BrianGT
Nice to see you back from your hiatus. I hope your nuptuals continue to provide comfort the rest of your days. BTW, what did you ever do with your 'wrong way' attenuator? I tried emailing you privately but never got a response. My email is not blocked so feel free to use it in your reply and we won't derail this post.
Nice to see you back from your hiatus. I hope your nuptuals continue to provide comfort the rest of your days. BTW, what did you ever do with your 'wrong way' attenuator? I tried emailing you privately but never got a response. My email is not blocked so feel free to use it in your reply and we won't derail this post.
How do people feel about the concentric shaft idea? Looks to cost about $4 a pot more, but is the best choice IMHO. And this is a rare opportunity to get them since we are doing a custom order!
It looks like both Brian's supplier and mine are well under $25 ea for 100. In fact the situation I proposed has come to pass: for the price we were expecting to pay each, we can now get 2!!
We still need to look into the other values. BUT it seems that the PEC people work on the basis of orders and don't havre much inventory, so it isn't likely that we can mix to get this price- but maybe since we are getting this large order, PEC could find some overuns from other production to supply also.
Also, we are far from being able to order 100. BUT there are about 25, 25k pots on the list. If each of these people orders 2 instead of 1, we are up to 50, and with the price around half, I suspect a lot of people from the "reasonably priced pot" thread will be interested.
ALSO, Brian is getting ready for another run of gainclones, and I'l bet that if he offers the pots, he could move about 50!
re the mil spec version: First we should determine what makes it mil spec. I don't think we require a stainless shaft insterad of aluminum, or a gasket at the panel. Maybe we don't even need gold terminal since we are soldering to them. Then again, as with the concentric shafts, we could possibly order only the gold terminals without any other mil spec items. Now if the standard shaft is plain steel instead of aluminum then there will be more interest in the stainless version, because some people are concerned about having magnetic materials anywhere in their designs.
all in all VERY good news!!!
Mark
It looks like both Brian's supplier and mine are well under $25 ea for 100. In fact the situation I proposed has come to pass: for the price we were expecting to pay each, we can now get 2!!
We still need to look into the other values. BUT it seems that the PEC people work on the basis of orders and don't havre much inventory, so it isn't likely that we can mix to get this price- but maybe since we are getting this large order, PEC could find some overuns from other production to supply also.
Also, we are far from being able to order 100. BUT there are about 25, 25k pots on the list. If each of these people orders 2 instead of 1, we are up to 50, and with the price around half, I suspect a lot of people from the "reasonably priced pot" thread will be interested.
ALSO, Brian is getting ready for another run of gainclones, and I'l bet that if he offers the pots, he could move about 50!
re the mil spec version: First we should determine what makes it mil spec. I don't think we require a stainless shaft insterad of aluminum, or a gasket at the panel. Maybe we don't even need gold terminal since we are soldering to them. Then again, as with the concentric shafts, we could possibly order only the gold terminals without any other mil spec items. Now if the standard shaft is plain steel instead of aluminum then there will be more interest in the stainless version, because some people are concerned about having magnetic materials anywhere in their designs.
all in all VERY good news!!!
Mark
Brian wrote to ask me to explain the concentric option better.
Concentric shafts means there is an inner 1/8" inch shaft and around it is a shorter 3/8" shaft . Each shaft is connected to one of the gangs.
The cool thing is that you can get knobs that are the same diameters but with different inner holes for the 2 shaft sizes. The one with the bigger hole has the hole all the way through
So: first you mount the pot in the panel, then you put the knob with the big hole on the outer shaft, then you put another knob with the 1/8" hole partway through, on last. That way you have 2 stacked knobs with the same diameter that you can use as I've described above; either grip them both for volume, or grip only one for balance.
Concentric shafts means there is an inner 1/8" inch shaft and around it is a shorter 3/8" shaft . Each shaft is connected to one of the gangs.
