The Boogie Board

Discussion Forum for Mesa Boogie Products
It is currently Wed Nov 21, 2018 3:43 am

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 463 posts ]  Go to page 1, 2, 3, 4, 5 ... 31  Next
Author Message
PostPosted: Tue Mar 13, 2012 3:03 pm 
Offline
Donating Member

Joined: Sat Aug 25, 2007 9:48 pm
Posts: 641
Location: Storrs, CT
EDIT: Much of what's in this first post is incorrect, despite being what I believe is an awesome mod. Thanks to msi, JCDenton6, and many others in this thread, I believe the following is 100% correct:

After everything that's been gone through, it really does seem there's only a slight difference between revisions. Most notable of C/D are the following:

1. Higher presence pot value (220k, I believe, instead of 100k) makes the entire amp brighter
2. No LDRs on the preamp cathodes means a slightly tighter, dryer tone
3. Different output transformer (which, although present on later revisions, I believe plays a role here with the aforementioned differences)


There are other changes, but as far as I can hear, that's what it takes to get C/D red modern. Because of the layout on later 2-channel revisions, there's no simple mod to get 100% accuracy.


I've been interested in the fabled "holy grail" pre-500 tone for years, as I'm sure most are. Through MANY hours of research and testing, I believe I've finally cracked the circuitry code and have found that by swapping TWO parts, your Rev. G Rectifier can have pre-500 tone. Why am I sharing my countless hours of hard work? Because for one, the two parts will take a skilled tech about 5 minutes to swap (and maybe 20 for an unskilled one) and come to a total cost of about $10, not at all warranting the huge amount of money the real pre-500s command. Two, because HOLY HELL it sounds amazing!

So what exactly is the difference in sound? Less flub, bigger midrange, and much more usable gain. At 11:00, the gain is about as much as you'd get from a Rev. G at 2:30 - 3:00. And when you do bring the gain to 3:00 for a huge amount of saturation, it stays tight! What's the drawback? Well, cleans suck again. And the thing is, the stock tone is still awesome. Yes, everything I just said is true, but at low gain settings, the stock setup will be a bit thicker (albeit not nearly as tight). Still, there's no harm in trying this setup, and I highly recommend taking the $10 and ~15 mins and trying it!

Before I get to the mod, here are some clips to show the difference. Please note that I am NOT an expert on recording techniques. These clips are meant to show the difference between the two setups, all else kept the same (except gain settings). No EQ except for a slight high pass filter
Stock
"Pre-500" tone
5150 (for perspective)

I used a Rectifier 4x12, MD421 close, and Studio Projects B1 for the room. Guitar is a Gibson R9 with a BKP Abraxas. Using an Mbox for mic preamps. Settings are as follows:
Treble and Bass: noon
Mids: 12:30
Presence: 8:00
Gain: 1:30 stock, 10:30 on the "Pre-500" (though in retrospect, I'd bring it up a bit in the chorus and down a hair in the verse)
Master: 10:30

The differences are a little more noticeable in the room, but I think they show well enough. Might have had the volume just a little too high.


On to the mod!

1. Change the gain pots to 1MA. Make sure you swap the cap that jumps the two lugs to the new pot.

2. Swap this capacitor to one valued at .005uF, with a voltage rating of at least 450. (0.0047uF Orange Drop is perfect)

Image

This should do it! Of course, changing the Red presence control to a 26k linear would be closer still, but the stock 100k gets you the same sound (just has more presence past 9:00).

If anyone else decides to try this, please share your findings! As for me? I like the Rev. G circuit very much, and would like to have both setups. However, in almost every case, I'd take this Pre500 configuration.

I think that covers everything, though please let me know if I've missed something!

_________________
Mesa / Gibson / Fender / Marshall / Celestion / WCR


Last edited by TheMagicEight on Thu Feb 28, 2013 3:51 am, edited 3 times in total.

Top
 Profile  
 
PostPosted: Tue Mar 13, 2012 5:22 pm 
Offline
Dual Recto
User avatar

Joined: Wed Jul 01, 2009 6:18 pm
Posts: 2977
Location: Weinerpeg MB Canada
Way cool. The modded recto is definitely tighter and clearer. EPIC crunch. Still, not much is lost by modifying the circuit slightly to support a serviceable clean tone. I'd prefer the 'pre 500' specs for crunch but honestly, pickups and cabinetry make a big difference and this allows the improved clean tone to stay.


Top
 Profile  
 
PostPosted: Tue Mar 13, 2012 5:48 pm 
Offline
Donating Member

Joined: Sat Aug 25, 2007 9:48 pm
Posts: 641
Location: Storrs, CT
YellowJacket wrote:
Way cool. The modded recto is definitely tighter and clearer. EPIC crunch. Still, not much is lost by modifying the circuit slightly to support a serviceable clean tone. I'd prefer the 'pre 500' specs for crunch but honestly, pickups and cabinetry make a big difference and this allows the improved clean tone to stay.

You could have both if you wanted, honestly. You'd just leave the orange channel pot stock or swap it to 500k. The orange crunch would be a little bit different from the red crunch, but not by much, and it would still sound great!

_________________
Mesa / Gibson / Fender / Marshall / Celestion / WCR


Top
 Profile  
 
PostPosted: Tue Mar 13, 2012 7:14 pm 
Offline
Mark IV

Joined: Wed Apr 28, 2010 6:33 am
Posts: 730
Location: Chicago, IL
Dude that sounds rad :D :D :D
Thanks for all of your findings on this and the clips, you can hear the change in tone.

_________________
B.C Rich Guitars
Mesa Amps/Cabs


Top
 Profile  
 
PostPosted: Tue Mar 13, 2012 8:52 pm 
Offline
Mark IV

Joined: Wed Apr 28, 2010 6:33 am
Posts: 730
Location: Chicago, IL
Forgot to ask something, so when you swap out the cap that jumps the two lugs to the new pot, what would be the value of the cap? (or would it come with the new pot?)

_________________
B.C Rich Guitars
Mesa Amps/Cabs


Top
 Profile  
 
PostPosted: Tue Mar 13, 2012 9:09 pm 
Offline
Dual Recto
User avatar

Joined: Wed Jul 01, 2009 6:18 pm
Posts: 2977
Location: Weinerpeg MB Canada
TheMagicEight wrote:
YellowJacket wrote:
Way cool. The modded recto is definitely tighter and clearer. EPIC crunch. Still, not much is lost by modifying the circuit slightly to support a serviceable clean tone. I'd prefer the 'pre 500' specs for crunch but honestly, pickups and cabinetry make a big difference and this allows the improved clean tone to stay.

You could have both if you wanted, honestly. You'd just leave the orange channel pot stock or swap it to 500k. The orange crunch would be a little bit different from the red crunch, but not by much, and it would still sound great!


Maybe I'll consider this next year when it is time for a CAP JOB! Rev F is getting ooold!


Top
 Profile  
 
PostPosted: Tue Mar 13, 2012 9:39 pm 
Offline
Donating Member

Joined: Sat Aug 25, 2007 9:48 pm
Posts: 641
Location: Storrs, CT
JCDenton6 wrote:
Forgot to ask something, so when you swap out the cap that jumps the two lugs to the new pot, what would be the value of the cap? (or would it come with the new pot?)

You'd just transfer the existing cap from the old pot to the new one.

_________________
Mesa / Gibson / Fender / Marshall / Celestion / WCR


Top
 Profile  
 
PostPosted: Tue Mar 13, 2012 9:53 pm 
Offline
Mark IV

Joined: Wed Apr 28, 2010 6:33 am
Posts: 730
Location: Chicago, IL
Ah, gotcha.
Thanks again.

_________________
B.C Rich Guitars
Mesa Amps/Cabs


Top
 Profile  
 
PostPosted: Tue Mar 13, 2012 10:43 pm 
Offline
Mark III

Joined: Sat Apr 04, 2009 10:16 am
Posts: 233
Location: Milwaukee, WI
Quote:
Well the cleans suck again


I have an observation about cleans and high gain. Kinda like active pickups. They keep the clarity and tightness on high gain, but lack the sparkle etc on the cleans. I think it has todo with the harmonic content. Too much during high gain turns to mud, not enough during cleans leads to dullness and sterility. You can't have it boh ways, sacrifice one for the other (except for the markv of course :wink: ). Seriously though, cool stuff. Thanks for sharing.

