# Soundstream Reference 700s @ 2 ohm mono?



## ChrisB (Jul 3, 2008)

I just received a Soundstream 700s that I pretty much stole on another forum. Anyhow, I was planning on using it to run my Kicker Solobaric that another buyer backed out on (grr), but I have concerns that running it at 2 ohms mono might turn it into a smokestream.

Oh well, I am off to email the guy I purchased it from. I figured I would ask the experts if this amp would have problems running @ 2 ohms mono.


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## tophatjimmy (Dec 16, 2005)

http://www.soundstream.com/manuals/AMP/REFERENCE/r5_7_10s/r5_7_10s.pdf

according to the owners manual, it's designed to handle 1/2 ohm stereo or 1 ohm bridged, so 2 ohms bridged should be no problem.

My Reference 604 barely breaks a sweat running a pair of 10's off the rear channels at 2 ohms bridged.


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## ChrisB (Jul 3, 2008)

I know the manual says so but I have been letting the limited research I have been performing about the auto-switching technology not working properly get to me. I guess I need to just hook it up and see if it automagically goes into "high current" mode or not.

ETA: I just received an email from the seller and he said that he only ran it at 2 ohms mono the whole time he had the amp. Sweet!


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## Mooble (Oct 21, 2007)

I think 2 ohms is fine. The problem was in the internal high power / high current switch. I'm pretty sure that it would still be running in high power mode at 2 ohms so therefore it would never switch. I don't know how long it would take it to switch. Maybe if you ran test tones on it for 10 minutes it would drop to high current mode, but I don't think you'd have a Smokestream unless you dipped to 1 ohm or lower.

Who knows though.


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## Mooble (Oct 21, 2007)

WTF! I only hit enter once and it still double posted me!


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## ChrisB (Jul 3, 2008)

Hmm, this is interesting. 

The amp clearly states it is a Reference 700s:









But the board says otherwise:


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## Guy (Feb 16, 2006)

Despite everyone's hypothesis of the problems with Soundstream's later Reference models (bad high current switches, defective power supplies, etc.), you have located a hint of the actual source of trouble. 
I won't get into the whole soap opera here, but the management wanted more power without extra cost and forced the engineers to redesign the Reference lineup to output more power from the existing board designs. 
The Ref 500 became the 700s as a result of this. The problem was that the output devices were not upgraded and protection circuits weren't in place. Prior to this the Soundstream amps had "overbuilt" output devices but in the name of cost cutting and marketing hype they went down the wrong path. When the amps melted down, Soundstream didn't respond appropriately, but that's another part of the soap opera that doesn't need retelling here.
Of the hundreds of SS amps I have owned (I still have one or two  ) I have never had a Reference S or SX series based on what I know (the 300s(x) are solid amps, however). 
Have fun with that thing- perhaps yours will be one of the few that has never caught on fire.  






06BLMUSTANGGT said:


> Hmm, this is interesting.
> 
> The amp clearly states it is a Reference 700s:
> 
> ...


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## ChrisB (Jul 3, 2008)

G Rahn said:


> Despite everyone's hypothesis of the problems with Soundstream's later Reference models (bad high current switches, defective power supplies, etc.), you have located a hint of the actual source of trouble.
> I won't get into the whole soap opera here, but the management wanted more power without extra cost and forced the engineers to redesign the Reference lineup to output more power from the existing board designs.
> The Ref 500 became the 700s as a result of this. The problem was that the output devices were not upgraded and protection circuits weren't in place. Prior to this the Soundstream amps had "overbuilt" output devices but in the name of cost cutting and marketing hype they went down the wrong path. When the amps melted down, Soundstream didn't respond appropriately, but that's another part of the soap opera that doesn't need retelling here.
> Of the hundreds of SS amps I have owned (I still have one or two  ) I have never had a Reference S or SX series based on what I know (the 300s(x) are solid amps, however).
> Have fun with that thing- perhaps yours will be one of the few that has never caught on fire.


Now I am starting to think I should have just sold the amp to the guy who was begging me to sell it to him on the other forum for 2x the price I paid for it. 

I guess I will give this SS a try. Worst case it will go up in smoke and I will replace it with one of my Orion HCCAs depending on what sub I end up staying with. Regardless, I was thinking that this amp was a tad bit small for a 700 watt RMS capable amp, especially if it was under-rated like the Soundstream amps I used to know. I really would hate to see this Reference 700s at 1/2 ohm stereo or 1 ohm mono, especially when my HCCA 225 is slightly larger


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## Mooble (Oct 21, 2007)

The specs on the Reference 500 and the 700SX are not very different. If the Reference 500 was solid, and it was, I don't see why the 700SX should blow up if they just carried over parts from the 500. Did they actually downgrade the power outputs from the 500? There is no reason to think a tweaked 500 could not put out the same power as the 700SX reliably. It had that much reserve already built into it. Now if they downgraded the output devices from what the 500 had, then I could see issues developing.


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## Mooble (Oct 21, 2007)

Very interesting...