The cool thing is that you can get knobs that are the same diameters but with different inner holes for the 2 shaft sizes. The one with the bigger hole has the hole all the way through
So: first you mount the pot in the panel, then you put the knob with the big hole on the outer shaft, then you put another knob with the 1/8" hole partway through, on last. That way you have 2 stacked knobs with the same diameter that you can use as I've described above; either grip them both for volume, or grip only one for balance.
I don't know if I'm any indication of everyone else but....my orderat $37 is two 25Ks I'd change my order to TO only 3 if we got to100 orders, but I'd increase that to6 if we were able to get to the 250 order point.
As for the concentric shaft pots I'd also be interested but it would depend on the cost of the knobs also. Variac how much does your supplier charge & what do they look like ( the knobs that is?) I guess I could always make my own knobs..but how long are the shafts? This would of course determine the overall height of the knobs.
By the way here is concentric pot. The only difference is this has a different value for each gang. But you can get the idea.
http://www.goldmine-elec-products.com/prodinfo.asp?number=G14790&variation=&aitem=41&mitem=95
Thx
As for the concentric shaft pots I'd also be interested but it would depend on the cost of the knobs also. Variac how much does your supplier charge & what do they look like ( the knobs that is?) I guess I could always make my own knobs..but how long are the shafts? This would of course determine the overall height of the knobs.
By the way here is concentric pot. The only difference is this has a different value for each gang. But you can get the idea.
http://www.goldmine-elec-products.com/prodinfo.asp?number=G14790&variation=&aitem=41&mitem=95
Thx
Well, I have ordered knobs from India via a friend I got to know on DIY Audio. He found a shop that makes custom knobs for manufacturers there and worked out the payments and shipping. He did this as a favor, as he is in the software business, but I suspect he would help us again. In fact I think he might be interested in some of these knobs.
I'd say a set of inner and outer knobs (enough for one pot) would cost about $10 delivered
Delivery time is about a month and a half, and since the pots will take a solid month, it could work out.
The important thing is to act quickly if we can figure out what we are ordering and not let this drag on until so much time has passed that people are too impatioent to wait.
I would order 3 at the 100 piece price. It looks like Brians place could get the concentric ones at aboutr $25 ea.
Attached is a photo of another concentric pot. This one is a 4 gang volume control adjusted by the inner shaft, and a balance dual gang controled by the outer, brass shaft.
I'd say a set of inner and outer knobs (enough for one pot) would cost about $10 delivered
Delivery time is about a month and a half, and since the pots will take a solid month, it could work out.
The important thing is to act quickly if we can figure out what we are ordering and not let this drag on until so much time has passed that people are too impatioent to wait.
I would order 3 at the 100 piece price. It looks like Brians place could get the concentric ones at aboutr $25 ea.
Attached is a photo of another concentric pot. This one is a 4 gang volume control adjusted by the inner shaft, and a balance dual gang controled by the outer, brass shaft.
Attachments
Well, I would have to design them, but I would think basically two cylinders- one 35mm dia. with a big hole all the way through, 10mm thick, with a setscrew.
and another 35mm dia. with a smaller hole not all the way through, 10mm high, and a setscrew. Stacked on the concentric pot shafts, they would look like a cylinder about 35mm (1.5") in diameter and about 20 mm high. Matte silver finish cooooooool
I'll look for some photos .. I WILL handle ordering the knobs if Brian orders the pots. If he sends the box o pots to me I will mail em all out together.
and another 35mm dia. with a smaller hole not all the way through, 10mm high, and a setscrew. Stacked on the concentric pot shafts, they would look like a cylinder about 35mm (1.5") in diameter and about 20 mm high. Matte silver finish cooooooool
I'll look for some photos .. I WILL handle ordering the knobs if Brian orders the pots. If he sends the box o pots to me I will mail em all out together.
