8004 Output Power

mark13 · 07-01-2009, 12:55 AM

I've just acquired an 8004 Valvestate power amp.
I vaguely remember hearing that apart from stereo(40w+40w) operation, these could be run in mono(80w).

There's nothing written on the back that helps.
I downloaded the user guide.
That's not much help either, although it does refer to "linked mono" if only one input is connected.

Does anyone know if this means that one input and one output(A in, A out) give 80w output? If it does, what would the impedance be?

Thanks.

Dave B · 07-01-2009, 04:00 AM

Quote:

Originally Posted by mark13

I've just acquired an 8004 Valvestate power amp.
I vaguely remember hearing that apart from stereo(40w+40w) operation, these could be run in mono(80w).

There's nothing written on the back that helps.
I downloaded the user guide.
That's not much help either, although it does refer to "linked mono" if only one input is connected.

Does anyone know if this means that one input and one output(A in, A out) give 80w output? If it does, what would the impedance be?

Thanks.

Have you tried e-mailing Marshall?, In my experience they are usually pretty quick replying.

mark13 · 07-01-2009, 02:13 PM

I e-mailed Marshall a week ago. No reply.

javier pintos · 07-01-2009, 04:59 PM

when yo connect only the channel b does sound come from both speakers (A and B), it could be that if the amp sees no input from the other channel it behaves like a mono amp (sort of like stereo channels on a mixer) and both outputs use the same input signal providing 40w+40w as output wich is not 80w.

I would guess that it only provides 40+40 and impedance should alway be 4 ohm minimum on any channel

rockinr0ll · 07-01-2009, 05:19 PM

Quote:

Originally Posted by javier pintos

when yo connect only the channel b does sound come from both speakers (A and B), it could be that if the amp sees no input from the other channel it behaves like a mono amp (sort of like stereo channels on a mixer) and both outputs use the same input signal providing 40w+40w as output wich is not 80w.

I would guess that it only provides 40+40 and impedance should alway be 4 ohm minimum on any channel

+1

mark13 · 07-03-2009, 01:36 PM

Quote:

Originally Posted by javier pintos

when yo connect only the channel b does sound come from both speakers (A and B), it could be that if the amp sees no input from the other channel it behaves like a mono amp (sort of like stereo channels on a mixer) and both outputs use the same input signal providing 40w+40w as output wich is not 80w.

I would guess that it only provides 40+40 and impedance should alway be 4 ohm minimum on any channel

Javier,
Given the lack of information on the amp itself, I'm inclined to agree with you.

I've e-mailed Marshall a second time - No Response.

I did see a review on Harmony Central that refers to "mono operation", so I'll keep looking for information.

mark13 · 07-09-2009, 09:37 PM

I finally got a reply from Marshall.
Extremely helpful, despite the delay.

Here's what they said:

"The 8004 outputs through both speaker outputs, if you are using the mono output of another preamp or processor, connect that to Input B on the 8004. The 8004 will link the mono input to be divided equally between both of its outputs as a mono sound."

So, that's solved that one.

07-01-2009, 12:55 AM	#1 (permalink)
mark13 Junior Member Join Date: Jun 2009 Location: Santa Monica, Ca Posts: 9	8004 Output Power I've just acquired an 8004 Valvestate power amp. I vaguely remember hearing that apart from stereo(40w+40w) operation, these could be run in mono(80w). There's nothing written on the back that helps. I downloaded the user guide. That's not much help either, although it does refer to "linked mono" if only one input is connected. Does anyone know if this means that one input and one output(A in, A out) give 80w output? If it does, what would the impedance be? Thanks. __________________ Gear: 9001 9004 DRP-1 8008 8004 1922 x 2

07-01-2009, 02:13 PM	#3 (permalink)
mark13 Junior Member Join Date: Jun 2009 Location: Santa Monica, Ca Posts: 9	Re: 8004 Output Power I e-mailed Marshall a week ago. No reply. __________________ Gear: 9001 9004 DRP-1 8008 8004 1922 x 2

07-01-2009, 04:59 PM	#4 (permalink)
javier pintos Senior Member Join Date: Sep 2008 Location: Mexico Posts: 323	Re: 8004 Output Power when yo connect only the channel b does sound come from both speakers (A and B), it could be that if the amp sees no input from the other channel it behaves like a mono amp (sort of like stereo channels on a mixer) and both outputs use the same input signal providing 40w+40w as output wich is not 80w. I would guess that it only provides 40+40 and impedance should alway be 4 ohm minimum on any channel

07-09-2009, 09:37 PM	#7 (permalink)
mark13 Junior Member Join Date: Jun 2009 Location: Santa Monica, Ca Posts: 9	Re: 8004 Output Power I finally got a reply from Marshall. Extremely helpful, despite the delay. Here's what they said: "The 8004 outputs through both speaker outputs, if you are using the mono output of another preamp or processor, connect that to Input B on the 8004. The 8004 will link the mono input to be divided equally between both of its outputs as a mono sound." So, that's solved that one. __________________ Gear: 9001 9004 DRP-1 8008 8004 1922 x 2

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode