Hi All,
I am preparing to build the Super Pensil Alpair 12.2p, but I had a few questions on the build materials, and thoughts on my amp pairing.
To start, I currently am running the tubes4hifi ST70 power amp and the tubes4hifi SP12 pre-amp. I am wondering if anyone else running a similar setup with the super pensil Alpair 12.2p speakers. If so, what are your thoughts? My room size is roughly 15'x20' with vaulted ceilings (I realize not the most ideal room, but it is what I have to work with).
Secondly, I have seen different advice on the build materials for the super pensil. Not the wood type, as that is clearly specified in the drawings, but the other components. Specifically the binding posts, internal writing, and stuffing.
From what i have gathered from other posts each speaker should have roughly 1.5lbs of pollyfill. I was looking at using the Acusta-Stuff from Madisound: https://www.madisoundspeakerstore.com/acoustic-damping/dampers-acousta-stuf/lb/
For the binding posts it was suggested to use these Parts Express Gold Plated Banana 5-Way Speaker Wire Binding Post Terminal
Lastly, for the internal writing it was suggested to use Cat-5E plenum cable, a twisted pair for each binding posts.
I was wondering if anyone else had built the Super Pensil 12.2p and had thoughts on my parts list, or advice in general.
Thanks for and help or advice!
I am preparing to build the Super Pensil Alpair 12.2p, but I had a few questions on the build materials, and thoughts on my amp pairing.
To start, I currently am running the tubes4hifi ST70 power amp and the tubes4hifi SP12 pre-amp. I am wondering if anyone else running a similar setup with the super pensil Alpair 12.2p speakers. If so, what are your thoughts? My room size is roughly 15'x20' with vaulted ceilings (I realize not the most ideal room, but it is what I have to work with).
Secondly, I have seen different advice on the build materials for the super pensil. Not the wood type, as that is clearly specified in the drawings, but the other components. Specifically the binding posts, internal writing, and stuffing.
From what i have gathered from other posts each speaker should have roughly 1.5lbs of pollyfill. I was looking at using the Acusta-Stuff from Madisound: https://www.madisoundspeakerstore.com/acoustic-damping/dampers-acousta-stuf/lb/
For the binding posts it was suggested to use these Parts Express Gold Plated Banana 5-Way Speaker Wire Binding Post Terminal
Lastly, for the internal writing it was suggested to use Cat-5E plenum cable, a twisted pair for each binding posts.
I was wondering if anyone else had built the Super Pensil 12.2p and had thoughts on my parts list, or advice in general.
Thanks for and help or advice!
Can't say I've heard of that particular combo, but should work fine. I doubt you'll run out of power. These speakers will play with authority with as little as 5 watts, but you'll probably want more than that for your room.
It seams a lot of pensil builders start out with too much stuffing, and eventually pull out some to tune the speakers to taste. My pair only have 280 grams each, but they have ultratouch denim insulation attached to the inside around the driver area. I'll see if I can find the pic of mine with the back baffle off, which you can attach temporarily for easier access to the interior.
Yes those will be fine. I'm using the round version of these: Parts Express Recessed Speaker Wire Terminal Cup Banana 5-Way Binding Posts
Yes, that will be fine. I'm using just a single twisted pair.
jeff
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Good to know thanks. Per the spec sheet for the speakers they can handle 35 watts RMS which the ST70 produces 35 watts at 8ohms
That photo is super helpful, would you recommend using the ultratouch denim in the same way?
Yes, I agree the round version looks better.
So just one strand from black and one strand from red?
Thanks!
FWIW, I tend to avoid terminal cups, although some of the low-mass binding posts are quite good -you don't necessarily get what you pay for / advantages from extremely fancy looking bits of kit. Two alternatives: Speakon connectors , or ye traditional eyebolts with lugs that you can screw down. Bit of copper-grease over them (carefully) -good as it gets.
more noise from the peanut gallery
280 grams of fill = 10oz, approx 1/2.4 of the 1.5lb suggested
I've used both single strand of #24 solid per pole, and "zip" wire up to #18 on dozens of builds with MA and Fostex full range drivers, and can't hear any big advantage with the thicker - in this application. Sub woofers - different story.
