BASH 500S Subwoofer Amp Review

[amirm]

This is a review and detailed measurements of the now discontinued, Indigo/Blade BASH 500 S subwoofer plate amplifier. It is on kind loan from a member and cost around US $250 when new.

This is a bridged class AB amplifier fed by a switching power supply. It is far beefier than the class D amps we have been testing.

I performed my testing as usual with crossover set to max and gain adjusted to 25 dB.

These are the guts in case you are wondering:

Old school design and assembly as we expect. Not so expected is the testing checklist include air leak! Heavy use of sealant everywhere assures that.

Owner mentioned it was recently recapped.

BASH 500S Subwoofer Amplifier Measurements
Feeding the amp 40 Hz signal and input adjusted to get 5 watts, gave us this dismal results:

Then again a couple of modern class D amps we have tested show similar results.

There is however excellent news in the form of frequency response:

Finally we have a flat in-band response with no overshooting due to high pass filter!

Power sweep shows that distortion sets in as soon as the amp is getting ready to produce any meaningful power:

Shame. Then again, the amplifier easily meets its spec of 500 watts.

The manual I found online said the minimum impedance was 4 ohm so I did not test at 2 ohm.

Sadly when I tried to measure max and peak power, the amp shut down and no longer operates.

Warm up was uneventful:

Conclusions
It is a relief to see that we can get flat frequency response out of a plate amp. But as if they are all copying each other as far as bad manners, SINAD is stuck in 30s (average for all full bandwidth power amps is in the 80s). Strangely the spec in the manual claims distortion is 100 times lower! Maybe something is wrong here.

While the other class D amps were very robust against being stressed, the 500S gave up the ghost while running considerably warmer.

I can't recommend the Indigo BASH 500s sub plate amp. A shame as this amp made quite a name for itself at the time.
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[Prana Ferox]

I have a subwoofer with one of these (I think it's the lesser 300w variant) that I built mostly to sit under my gaming desk and make thumps, far before any serious hi-fi aspersions came into my interests. One nice thing about these was that you could tune the low pass filter cutoff and Q to better tune the sub; the bad thing was you had to unsolder and replace resistors to do so, but at least it came with a table, so you could plug the numbers into WinISD and have a decent idea if your sub was sort of flat and at least unlikely to blow itself past xMax.

 

[Grenadine]

Interesting results. I purchased this unit from parts express several years ago. I believe it's class d, not AB. anyway, the amp completely stopped working after light usage and had a scratchy gain potentiometer. I found someone on eBay that can repair it for $150, and owner covers shipping both ways. Fixed the gain knob as well. Since it died again in Amir's testing, I'm curious if something is seriously flawed with it, based on the distortion results. After the recapping, I doubt it had more than 1 hour of light usage.

 

[AndreaT]

Why such a massive distortion? Where is the engineering mistake? We are at levels of a 1960 cheap tube amplifier. Thank you Amir for these reviews: they removed any desire to build a diy sub.

 

[levimax]

Thank you Amir for these reviews: they removed any desire to build a diy sub.

Just get a Crown PA amp or similar. Much easier than building a plate amp into a box and they are powerful, clean, and bullet proof and have extensive DSP and protection capabilities.

 

[markk]

Why such a massive distortion? Where is the engineering mistake? We are at levels of a 1960 cheap tube amplifier. Thank you Amir for these reviews: they removed any desire to build a diy sub.

Nothing wrong with a DIY sub. Just don't expect a $100-300 plate amp to be that good.

I still would like to see Amir test a new Hypex amp. No reason it shouldn't be much better. There is sort of a minimum cost associated with building a decent amp. Once you drop below that, you end up sacrificing something.

DIY subs are some of the best bang for the buck upgrades. Just don't cheap out on an amplifier or a driver.... for example, $355 for a 250w Hypex plate amp plus ~$250 for a good high Xmax 15" sub, build your own cabinet, and you can put together a sub that will rival some of the best, short of feedback/motion control setups.

 

[Lednek]

I am really enjoying the plate amps reviews. Now im wondering what would be considered a good amplifier for a subwoofer.

 

[Chrispy]

Well, a bit better than the last coupla car sub amps.

 

[Chrispy]

I am really enjoying the plate amps reviews. Now im wondering what would be considered a good amplifier for a subwoofer.

Various pro amps work quite well. Plate amps are a pain to build into your diy sub and not particularly beneficial.

 

[dtaylo1066]

What a bummer and eye opener on these sub amps. Come on, producers, it is not that hard to have some clean power and a good response curve. It makes me think a lot of people are listening to deep bass thumping with a lot of distortions and don't realize it.

The Fosi sub amp at 136 watts is far, far better than this crap.

 

[Chrispy]

What a bummer and eye opener on these sub amps. Come on, producers, it is not that hard to have some clean power and a good response curve. It makes me think a lot of people are listening to deep bass thumping with a lot of distortions and don't realize it.

The Fosi sub amp at 136 watts is far, far better than this crap.

Depends what you use for a sub amp. If your goal is simply cheap, the amps reviewed so far at least are interesting in their measurements, but not particularly surprising.

 

[HighFutility]

Thank you so much for these reviews. I will never buy a plate amp again. Crown XLS amps or nothing, I guess.

 

[kyuu]

Oof. Man, the sample size is small still but it's really starting to look like the subwoofer plate amp manufacturers have been producing some cheesy crud. Granted, 500W for not a lot of money isn't nothing, and you hardly need 100dB SINAD for a sub. But 30dB? C'mon man.

 

[Chrispy]

Oof. Man, the sample size is small still but it's really starting to look like the subwoofer plate amp manufacturers have been producing some cheesy crud. Granted, 500W for not a lot of money isn't nothing, and you hardly need 100dB SINAD for a sub. But 30dB? C'mon man.

Look at the price point....

 

[Billy Budapest]

I thought the BASH amps were Class G or Class H?

Wow, the distortion measurement is pretty bad. This is making me wonder if a subwoofer plate amp with respectable performance was ever produced.

 

[kyuu]

Look at the price point....

Yes, that's why I said the part about 500W for not a lot of money not being nothing.

I thought the BASH amps were Class G or Class H?

Those are just variants of class AB.

 

[Chrispy]

Thank you so much for these reviews. I will never buy a plate amp again. Crown XLS amps or nothing, I guess.

PowerSoft and SpeakerPower make some pretty good sub amps. Some even in plate form.

 

[Billy Budapest]

Yes, that's why I said the part about 500W for not a lot of money not being nothing.

Those are just variants of class AB.

Sort of, but you could make a similar argument that Class AB is just a variant of Class B.

 

[Chrispy]

Sort of, but you could make a similar argument that Class AB is just a variant of Class B.

LOL not really.

 

[Grenadine]

PowerSoft and SpeakerPower make some pretty good sub amps. Some even in plate form.

I have the Speakerpower HTB-700, standalone version. According to the designer, its the same dsp/amplification that's used in the plate version, just laid out differently:

SP1-700-HT

Mono Block Subwoofer Plate Amplifier Home Theater (HT) STABLE at 2 ohms 1000W @ 2.7 ohms 700W at 4 ohms 350W at 8 ohms 53 VRMS (75 Vp) at Hi-Z Subwoofer DSP Controls OVERVIEW: This product is uniquely designed to produce high power output at extremely low frequencies, making it perfect for...

www.speakerpower.com

I'm intrigued by the new dayton 1000 watt sub AMP with dsp and auto room correction $800: