Thanks forr the lesson
Thanks Andrew for the detailed explanation. I do read the data sheets and now I'll understand them a bit better.
Thanks Andrew for the detailed explanation. I do read the data sheets and now I'll understand them a bit better.
Most Frightening Post on diyAudio
I'm just thinking through all the variations garnered from my ambiguous post !
One of the most impressive qualities of the Mod86 is, one sees the speakers but quickly after starting music, eyes are drawn away from the speakers to the great, accurate, sound stage.
The sound stage, front to back and left to right is outstanding. It's like there are no speakers in the room. Others that have heard my system, from pro musicians to people that listen to radio, have had the same response when I ask them about their impression. They see the speakers when they walk into the room but it's like they are not there while listening.
I can't wait to hear the Parallel86 in my big room with the Audible Illusions M3A. If it does the same thing I'll let everyone know. I expect it will.
The sound stage, front to back and left to right is outstanding. It's like there are no speakers in the room. Others that have heard my system, from pro musicians to people that listen to radio, have had the same response when I ask them about their impression. They see the speakers when they walk into the room but it's like they are not there while listening.
I can't wait to hear the Parallel86 in my big room with the Audible Illusions M3A. If it does the same thing I'll let everyone know. I expect it will.
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You have arrived, welcome to the club.
Even quite low noise, and quite low distortion contrive to destroy image precision.
Tom's design is correct in minimising N&D, and dynamic (layout) effects.
Dan.
Thanks guys! I appreciate the kudos.
Minimizing THD+N by maximizing loop gain is actually a good summary of what I did with the MOD86. That gives you the high PSRR as well, which further tightens up the measurements (and sound quality).
Tom
Minimizing THD+N by maximizing loop gain is actually a good summary of what I did with the MOD86. That gives you the high PSRR as well, which further tightens up the measurements (and sound quality).
Tom
For those of us using transformers with electrostatic shields and our own PS, where would you like us to connect the shield wire? To the closest possible chassis ground (hence lowest impedance) or is it ok to run a long wire to the chassis ground closest to the IEC ground tab?
Thanks,
Anand.
Thanks,
Anand.
Lowest impedance.
The electrostatic shields replaces the normally interwinding capacitance with a pair of series connected capacitances. The junction is taken to enclosure with that short wire.
This C1+Z+C2 forms a T filter.
The effectiveness of this T filter depends on the ratios of the C1+Z and the Z+C2 of the two halves of the T filter.
If Z = C1, then you don't have a filter, instead you have an impedance ladder with no attenuation that changes with frequency.
To work effectively as a filter the Z of the wire connection must be very low. That requires a VERY SHORT low INDUCTANCE wide thin trace/foil connection to the enclosure right beside where the "wire" comes out of the insulation wrap.
But no one provides a low inductance flat thin strip connection. They all do a thin stranded wire that is far too long.
The electrostatic shields replaces the normally interwinding capacitance with a pair of series connected capacitances. The junction is taken to enclosure with that short wire.
This C1+Z+C2 forms a T filter.
The effectiveness of this T filter depends on the ratios of the C1+Z and the Z+C2 of the two halves of the T filter.
If Z = C1, then you don't have a filter, instead you have an impedance ladder with no attenuation that changes with frequency.
To work effectively as a filter the Z of the wire connection must be very low. That requires a VERY SHORT low INDUCTANCE wide thin trace/foil connection to the enclosure right beside where the "wire" comes out of the insulation wrap.
But no one provides a low inductance flat thin strip connection. They all do a thin stranded wire that is far too long.
I'm building a parallel86 and was just about to order binding posts. Then thought why use binding posts. The speaker wires connect to the J1 screw down connectors.
I'm thinking of using the four holes in the back panel, were binding posts would have been, with rubber grommets inserted to protect the wires and running wires directly to the speakers.
I don't plan on moving the par86 and one less connection seems like a good thing. If I do decide to move the amp just loosening the top cover screws, sliding it towards the front of the case and loosening four J1 screws is all it would take. Does anyone see a downside to this?
