Wiring cabs to amp...need some urgent input on this... - diyAudio
Go Back   Home > Forums > Live Sound > Instruments and Amps
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Instruments and Amps Everything that makes music, Especially including instrument amps.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 31st January 2010, 11:10 PM   #1
diyAudio Member
 
Join Date: Sep 2008
Arrow Wiring cabs to amp...need some urgent input on this...

Hi folks...newbie talking here, so please bear with me

I need maximum loudness out of this setup:

The scenario is a Marshall Valvestate 80 + 80 watt poweramp and two cabs 16 ohm each.

The options are one cab on each channel of the amp, or the two cabs wired in parallel on one channel.

Try and listen is not possible at the moment, I need some theoretical answer to this, please.

Regards from near the north pole
  Reply With Quote
Old 2nd February 2010, 05:01 PM   #2
diyAudio Member
 
firechief's Avatar
 
Join Date: Sep 2008
Location: Near Seattle Wa
Kiulseth -- I am having a hard time pinpointing just what amp you have. Could you post a link to a technicial description of the beast? From the title it sounds like you have two seperate power sections, although that is pretty rare. If so, you must connect a speaker of the approriate impeadance to each output to avoid possible damage. So right off the bat one speaker on each output sounds right. Also a picture would help. No matter how you cut it the total power avaiable is just that.
  Reply With Quote
Old 2nd February 2010, 06:27 PM   #3
godfrey is offline godfrey  South Africa
diyAudio Member
 
Join Date: Nov 2009
Location: Cape Town
Is it one of these? Marshall Amps :: Heritage

That looks like a two channel amp with one 12" speaker built-in?
Sounds like a solid-state output so there's no impedance taps?

If one amp channel is used for a built-in speaker, then it's probably best to connect both 16 ohm cabs in parallel on the other channel.

If not, then a separate amp channel for each cab might give a bit more power.

edit:
[rant]Whole pages of waffle on their website about how great it sounds, but no mention of how to connect or use it - not even in the PDF "manual" [/rant]

Last edited by godfrey; 2nd February 2010 at 06:33 PM.
  Reply With Quote
Old 4th February 2010, 11:03 AM   #4
diyAudio Member
 
Join Date: Sep 2008
Hi again, thanks for the replies, and sorry for my late respons....was away for a couple of days

The amp is a Marshall Valvestate, Model 8008. Rackmounted SS power amp.

Click the image to open in full size.

PDF: http://www.drtube.com/schematics/mar...4-8008-hbk.pdf

Two inputs, two outputs 80 watts each, bridging not recommended (they say it can kill the amp).
  Reply With Quote
Old 8th February 2010, 10:17 PM   #5
diyAudio Member
 
Join Date: Jan 2010
The PDF doesn't specify the recommended impedence load, but amps designed for guitar generally tolerate mild impedence mismatches well. Its probably designed to take an 8 ohm load per channel. I'd put a cab on each channel.
  Reply With Quote
Old 8th February 2010, 11:47 PM   #6
infinia is offline infinia  United States
diyAudio Member
 
infinia's Avatar
 
Join Date: May 2005
Location: SoCal
Quote:
Originally Posted by kiulseth View Post
Try and listen is not possible at the moment, I need some theoretical answer to this, please.
Regards from near the north pole
Your answer is ...Run them in parallel for an 8 ohm load on one channel.

Amps (voltage FB) that are rated for it, provide more power at a lower impedance ( ohms law with fixed voltage).
Your amp is rated for 4 ohms so 16//16= 8 is no problem (see attached highlight)

Keep warm
Attached Images
File Type: gif Marshall 8008.GIF (115.0 KB, 37 views)
__________________
like four million tons of hydrogen exploding on the sun
like the whisper of the termites building castles in the dust
  Reply With Quote
Old 17th February 2010, 11:19 PM   #7
Minion is offline Minion  Canada
diyAudio Member
 
Join Date: May 2006
Location: Cowican Bay , vancouver island
Why don"t you just rewire each cab to 4 Ohms ,a 16 ohm 4x12 will have four 16 ohm speakers which wired in Pairs in paralell then each paralell pair in series to get 16 ohms , Which can also be wired with all 4 speakers in paralell for 4 ohms .....

That way you will get 4 times the output power from your amp and speakers ....

An amp that puts out 80w into 4 ohms is only putting out 20w into 16 ohms ....

It is simple to do and will make you a LOT louder .....

Cheers
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Wiring for XLR input on unbalanced amp Arx Chip Amps 3 16th April 2007 06:57 AM
Tannoy 15" Reds for sale with crossover and cabs (local pickup for cabs) saletel Swap Meet 0 27th October 2006 10:01 PM
Direct Wiring a DDDAC USB-->I2S to a P3A DAC I2S DIN input dkj7a Digital Source 1 26th March 2006 05:46 PM
XLR Audio Input Wiring haldor Parts 0 5th February 2003 02:59 PM


New To Site? Need Help?

All times are GMT. The time now is 04:46 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki