The Boogie Board

Discussion Forum for Mesa Boogie Products
It is currently Wed Jun 28, 2017 8:59 am

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 9 posts ] 
Author Message
PostPosted: Thu Jan 19, 2017 2:30 pm 
Offline
Bottle Rocket
User avatar

Joined: Fri Oct 21, 2016 5:02 pm
Posts: 10
Location: NYC
Hello all, I'm fairly new to this forum and I was hopping someone might be able to help me here. I am currently playing a Roadster combo which I love but I recently bought a Mark V head which I'm also loving. They are both great amps but very different. I would like to be able to use the MKV for some patches and the roadster for others. In a perfect world I would love to run them both using the 212 speakers in my Roadster. I know I could rewire the 2 speakers from parallel to stereo and have a speaker for each the roadster and the MKV. However I saw the Engl E212HB pro which has toggle switch that goes from stereo to mono. I would love to do this with a small box outside the amp so I could easily chose between mono or stereo depending if I want to use the MKV or not. I just don't know how this is done. Any input would be greatly appreciated.

Here is a link to a picture show the back plate of the Engl E212HB pro.

Image


Top
 Profile  
 
PostPosted: Thu Jan 19, 2017 4:16 pm 
Offline
Donating Member
User avatar

Joined: Thu Oct 15, 2009 1:30 pm
Posts: 2530
Location: San Francisco Bay Area, CA
Relatively easy, but with consequences.

1. The speakers in the recto 2x12 are 16 Ohm wired in parallel to both jacks wired in parallel. Rewire one speaker to each speaker input jack (parallel out would then be input for one speaker, input would be input for the other speaker). This makes your recto cab stereo 16 Ohm 60W/channel max.

2. You need to use a heavy-duty high-current switch (100W into 8 Ohms is 3.5A max). In order to mimic the switch on the Engl cab, you just need a DPST that shorts the two sets of wires together (T and S of speaker cable 1 to T and S of cable 2) to make the speakers work in parallel. This would make the cab have the normal recto spec: 8 Ohms, 120W max.

3. You would need to be careful not to switch the box from stereo to mono while both amps are connected or you will short that amp outputs to each other and probably blow them up. You could avoid that by using a more complicated switch that disconnects one input when it shorts the two outputs together.

4. Note that in stereo the speaker cab is only good for 60W max from each amp, as the speakers are 60W each.

_________________
Electra Dyne Head
JP-2C WICKER, Baby!
Mini Rectifier blue LED
Recto 2x12 Horizontal
2x Recto 2x12 Vertical


Top
 Profile  
 
PostPosted: Fri Jan 20, 2017 12:12 pm 
Offline
Bottle Rocket
User avatar

Joined: Fri Oct 21, 2016 5:02 pm
Posts: 10
Location: NYC
Elvis,

Wow, Thanks for the super detailed answer. I understand most of what you are talking about but I do have some follow up questions. Before I get into that I just have to ask you, would you be the same Elvis that answers so many questions on the TC Electronic forum for the G-system? If so, I can't tell you how much your knowledge has helped me out. Without both you and Laird, I wouldn't even be able to use the G-system.


Top
 Profile  
 
PostPosted: Sun Jan 22, 2017 4:09 pm 
Offline
Bottle Rocket
User avatar

Joined: Fri Oct 21, 2016 5:02 pm
Posts: 10
Location: NYC
I don't know much about DPST heavy-duty high-current switches. When you say 100W into 8 Ohms is 3.5A max does that mean the DPST just has to be at a minimum of 3.5A? The one I was looking at is an DPST On-Off Toggle Switch and the specs are Single Pole Rated: 10A/277V AC; 20A/125V AC; 21A/14V DC; 3/4 HP 125-250V AC.
Double Pole Rated: 10A/277V AC; 20A/125V AC; 21A/14V DC; 1-1/2 HP 125-250V AC.

Here is the link to the page. I just want to make sure I'm getting the right DPST. There are so many versions of these things.

https://www.delcity.net/store/Heavy!Dut ... 6.h_789014

Also, after reading about the danger of switching from stereo to mono while both amps are connected makes me want to use a more complicated switch that disconnects one input when it shorts the two outputs together. How would I find this? Is there a name for this? I'm not sure how to find it. Again I appreciate you help. An input would be greatly appreciated.


Top
 Profile  
 
PostPosted: Mon Jan 23, 2017 10:32 am 
Offline
Mark II
User avatar

Joined: Fri Nov 16, 2012 4:55 pm
Posts: 55
Location: East Coast, New Jersey
Not sure if this is what you're looking for...

https://www.tubesandmore.com/products/jack-plate-plug-and-play-monostereo

_________________

93 97 98 PRS CE24
94 98 G&L Legacy
94 G&L ASAT Special
95 G&L S-500
99 Peavy Wolfgang
11 Gibson LP Studio 60

69 Bandmaster Head
88 Quad Pre
91 & 92 Simul 295
92 DC-5
96 Mark IV Maple/Wicker
98 5150 combo
08 Mark IV Wide


Top
 Profile  
 
PostPosted: Mon Jan 23, 2017 6:03 pm 
Offline
Bottle Rocket
User avatar

Joined: Fri Oct 21, 2016 5:02 pm
Posts: 10
Location: NYC
Wow, this looks great. Thank jediguitarist! Love that name btw. My only concern is that in all the schematics it show two 8 ohm speakers being used. My boogie cab is running two 16 ohm speakers. I'm not sure how this would effect the functionality of the plate.


Top
 Profile  
 
PostPosted: Tue Jan 24, 2017 12:17 am 
Offline
Donating Member
User avatar

Joined: Thu Oct 15, 2009 1:30 pm
Posts: 2530
Location: San Francisco Bay Area, CA
Plate will function fine, but you would have to multiply all the impedances by a factor of two. So the labels would be wrong, that's it.

Yes, I am that elvis as well. Glad to be of help, and thanks for the kind words!

_________________
Electra Dyne Head
JP-2C WICKER, Baby!
Mini Rectifier blue LED
Recto 2x12 Horizontal
2x Recto 2x12 Vertical


Top
 Profile  
 
PostPosted: Tue Jan 24, 2017 12:07 pm 
Offline
Bottle Rocket
User avatar

Joined: Fri Oct 21, 2016 5:02 pm
Posts: 10
Location: NYC
Yep, I did a bit more reading on their site an you are right. This should work perfectly and it will definitely simplify my work. Good to know you are the same Elvis! You are very welcome. Like I said, you've been a big help. Thanks.


Top
 Profile  
 
PostPosted: Fri Feb 03, 2017 1:56 pm 
Offline
Mark II
User avatar

Joined: Fri Nov 16, 2012 4:55 pm
Posts: 55
Location: East Coast, New Jersey
Glad I could get you pointed in the right directions. :mrgreen:
I'm doing the same thing to one of my 2x12 cabs. It'll be great to be able to use one cab for multiple heads or power amps or as an extension. I just have to take the speakers out to check the ohms. They're front loaded.

_________________

93 97 98 PRS CE24
94 98 G&L Legacy
94 G&L ASAT Special
95 G&L S-500
99 Peavy Wolfgang
11 Gibson LP Studio 60

69 Bandmaster Head
88 Quad Pre
91 & 92 Simul 295
92 DC-5
96 Mark IV Maple/Wicker
98 5150 combo
08 Mark IV Wide


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 9 posts ] 

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 2 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