[Captainhemo]

I am not a big fan of the Bash amps. But that little Dayton amp will work just fine.

Hey danny,  just out of curiosity, is there anything specific you don't like about the BASH amps  ?  I've been  using one  (300W version) for a few years now to  drive my SDX10  (hopefully to be replaced by one of your sevo 12's one of these days)  and it eems to perform very well. 

Just interested to know
-jay

[Danny Richie]

Hey danny,  just out of curiosity, is there anything specific you don't like about the BASH amps  ?  I've been  using one  (300W version) for a few years now to  drive my SDX10  (hopefully to be replaced by one of your sevo 12's one of these days)  and it eems to perform very well. 

Just interested to know
-jay

The switching supplies have been known to be a bit noisy.

[bdp24]

All HX* amps from our nomenclature are based on Hypex Ucd modules.  Our finished sub LV12R is based on Ucd module and we have been selling them for 9 months now. We almost sold out the first batch and arranging a second batch. 

Each Ucd module is most cost-effective when seeing a 4ohm load. That is what we are shooting for.  It also helps us the standardize the load. We use to have 8ohm version of 12" and 15" drivers, we stop them a while ago in favor standard 4ohm drivers. But 8" driver seems to bring back the old problem again for a different reason. Some may want to simply the crossover and put four 8" driver in each channel (like two in fornt and two on the back).



Here is a photo of what I have for my prototype. It is 12" wide, 20" high, and 14" deep. The white dots on the dust cover are my markers, not something you will see from production units. With two 8" driver, its output is very comparable (albeit a bit less) to a typical DS1200 or SW12-04 driver.



This is the close-mic frequency response of prototype. The final production will be a bit different. This should give you some idea of the frequency response.  Note that this is close-mic, if one consider baffle loss in real application, the upper will be slightly emphasized and that makes the upper end extension a bit higher than this plot.  Objective of these 8" subs to simplify crossover design. I have seen some advocating MBM. In my view, MBM just adds crossover complexity. If we can have enough number of these smaller driver, at the same time, provide sufficient low end extension, it should be a better alternative. 

We recommend to have the driver fully populated.  Ucd is self oscillation class-D. If you don't put a load, the output can see a high DC. I am not sure how that is going to affect long term reliability.

Sealed version of 8" driver (DS800) will be $139 each list price (a bit more expensive) than Danny's SW08 drivers.  HX580 (we should have name these HX600, but we already have a model H600, so we name the amp HX580 to avoid confusion) has list price of $379, and HX300 has a list price of $289. Please note each HX amp is a mono amp regardless how many Ucd modules it uses.

We do encourage the customers to use a pair of HX580 driving four DS800, we have a package price of $1179 for that.

Brian, do you have a package price for one HX300 plate amp with a pair of DS800 8" woofers?

[rythmik]

Hey danny,  just out of curiosity, is there anything specific you don't like about the BASH amps  ?  I've been  using one  (300W version) for a few years now to  drive my SDX10  (hopefully to be replaced by one of your servo 12's one of these days)  and it seems to perform very well. 

Just interested to know
-jay

You will hear a big difference when you switch from Bash to other amps.  First Bash was designed by a switching power manufacturer (a Canadian company that later sold the design/patent to the current BASH manufacturer in China) . The specialty of the original manufacturer was on switching power supplies.  BASH is  supposed to compete with ICE-power or Hypex UCD for higher end "high efficiency" amplifiers. But we don't see they being deployed or talked about in any application other than subwoofers.   BASH drew my attention about 7 years ago.  I built a prototype servo amps, and the sound characteristic is a very "thick" bass, as in "thick fog". For some people, the thick bass can be interpreted as "potent". But for us, that "thick" bass actually masks out detail.  Almost everyone switching to our amps from BASH immediately notices the sound becoming more articulate and transparent.   

I studied the patent of BASH. The trick that they did is delay the audio signal driving the power amplifier vs the audio signal driving the switching power supply by say 2 millisecond. They feed the rectified audio signal to the switching power supply so that the power supply can be kept say 5 V above the needed power. But the problem is for high frequency signal, the power supply will have a slower response time and therefore their trick is to delay the audio signal for a finite amount of time so that switching power is always above the required voltage rail. That sounds good. But that means there are two events in a short amount of time. First phase is the raising of power supply when the audio signal has not gone through the amplifier and therefore the amp output is supposed to stay at 0.  Then  the "delayed" signal arrives at the amplifier and it makes the output that we want. However, there will always be some feedthrough in the first phase from the power rail change to the amplifier output (in OP amps, that is called PSRR) that can contribute to a tiny but significant audible signal at amplifier output and the two mixed together produces a blurred image. This is my theory why BASH cannot compete with ICE-power or Ucd at high frequency application. BTW, non of this will show in a steady state sine wave test. That just explain how limited our traditional test methods have been and yet a lot of us are still depending on it to make "objective" assessment.

