Soundcraftsmen amps in mono driving a four ohm load???

S

SleeperSupra

Super Member
Well, I just bought two Soundcraftsmen PA5001 250wpc amplifiers and I plan on running them mono to drive my four ohm Thiel CS2 speakers.

I know the amplifiers will each put out 750 watts in bridged mono driving an eight ohm load, but will they be stable driving a four ohm load in bridged mono configuration. Any idea of how much power they will put out and do you think my speakers will be OK with that much power driving them?

My system consists of:

Audio/Video Gear
Hitachi Ultravision 60SBX72B 60" Rear Projection TV
Mitsubishi HSU780 S-VHS Stereo Hi-Fi VCR
Sony DVP-CX985V 400 DVD/SACD Player
Onkyo Integra TXDS939 AC3/THX Surround Receiver
Soundcraftsmen MA5002A Power Amplifier
2 (two) Soundcraftsmen PA5001 Amplifiers
Soundcraftsmen TG3044R Third Octave EQ
Monster Interconnects and Cables
Thiel CS2 Coherent Source Speakers (for two channel)
JBL HT1F THX Surround Speaker System (has two passive 12" subs, three MTTM speakers, and two dipole TM/MT surrounds)
Custom Center Channel Speaker (one 3 1/2" fiberglass mid tweeter with a phase plug, first order crossover, two 10" mid bass drivers and a 15" passive radiator)...

I also have a Onkyo M504 Power Amplifier and a NAD 2400 PE Power Amplifier that I will be no longer useing.
 
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I have an MA5002A and a PA5001, and I believe they are 375 wpc into 4 ohms. They should put out over 1,000 watts RMS into 4 ohms. Yes, they are stable with 2 ohm loads.
Soundcraftsmen amps are fine sounding amps and very rugged for severe duty--so much so that they were often used in PA and professional systems.
There is probably no speaker system they could not drive properly.
 
Thanks Pete. :thmbsp:

I have to find an autobridge now; I have been looking on e-Bay for a long time but have never seen one for sale.
 
SleeperSupra said:
Well, I just bought two Soundcraftsmen PA5001 250wpc amplifiers and I plan on running them mono to drive my four ohm Thiel CS2 speakers.

I know the amplifiers will each put out 750 watts in bridged mono driving an eight ohm load, but will they be stable driving a four ohm load in bridged mono configuration. Any idea of how much power they will put out and do you think my speakers will be OK with that much power driving them?
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The 4 Ohm bridged output would theoretically be twice the 2 Ohm watts per channel rating (if that's available and if the power supply and the mains can keep up).
 
Bully knows a little about them,as I recall! :scratch2: If it helps,my PM840 is rated 205w x 2 @8ohm,and 375w x 2 into 4 or 2 ohm,continuous,no headroom.You already seem to know more about the mono configuration than I recall without digging out the manual.Sounds like a killer setup!
 
oops, :sigh: My mistake!I have a different power supply,I think.I have the SS power supply.The main thing I wanted to get across is to be cautious when approaching clipping.The red lights really DID mean back off the gain,in my case.Zero headroom.Drivers and downtime are expensive!
 
Dx4200

Thanks for the replys. :thmbsp:






bully said:
You could buy my DX4200 preamp/EQ. It provides proper connections.
Click to expand...

How much do you want for it, is it in good shape, any issues, and do you have any pictures?

Thanks,

Robert
 
HMMM, I was just thinking about switching my boat anchors (MA5002/MA5002A/Pro-Power3) to 16 ohms and having some mercy on the output transistors, although stable at 2 ohms, that's damn near a direct short, not to mention what will happen with impedance swings on the speakers. :nono:
 
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Is it just me, or after about 1985, did Soundcraftsmen basically sell the same amp under a zillion different model numbers? There's a 205wpc version and a 250wpc version and some have pro-type connectors (XLRs and phone-type jacks), and some have LED meters and some have none, but they all seem to be the same amp underneath.

Or are they?
 
That's a pretty fair assessment.
The service manual for the Class H amplifiers includes the PA5001 (I have this one), MA5002, EA5003, PA5001A, MA5002A (I have this one, too), RA7500 series, & RA6501.
 
Pete,do you know of an information archive somewhere we can study up on the tech side of these things?Seems I've forgotten more than :scratch2: :scratch2: I knew to begin with....
 
Thanks,Bully! That outfit doesn't list my PM840,but I'll email and ask.They DO have info on my Airline 9056(RCA 6L6GCs + 12AX7s) :thmbsp: I agree with the idea they did some weird things before the company was bought out by MTX,About 1990-91 or so,I recall.Ifound info on the PCR series,similar to my PCM.Testing showed pretty low output levels at 4 and 2 ohm.My manual stated a lot higher numbers than the PCR,and QC did things like operate it into a direct short at full power,etc.It does have the mosfet circuit in the power supply.These things are getting some age on'em,so I'm not hopped up on running them on much less than a 4 ohm load.But at 4 I'd let 'er eat.Thanks again for the link,I've been looking for info on that old amp for months!
 
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