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#81
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"Ben Bradley" wrote in message ... I'd make my slice selling the PC boards and writing it up for the magazines. Speaking of PC boards, would it be all thru-hole, or any surface mount? You're of course aware that more and more parts are only available in SMT thesedays, and some people won't want to solder SMT parts (even though the .050 pitch pins aren't hard). Or does it depend on IC options? You could make a dual thru-hole/surface mount layout for the chips that come in both. Through-hole. I'm too shaky to solder SMT myself. The ICs are nothing exotic, and available in 8-DIPs. Peace, Paul |
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#82
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Sorry yes "piqued" Had a few drinks and was in a hurry. Piqued.
cheers garrett On 2004-11-13 10:04:50 -0800, "normanstrong" said: Garrett Cox wrote in message ... How much to build the powersupply? I assume we'd be building it. I'd be interested. I love reading the DIY also. Still want to piece together a few of Scott Dorsey's passive EQ's. I hope it'd sound pretty awesome 220 per channel is a bit of cash. I won't say steep but it is a DIY project for almost 2 grand. (If you do 8 channels) mark me down for interest peaked. I think the word you're looking for there is 'piqued'. |
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#83
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Sorry yes "piqued" Had a few drinks and was in a hurry. Piqued.
cheers garrett On 2004-11-13 10:04:50 -0800, "normanstrong" said: Garrett Cox wrote in message ... How much to build the powersupply? I assume we'd be building it. I'd be interested. I love reading the DIY also. Still want to piece together a few of Scott Dorsey's passive EQ's. I hope it'd sound pretty awesome 220 per channel is a bit of cash. I won't say steep but it is a DIY project for almost 2 grand. (If you do 8 channels) mark me down for interest peaked. I think the word you're looking for there is 'piqued'. |
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#84
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#86
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#87
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#88
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#89
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#90
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From: Bob Cain come up with a battery operated unit at $50/channel. At a trade show a couple of years back, Dan Kennedy sketched something out for me on a yellow legal pad. I still have the sheet. I built up a channel and it looked like it would work out fine, but I never packaged it. Same old story. What I'm dying for is a four channel as per above but with a form of gain control that will allow any number of channels to be ganged and operated with a single control. Some kind precision voltage controled pot on each channel if such a thing exists. Check out the Burr-Brown PGA2500. It's a digitally controlled mic preamp chip. I'm not sure if I've heard one, but it's what Mackie is using in the mic preamp module of their new dxb console. That module appears to have a component made of unobtanium, maybe it's the PGA2500. -- I'm really Mike Rivers ) However, until the spam goes away or Hell freezes over, lots of IP addresses are blocked from this system. If you e-mail me and it bounces, use your secret decoder ring and reach me he double-m-eleven-double-zero at yahoo |
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#91
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From: Bob Cain come up with a battery operated unit at $50/channel. At a trade show a couple of years back, Dan Kennedy sketched something out for me on a yellow legal pad. I still have the sheet. I built up a channel and it looked like it would work out fine, but I never packaged it. Same old story. What I'm dying for is a four channel as per above but with a form of gain control that will allow any number of channels to be ganged and operated with a single control. Some kind precision voltage controled pot on each channel if such a thing exists. Check out the Burr-Brown PGA2500. It's a digitally controlled mic preamp chip. I'm not sure if I've heard one, but it's what Mackie is using in the mic preamp module of their new dxb console. That module appears to have a component made of unobtanium, maybe it's the PGA2500. -- I'm really Mike Rivers ) However, until the spam goes away or Hell freezes over, lots of IP addresses are blocked from this system. If you e-mail me and it bounces, use your secret decoder ring and reach me he double-m-eleven-double-zero at yahoo |
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#92
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Kurt Albershardt wrote:
Mike Rivers wrote: Actually that isn't too difficult. If you're going to build a $2,000 preamp, you're probably into building things and you don't have to start out by buying every tool that you need, because you already have a decent shop. A good start for audio projects is a set of Greenlee chassis punches for male and female XLR connectors, about $40 a piece. I thought these punches were more like $200-250 each? You are talking about the ones with the slots for the mounting screws, right? No, he is talking about round Greenless punches, without holes for mounting screws. You punch the hole, put in the connector, and then drill the screw holes. I did not know that there were ANY hand punches that will do all three holes in one operation! If you know of one, I would really like to know. I have used a small hydraulic press with custom tooling, a combination that cost a lot more than $200 and was not convenient to take into the field. A hand punch that would do all three holes would be wonderful for field modification work. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#93
