Anyone convert their MKIII to a MKIII+ (IIC+)

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How does one get a hold of Mike B, as I have a question for him on my Mark 3 Coliseum 300. Thanks
 
Woah. A MK3 Coli? How'd you get ahold of one of them!? You lucky man, you. :lol:

As far as contacting Mike B, I'd imagine you call into the front desk, and ask for him right off the bat. Or, if you know his Ex.#, then just call him right away.
 
Ok thanks will try calling. My Mark 3 is a no stripe with KDRG 35 written on it and serialized #K532, on reading all the info I thought they only went to #500.
 
Hi,

I got a fully loaded Blue stripe (Simul). I have been reading this and similar topics for a long time. Some of the information is clear but the rest is really confusing. Could anybody resume the modifications for me, please!

1. Everybody say about putting 1000pf in c30 slot, but it is still not clear what is the value for this on the Red stripe and on the IIC+? Is this the only difference in the lead channel between the Blue and Red stripes?

2. Following the M.B. suggestions, the 1000pf in c30 should be the same as IIC+, BUT another user reported on having a 2000pf in his Black dot Mark III. Aren´t the Black stripes the same preamp as the IIC+?!?!?! Then what is the correct value for c30?

3. Somebody talks about c30 being from the pin 6 of v3, but also reported that by changing the cap from 500pf to 1000pf in the pin 7, v3 path you will get more effect. So, please, again what is the IIC+ mod exactly?

3. At the beginning you are talking about 20pf in the c27 to get a smoother tone, but in another post a user was told by M.B. that "10pf is definetely smoother". So what is the truth?

Thank you very much for your time and help!

Regards,
Yavor
 
bigjav said:
Hi,

I got a fully loaded Blue stripe (Simul). I have been reading this and similar topics for a long time. Some of the information is clear but the rest is really confusing. Could anybody resume the modifications for me, please!

1. Everybody say about putting 1000pf in c30 slot, but it is still not clear what is the value for this on the Red stripe and on the IIC+? Is this the only difference in the lead channel between the Blue and Red stripes?

2. Following the M.B. suggestions, the 1000pf in c30 should be the same as IIC+, BUT another user reported on having a 2000pf in his Black dot Mark III. Aren´t the Black stripes the same preamp as the IIC+?!?!?! Then what is the correct value for c30?

3. Somebody talks about c30 being from the pin 6 of v3, but also reported that by changing the cap from 500pf to 1000pf in the pin 7, v3 path you will get more effect. So, please, again what is the IIC+ mod exactly?

3. At the beginning you are talking about 20pf in the c27 to get a smoother tone, but in another post a user was told by M.B. that "10pf is definetely smoother". So what is the truth?

Thank you very much for your time and help!

Regards,
Yavor
1. The red stripe has a 500pF cap at C30, the blue stripe is empty. I can't say if that is the only difference between the blue and the red stripes.
2.The black stripe is NOT closer to the C+ tone. It does NOT have the same preamp as a C+.
3.Try C30 first, then do the other if needed.
4.@C27 a 10pF is darker sounding than a 20pF.
 
Thank you for the fast reply!

I have some more doubts, please:

1. Does everybody know what are the differencies between the RED and BLUE Lead channel? Only the 500pf in c30?
As we know, the RED is akin to the IIC+ preamp, and the BLUE is akin to the IIC+ power amp. If the RED c30 is 500pf why I have to put 1000pf then? I assume the c30 is not the only difference, so what is it then, please?

2. 10pf in c27 is smoother than 20pf. OK, great. Curious to know what is it in the RED? We know that the BLUE Rhythm 1 "was further reshaped and more agressive". This doesn´t have to do much with the idea of c27 10pf being smoother, aren´t the BLUE´s the brightest Mark III´s? I am asking this because somebody said c27 affects all channels, so the LEAD should be affected also by the c27?

Regards,
Yavor
 
I think that you're making some assumptions that are leading you to wrong conclusions. In my opinion you have some overly strong assumptions about what is a IIC+, what is a red stripe and what is blue stripe.

I don't think that anyone with authroity (ie, anyone from Mesa who's old enough to actually know...or boogiebabies, if he's lurking here, he would know) claims that the red stripe pre-amp is the pre-amp from the IIC+. I also don't think that anyone with authority claims that the blue strip power-amp is the power-amp from the IIC+. Finally, implicit in your questions, is the assumption that this is a single design for the IIC+. Sure, these assumptions are stated on the web occasionally, but there's lots of not-quite-right information out there. Let's discuss them a bit...and let's start with the last...

