HELP:Thinking about "+" mod on MARK III BLUE STRIPE COLISEUM

[thp]

Hopefully some of you good boogie comrades can extend a little advice on this matter? I was quite fortunate recently to purchase a Mark III blue stripe Coliseum. It is a wonderful amp as many of you know. I use it exclusively in high gain settings. It has most of the character that I am looking for with a couple of small exceptions. I am basically chasing the tone of my Quad Preamp and Strategy 500 power amp. This is my main amp, but it is too big to take to some of the playing engagements that require me to fly. Knowing that the Mark III is a different amp I am hoping to smooth out the top or "fizzy" end of the high gain and also achieve some more suction in the low end department when I "chunk" or mute a chord. The Strategy 500 has a "deep extend" that gives stunning low end with no flub, just pin point precision and enveloping tight low end. First, would a "+" mod smooth out the gain while keeping the same amount of gain available? and second: Has anyone done a "deep extend" mod?
Any thoughts on the matter would be greatly appreciated!!!

 

[themisfit138]

I have a black dot with the + mod. I never heard my amp with out it but it seams like compared to my friends red stripe I have to have the gain settings higher to achieve the same gain, so it may have lost some gain or that is just how the black dots are. To really get that Justice tone, I have found that is you keep the 80 slider at half or or lower you really get that growl and chug. I keep my 80 slider below the quarter mark. Also, you can have the 240 slider up pretty high and get the good lows.

 

[thp]

Thanks for the response, I appreciate the advice!! I tried out a regular Mark III blue stripe before I got the Coliseum and noticed that it has a bit less gain. I wonder if there is enough internal gain within the Coliseum to lose a little and achieve what I am looking for with the "+" mod??

 

[themisfit138]

I don't see why not. I don't find mine lacking for gain at all. The + mod should smooth out the top end and still have plenty of gain.

 

[thp]

That is what I am thinking as well. Thank-you!!

 

[themisfit138]

No Problem!

 

[fretout]

As the proud owner of both a stock, Blue Stripe head, and a Blue Stripe Coliseum, I've A/B'd these amps extensively, and there is certainly a difference other than the perceived volume.

For starters, the Blue Stripes may have the most gain of any Boogie made. Ever. The Mark III amplifier line is known for having more gain than than any other Mark that came before it (yes, including the Mark IIC+), and certainly has more gain than the Mark IV (i currently own two of these) and Mark V. Even when placed against Mesa's Dual (i own 2 early revisions) and Triple Rectifiers (I owned one, recently sold it), the a Blue Stripes have more gain than even these iconic amps! So, if you need more gain than Mesa's highest gain amp to date, I'd have to humbly say you're probably doing something wrong.

As for the bass response or "depth", the Coliseum is going to be much tighter than a 4 power tube Blue Stripe. Also, the "bloom" (the sound of muting or chugging palm muted notes/chords), will have that "pin-point attack" due to the higher headroom and the fact that the Coliseum uses the same power transformer as the Bass 400+ (and IIRC, the Strategy 400 power amps). So in the bass/low-end department, I don't think there's a mod available to tighten this up any more than it already is. My best advice is to use either a higher-rated speaker (the old EVs and C-90s would be a great, tight, transparent option), or use a clean boost up front to tighten up the entire amp (a TS9 or Maxon 808 would be a good start).

As for the III+ mod, it will definitely smooth down the gain of the amp, and make the Presence/Treble/Gain have more "sweep" to them, and will require you to have the setting higher than normal to bring the amp back to the original capabilities. The reason I would recommend against the III+ mod is it will voice the amp darker, and so while it will tame down the gain, the darker character of the amp may not be what you're looking for from the low-end.

Just my .02 based on my experiences, but overall, I think you may have the foundation for the tone and response you're looking for, but you may want to look to the speakers and boost for the answers to your problems.

 

[kdorsey]

As an alternative to the + mod, consider a darker 12ax7 in V3, like an NOS RFT. It will retain the gain but shift the fizz out of the EQ. I use it as almost a "spice" to de-brittle ch3. Other tubes may work, I just have experience with that particular one. Plus, no soldering iron required!

Good luck!

 

[thp]

Thanks for the responses and insights gentlemen!! I actually decided a couple of weeks ago to do the "+" mod, I am now wondering if I will regret it? I guess I can always have it switched back. The guys at boogie were also pretty clear that they thought I should have 5881's in the power amp section. I explained that this amp will be used exclusively for high gain applications and punch. They felt that it would be the right way to go? So I decided to try something new. I have never used these tubes. From the general description I would not have tried them had they not been suggested. I normally use 440's. Does anyone have an opinion on this? Also, is there a preamp tube that could be placed in any particular position that you feel could reverse a bit of the "+" mod if I didn't love it (or change the voicing for high gain applications)? I know I am doing all of this backwards. I have used a quad preamp and strategy 500 poweramp for so long that I now realize I don't quite know the in's and out's of the conventional heads. I know the tone I am looking for, it's just how to get it? Thanks again everyone...

 

[Seanboy]

I too was about to do the "+" mod, I took Kdorsey's advice and put a nos RTF in the V3... My amp has never sounded so good, the change is remarkable! Best thing I've ever done with the amp.

Sean

 

[kdorsey]

I too was about to do the "+" mod, I took Kdorsey's advice and put a nos RTF in the V3... My amp has never sounded so good, the change is remarkable! Best thing I've ever done with the amp.

Sean

Thanks for the nod. 8) And I'm glad it worked out for you, too.

The big revelation, for me, was the tonal impact of that one tube. No other 12ax7 made that much of a difference before. I had switched speaker cabs, speakers, EQ, etc. but nothing tamed that brittleness. Granted, the green stripe has all of these mods already, so YMMV, but having a completely reversible solution was very attractive to me.

I would have no idea how to tonally reverse the + mod.

 

[fretout]

To the OP...

So, how do you like the III+ mod? Did it give your amp the solutions you were looking for?

 

[rgx612a]

what the hell is a "nos RFT" and where do i get one?

 

[Rhoads]

http://www.kcanostubes.com/content/nos-rft-12ax7

 

[mesaboogie6L6]

These tubes are the real deal and sound better than any i've tried so far in the V1 in my Coli. I put one in the V1 in my 2 channel dual rec and BAM!

 

[ryjan]

A 5751 in V1 would smooth things out also.

 

[rgx612a]

$60 for a single 12ax7?? :shock:

 

[Seanboy]

Yep, and worth every penny!

 

[mesaboogie6L6]

I bought 3. I have these in V1 and V3 in my Coli. I have one of these in V1 in my two channel dual rec. Totally BADASS!

Yes worth every **** penny, believe it. I've tried RCA blackplate, JJ, Penta, Mesa, Tung Sol RI, Sovtek. JJ's sound good, but none come close to an RFT.

 

[Seanboy]

I was about to sell my Mark III, I just couldn't find that tone I was looking for, it was just too fizzy. I took the advice of KDORSEY'S, and bingo!! That was exactly what the amp needed. The amp is now the beast that everyone says they are. Buy one and give it a try, if you don't like it, I'm sure there's plenty of members on here who who buy it off you.

Sean