MiniDSP
OT Tom, but I'm looking at the MiniDSP 2x4HD (along with the much more expensive DEQX Express II processor) which I guess is similar to your MiniDSP 4x10.
Did you happen to try any DEQX products before deciding on the MiniDSP 4x10?
Thanks
OT Tom, but I'm looking at the MiniDSP 2x4HD (along with the much more expensive DEQX Express II processor) which I guess is similar to your MiniDSP 4x10.
Did you happen to try any DEQX products before deciding on the MiniDSP 4x10?
Thanks
Some of us > 18KHz. In my case the ribbon will do 500Hz and up. Makes having a 3-way system seem wasteful
DEQX and miniDSP are a bit much of a muchness from a crossover viewpoint*, but DEQX can do more IF you want it to. . If you are buying new the Hypex units are also worth looking at. I would pick the cheapest that does what you want and see if you really need the extra 3K worth of features of the DEQX. I've not played with Dirac on miniDSP so cannot tell you if that is comparable with all the magic processing DEQX does. Oh and MiniDSP has good resale value even if you upgrade later.
*There are some fancy crossover topologies that you could consider that would limit choice, but suspect that you are not looking at those.
*There are some fancy crossover topologies that you could consider that would limit choice, but suspect that you are not looking at those.
I think you are mixing power requirements with driver displacement. Drivers reach maximum displacement at low frequencies at much lower power much easer below 40Hz. Generally power rating of drivers are based on a wide band spectrum limited by heat dissipation.
I recall back in the 80s, there someone designed a state variable 3 way active filter picking 3KHz and 300Hz as the xo points because it somewhat let the amplifiers each be responsible for an equal amount of power spectrum. I still have a set somewhere around.
But really, I think just when we start considering all this, different designers are going to make different assumptions for design basis. Chip based amps are powerful enough to handle most home usage nowadays that power and resolution are the leased concerns. Perceived resolution is a different issue which involve lots of psycho acoustics and other sources of sound coloration. If you really look at technical resolution data, it really has no direct relation with the perceived resolution expresses in audio terms.
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I'm with Bill on this one. While I'm sure your musings are interesting to some, they would have a much better chance of getting the attention they deserve if you posted them in other parts of the forum, for example the lounge.
Also, it's really not for you to question Bill's priorities. He makes progress at the speed he is able given whatever else life throws at him.
Tom
Also, it's really not for you to question Bill's priorities. He makes progress at the speed he is able given whatever else life throws at him.
Tom
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The MiniDSP 4x10HD sorta fell into my lap. A collaborator/client needed me to measure it and I needed to build him an amp. I ended up liking the 4x10 so I offered a trade.
While the 4x10 has room for improvement (see my measurements of it), it works quite well for me.
It would be nice if it approached the THD performance of the Modulus-86, but MiniDSP is just not there yet.
Tom
I just respond when see an interesting issue. In this case, the power supply.
Life is unpredictable, I lost the window of opportunity last year to work on the Mods, but the window of opportunity is close again. The only thing is Bill will not be happy if I do post test data on power supplies [emoji849]. But I really would like to see what he's built.
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Given Tom has characterised the power supply +Mod performance with more accurate measuring equipment that the rest of us have access to* I am not sure I will be bothered. I posted pictures last week of progress, so you can see what I have built and am building. As part of these measurements you can see the difference between a regulated lab supply and a simple unsnubbed transformer on the bench type PSU. He's also posted measurements with the SMPS-86. All laid out in dB for you. Spoiler alert: with good PSRR in your amplifier the differences are minimal and most certainly inaudible.
* He also knows how to use it. There are some on this site who fall into the 'all the gear and no idea' camp.
* He also knows how to use it. There are some on this site who fall into the 'all the gear and no idea' camp.
Sorry, I really don't follow these forums actively, but if the notices show up on my phone, they don't go away until checked out individually. I have a few seconds to determine if I want to respond. PSSR really has nothing to do with whether a power supply is going to comply with EMI/EMC requirements. The MW modules pass certification in the Class II configuration, but it does not assure EMC compliance for Class I or other classes.
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Oddly enough DIY kits don't need to pass EMC compliance. The SMPS -86 probably would pass as it uses compliant modules and Tom knows what he is doing.
You can unsubscribe to threads very easily. Or not read every notification that comes in. If you suffer OCD and have to read every email then the unsubscribe might help you.
You can unsubscribe to threads very easily. Or not read every notification that comes in. If you suffer OCD and have to read every email then the unsubscribe might help you.
If they are connected in Class II configuration, then yes, they will pass. Connected in other configurations, then it is likely you are injecting noise into your mains power.
You know, if you just ignore me, it would be a lot easier, I enjoy the quick read. But you might find me irresistible.[emoji849]
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You know, if you just ignore me, it would be a lot easier, I enjoy the quick read. But you might find me irresistible.[emoji849]
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I listened to a system using the 4x10HD in July, compared to another system the owner had, it was a bit fatiguing to me, the owner attributed it to the electronics, but I never spent time to verify the difference between the two.
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This provides a most excellent idea for another page at Neurochrome.com. That is what customers use for speakers sources, input, and the like.
Those examples would help so very many.
Well, it would illustrate how to use a clean amplifier, pleasantly.
Makes sense--clean amplifiers are rare and the need isn't.
Yes. There are many downsides to housing the supply separately. You maximize the supply impedance that way, which is never a good idea. Also, the currents drawn by a Class AB output stage are not pretty. Each amp half draws a pulse each half of the signal cycle, so the currents are relatively high bandwidth --> good sources of EMI.
Separating the supply from the rest is sometimes done on phono amps where hum is the main concern. Even on those amps, you still have the drawback of the increased supply impedance, but at least the currents drawn by such an amp are usually pretty nice as the amp runs (mostly) in Class A and doesn't draw that much current. In phono and preamps, you could also implement local supply regulation in the amp enclosure to minimize the supply impedance.
Then again, in my DIFF PRE 8x2, I used a pair of switching power bricks for the supply and the worst case mains hum I measure on the output is -115 dBV (1.8 µV). In the HP-1 I added regulators to the switching supplies and pushed the mains hum down below -136 dBV (160 nV).
Something tells me that doubling the chassis cost by having to build two enclosures isn't necessary for good performance. One just have to pay attention to the circuit layout.
Tom
So my boards have finally turned up from Canada to the UK. It took 20 days using the slow post. I can never workout why these things take so long given that they go by air. However it was expected. This saved a little money but gave me the time to work out the build details.
As a bonus I got to pay an additional £22.27 VAT, ah no, but wait I need to pay another £8 processing fee to the Royal Mail. So the total cost to the UK is £188.76 for 2 off MOD-86 & 1 off PWR-86. For anyone considering this build what you have to remember is that you are paying for Tom's engineering ability and not just a few cheapo PCBs not to forget his undivided attention here and via email.
At least they are here safe and sound, thanks Tom!
I'm going to be good and take my time with thier build especially as I'm away this weekend...
Hmm, Nope, just could not resist:
For the heat sink I filed down the threaded inserts a little so that they were flush with the PCB and then used two screws (PC Case) to fix it firmly. Just felt it was a little better than soldering.
As a bonus I got to pay an additional £22.27 VAT, ah no, but wait I need to pay another £8 processing fee to the Royal Mail
. So the total cost to the UK is £188.76 for 2 off MOD-86 & 1 off PWR-86. For anyone considering this build what you have to remember is that you are paying for Tom's engineering ability and not just a few cheapo PCBs not to forget his undivided attention here and via email.At least they are here safe and sound, thanks Tom!
I'm going to be good and take my time with thier build especially as I'm away this weekend...
Hmm, Nope, just could not resist:
An externally hosted image should be here but it was not working when we last tested it.
For the heat sink I filed down the threaded inserts a little so that they were flush with the PCB and then used two screws (PC Case) to fix it firmly. Just felt it was a little better than soldering.