A Single IIC+ Design: This is definitely false. Your question regarding the Mark III C27 cap is a good example. The equivalent cap in the IIC+ can be either a 10pF or a 20pF. It depends upon which model you have. I believe that most of the Simul-Class amps have the 20 and that many of the non-Simul-Class amps have the 10pF. IMHO, though, that has only a small impact on the sound compared to the other changes. A variation in IIC+ design which has a bigger impact on the sound is the simul vs non-simul class power amp. Also, inside the amps, the IIC+'s all have a wide variation in the type (composition) of the capacitors used throughout. This can have a moderate impact on the tone, too (some say that they have a large impact on tone). The guys at Mesa were always trying to improve the tone...or trying to compensate for changes in tone resulting from other component changes. Some IIC+'s include a 100K resistor heading into the Treble pot, while some don't (this one is also a very small difference, IMO). Some IIC+'s have the 105 power transformer and some have the earlier one. That makes a difference. Finally, many IIC+'s have gone back to the factory at some point in their life for a maintenance overhaul. Power tube rewiring (pentode vs triode), for example, is is not an uncommon mod performed by Mike B during these overhauls. So, just based on this list alone, be careful when your trying to mod your amp to be like a IIC+. Which IIC+ are you aiming for? There's no single standard.

Red Stripe is a IIC+ Pre-amp: This one is "conventional wisdom" that I had heard before. On your specific question of 500pF vs 1000pF, the answer is that most (all?) IIC+'s have a 1000pF cap at the location that you are talking about. I don't know what's in the red stripe. Furthermore, the red stripe does not "have" the IIC+ pre-amp...mostly because it is not a IIC+. Sure, maybe it has (or can be modded to have) all the same component values as someone's IIC+, but this does not make it a IIC+. The problem is that the Mark III has a Mark III circuit board and IIC+ has a IIC+ circuit board (or an modded IIC circuit board...there's another difference between various IIC+'s). The Mark III board is built using a different process (the IIC+ circuit board was built in a very old-fashioned style compared to the III). One key difference is that traces on the two circuit boards have fairly different routes. In a high-gain circuit, this matters...and it's definitely an art and not a science. I've built my own amps and, even if the schematic is the same, if I route the wires differently, the high-gain sounds different. It's effect on tone is not the size of the difference between a Mesa and a Marshall, but it can certainly be equivalent to the size of difference between the 500pF and a 1000pF cap that we've all been discussing. The Mark III also uses different types of capacitors (and probably resistors) as the IIC+ (simply because there is no one IIC+ choice), and this matters somewhat. So, IMHO, the red stripe might (or might not) have the same pre-amp schematic (ie, the same values for the caps and resistors) but it is not a IIC+ pre-amp because its circuit board is different, its circuit traces are routed differently, and its circuit elements are of different compositions.

Blue Stripe is a IIC+ Power-Amp: Similar arguments as used above for the pre-amp...circuit-board, traces, component compositions. A Mark III can never "be" a IIC+ because of these differences. The schematic can be the same, but the physical circuit will be different because it was physically built in a different way. Also, and even more important, is that the output transformer is different in most mark III's compared to most mark IIC+'s. Transformers matter...especially at higher volumes. The power transformers are different, too, and that can have a big impact at high volumes as well.


So, with all of this discussion, please keep in mind the assumptions that are in your questions. Please remember that there is no single IIC+ design to match. Also, the red stripe preamp is not (and cannot be) the IIC+ pre-amp. Finally, the blue strip power-amp is not (and cannot be) the IIC+ power-amp.

If you goal is to make changes to your amp to be more like a IIC+ by changing the values of the capacitors and resistors...well, that is a really fun process. It's extremely educational and will make you appreciate your amp (whatever brand or model) in a whole new way. Have fun, man! But, please keep it in perspective. The values of the capacitors and resistors is a very important factor of an amp's tone, but it is not the only factor. There are lots of factors that are not captured by the schematic.

Good luck and have fun!

Chip
(PS, since you sat through my long diatribe, I'll try to answer your questions directly...most Mark IIC+'s have the 1000pF. This matters for the lead channel but has no effect at all on the clean channel. Also, for your other question, most Simul-Class Mark IIC+ have the 20pF cap. The non-simul-class amps tend to have the 10pF cap. This cap affects the clean channel more than the lead. On a Mark III, which has the 2nd rhythm channel, this cap will affect that channel as well).
 
That reply should be "chipped" in granite and erected in Petaluma, CA. 8) Very intelligently, and respectfully, presented. That epitomizes these boards. Thanks Chip for your comments. And as an owner of a MkIII, thanks for the thorough explanation.
 
Also, please don't view my post as getting up on a high horse about the supposed awesomeness of the IIC+ vs the lowly III. That was not my intention at all. My points about not being able to turn a III into IIC+ apply the other way, too...

I once tried to add the R2 channel to my IIC+. I followed the schematics (I found a couple variants of R2) as exactly as I could. You know what happened? It didn't sound right at all. You just can't turn a IIC+ into a III.

