# Soundstream Old School - Reference 300 vs. Rubicon 302 cs. Rubicon 300.2



## JJAZ (Feb 17, 2006)

Hi All,

I need an amp with a small footprint, and have found the following three old school Soundstream amps:

Reference 300
Rubicon 302
Rubicon 300.2

They all seem to share the same footprint and the same specifications.

Can anyone elaborate on the differences between them?

In my application they will either drive a set of tweeters or a 2-way center channel.

Greetings
Johnny


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## azvrt (Nov 11, 2010)

Ref 300 '94/'95
2.5 volt gain, no crossovers.

Ref 300s '96 300sx '97
5 volt gains (separate left/right), crossovers

Rubicon 302 '98/'99 last of the USA built amps
5 volt gains (separate left/right), crossovers, Hawkings bass control

Rubicon 300.2 first of the Asian built amps. Has the made in USA sticker still on it.

A bit overkill for tweeters but the headroom won't hurt.
Specifications are not the same. Ref 300 and Rub 302 are more powerful in 4 ohms stereo than 300s/300sx.
Keep in mind they are all much more powerful than stated in the manual.
Good luck they are great amps.


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## JJAZ (Feb 17, 2006)

Thanks a lot for the help!

Overkill for tweeters, maybe, maybe not 
I am using the JBL MS-8 and tried powering my tweeters from its internal amplifiers (18W RMS @ 4 Ohm).
When I play it fairly loud the tweeters are clearly distorted, so my guess is that I am hitting the limit of the internal amplifier. As a check I am now running the tweeters passively crossed on my PG Xenon 200.4 (same channels as my mids) and it sounds a LOT better.

I will look for either Ref 300 or Rub 302, then.. Might be nice to get the Rub 302, the crossover and separate gain controls could come in handy one day.


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## 07azhhr (Dec 28, 2011)

azvrt said:


> Ref 300 '94/'95
> 2.5 volt gain, no crossovers.



I know this is an older thread but thought I would give SoundStreams info on these model year amps. I recently aquired a ref405 that is spec'd with 2.5 input voltage so I contacted SoundStream and they said that the amps can handle up to 5v and that HU's of the time did not commonly use more then 2v outputs.


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## bigdwiz (Oct 7, 2010)

I tested an original Reference 300 for RMS wattage output just a few months ago. It was part of an old school 75x2 amp shootout I performed...

Soundstream Reference 300 Power Output Test - Old School - YouTube


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## 07azhhr (Dec 28, 2011)

Very interesting. I wonder how my 405 would fair in a bench test like that?


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## azvrt (Nov 11, 2010)

07azhhr said:


> I know this is an older thread but thought I would give SoundStreams info on these model year amps. I recently aquired a ref405 that is spec'd with 2.5 input voltage so I contacted SoundStream and they said that the amps can handle up to 5v and that HU's of the time did not commonly use more then 2v outputs.


Be careful with this information. The Soundstream you contacted is a totally different company than the one that made your amp. It has been sold at least once since, most of its original employees sacked. I'm not saying they don't know what they are talking about but I wouldn't fully dismiss the possibility.

Anyway, the Reference s / sx and Rubicons have 5 volt input gains. I doubt the original Refs can handle 5 volt input as they are supposed to saturate (reach full power output) with an input voltage of 2.5 volts.

Anyway, it doesn't really matter. If you have an 8 volt head unit and the amp starts clipping at some point (no matter at which point exactly, 2.5 or 5) the sound should clearly be distorted which would be a sign you should turn the volume down.


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## 07azhhr (Dec 28, 2011)

azvrt said:


> Be careful with this information. The Soundstream you contacted is a totally different company than the one that made your amp. It has been sold at least once since, most of its original employees sacked. I'm not saying they don't know what they are talking about but I wouldn't fully dismiss the possibility.
> 
> Anyway, the Reference s / sx and Rubicons have 5 volt input gains. I doubt the original Refs can handle 5 volt input as they are supposed to saturate (reach full power output) with an input voltage of 2.5 volts.
> 
> Anyway, it doesn't really matter. If you have an 8 volt head unit and the amp starts clipping at some point (no matter at which point exactly, 2.5 or 5) the sound should clearly be distorted which would be a sign you should turn the volume down.


I understand what you are saying and I will keep that in mind. I will be using only 4v on it so it should not matter.


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## azvrt (Nov 11, 2010)

Unless I am mistaken, usually one does not reach his or her full pre-out voltage on the head unit (under normal conditions).

For instance, my Eclipse CD8445E hu has 8 volt pre-outs. The max volume setting is 80. Let's say that at 80 you have 8 volt, then one might think that at 79 it has 7.9 volts. From what I understand, it doesn't work that way.
I might have read somewhere that which each step in volume decrease there is a certain percentage decrease.

Let's say that that percentage is 10% (just as an example).
I think that when at 79, the voltage is 10% lower that at 80, so one would go from 8 volts to 7.2 (again, the 10% is entirely fictional). So if you decrease a small number of steps the voltage decreases drastically. So at volume 50, the pre-out voltage is already very low.

A friend of mine has the exact same head unit and has a full Soundstream 2.5 volt setup. I think he still manages to reach over 50 without the amps reaching their full output (which means that at 50 the pre-out voltage is still lower than 2.5 volts), so unless you turn the volume of your HU all the way up you should be fine.


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## sqshoestring (Jun 19, 2007)

I have a couple 302 but have only used one on a single 12. It seemed to have a lot of power for 300w. I have used the D series a lot and they are nice, though I'd not choose them for sub use others seem to have better bottom. I'd say the 302 and its sisters are one of the best, like other amps around then they have the most features and still a USA build quality (the last usa model iirc).

Power to dB, its a log function. Check this chart you see as more power is applied you get less dB increase. You volume on your HU is made to increase dB evenly not voltage, so it is actually giving little voltage and at max it dumps more voltage like crazy. So your actual power use at the amp is opposite that chart; power use is very low at low to mid volume and then ramps up quickly to a peak of highest power at max output.

http://www.soundenvironments.org/images/ig/Power_vs_SPL_10_1000.jpg


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## 07azhhr (Dec 28, 2011)

HMMMM. My factory Pioneer HU is said to be low level only and with the volumn all the way down I measured 6 volts. So if either of your statements is true then WTF voltage is that deck capable of putting out???? Maybe I am measuring wrong though.


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## azvrt (Nov 11, 2010)

07azhhr said:


> HMMMM. My factory Pioneer HU is said to be low level only and with the volumn all the way down I measured 6 volts. So if either of your statements is true then WTF voltage is that deck capable of putting out???? Maybe I am measuring wrong though.


You might be doing something wrong.

The first-gen Rubicons (such as 302, 502 etc) are indeed the last of the USA-made amps.
The second gens (300-2, 500-2) are Asian made.

Yes the older D-series are very nice amps, but on subs the Refs and Rubis are magnificent. Always have been and always will be.


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## sqshoestring (Jun 19, 2007)

07azhhr said:


> HMMMM. My factory Pioneer HU is said to be low level only and with the volumn all the way down I measured 6 volts. So if either of your statements is true then WTF voltage is that deck capable of putting out???? Maybe I am measuring wrong though.


The speaker leads will have ~6v on them all the time, but the RCA signal is the voltage we are talking about for say a 4v or whatever HU. The amplifier simply raises the voltage to 20v or 30v (+ and - power rails) or whatever it takes to get the wattage it puts out, so it will mimic the HU RCA voltage it just multiplies it. Assuming the HU does not clip and makes 4v output, the amps should reach their max unclipped output voltage the same time with properly matched gains. The point is as you have less than max output the voltage drops like a brick as does power usage due to the dB to watt difference. At low outputs the voltage changes far less, approaching max output it spikes up. As dB output goes higher it takes multiples of power to make more dB, so the volume control (audio taper) will output far more power as you approach max output. You will only see 4v on a 4v HU at max volume, the rest of the time you will see far less.

Amp 101 in case anyone needs to know: 
The speaker leads on a HU have 6v on them because that is the way to make an amplifier run on ~12v without a power supply. You need a + and - supply to move the speaker so you 'split' the 12v in half at 6v and use 12v for the positive rail and 0v for the negative rail. +/-6v gives you about 18wrms. A car amplifier is larger because it has a power supply with a transformer than provides maybe +/-20v or more, plus larger amplifier section to handle more power, plus a preamp section with the xovers and all that in it. Clipping is when the amp applies the entire rail voltage to the speaker at the top or bottom (+ or -) of the audio wave and it creates a flat spot on the peak. That spot makes distortion that was not in the music to start with. Clipping will always happen when an amplifier of any size has no more voltage left to apply to the speaker, of course bass notes take the most voltage because they move the speaker more. The actual current (such as RMS wattage) that passes through the speaker is determined by the impedance of the speaker and the amp's ability to flow that current at max voltage. Most amps can 'flow' rated current specs at rated ohms. Note that the AC voltage you measure out of the amp is different than the +/- rail voltage you would actually see on a scope in the waveform or measure on the rail inside the amp (except hybrids that vary the rails).

IIRC the old rub had flat fins as mine do, the Asian models had a double hump in the fins but were very similar. Isn't there now a new rub? Some say the humped rub was not much different than the original and are not bad amps, I don't know I'd rather a US made amp so I got those. Yes that little 302 rocked on a single 12 and I was temp running it on a 8ga wire off of the fuse box lol. It went loud but was a spl sort of sub in a sealed that I didn't like.


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## azvrt (Nov 11, 2010)

Thanks for the info.

Regarding the Rubicons, in some cases the Asian made second gens (yes with the strange 'wave' in the heatsink) have the same internals as the USA made first gens.

They first used original Rubicon boards for these amps until they ran out, then used newly made boards. The newly made boards resemble the originals quite a lot I believe, so they should not be bad amplifiers.
There's even a Made In USA mentioned somewhere on these amps or their boxes. Rumors say final assembly might have been done in the USA, in that case it would not be a 100% lie 

It all depends whether you prefer your amp has been assembled by a barely paid 11-year old Asian kid or an underpaid immigrant 
No, what really matters is the quality of the board and its components.


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## 07azhhr (Dec 28, 2011)

sqshoestring said:


> The speaker leads will have ~6v on them all the time, but the RCA signal is the voltage we are talking about for say a 4v or whatever HU.


This makes more sense then the wires actually being low level inputs. I just bought my HHR and joined up on a HHR specific site so when multiple threads were found saying the input to the amp were low level I just trusted/assumed that they might know what they were talking about. This also explains why these wires made an older amp of mine smoke on the input side.


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