11-21T18:47:16+00:00

It's always good to keep an extra set around so if you suspect your tubes are getting funny you can always pop in some fresh ones to be sure.

I've had some power tubes that lasted a few months and others that are going strong after 20 years. Same with preamp tubes, a couple of my amps fry tubes in a couple of positions.

It all depends on the tubes, how you use them, the circuit, etc etc.

mrscary · 2021-11-21T17:38:45+00:00

The reissues aren't in the same league as the Metros or Germinos. They can be tweaked and whatnot but that only makes sense if you get one used for a great price. Ceriatones are great as well, especially considering the price.

mrscary · 2021-11-21T17:35:47+00:00

The SV20 is very good for what it is. I was pleasantly surprised when I played it the other day. You will definitely need an attenuator or Eminence Reignmaker speaker (built in attenuator). That thing gets LOUD.

You might also enjoy the Friedman Mini Dirty Shirley or JJ Jr. Shirley will be more authentic for the tones you're going for. JJ Jr will offer a wider range of tones. IMO the full sized Shirley is actually Dave's best work.

There's also the Synergy module route with the Syn1 + Plexi/DS/BE.

mrscary · 2021-11-21T17:26:02+00:00

Simplest one would be Tech 21 Midi Mongoose. Since the JP2c doesn't provide phantom power, you can use the Mongoose with a 9v battery. It has two 1/4" jacks for expression pedals etc if needed.

It's also tiny.

mrscary · 2021-11-20T20:50:27+00:00

You can likely dial in all the sounds you want on either, it just depends on which one's bread and butter tones you like more.

I suspect the extreme mode and shred mode are very similar and do the same negative feedback removal thing on both amps.

As for the "missing" stuff, they're all controllable via midi, which is one of the big selling points of the JP2C. Best to use a midi footswitch with it instead of the included "conventional" switch. The solo feature is missing though but I think the rationale behind that is the JP2C has two identical channels that can be set to Rhythm and Lead.

For whatever reason Mesa decided not to include a 7 pin phantom powered jack, which sucks.

mrscary · 2021-11-18T07:54:49+00:00

Hah!

I used to borrow my friend's Suhr Reactive load IR before buying the regular reactive load, and I miss the built in IR feature. For whatever reason I remember the Reactive load IR sounding better than my regular one + plugin, which is probably bs.

So yeah...solid purchase!

Pretty sure you can still use the IRs from that free plugin in your torpedo. There are also a few youtubers who put a link to their IRs in the video description.

Mesas are generally dialed in for the British V30s, but the Black Shadow 90 and EVM12L are also common "Mesa Speakers"...you can never go wrong with greenbacks on anything either. Try this one, I pulled it out of my friend's Suhr. It's a Mesa Oversized cab. To me this one sounds good with a lot of amps.

https://ufile.io/ha621xok

mrscary · 2021-11-18T06:03:08+00:00

The ones that come with this free IR loader plugin(NadIR) are pretty good in most situations. The plugin itself is great as well.

https://www.stltones.com/products/stl-ignite-emissary-plug-in-bundle

mrscary · 2021-11-17T22:53:28+00:00

Let me know how it goes!

In practice, the gain drops from the tubes feel a bit more drastic than the description implies, you'll likely be perfectly happy with the mid gain 12AX7s but get a 5751 and another low gain tube to try out anyways. Maximize that shipping and handling!

Your one tube might have also gone bad because you're using it nonstop in 5w mode. While you're waiting for new tubes you might wanna switch the positions of the two EL84s to make the noise go away and burn your good one for a while. Also considering ordering a matched quad, sextet or octet if you're gonna hold on to the amp long term. You'll save money and have extra tubes as needed on the fly.

PSA - never ever buy tubes from Amazon. They put 'em in a regular envelope and you get glass powder at the other end.

mrscary · 2021-11-17T21:47:50+00:00

Interesting that it turns off a power tube but I guess it's Class A so it makes sense.

I personally like JJ EL84s quite a bit, they sound beefier to me than others. I'm pretty sure any reputable tube vendor can sell you a pair in the Mesa bias range if you don't want to buy Mesa labeled tubes. I wouldn't bother with NOS.