Thanks,
henry
I'm thinking of using the four holes in the back panel, were binding posts would have been, with rubber grommets inserted to protect the wires and running wires directly to the speakers.
I don't plan on moving the par86 and one less connection seems like a good thing. If I do decide to move the amp just loosening the top cover screws, sliding it towards the front of the case and loosening four J1 screws is all it would take. Does anyone see a downside to this?
Thanks,
henry
Lowest impedance to the chassis is best. Or use the SHIELD terminal on the Power-86 board. The former will be slightly better in theory.
Tom
Unless you plan to use a cable clamp to ensure that the cable doesn't move, I would be concerned with the connections becoming loose from vibration. I would also be concerned with the stress imposed on the circuit board and terminal block by the pulling forces of the wires (unless you use a cable clamp to the chassis or have some plan in place to suspend the gravitational forces imposed on the speaker cables).
I do agree that binding posts aren't the best connectors out there. They're a pain to use and unless you use something like a Cardas clamping type, you generally can't get enough clamping force onto the spade connectors to prevent the speaker cables from rattling loose over time. The downside of the Cardas clamp is that they don't work with banana connectors. (Yes, I know Cardas offers a clamping piece that'll sorta work, but it's really quite an afterthought).
The solution to this is the Neutrik speakON connectors. I linked to them just a few posts back.
If you really-really-realy don't like the speakON connectors, I suggest going with banana plugs. The speakON are so nice to use, though. Plug in, rotate, click! Done! No worries about polarities or anything. No worries about connections becoming loose over time. They. Just. Work.
Tom
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Thanks for all the replies. I plan to use small cable clamps inside to avoid any pulling or stress on J1. An example of how often I move my amps are: I moved the Aragon once about about 15 years ago. The same goes for the amp in the 2nd floor closet.
I still like just having connections at J1 with small internal wire clamps.
I still like just having connections at J1 with small internal wire clamps.
I was thinking about wire clamps inside the back panel to avoid stress on J1 connectors. Initially I was thinking of clamping the + & - wires, for each channel, together just before they exit the back panel through the rubber grommets.
Then thought why not just tie the two wires in a small knot just before they exit the back panel through the rubber grommets...no clamps. If twisting is so strongly recommended I wouldn't think a knot would be bad. Any thoughts on that?
Then thought why not just tie the two wires in a small knot just before they exit the back panel through the rubber grommets...no clamps. If twisting is so strongly recommended I wouldn't think a knot would be bad. Any thoughts on that?
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SpeakOn is the best solution, IMO. Forget about the direct connection to the PCB. One mistake, and someone is going to be crying, then paying ($).
Knots in wire have been used for years to keep wires from pulling out of cases or instrument enclosures. If there is ever a problem I'll post it and admit it was a foolish idea.
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Solder is very poor mechanically. I would not do this, the solder joints will fail.
You will not hear any degradation with binding posts or Speakons.
You will not hear any degradation with binding posts or Speakons.
Please, Henry. Stop. You are barking up the wrong tree here and everybody is telling you so. Please listen.
Just because something can be done or has been done doesn't mean it's a good idea to do so.
There are three commonly used connector types for speaker output:
- Banana
- Clamping binding posts
- SpeakON
Please choose one of these.
If you would rather discuss whether knots, clamps, or whatnot could be used or whether an overhand knot is better than a reef knot, please start a thread elsewhere as that is so far out on the irrelevant scale it's not even funny.
Tom
Just because something can be done or has been done doesn't mean it's a good idea to do so.
There are three commonly used connector types for speaker output:
- Banana
- Clamping binding posts
- SpeakON
Please choose one of these.
If you would rather discuss whether knots, clamps, or whatnot could be used or whether an overhand knot is better than a reef knot, please start a thread elsewhere as that is so far out on the irrelevant scale it's not even funny.
Tom