[rak313]

I just noticed the servo 8" drivers and single 300W and dual 300W amps are now on the rythmik site.

Edit:  Brian has added the T/S parameters.

[Greggo]

Is it possible to bypass the crossover in HX580?  And if so, is there any risk to the servo behavior above a certain frequency?  I am looking to run woofers from 20 to 300 or maybe 350 Hz in a 3-way design I am considering.  Of course, any updates on amps and drivers in general are always welcome : )

[Danny Richie]

Is it possible to bypass the crossover in HX580?  And if so, is there any risk to the servo behavior above a certain frequency?  I am looking to run woofers from 20 to 300 or maybe 350 Hz in a 3-way design I am considering.  Of course, any updates on amps and drivers in general are always welcome : )

I have tried using them higher up as well. 300Hz to 500Hz is the heart of the mid-range. Getting up into that range with the crossover point doesn't work out too well. I found that keeping them around or below the 200Hz range works well.

And I don't think there is any by-pass on the crossover function of the amp.

[Greggo]

Thanks for the quick reply... I was just wondering how much room I would have to experiment.  Of the 3 or 4 midrange drivers I am considering, one makes me a bit nervous as to how well it will manage anything under 300 Hz, and that is the B&G Neo 10.  I know that you cross them lower than that in one of your designs, but you are using four of them as well, where I will use just one or maybe two.  I suppose I could crank the Hypex crossover up to 200 Hz and select 12 db/octave slope, which I think would place the actual crossover point at 300 Hz ??? and then slowly back it down while also lowering the settings on the Neo10 and see how it goes.  I will be using MiniDSP which I know you are not a fan of, but it will allow me to get started easily and then in a year or two I can upgrade to something better.  I really like your servo 8 option because it seems to be a nice option to cover both woofer and subwoofer duties for some of us who don't need reference and above home theatre SPLs down to 15 Hz.  I really just want to get down to the mid to upper 20's and only for music listening purposes in a small/medium room (14 x 22) in my basement.

[Danny Richie]

The Neo 10 is a tricky driver and it is all about the baffle. I can get a single unit to play down to 200Hz in an open baffle, but there is a trick to it. If the baffle isn't designed correctly then it will never get there. There is a catch 22 involving that baffle too and I have figured out a way around it. You'll see it in a Serenity Acoustics model that uses a single Neo 10 and Neo 3 in an open baffle with three of the servo 8's.

Yeah, Mini DSP.... Might as well just go back to cassette players.

[rak313]

I purchased the dual 8" servo kit with HX580 amp from Brian and built a test box 21"H x 12"W x 13.5" deep.  The kit comes with 4 woofers and 2 amps, but I only built 1 for testing. 

I am planning on building a pair of subwoofers that look like stands, that I will put in the back of the room.  They will be 46" high and slope from 11" x 11" at the bottom to 9.5" x 9.5" at the top.  But before I went that route, I wanted to see what performance I would get with the box that Brian has shown as a prototype.

For grins, I uploaded a video to youtube playing a Ginger Baker drum solo. This was playing in stereo mode (with the AVR set to "large" for the LS-6s).

 http://youtu.be/zU7S_vWYZMQ

[bdp24]

Yep, that's what DW drums (Ginger's brand) sound like!

[neofeed]

Hi,
I'm wondering if there is any way to get these drivers or kits here in France ?

Thanks

[Danny Richie]

Hi,
I'm wondering if there is any way to get these drivers or kits here in France ?

Thanks

Sure, just order them and I can send them over via USPS.

And welcome to AC.

[neofeed]

Sure, just order them and I can send them over via USPS.

Hi Danny,
Thanks for your answer but buying from Europe would probably be a dealbreaker regarding shipping costs and custom duties... I hoped there was a way to purchase these directly in Europe. Too bad

And welcome to AC.

Thanks !

[bdp24]

Hi Danny,
Thanks for your answer but buying from Europe would probably be a dealbreaker regarding shipping costs and custom duties... I hoped there was a way to purchase these directly in Europe. Too bad

Thanks !

I can pick them up for you in Texas and bring them with me when I fly over to Europe. Email me to get my info for when you buy the round-trip ticket