Variac said:Well, I would have to design them, but I would think basically two cylinders- one 35mm dia. with a big hole all the way through, 10mm thick, with a setscrew.
and another 35mm dia. with a smaller hole not all the way through, 10mm high, and a setscrew. Stacked on the concentric pot shafts, they would look like a cylinder about 35mm (1.5") in diameter and about 20 mm high. Matte silver finish cooooooool
I'll look for some photos .. I WILL handle ordering the knobs if Brian orders the pots. If he sends the box o pots to me I will mail em all out together.
I don't have time to handle any pot ordering now, i was just helping out research the price so that this will go somewhere. I am looking at ordering more LM3875/LM3886/LM4780 boards, so I will be tied up for quite a while.
--
Brian
I would definitely get 3 pots at the 100 unit price, perhaps even 4.
If orders get to the 250 price, I will get 4.
I don't mind the concentric shaft if the price savings is substantial. I'm worried, however, that this might not work out in one commercial preamp that I'm retrofitting with the pot. I want to use the existing knob, a 1/4" with a set screw.
Also, this would limit the knob choices severely, wouldn't it? I'm curious as to how the knob will turn out.
KT
If orders get to the 250 price, I will get 4.
I don't mind the concentric shaft if the price savings is substantial. I'm worried, however, that this might not work out in one commercial preamp that I'm retrofitting with the pot. I want to use the existing knob, a 1/4" with a set screw.
Also, this would limit the knob choices severely, wouldn't it? I'm curious as to how the knob will turn out.
KT
OK, The concentric shaft is my dream it appears. It has nothing to do with a 4 gang pot or balanced applications.The reason I have always wanted to get this type of pot is that the main complaint about regular two gang pots is that the 2 channels don't track evenly, ie one channel gets louder for awhile and then the other as the knob is turned. A very high quality pot such as this should be a lot better than a cheaper one, but they are only obligated to be within 10% which is pretty bad for our purposes considering that you can make a stepped attenuator with 1% resistors.
Commercial preamps have a balance control which can be used to compensate for this - and some room effects, but most people around here don't want to add yet another pot to their circuit, which might negate the advantages of the fancy volume pot.
I have used a pair of single gang pots, which is wonderful for adjusting the balance, but a pain to use because you have to turn two knobs to adjust the volume, then listen to check the balance.
The concentric pot costs MORE, about $4 , because it needs the 2 concentric shafts.
Concentric pots are used in commercial gear sometimes, with the center knob as a volume control, and the outside shaft knob as a balance control.
My proposal is to use the center shaft as one channel and the outer shaft knob as the other channel. That way if we use knobs of the same diameter for both, it is easy to quickly adjust the volume by gripping both. To adjust balance one just turns one.
Yes, we would be stuck with one knobset, but they are very nice- I will post a photo of one made by this guy. But not the concentric setup.
I realize there are compromises invoved in this order- probably only one value - 25k , for instance, and I will go along with the majority- we need a big order to pull this off!
Hey original guys! are you going to organize this? Brian isn't interested for good reasons, and I haven't volunteered (yet)
Mark
PS. We need a list on the WIKI pages so that people can update the number that they are ordering. Otherwise it is a pain for the organizers to keep updating a list as they have done on this thread before. I can get to it in a day or so, but it isn't hard - whay doesn't someone give it a try- just copy what other group orders have done...
Commercial preamps have a balance control which can be used to compensate for this - and some room effects, but most people around here don't want to add yet another pot to their circuit, which might negate the advantages of the fancy volume pot.
I have used a pair of single gang pots, which is wonderful for adjusting the balance, but a pain to use because you have to turn two knobs to adjust the volume, then listen to check the balance.
The concentric pot costs MORE, about $4 , because it needs the 2 concentric shafts.
Concentric pots are used in commercial gear sometimes, with the center knob as a volume control, and the outside shaft knob as a balance control.