_________________
Roadster 2x12
Mark III SRG Blue Stripe
Mark IV
Mark V
RA 100
Triaxis
PortCity 2x12 OS


Top
 Profile  
 
PostPosted: Tue Mar 13, 2012 11:26 pm 
Offline
Mark II

Joined: Fri Sep 02, 2011 10:45 am
Posts: 143
Location: Mesa, AZ
You can also change the "Bright" caps on the Gain pots to a .001uf/450V Orange Drop to smooth out the high-end a bit more, too. The stock ceramic caps are a little too crisp IMO.


Top
 Profile  
 
PostPosted: Tue Mar 13, 2012 11:37 pm 
Offline
Donating Member

Joined: Sat Aug 25, 2007 9:48 pm
Posts: 641
Location: Storrs, CT
Third Age Amps wrote:
You can also change the "Bright" caps on the Gain pots to a .001uf/450V Orange Drop to smooth out the high-end a bit more, too. The stock ceramic caps are a little too crisp IMO.

Thanks; might have to give that a shot!

_________________
Mesa / Gibson / Fender / Marshall / Celestion / WCR


Top
 Profile  
 
PostPosted: Wed Mar 14, 2012 2:57 am 
Offline
Donating Member

Joined: Sat Aug 25, 2007 9:48 pm
Posts: 641
Location: Storrs, CT
TheMagicEight wrote:
YellowJacket wrote:
Way cool. The modded recto is definitely tighter and clearer. EPIC crunch. Still, not much is lost by modifying the circuit slightly to support a serviceable clean tone. I'd prefer the 'pre 500' specs for crunch but honestly, pickups and cabinetry make a big difference and this allows the improved clean tone to stay.

You could have both if you wanted, honestly. You'd just leave the orange channel pot stock or swap it to 500k. The orange crunch would be a little bit different from the red crunch, but not by much, and it would still sound great!

So I just tried this, using a 500k pot on the Orange channel. Cleans are okay. Nothing spectacular, but with a little reverb, they're pretty good; certainly not terrible. Vintage mode, on the other hand, is excellent! In fact, I like this setup on the Orange channel more than I did with the 1M pot! The distortion is the same character as on the Red channel, just a little less, which for me is perfect. The dynamics you get out of it are incredible! And I have to say...with the 500k pot, it's beginning to creep into SLO territory...

I'll make clips if they're requested!

_________________
Mesa / Gibson / Fender / Marshall / Celestion / WCR


Top
 Profile  
 
PostPosted: Wed Mar 14, 2012 3:08 am 
Offline
Mark IV

Joined: Wed Apr 28, 2010 6:33 am
Posts: 730
Location: Chicago, IL
That sounds like a plan, I'd like to hear what you've done with the 500k pots.
I heard the other clip you posted on rig talk and man you can really hear the tonal change!

_________________
B.C Rich Guitars
Mesa Amps/Cabs


Top
 Profile  
 
PostPosted: Wed Mar 14, 2012 3:20 am 
Offline
Donating Member

Joined: Sat Aug 25, 2007 9:48 pm
Posts: 641
Location: Storrs, CT
JCDenton6 wrote:
That sounds like a plan, I'd like to hear what you've done with the 500k pots.
I heard the other clip you posted on rig talk and man you can really hear the tonal change!

And it's SO much better in the room! :twisted:

I'll get something going tomorrow. Maybe just play around with some different sounds. After putting the 500k pot into the Orange channel, the amp is really coming together!

_________________
Mesa / Gibson / Fender / Marshall / Celestion / WCR


Top
 Profile  
 
PostPosted: Wed Mar 14, 2012 10:18 am 
Offline
Dual Recto
User avatar

Joined: Wed Jul 01, 2009 6:18 pm
Posts: 2977
Location: Weinerpeg MB Canada
CLIPS PLZ


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 463 posts ]  Go to page 1, 2, 3, 4, 5 ... 31  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 6 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group