Mark IV, new Tubes - Mark II agression! :)

[boola]

I've just re-tubed my Mark IV after buying it second hand.

I got 4 Svetlana winged C 6L6's and 2 EL34's.

I mostly play metal on it and found the EL34's to give a crunchier distortion, I definitely prefer them to the 6L6's.

I got 5 harma cryo 12ax7's, 1 7025 high gain for V1, 3 STR's for 2,3 and 4 and one balanced 7025 for V5.

I had a mix of all sorts of 12ax7's in it before and I experimented using some old and new.

In the end I found that while the harma 7025 in V1 produced very clear, crisp distortion with brilliantly defined bass, there was quite a lot of hiss or hum, even on clean.

The surprise for me was the little sovtek 12ax7-LPS that was already in there. Used in V1, it produces a lovely clean tone and there is no noise on lead. It produced a slightly looser maybe even more distorted lead tone than the harma 7025. It made the lead distortion more open like a rectifier. It just works so well to my ears.

Another surprise was that I found the Mesa spax7 in V1 made it sound compressed - perhaps it's a bit old? I thought the spax7 would be a good tube.


Finally I settled on:

V1 : sovtek 12ax7-LPS
V2 : harma cryo 7025
V3 : harma cryo STR
V4 : harma cryo STR
V5 : blanaced harma cryo 7025

2 Svetlana W-C EL34's and 6L6's

I'm playing with class A, harmonics and tweed or full power depending how late it is : )

Just thought I'd share my experience incase anyone will find it useful. I find this gives an awesome Metallica/Megadeth tone and combined with my channel settings I have got the mark IV sounding raw and aggressive as hell like a IIC, not compressed and 'boxy' like it can sound.

What an amazing amp!

 

[boola]

http://www.youtube.com/watch?v=ozgxMstSVBE

I have posted a short clip of the Mark IV in action, hopefully you can hear the bite and evilness I have managed to coax out of it : )

I realise that post should have gone in the tubes section, maybe someone will move it.....

I have switched to a harma 7025 in V1 and V2 now with the sovtek in 3 - it changes the tone when I kick in the reverb.

 

[tunedown]

I'm a brand new Mark IV user (short head + 1960A cab) and I've experienced some of the same things as you have. I play heavily distorted but not "Metal" so I like the amp to sound very raw and aggressive in the same way you described without sounding too tight or crisp in a "solid state distortion" kind of way.

I purchased the amp a week ago with 4 6L6's and it looks like a full set of 12ax7s and I believe all of the tubes are GT.

I understand that these amps take a bit of tinkering to find the sound that you're looking for, but I had the thing sounding pretty **** good when I demo'd it from the guy I was buying it from. I've read a lot of people's accounts that it took them months to get it to sound the way they want it to, but I've not had that problem at all.

I run all 4 tubes (Simul-Class) and full power. I drive the pre-amp pretty hard and I started in Pentode mode but switched to Triode to smooth it out and I really like what I got. Some people say it sounds "creamier" and that's not far from the truth. In Pentode it tended to be a little too "Crispy Metal" for my taste and I'm not sure I lost too much "punch" when i switched.

I switched from a 100 watt JCM 800 I was trying to drive the hell out of, and I love that I can switch the head to TWEED and get a very very similar tone that makes me not really miss my 800...

My MKIV is brand new to me, but I'm upset that I never bought one years and years ago.

QUESTION: How do I deal with the trading out of power tubes in this head? If I want to run two 6L6s on the inside and 2 EL34s on the outside (instead of 4 6L6 like I currently have) what do I do? How do I deal with Bias issues? The manual says that the head has "fixed bias". Can it really be that easy?

Thank you and sorry so long.

JP

 

[boola]

Just put the EL34's in the outside sockets and that's it! That really is it You don't need to bias Boogies but the tubes must be within specification - not a problem if you've bought Boogie tubes and over here in the UK, Watford Vavles made sure my Svetlanas were in range.

I have a 2203 as you can see in the video, I think it compliments the Boogie very nicely, perhaps I just haven't worked out how to get that Marshall sound of it yet - It does take a while to get the sound you want, the settings all interact and change depending on volumes but this just increases the amount of possibilities. The sound you are looking for is certainly in there somewhere, good luck!

 

[tunedown]

I have a 2203 as you can see in the video, I think it compliments the Boogie very nicely, perhaps I just haven't worked out how to get that Marshall sound of it yet - It does take a while to get the sound you want, the settings all interact and change depending on volumes but this just increases the amount of possibilities. The sound you are looking for is certainly in there somewhere, good luck!

The way I'm running my jcm800 2210 (hard with 6L6s), I can get a very similar sound out of the Mark IV in R2, on pentode, running the amp on Tweed power. varying volumes, gains, and presences it's plenty warm when I want it to be and it's plenty cold and cutting when I have a 5150 II to pair up with

I haven't tried to pair up 6L6s and EL34s yet, what should I expect?

 

[boola]

I drew an ascii pic in here but it didn't come out when submitted

 

[boola]

Ah should have figured you'd have 6L6s... my JMP has EL34's.

The best way I can describe it is the EL34's have more top end crunch and a more mid scooped sound. The 6L6's have more lower mids/upper bass and are smoother.

I like the combination of the 2, it gives the amp a 2 dimensional feel to it.

 

[tunedown]

Ah should have figured you'd have 6L6s... my JMP has EL34's.

The best way I can describe it is the EL34's have more top end crunch and a more mid scooped sound. The 6L6's have more lower mids/upper bass and are smoother.

I like the combination of the 2, it gives the amp a 2 dimensional feel to it.

I'll have to give that a shot here one of these days. Geez, talk about a unique head... With 3 channels, independent tone controls, simul-class and class-A, Pentode and tri, a high-gain stage for R2 and Lead, reverb, the EQ, AND I can also run any combo of 6L6s, 6V6s, or EL34s, (etc) whenever I want without a re-bias?

It's no wonder people feel like they can make it sound any way they want. (but it still has that "distinct" sound as a Mark IV).

It never ends. When does it turn in to a yellow race car?

 

[boola]

I can also run any combo of 6L6s, 6V6s, or EL34s, (etc) whenever I want without a re-bias?

No rebiasing is needed ever but you can't just stick any tube in.

the cobos are:
2 EL34's in the outer sockets + 2 6L6's
all 6L6's
or 6V6's but must be run in tweed + simul

Seriosuly download the manual from the Boogie site, it covers all this and a lot more that will get you started. Read it a few times and you'll have much more control over the amp.

ps if you think the Mark IV is versatile, checkout the Road King, it is crazy!

 

[HalfDeaf]

+1 for the SED winged C EL34s.

In my other amps, I've been using the winged C 6L6s for years, and I just happened on a pair of EL34s. The winged C 6L6s have quite a good reputation (and well deserved), but nobody talks much about their EL34s. I find them to sound significantly different than EL34s Mesa sells, definitely a bit more vintage sounding to me - perhaps more harmonic content.

Running them in my mkiv class A/full power/pentode with moderate gain on R2 or Lead makes for an amazing tone.

Also, they have a great blues sound when the amp is in class A/tweed/triode on R1 with the gain low and the bright pulled (and the output turned up - the key here is to get those EL34s cookin' a little).