In the end, I suppose what matters is whether you enjoy listening to music with your setup.
My only beef with the snake oil industry is that pseudo science, junk science, and flat-out non-science tend to be propagated as gospel and given higher validity than actual science. That's not a problem unique to audio, by the way.
I feel sorry for the folks who are relatively new to the electronics field who are trying to sort the wheat from the chaff and are getting bombarded from all sides. All I can do about it is to base my recommendations on science and engineering rather than marketing babble.
Tom
My only beef with the snake oil industry is that pseudo science, junk science, and flat-out non-science tend to be propagated as gospel and given higher validity than actual science. That's not a problem unique to audio, by the way.
I feel sorry for the folks who are relatively new to the electronics field who are trying to sort the wheat from the chaff and are getting bombarded from all sides. All I can do about it is to base my recommendations on science and engineering rather than marketing babble.
Tom
Code:
Oregonian Myrtlewood is out of season so I was going to machine them from unobtainium, but couldn't find any. At least the carpets are grounded.
Is there any preferred stand-off material? I need 4-40x3/8" long male female stand-offs. Mcmaster has nylon at $12 for 50 pcs. I doubt I will ever use that many. I'm leaning toward the aluminum ones at $0.36 each. I only need 12, thats $4.32.
metal requires you to be careful with what is near that metal on the PCB.
But it is stronger than any of the plastics.
But it is stronger than any of the plastics.
I just learned of the EAR vibration damping stand-offs. Even thought I've been told vibration wouldn't be an Issue I think expansion/contraction will be occurring. It seems the EAR device's flexibility should make that a non issue.
Audiophile sites them sell for $4 or more but I found a non-audiophile site selling them for $2 and don't mind spending $24 for 12 pcs.. I consider the mod86 amp a great. bang for the buck. product so I'm very comfortable spending a few extra $ for what may be optimal parts. Before I found this amplifier I was looking at spending $2k to $3K. Are the EAR stand-offs considered part of the snake oil side of audio?
Audiophile sites them sell for $4 or more but I found a non-audiophile site selling them for $2 and don't mind spending $24 for 12 pcs.. I consider the mod86 amp a great. bang for the buck. product so I'm very comfortable spending a few extra $ for what may be optimal parts. Before I found this amplifier I was looking at spending $2k to $3K. Are the EAR stand-offs considered part of the snake oil side of audio?
Last edited:
Stand-off strength
The boards weight almost nothing and they will have the heaviest component screwed to a heatsink. I'm guessing the strength difference would not be important. I actually think some flexibility might be desirable.
If it's the 3M Aearo E-A-R then it's not snake oil. However, it's solving a problem that doesn't exist in this particular application.
There's no need for vibration dampening mounts. They're useful in some vacuum tube circuits as some vacuum tubes (mainly directly heated types) are microphonic. There are no microphonic components in the Modulus-86 or any other solid state circuit I offer, so there is no need for vibration dampening mounts.
I use nylon standoffs, 5 mm in length. Nylon does compress a little, so you might get a better mechanical solution if you use metal standoffs. If you do use metal standoffs, ensure that they're no more than 5 mm in outer diameter.
Tom
I use nylon standoffs, 5 mm in length. Nylon does compress a little, so you might get a better mechanical solution if you use metal standoffs. If you do use metal standoffs, ensure that they're no more than 5 mm in outer diameter.
Tom
grounding Modushop case panels
I think I mentioned, in an earlier post, that Gianluca at Modushop has been very helpful and a pleasure to work with. I recommend them without reservation.
My question regards grounding case panels. Since the black coating is not conductive I will lightly grind away the coating wherever I will be connecting a ground wire.
I plan to connect the ground wire from the AC entry module and a wire from each XLR pin1 to the back panel. I will also use a very short ground wire from the PWR86 to the bottom cover.
Should I connect the other four panels to ground for safety reasons?
I think I mentioned, in an earlier post, that Gianluca at Modushop has been very helpful and a pleasure to work with. I recommend them without reservation.
My question regards grounding case panels. Since the black coating is not conductive I will lightly grind away the coating wherever I will be connecting a ground wire.
I plan to connect the ground wire from the AC entry module and a wire from each XLR pin1 to the back panel. I will also use a very short ground wire from the PWR86 to the bottom cover.
Should I connect the other four panels to ground for safety reasons?
Transformers in my other three amps vibrate with a 60 cycle hum. I know some manufacturers put vibration damping material under transformers to reduce/eliminate vibration from reaching other solid state components. I'm referring to all solid state...no tubes.
My Aragon 8008BB has it and I know Mccormack does this on some of his deluxe edition and modified amps. Mccormack also includes a spike to couple the bottom near the transformer with the shelf it is resting on. That makes me think there might be good reasoning behind those features. Any thoughts on that?
My Aragon 8008BB has it and I know Mccormack does this on some of his deluxe edition and modified amps. Mccormack also includes a spike to couple the bottom near the transformer with the shelf it is resting on. That makes me think there might be good reasoning behind those features. Any thoughts on that?
All metal bits accessible by the end user should be grounded. That's a safety thing.
Re. humming transformers: I haven't had any issues with hum in any of the toroidal transformers I've used the past couple of decades. All the vibration dampening I've used has been the two rubber pads that come with the transformer.
Tom
I am using the same eBay BZ4309 case as Tom. I found that by running a M4x0.7 tap down each of the threaded holes in the case, hitting each head recess with a countersink to clean metal and substituting plated screws for the black oxide screws supplied with the case I have very good conductivity (<0.1 ohm) between all of the elements of the case.
Public service announcement: It looks like Newark in the UK has received a shipment of LM4780s. If you have a Parallel-86 board needing an IC, you have a reliable source - until they run out.
LM4780TA/NOPB - TEXAS INSTRUMENTS - Audio Power Amplifier, AB, 2 Channel, 60 W, 20V to 84V, TO-220, 27 Pins | Farnell element14
Thanks David for the tip.
Just to be clear: With the LM4780 being crucial to the Parallel-86, the IC drifting in and out of stock, and no replacement provided by TI, I have no plans for starting up another board run. I can't justify the expense when I can't fully support the project due to lack of IC availability.
Tom
LM4780TA/NOPB - TEXAS INSTRUMENTS - Audio Power Amplifier, AB, 2 Channel, 60 W, 20V to 84V, TO-220, 27 Pins | Farnell element14
Thanks David for the tip.
Just to be clear: With the LM4780 being crucial to the Parallel-86, the IC drifting in and out of stock, and no replacement provided by TI, I have no plans for starting up another board run. I can't justify the expense when I can't fully support the project due to lack of IC availability.
Tom
Last edited:
I think I actually ended up tightening the supplied screws hard enough to wear through the anodization. At least the panels in my amp are grounded without the use of special tricks. The eBay chassis uses four rectangular bars, one in each corner, to hold the panels together. I suspect the connection I get is through there.
With the ModuShop chassis, I'd probably attempt to make the connection via the mezzanine plate (the holy false bottom).
Tom
I didn't get a false bottom plate. Just four sides, top and bottom. I like the black screws so will drill four holes, grind away the coating and connect all the panels with a short length of wire.
I'm going to connect the Antek, before I put isolation material under it, to determine how quiet it is. The transformers , especially in the Mccormack, have audible hum.
However, the Mccormack is the best sounding, most musical amp, by far, of everything I've owned. If the Modulus is equivalent or better I'll be happy.
I'm going to connect the Antek, before I put isolation material under it, to determine how quiet it is. The transformers , especially in the Mccormack, have audible hum.
However, the Mccormack is the best sounding, most musical amp, by far, of everything I've owned. If the Modulus is equivalent or better I'll be happy.
I'm using the Modushop 2U chassis. The amp is only partially assembled right now, but the ground pin of the IEC module is connected to the "holy" base plate by a 4 wire and a bolt. All other points on the chassis show good conductivity to the IEC module ground lug with no special attention payed to making electrical connections. No wires are needed between panels. The XLR jacks have a ground lug connected to the shell that I connected to pin 1; I buffed the paint away from the screw holes for the jacks on the interior of the chassis and will use nuts with star washers to make double sure of a good connection there.
My only concern right now is that the transformer hold-down plate will be very close to the top panel of the chassis. I don't think the bolt can touch, but I may apply an extra insulation layer to the inside of the top to prevent any incidental contact. Maybe a coat of PlastiDip in that area?
Bill
My only concern right now is that the transformer hold-down plate will be very close to the top panel of the chassis. I don't think the bolt can touch, but I may apply an extra insulation layer to the inside of the top to prevent any incidental contact. Maybe a coat of PlastiDip in that area?
Bill
I got the 120mm tall case so there is a lot of clearance above the top of the bolt. Initially, I was going to get a 80mm high case. If you have a 80mm case I would strongly recommend a plastic cap over the top of the transformer bolt and nut.
+1
If there is any risk that the mounting bolt will touch the inside of the metal chassis, shorten the mounting bolt. If there is a small gap and you are worried that, say a stack of books atop the amp will bring the top plate into contact with the mounting bolt, I'd cover the inside of the lid with a rubber pad in the area over the mounting bolt. Shortening the bolt is the best solution.
Letting the top of the mounting bolt touch the insides of the metal chassis is a good way to create a spot welder. Needless to say, this is not the preferred application for a high-end audio amp.
Tom
Last edited:
Goop on wires
Years ago I developed the habit of dipping the stripped ends of wire in Caig Gold. I only did that to wires not intended to be tinned or soldered. Just bare un-terminated speaker wire prior to insertion in binding posts or crimped in spades.
I recently saw some youtube vids showing wire crimping and some brushed the wire with the Caig stuff and some used a silicone dielectric prior to crimping. If that is a good practice I would think the same should be done to bare un-tinned wire before putting it in a screw down connector. Does anyone think that practice has any value.I know my bare wire connections to binding posts and spades stayed bright for years.
Years ago I developed the habit of dipping the stripped ends of wire in Caig Gold. I only did that to wires not intended to be tinned or soldered. Just bare un-terminated speaker wire prior to insertion in binding posts or crimped in spades.
I recently saw some youtube vids showing wire crimping and some brushed the wire with the Caig stuff and some used a silicone dielectric prior to crimping. If that is a good practice I would think the same should be done to bare un-tinned wire before putting it in a screw down connector. Does anyone think that practice has any value.I know my bare wire connections to binding posts and spades stayed bright for years.