Chip
 
chipaudette said:
(PS, since you sat through my long diatribe, I'll try to answer your questions directly...most Mark IIC+'s have the 1000pF. This matters for the lead channel but has no effect at all on the clean channel. Also, for your other question, most Simul-Class Mark IIC+ have the 20pF cap. The non-simul-class amps tend to have the 10pF cap. This cap affects the clean channel more than the lead. On a Mark III, which has the 2nd rhythm channel, this cap will affect that channel as well).

How about the bright reduction mod that is done to the simul C+? I have one of these modded amps. In this schematic, http://www.grailtone.com/forum/viewtopic.php?f=3&t=9999, the 20pF cap in between pin 6 of V1B and pin 2 of V2A is changed to a 10pF. The .001 (1000pF) cap(normally deleted in Simulclass amps) is connected to pin 1 of V4A(in parallel with the 270K resistor). These two mods are direct replacements from the 60/100 versions, and are meant to tame the brightness of the Simul amps. It makes a little difference, but nothing that cannot be made up for in the controls. The Pull Bright on Volume 1 gets the brightness back, if you want it.


Bottom line is that the 3+ mod smoothes out some of the rough edges of the Mark III, just like the "+" mod smoothes out the rough edges of the Mark IIC. Think of them as revisions, and not conversions. 8)
 
Thank you very much guys,, especially to chipaudette for all this extremely useful information!

While I was reading your answers I realized that actually I have formulated not exactly what I am after. That is why I opened a separate topic you can read it here:

http://forum.grailtone.com/viewtopic.php?f=3&t=52417

Warm regards,
Yavor
 
I picked up a Mark III - Red Stripe yesterday, and talked to Mike B., and he told me all the same things here everybody has mentioned... That being said, I'm going with the mod, and going to send it off to him within the next couple of days!
 
Sorry to bring life to an old topic, but I guess this is of interest anyway.

I just did the 3+ mod to my black dot MKIII, and whoaah!!
If any of you out there still hesitate, do it.

What I did was replace the three caps, C27, C30, C516 just as member ahoy posted at page 1.
I bought them at audio cap UK, and I had to buy ten sets of all three to get up to an amount that was enough for them to ship.
So now I can mod nine more MKIII's. :lol:

I've done A/B comparison with my C+, (both simul X101's) and it is very close. Obviously you can hear a little difference, but the III sounds very very good, and is very close to the IIC+ (I guess it will be even closer if I get the same tubes all over on both amps)
The bottom end is much tighter and punchier than before, and the clean is not as snappy as it was.

So again, if you hesitate with your III, go for the 3+ mod.

Now……Back to playing.
 
I had the "3+" mod done to both a black and red stripes. It makes the a III better. The problem is the C+ and most of all III's have different plate voltage and all have different bias settings. I did get my black dot to sound really close to a C+. But the secret is they both have the 105PT. And I have a bias probe which reveals the truth to make them similar. Similar as they can be of course with the soup being different.

GET A BIAS PROBE.....
 
1. The red stripe has a 500pF cap at C30, the blue stripe is empty. I can't say if that is the only difference between the blue and the red stripes.
2.The black stripe is NOT closer to the C+ tone. It does NOT have the same preamp as a C+.
3.Try C30 first, then do the other if needed.
4.@C27 a 10pF is darker sounding than a 20pF.

_________________
"One of these days, I'm gonna change my evil ways....... one of these

Makes me wonder if there's a cheat sheet for the caps and their effect, such as "darker sounding" then the 20pF...? Specific to the mark 3's hopefully... Also interesting how changing tubes changes the tone..
 
I know this thread is kinda old but I wanted to see what values my purple had compared to others and the "+" mod. It turns out my C30 was 2000pf instead of the recommended 1000pf. I was wondering why the lead was so dark. This makes sense now.

My other main question is with my C27. I don't know what value it is? This is what it says:
Mexico
52L
30K
1KV

I have no idea what value it is by these codes and my meter wont read pf. PLEASE help. Thanks
 
I just got my amp back from Mesa today....Mike B. converted my green stripe to a "3+" :D WOW, what a difference! Just like the other posts say, it smoothed out the lead channel (pretty darn close to IIC+, as far as I'm concerned) and the clean channel is more refined. Overall the amp is less bright & aggressive, which is what I wanted. I can't wait to gig with it this weekend.
 
I recently picked up a Mark III No Stripe Coliseum that had the III+ mod done to it, and to be honest, I'm not too sure I like it yet. Compared to my unmodified Blue Stripe Coliseum, the III+ is much darker, and lacks the "edge" of the Blue Stripe. I'm still working with it, but as of right now, I could see using the III+ as a rhythm and "smooth lead" tone.

If want to lose some of the aggression of the Mark III, but have some more "useability" of the prescence knob, get the Mark III+ mod. But, you will lose some of the bite and aggression.
 
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