The Reference 700SX no longer advertises the 1,920w Darlington output stage and it's not silk-screened on the board. All of the bigger Reference Series and Class As had it. The 700SX has the same number of output FETs, however, and in the very same locations too, but maybe they used cheaper FETs with lower capacity. (Although I can't see why they would do this. Going with the same number of cheaper FETs might save them what, $10-$20 total)

I think I was right in saying that a tweaked 500 would have no problem putting out the same power as the 700SX, but the 700SX wasn't a tweaked 500, it was actually a downsized 500. Maybe it was more like a tweaked 300 which only had a 900w Darlington output stage.


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## ChrisB (Jul 3, 2008)

Well, I always wanted a reference 500.... So now I have one... I guess...

All of a sudden I am having the urge to just let Ray mod my purple LP150z and use that to drive my two 10" JL Audio 10w3v2s. Then again, I already have a modded LP 1752 that should be more than capable of doing the job... Oh snap, went off on a tangent when I saw your sig. Sorry!


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## Mooble (Oct 21, 2007)

06BLMUSTANGGT said:


> Well, I always wanted a reference 500.... So now I have one... I guess...
> 
> All of a sudden I am having the urge to just let Ray mod my purple LP150z and use that to drive my two 10" JL Audio 10w3v2s. Then again, I already have a modded LP 1752 that should be more than capable of doing the job... Oh snap, went off on a tangent when I saw your sig. Sorry!


Sadly, I think that's the point--you don't have a Reference 500. If you did, you'd have no problems. The Reference 500 apparently had a much stronger output stage than the more powerful 700SX.

Still, 2 ohms shouldn't smoke this amp. Even if we assume that it only has a 900w output stage, it's still pretty powerful although you might want to sell it if someone really wants it.

I think you might have the same problem with modded LPs. The only LPs I had modded were for SQ purposes and they made no more power than stock. I've seen the inside of the DPS350 (almost the same as the LP150z) and it's just not that robust. I can't imagine that thing putting out 700w RMS modded. No way. I know plenty of people with modded LPs and they do put out sick power, but maybe that's more a tribute to how well they were originally built rather than their ability to truly handle that much power. The DPS350 was nothing like "real" 700w amps. That's just too much heat for that little chassis methinks.


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## ChrisB (Jul 3, 2008)

I have been on the lookout for a LP 5002IQ but I don't want to pay a small fortune for one (lol). 

Sadly, someone stole mine during the Hurricane Rita cleanup at my Grandparent's house. I had left a few things there because I used to travel a lot for my job and was rarely at my own house. I never thought I would lose a couple of Coustic XM-3 crossovers, the LP 5002IQ, a Hifonics Zeus V1, and Russian SKS rifle to theft from a family member!


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## GlasSman (Nov 14, 2006)

A Reference 500 and a Refrence 700 S/Sx both have 24 output devices. 

The power supply on the 700 is a bit different with the same number of devices but with 2 torroids.

So the amp should make more power but comparing to a Reference 500, that seems overbuilt while the 700 S/Sx does not.

I've stayed away from the S/Sx amps but my brother did run 2 300 Sx's for several years with no problems. 

The sub amp was running a SVC 2 ohm sub with the other on a component set.


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## ace956 (Aug 28, 2009)

chrisb,
Here is some information i thought you would like to have.

ace956


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## ace956 (Aug 28, 2009)

ChrisB said:


> I just received a Soundstream 700s that I pretty much stole on another forum. Anyhow, I was planning on using it to run my Kicker Solobaric that another buyer backed out on (grr), but I have concerns that running it at 2 ohms mono might turn it into a smokestream.
> 
> Oh well, I am off to email the guy I purchased it from. I figured I would ask the experts if this amp would have problems running @ 2 ohms mono.


chrisb,
I don't know if this info is too late but I'm the engineer that designed all the old soundstream stuff and the original 500 had three pairs of output transistors. the 500s had four pairs and the 700s had six pairs. onother thing is i don't know about reported problems with these amps or the auto hi-current but they worked great. i would track failures from soundstream service to see if we had any high failure rates on amps that may need some sort of adjustment but we never had any real problems with those amps.

ace956


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## ChrisB (Jul 3, 2008)

Sadly, that amp is long gone. The amp was rock solid but those GD switches were a thorn in my side because every time I flipped one, I had the pleasure of changing it!


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## GlasSman (Nov 14, 2006)

ace956 said:


> chrisb,
> the original 500 had three pairs of output transistors. the 500s had four pairs and the 700s had six pairs.


The original Reference 500 has 6 pairs per channel. 24 total output devices.....just as the Reference 700Sx has.


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## ace956 (Aug 28, 2009)

GlasSman said:


> The original Reference 500 has 6 pairs per channel. 24 total output devices.....just as the Reference 700Sx has.


GlasSman,
Actually I was using the number of devices in the 500s and 700s. The truth is I don't have schematics of the original 500, sorry. In the later models we limited the bandwidth of the amplifiers to 10 HZ and that allowed us to get more power out of less devices. I checked with my old production manager and it turns out you were correct, the original 500 had six pairs per channel. Once again I'm sorry.


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## ace956 (Aug 28, 2009)

Chris B.
Hello chris this is wade stewart the engineer that designed the 700s. this amp is rated at 700 watts bridged into 2 ohms or 1 ohm. trust me this amp won't smoke run like this. I am including a copy of the owners manual.

wade stewart, ace956


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## ace956 (Aug 28, 2009)

Chris B.
Here is a copy of the owners manual for the 700s.

wade


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