yeah, but DIN are still used in some hifi products today. cheaper than XLR, take up less space etc. It's valid. Just not those awful 2-pin speaker connectors. *
Integrated DAC I'm not ready for, but as the miniDSP 2x8 pumps out 18dBU balanced I can at least run nice and hot to the (active) speakers
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*If you buy your XLRs by the thousand as I am sure some here do cost per connector is a lot less of an issue!
Removing speaker connections down to just the screw terminals on the modulus board will give me a lot of satisfaction!
Integrated DAC I'm not ready for, but as the miniDSP 2x8 pumps out 18dBU balanced I can at least run nice and hot to the (active) speakers
. *If you buy your XLRs by the thousand as I am sure some here do cost per connector is a lot less of an issue!
Removing speaker connections down to just the screw terminals on the modulus board will give me a lot of satisfaction!
Optical links are also wonderful for breaking ground loops.
Injecting noise onto the speaker connections would involve injecting noise into a rather low-impedance node. At least for audio band noise, I would look elsewhere for coupling mechanisms. For RF, it's another story and you're right that longer cables would result in a higher potential for issues. For most, it's a non-issue, but if you do happen to live with a TV transmitting tower (or HAM radio operator with a 1 kW HF transceiver) next door, you're more likely to see issues. In those cases, you'll be looking at ferrite cores and winding your speaker cables onto them. I doubt the 50-75 cm cable of a mono block vs 2-3 meter cable of a stereo amp will make a meaningful difference there. In theory, yes. In reality, a few dBGF (dB Gnat Fart - thanks Bill).
A more likely coupling path for audio frequencies is through the amp input as it is relatively high impedance (48 kΩ) and has gain to the output. That said, when the amp is hooked to a source, the impedance of the node drops to the source output impedance (assuming it's low) - within the audio band. For RF, it's another story. That's what the RF filter on the input of the MOD86 is for.
As you point out, there is a length of wire from the input connector on the chassis and the MOD86 board. RF could be radiated from it. If this is a concern, place a couple of 100 pF caps from pins 2, 3 to pin 1 on the XLR connector.
The Neutrik EMC connectors are pretty badass, though. That's probably as good as it gets for RF filtering.
That said, aside from the rogue GSM cell phone, RF interference in residential settings is largely a non-issue. I have had a few amps in the past that were sensitive to GSM, switch transients (furnace, fridge turning on creating a pop in the speaker), etc. I have no such issues with the MOD86 in an aluminum enclosure.
Tom
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Curious: Who uses DIN connectors? I've only seen them on B&O products from the 1960ies and 70ies. Along with the awful DIN speaker connectors.
The only issue I have with the DIN connector is that it can be a bit of a challenging getting the cable to fit in them and the plastic tends to melt if you aren't careful with the soldering iron. Aside from that they're really not bad connectors.
How much do you pay for a Neutrik XLR connector where you're at? At Parts-Express, they're $2.69/each (QTY 1). To me, that's not far from the cost of an chassis-isolated RCA connector.
Tom
NAIM still use them in some of their amplifiers. And in some funny ways!
Last time I looked for for XLRs neutriks were around £4 each. Quick look at maplin as they are the nearest thieving bastrads and DIN is about half the price of XLR. Although their 3m XLR-XLR mic cables are only £12. 6pin mini DIN is also very cheap.
Choice is good even if I will probably wuss out in the final analysis!
Last time I looked for for XLRs neutriks were around £4 each. Quick look at maplin as they are the nearest thieving bastrads and DIN is about half the price of XLR. Although their 3m XLR-XLR mic cables are only £12. 6pin mini DIN is also very cheap.
Choice is good even if I will probably wuss out in the final analysis!
I'm not particularly a fan of XLRs or SpeakOns and binding post/bananas/maggies/spades arrangements for size reasons either. My current build's the sort of multiamp arrangement composite chipamps like the Modulus enable so I'll need 24-30 pins through the chassis depending on final configuration. Four pole XLRs offer a decent connection density for this sort of thing and one can get 'em up to 10A/pin at OK cost. Eight pole SpeakOns are a little bit higher density but as the connectors will be visible I'm trying to stick with black. Go back and forth on direct speaker cable runs at least once a year but have never really found an arrangement I like.
The 2x8 balanced datasheet actually says +20 dBu. Pro levels are nice that way, moreso for home use if one has a low gain power amp.
Yah, that was also discussed earlier in this thread when the Neutrik EMCs came up. Might be something for the Modulus manual if it's not already in there; that's likely a more useful place than having it come up here every 100 pages or so.
Hence my remark it's a non-problem in need of non-solving. Though how well an antenna works depends on whether you build it for the proper frequency. Those lengths offer a choice between FM and TV reception.
MiniDSP seem to not quite hit specs on levels. I am hoping so as my planned gain management stage hits the rails at +19dBu. That or -2dBFS fixed attenuation in the MiniDSP. Something I have to measure when the next round tuit order comes in
And pretty much anything from Philips in the 60's and 70's. But yes, NAIM still uses them (in strange ways).
and on their latest stuff they use a single 3 pin XLR for stereo! https://www.naimaudio.com/product/nap-250
So you get a DIN to XLR cable in the box for your pre-power connection.
So you get a DIN to XLR cable in the box for your pre-power connection.
Probably because using proper separate, balanced XLR's smells too much like pro audio, and as we know, professionals really don't understand proper audiophile sound quality...
Two.
I built a pretty compact amp with four MOD86 boards powered by a PWR86 board (and Antek AS-2222 transformer). No screening or other secret sauce was used. No issues there that I could tell. The amp has a built-in MiniDSP and is used to drive a pair of LXmini speakers. It works rather well. See the Modulus-86 Build Thread Post #888: http://www.diyaudio.com/forums/chip-amps/267802-modulus-86-build-thread-89.html#post4399918
Tom
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It depends on the earthing arrangements of the amp.
The 100p caps need to be CERAMIC and need to go to the CHASSIS with the shortest possible leads.
The Neutrik EMC connectors essentially do this and have an inductor on the leads penetrating the chassis. Yes. They are very effective but you can't rely on the punter using them.
The problem is ANY lead (and its the screen) which penetrates the chassis can act as an aerial and radiate stuff into the box to be picked up by the sensitive parts which might be on the other end of the box.
With speaker leads, you need ceramics from BOTH +ve & -ve to chassis AT the terminals themselves.
There are VERY expensive professional monitor active speakers that will announce to all & sundry that you have received an SMS ... so even the big boys get it wrong sometimes ... and why some studios ban mobile phones. (The Harman active monitors appear OK)
I've also seen expensive pro gear with inductors & ceramics on a little PCB connected to the sockets via 2" of ribbon cable .. making them almost useless. The 2" is sufficient to radiate RFI to bother a line level device.
IM not so HO, this is one of the aspects which truly differentiate good gear from the toys.
There's various papers by Muncy, Whitlock et al, many of which are on the Jensen website IIRC, that discuss this problem, "how to check" and solutions. Also a special issue of JAES on this.
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Really? I see over 1700 options on Digikey for a 1000pF C0G/NPO cap, various sizes 0402 on up.
That's pretty funny. Right idea, horrible execution. Not only are you adding an antenna, you're also adding inductance in series with the cap, thereby reducing its effectiveness. Plus a small PCB with some ribbon cable will greatly increase production cost (mostly the assembly cost).
Tom
The inductors are in series and the caps in parallel with the signal. There's also various 'Zobels' that might be required .. especially with a transformer output.
Ferrite beads are much better than 'good' inductors in not needing 'Zobels' though you should always test to see.
A look at Dip. Ing Wuttke's circuit for his Schoeps mikes illustrates what you need to do for the best RFI/EMI immunity. Of course a schematic does not show the physical mechanical layout & EXACT details of earthing/grounding which are equally as important.
I'm sure the assembly was by Virgins so added immense Clarity & Definition. Expensive though.
Thanks for the reply, sorry if I missed it but do you have performance data for 4ohm loads?
I built a pretty compact amp with four MOD86 boards powered by a PWR86 board (and Antek AS-2222 transformer). No screening or other secret sauce was used. No issues there that I could tell. The amp has a built-in MiniDSP and is used to drive a pair of LXmini speakers. It works rather well. See the Modulus-86 Build Thread Post #888: http://www.diyaudio.com/forums/chip-amps/267802-modulus-86-build-thread-89.html#post4399918
Tom[/QUOTE]
I built a pretty compact amp with four MOD86 boards powered by a PWR86 board (and Antek AS-2222 transformer). No screening or other secret sauce was used. No issues there that I could tell. The amp has a built-in MiniDSP and is used to drive a pair of LXmini speakers. It works rather well. See the Modulus-86 Build Thread Post #888: http://www.diyaudio.com/forums/chip-amps/267802-modulus-86-build-thread-89.html#post4399918
Tom[/QUOTE]
Year 2011 B&O started to replace 8pin DIN by RJ45, some current products still have that DIN I believe, but newer products won't, probably more wireless connections too.
Why not (mini)TRS? Even smaller than 3 pin DIN, only problem is finding appropriate small diameter shielded twisted pair cable. If anybody has suggestions, please.
I used the link provided and quoted in my post.
Did you enter a new search string?
post the search string and I'll use it.
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