SpeakerPower

40 minutes ago, Pradeep said:

Someone over at AVS received an sp1-4k or 6k recently and looks like they are using an internal cover again on the plate models. Glad to hear Brian's potentially still got some input there even if he does spend most of his time sitting on a beach drinking rum now.

Hey I resemble that remark!

Confucious say, "Man with two watches never know what time it is"

I admit that I'm also sad to see the Speakon connectors go, and the DSP features are throw away to me.  But I realize not everyone feels this way.  Actually, the delay knob will be an excellent feature for more typical home users who don't have or want the complexity of an outboard DSP unit.

 

The drop in price is a big plus to me because what I am contemplating will require a lot of different amps.  Now what I'd really like to see is a single channel plate amp to fill the gap between the SP1-700 and the SP1-2400.  It appears there is a 2 channel plate amp available with 2 X 700W, the SP2-1400, but unless it's bridgeable or else one can safely run one channel of each voice coil in a DVC driver, it's not really useful to me.  Its footprint is also too big for the subs I'm planning.  Haha!

The SP2-1400 is not bridgeable but can run a dual voice coil driver with one 700W amp per coil. The footprint is about 11 x 11". Your cabinet is smaller than that? What dimensions would fit?

Later this year I will have a 1200W amp with the same feature set. It will probably be the same width as the SP1-700; 7.2" and taller, about 14" vs 10.75"

Looks like you are correct in relation to the rack mount versions.  However, the HT version of the plate amps is cheaper than the pro version, which is what I use along with Reaction, JTR, Seaton, PSA, etc.  So there is definitely an advantage there.

 

SpeakerPower is primarily a company focused on providing amps to OEMs.  OEMs will have access to the internal DSP, which is where the serial port comes into play.  A non-OEM user will not get access to the internal DSP. 

Right on all counts. Regarding the price difference, it amazing how many HT features you can add in when you not paying for very heavy and expensive Powercon connectors and such that HT does not care about.

I think new is slightly charitable frankly! It remains a pretty terrible circa 2000 website.

 

What is the difference between the DP and HT models? Is it just that HT means the different front end? Is it a DSP? Any impact on performance (eg rolloff)? I couldn't see specifics on that.

Yea but its WAY better than the 1995 web site it replaced! Actually it is a work in progress and more info will be added soooon. 

The DP has no DSP, just a dataport connection to the QSC Qsys DSp. The HT has knobs for HT specific functions implemented in the DSP.

Ricci is right. And rails typically will sag as current ramps up. I've never seen higher maximum voltage at lower load impedances either.

brian

 The long term sine wave testing at this lower impedance load is a little more interesting. The K20 exhibited some limiting during this and was held about 3-4dB below clipping for large sections of the sweep. The general trend is that the K20 would produce near full power for a section of the sweep then reduce output for a while and then ramp back up and then limit a bit for awhile. We can see that the K20 starts off with a bit higher output down in the resonance of the earth frequencies of 2-5Hz and then the SP2-12000 takes over from 5-15Hz. The K20 rises back up and takes back over from 16-34Hz. Then the SP2-12000 takes over or runs even with the K20 over the 35-70Hz octave. The K20 comes back on from 70-120Hz and produces a bit higher output again. To me this looks like long term current limiting going on in the K20. The Digam series of amplifiers has a number of settings for limiting the amplifiers output or matching it to the circuit that it is on. The maximum current setting is 33A which is a long term average which is there to prevent tripping breakers. With typical content I doubt that this is ever an issue but the sine wave measurement used here is 100% duty cycle for 23 seconds or so and with the relatively low impedance minimums and the amplifier being run at full output I suspect this may actually be coming into effect and the software may be limiting the current a bit. The most notable area of the K20's measurement is between 30-40Hz where clearly the output is limited abruptly for a bit.  If this set of sweeps is compared with the impedance curve of the driver provided earlier we can see that the output squishing happens in the areas of high current demand. I will say that there is no way that I could hear anything happening or tell anything different during this measurement by ear. The entire house was being shook violently and a reduction of a couple dB in output simply doesn't audibly register to me when my home and body is being punished like that. Perhaps outside...I don't know. Anyway I'd call the 2 ohm long term sine wave test a draw or a slight win for the SP2-12000.

 

 

sp2-12k 2 ohm stereo vs k20 4 ohm bridge.jpg

Good job on your testing! It has been a pleasure to interact with you during the process. I feel you have been very fair and well grounded in reality. The results are about what I expected. The K20 has a higher voltage power supply so I expected it to take the honors on the burst test and it did. The SP2-12000 is not your average amplifier designed for light duty cycles and higher frequencies. It shines at very low and infrasonic frequency performance and high duty cycles. It takes special testing to reveal this performance.  My long term sine wave testing is done a single frequency at a time. The initial input level is set to get the maximum undistorted short term power level. Then I graph the output power versus time. This allows you to see how the amp loses power at lower frequencies, how long it holds full power before it cuts back, how smoothly it cuts back (some go into oscillation, some cut off) and what power level it eventually settles at. In your test, the back and forth of which amp is higher may be due to the time constant of the protection circuits interacting with the sweep rate of the test signal as the impedance changed in the load. I don't mean to criticize; it just demonstrates how hard it is to test this stuff.