The only downside I've found with the CAT5 is that with a poorly set up stripper, it's easy enough to nick, and the wire is annealed stiffly enough that it breaks easily.
I quite like the cheapie dual 5-way binding posts with plastic nuts - admittedly they do have more metal mass than the Eichmann cable pods, but at less than 2% of the retail price, I'll live with them.
280 grams of fill = 10oz, approx 1/2.4 of the 1.5lb suggested
I've used both single strand of #24 solid per pole, and "zip" wire up to #18 on dozens of builds with MA and Fostex full range drivers, and can't hear any big advantage with the thicker - in this application. Sub woofers - different story.
The only downside I've found with the CAT5 is that with a poorly set up stripper, it's easy enough to nick, and the wire is annealed stiffly enough that it breaks easily.
I quite like the cheapie dual 5-way binding posts with plastic nuts - admittedly they do have more metal mass than the Eichmann cable pods, but at less than 2% of the retail price, I'll live with them.
It's not considered to be essential, which may be a good thing, as the 1/2" thick ultratouch seems to be getting harder to source for some reason.
jeff
Recycled denim is becoming more popular for insulation. Home insulation. It is readily available in various thicknesses. My suggestion is to acquire whatever thickness of recycled denim os available. Just peel it down to 1 1/2" thickness and use that to line the enclosure. Use full width for sealed cabinet woofers.
Polyfil is best and least expensive when purchased from fabric stores as polyfil for pillows. Better yet, use "real wool" (natural wool) quilt fill. Unroll it and use it in multiple layers hung loosely from the top draping down the sides of the cabinet.
Polyfil is best and least expensive when purchased from fabric stores as polyfil for pillows. Better yet, use "real wool" (natural wool) quilt fill. Unroll it and use it in multiple layers hung loosely from the top draping down the sides of the cabinet.
What is the issue with the terminal cups, just out of curiosity? The Speakon suggestion seems great, actually.
Yeah, that is much less than 1.5lb
That is interesting, thank you!
I worked in low-voltage for a while and the right cable strippers are much less likely to nick the wire
Are these the Eichmann cable pods you are referring to Eichmann Cable Pod 5-Way Binding Post (black) ?
So, I am still a bit confused on the material to use for the fill - should all denim be used, or should a mix of denim and polyfil be used? What is your thoughts on this material then: https://www.madisoundspeakerstore.com/acoustic-damping/dampers-acousta-stuf/lb/ ?
Hi lthursdayl,
For the Pensil cab, denim if used, is used to line a few inches of the two side-walls, inside of the top, and inside of the back of the cabinet around the driver area (maybe line 14-16 inches from the top).
The poly-fill is fluffed up and used as "stuffing" throughout the cabinets (picture provided by vinylkid58).
For the Pensil cab, denim if used, is used to line a few inches of the two side-walls, inside of the top, and inside of the back of the cabinet around the driver area (maybe line 14-16 inches from the top).
The poly-fill is fluffed up and used as "stuffing" throughout the cabinets (picture provided by vinylkid58).
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Yes, I've used them (once), but the price kinda dissuaded me from repeat business. They "sound" nice enough (i.e. don't) , as do the Bullet RCA plugs, but I'd prefer to spend less on my connectors than the drivers.
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The little round cups we use cost less than $3/ pr when purchased in bulk/ (250 pr) . For one or two pairs, the shipping costs more than the goods.
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Yes that's a good point regarding the density of the stuffing. We've seen people pack the entire Pensil with quite dense polyfil, and then complain that the speakers don't sound very good. If it comes densely packed, then take some time to tease it into a fluffy mass before filling the speaker box.
jeff
okay, this is good to know. For clarification you mean that the denim is used about 14" to 16" down the sides from the top to the bottom, and the entire back of the cabinet. In addition to this you also wrap the back of the driver with the denim as well?
Entire (inside) of the back panel is probably not required, again 14"-16" from the top would be sufficient.
Haven't seen any of the members using MA drivers wrap the back of the driver (the magnet?) with denim.
Okay, thanks! Just use the 1/2" thick denim on the sides and the back from the top of the cabinet, running down about 14" - 16".
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