My proposal is to use the center shaft as one channel and the outer shaft knob as the other channel. That way if we use knobs of the same diameter for both, it is easy to quickly adjust the volume by gripping both. To adjust balance one just turns one.
Yes, we would be stuck with one knobset, but they are very nice- I will post a photo of one made by this guy. But not the concentric setup.
I realize there are compromises invoved in this order- probably only one value - 25k , for instance, and I will go along with the majority- we need a big order to pull this off!
Hey original guys! are you going to organize this? Brian isn't interested for good reasons, and I haven't volunteered (yet)
Mark
PS. We need a list on the WIKI pages so that people can update the number that they are ordering. Otherwise it is a pain for the organizers to keep updating a list as they have done on this thread before. I can get to it in a day or so, but it isn't hard - whay doesn't someone give it a try- just copy what other group orders have done...
The concentric shafts has nothing to do with a 4 gang pot or balanced applications. please read my post above. (Pars' post was before mine above but got lost in moderation)
The will probably NOT be a mix of values at this price, so it will probably
just be one value available, probably 25k.
The will probably NOT be a mix of values at this price, so it will probably
just be one value available, probably 25k.
If PEC offers concentric shaft feature at $3 premium, I would strongly suggest to take advantage of it. Those pots are not like Alps or Nobles, and in some of them the tracking difference (between channels) will be quite noticable. Concentric shaft option allows you to perfectly match channel balance, in most frequently used pot position.
Once adjusted, you don't really have to use that feature at all, and can mount a regular knob.
Once adjusted, you don't really have to use that feature at all, and can mount a regular knob.
Thanks for your input Peter. In the scheme I propose, the balance could be adjusted at any volume- if you feel like it .
You can imagine that I don't want to get into a long discussion about knobs, but I will post a diagram showing how they would work and some photos of knobs ordered in the past.
EDIT : If the outer shaft is actually 1/4" inch then Peter is right!
We should first check if it is . If so, then the major problem- needing one particular knob set is not a problem anymore!
You can imagine that I don't want to get into a long discussion about knobs, but I will post a diagram showing how they would work and some photos of knobs ordered in the past.
EDIT : If the outer shaft is actually 1/4" inch then Peter is right!
We should first check if it is . If so, then the major problem- needing one particular knob set is not a problem anymore!
This is very difficult to keep track of . To try and help, I have created
a wiki page to list how many concentric 25k pots people might be interested in:
http://www.diyaudio.com/wiki/index.php?page=PEC+Carbon+Potentiometer+Group+Buy
I'm not trying to hijack the order and Cdoggy is welcome to use this info, but I am willing to do the work for the 25k concentric shaft model only. If he would rather do it, or start a buy of standard dualtrack pots then that's fine with me!
We don't yet know if we can mix values- my understanding at this point is we can't.
I know I can get nice matte aluminum knobs that will work and look great. I will soon include diagrams and a photo of a similar knob.
At the moment there is no obligation, its just a convenient way to keep track. Even if you have recently listed how many you are interested in, please also list here on the WIKI. Just click on the "Click here to edit WIKI page" line and add your name and desires to the chart!
Thanks
Mark
a wiki page to list how many concentric 25k pots people might be interested in:
http://www.diyaudio.com/wiki/index.php?page=PEC+Carbon+Potentiometer+Group+Buy
I'm not trying to hijack the order and Cdoggy is welcome to use this info, but I am willing to do the work for the 25k concentric shaft model only. If he would rather do it, or start a buy of standard dualtrack pots then that's fine with me!
We don't yet know if we can mix values- my understanding at this point is we can't.
I know I can get nice matte aluminum knobs that will work and look great. I will soon include diagrams and a photo of a similar knob.
At the moment there is no obligation, its just a convenient way to keep track. Even if you have recently listed how many you are interested in, please also list here on the WIKI. Just click on the "Click here to edit WIKI page" line and add your name and desires to the chart!
Thanks
Mark
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.