Roughly 375hz and 5500hz (ribbon tweeter). I can see myself needing to adjust the levels but I'll measure that using REW and a microphone and possibly replace the fixed resistor, but if my current miniDSP config. is an indicator I'm only adjusting for a 1-2dB difference in the treble.
I'm using Roon to consolidate my Qobuz and ripped CDs and that has a Convolution/Procedural EQ feature to apply room adjustment based on the REW filter settings so there's still options to play with.
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It´s a very common problem, for some unknown reason even more common in Musical Instrument amplifiers (maybe because often very high gain stahes are involved and extreme EQ) so designers generally ploay it safe and routinely add some kind of turn-on AND turn-off mute.
PA type amplifiers incorporate relays to switch speakers off, for the dual purpose of muting and DC protection; but for smaller (cheaper) amps relays are bulky and expensive, so simple muting using Fets or even plain transistors are good enough and need no coil supply.
You´ll find such mutes in about 60% of MI amplifiers.
PA type amplifiers incorporate relays to switch speakers off, for the dual purpose of muting and DC protection; but for smaller (cheaper) amps relays are bulky and expensive, so simple muting using Fets or even plain transistors are good enough and need no coil supply.
You´ll find such mutes in about 60% of MI amplifiers.
I haven't had chance to connect it up yet, although I've used my miniDSP with a similar 24dB LR over the last couple of years, the miniDSP is capable of implementing a 48dB LR so it's not that steep in comparison.
Today I recieved two chassis, and work has begun, I'm mounting everything on a double sided copper clad with walls to shield, still waiting for 2 small toroids, 2 super regulators, and all of the rca connectors.
The copper clad is slides in in slots, so there's a 10mm gap underneath, all power cabeling will be done underneath.
The copper clad is slides in in slots, so there's a 10mm gap underneath, all power cabeling will be done underneath.
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Nice, like it. I need to get back on mine. I've got some steel mesh (used for PC cases) that can be bent into various shapes to shield, this with my idea to mount the crossover boards in the rear corners, the super regs in the front corners and have the transformer centre/rear should help with isolation.
I did spend yesterday, re-introducing my preamp and DAC into my setup, removing one of the miniDSPs and configuring it for 2 channel (bass & mid) and then temporarily introducing a 2nd order passive crossover (4.7uf/2.2ohm) for the treble. So I've got my Raspberry Pi 4 (Roon endpoint) into my DAC, my DAC into my preamp and then using the dual pre-outs for the miniDSP and direct to the 'treble' amp. TBH, it sounds bloody good! I ran a few REW sweeps and the response is still pretty good and all nicely balanced, does make me wonder whether I should stay passive for the tweeter!
I did spend yesterday, re-introducing my preamp and DAC into my setup, removing one of the miniDSPs and configuring it for 2 channel (bass & mid) and then temporarily introducing a 2nd order passive crossover (4.7uf/2.2ohm) for the treble. So I've got my Raspberry Pi 4 (Roon endpoint) into my DAC, my DAC into my preamp and then using the dual pre-outs for the miniDSP and direct to the 'treble' amp. TBH, it sounds bloody good! I ran a few REW sweeps and the response is still pretty good and all nicely balanced, does make me wonder whether I should stay passive for the tweeter!
A little update from me.
Today I finally finished the two filters, I had some trouble with the psu toroidals I bought, they should have been 18 volt ac, but instead they delivered 25 volts, way to much for my boards, well they were old stock and at that time grid power was lower, remedy was removing 70 turns on each toroid.
I think they came out quite nice.
How is your project moving along?
Today I finally finished the two filters, I had some trouble with the psu toroidals I bought, they should have been 18 volt ac, but instead they delivered 25 volts, way to much for my boards, well they were old stock and at that time grid power was lower, remedy was removing 70 turns on each toroid.
I think they came out quite nice.
How is your project moving along?
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That looks really good, I like the form factor, considerably smaller than mine, makes me want to mount it in something smaller.
Great work on the toroidals. How did you workout the number of turns to remove?
I will need to make a few adjustments as I've replaced the tweeter and woofer in the last few weeks so, should only need the resistors replacing to the sizes I used in the low-mid. Although I will validate all of these using my miniDSP and UMIK-1.
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Well I just removed 5 windings , hooked it up to power and noted the difference, calculated roughly 60 some windings but ended on 70 to correct voltage, after that tightly wound insulation tape around, and made a copper belly band soldered and grounded.
I do like your chassis to, I had a similar for my hypex dlcp, it's a shame good chassis are so expensive, I have several projects without chassis and not running,
I do like your chassis to, I had a similar for my hypex dlcp, it's a shame good chassis are so expensive, I have several projects without chassis and not running,
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Another update.
Today I spend some time with the filters and arta, and I noticed a lot of high frequency noise, from 50 to my max, 100 khz, so I tried some stuff, and this is what did the trick,
I removed the 3 pots on output, and ran a 100 ohm straight from resistor to RCA plug.
All soft cables are switched to solid core, and a ground guard along the input wire straight to the input 1k resistor, also changed the 100k on input to 15k, that somehow helped on my DC output, its lower but not perfect, probably due to the ne5532 notorious for DC, I might go opa one day.
Added a pic to show the tweaks.
Today I spend some time with the filters and arta, and I noticed a lot of high frequency noise, from 50 to my max, 100 khz, so I tried some stuff, and this is what did the trick,
I removed the 3 pots on output, and ran a 100 ohm straight from resistor to RCA plug.
All soft cables are switched to solid core, and a ground guard along the input wire straight to the input 1k resistor, also changed the 100k on input to 15k, that somehow helped on my DC output, its lower but not perfect, probably due to the ne5532 notorious for DC, I might go opa one day.
Added a pic to show the tweaks.
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