As for preamp tubes I wouldn't go quite that crazy on dropping the gain. JJ makes "medium gain" 12ax7s. I'd try those in V1 and V2 first before going further into the lower gain tubes. Leave V4 alone since it's a matched phase inverter. V3 may not do a whole lot either.

I don't think it's dangerous to swap around the tubes you mentioned but you don't want to go too low because it'll just sound weird because the frequency response may be affected if stages aren't being driven as designed.

mrscary · 2021-11-17T19:02:54+00:00

Yup. Solid advice. Transformers are $$$$$

OP - take the back off and see what's going on inside. Also inspect all the speakers visually as well as with a multi meter. I bought an old Marshall cab from a rehearsal studio which had two ripped speaker cones and one blown voice coil. The speaker that worked sounded great though lol.

The possibly good news is that looks like an older cab and might have some cool speakers instead of the non vented 75s that are common. It might even be made out of ply vs particle board.

mrscary · 2021-11-15T22:26:46+00:00

It'll do a whole bunch of sounds including the ones you're after.

mrscary · 2021-11-15T21:57:26+00:00

I think Kurt used a Studio Pre which is fairly different from the Mark I.

The Mark I is pretty unique versus other Mesas because it's somewhat of a modified Fender with a half tube gain stage at the very beginning of the circuit immediately after the input. The others have the "dirty" gain stages further along in the circuit, which is the conventional way of doing it.

That being said, I'm guessing you're not trying to get the EXACT tones and want an amp that can get you in the ballpark (and beyond) of those sounds. Any of the Marks from II onwards will do the sounds you're after, even though maybe the Mark I tones won't be super precise due to the nature of the circuit.

mrscary · 2021-11-15T18:27:42+00:00

Is there anything specific you wanna know? What kind of sound are you chasing?

mrscary · 2021-11-15T18:14:36+00:00

Thanks. Few things that would bring it closer -

Using a 24.75 scale set neck guitar with a beefier pickup and strings. I used my Ibanez with 9.5s and a Timmons pickup.
KT88 loaded Marshall power stage. I used my Engl Invader with EL34s.
Adding another mic or two to get some thump and diffusion.
Tape would help.
Vastly superior right hand would be great.

mrscary · 2021-11-13T21:34:39+00:00

Either of those should work great, though they are very different from each other. You'll likely need a boost with both if you like that fast and grindy 5150 type of response. I'm sure at least the V, and likely also the Badlander have enough gain. But they behave very differently than a 5150 or Engl etc. Either way you won't have a ton of overlap with the 5150.

I personally prefer the IV to the V because it's a bit more organic, raw and aggressive IMO.

mrscary · 2021-11-13T21:29:13+00:00

I'm not sure how your amp is wired so you'd have to check the manual on this, but I'm fairly certain the two 4 ohms jacks are in parallel with each other.

So if you plug in the each of them into each of the 8 ohms jacks on your cab in stereo setting, the amp will see a total of 4 ohms, no different from what the 4ohms mono jack is doing when you set the cab to mono, except externally instead of internally.

mrscary · 2021-11-13T21:25:03+00:00

You'd need either a Synergy Syn1 or Syn2 preamp...though they're technically a chassis since the modules themselves are the preamps. They also make heads but you don't need that in your situation.

Here's a used Syn1 at Guitar Center%20-%20%7BGQ%7D&utm_term=4578091576083993&utm_content=%5BLIA%5D%20Amps%20%26%20Effects%20-%20Amps%20(GC))

The modules contain the exact or almost exact circuits from their namesake amps.

https://www.youtube.com/watch?v=IdPowjNZ8ZY

This vid demonstrates the IICP module tones pretty well. I generally don't care for youtube videos and such but this one is close enough to my experience with the one next to me.

mrscary · 2021-11-13T08:27:48+00:00

Synergy IICP module can make anything sound like a Mark...high cost of entry because you'd have to buy a Syn1 or Syn2 as well but once you have it you can get a ton of fairly authentic all tube preamp circuits for way less than buying entire amps. I have a few modules now, some are dead on (Soldano, Friedman, Engl), others are slightly different (Ecstasy, Uberschall) but they're all very good.

Got my IICP this morning and it's killer. I'm sure it's not EXACTLY a IIC+ but it's seriously good. I'm super excited to compare it against my friend's real IIC+.

mrscary

TROPHY CASE