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Kurt Albershardt wrote:
Mike Rivers wrote: Actually that isn't too difficult. If you're going to build a $2,000 preamp, you're probably into building things and you don't have to start out by buying every tool that you need, because you already have a decent shop. A good start for audio projects is a set of Greenlee chassis punches for male and female XLR connectors, about $40 a piece. I thought these punches were more like $200-250 each? You are talking about the ones with the slots for the mounting screws, right? No, he is talking about round Greenless punches, without holes for mounting screws. You punch the hole, put in the connector, and then drill the screw holes. I did not know that there were ANY hand punches that will do all three holes in one operation! If you know of one, I would really like to know. I have used a small hydraulic press with custom tooling, a combination that cost a lot more than $200 and was not convenient to take into the field. A hand punch that would do all three holes would be wonderful for field modification work. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#94
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Bob Cain wrote:
Geoff Wood wrote: I'd be more interested in variable input impedence. Which reminds me of a question that came up on another forum. Seems that pre impedences are down in the 2K Ohm and below range. Have they always been that low and why such a relatively big load? Well, first of all because audio guys were used to dealing with 600 ohm balanced lines for everything at the time (which is a holdover from telco practice, which is a holdover from open wire transmission lines that had a 600 ohm characteristic impedance). Or 150 ohm lines if you worked at CBS. Secondly, the low impedance reduces electrostatic noise pickup, which is high voltage noise with not much induced current. The signal current swamps the noise current. 50 ohm impedances were not unusual at one time, back when everything was transformer coupled so the disadvantages of extremely low impedances were not as great. The major disadvantage of the low mike impedances is that you need such a high ratio transformer to get it into the grid of the first preamp tube, and high ratio transformers with good high end response are hard to make. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#95
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Bob Cain wrote:
Geoff Wood wrote: I'd be more interested in variable input impedence. Which reminds me of a question that came up on another forum. Seems that pre impedences are down in the 2K Ohm and below range. Have they always been that low and why such a relatively big load? Well, first of all because audio guys were used to dealing with 600 ohm balanced lines for everything at the time (which is a holdover from telco practice, which is a holdover from open wire transmission lines that had a 600 ohm characteristic impedance). Or 150 ohm lines if you worked at CBS. Secondly, the low impedance reduces electrostatic noise pickup, which is high voltage noise with not much induced current. The signal current swamps the noise current. 50 ohm impedances were not unusual at one time, back when everything was transformer coupled so the disadvantages of extremely low impedances were not as great. The major disadvantage of the low mike impedances is that you need such a high ratio transformer to get it into the grid of the first preamp tube, and high ratio transformers with good high end response are hard to make. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#96
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"Mike Rivers" wrote in message news:znr1100391373k@trad... Mr. Marketing here . . . How about presenting it as a two-channel preamp which, I suspect, is more in demand than an eight-channel preamp. Make a two-channel board with pads to mount components for phantom powering, the high-pass filter, and the additional components for the balanced output. Let the user decide what extra features he wants to add for more flexibility rather than what features he wants to leave out to save a few bucks. The power supply will handle up to eight channels worth of boards, so the preamp can grow as the users' needs grow. It's already a two-channel preamp if you only buy two preamp boards. And since the users are buying the parts, they get to decide what to leave out. I'll make it clear, if I market the boards, just what parts are mandatory and what parts aren't. The chassis, panel, and case will remain a stumbling block for many, however. But not all; I'm aiming this at folks who have had at least some experience with DIY. And I have a guy who's willing to make and sell panels and/or cases. If someone wanted fewer than 8 channels, they could always put plugs into the unused front-panel holes. Peace, Paul |
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#97
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"Mike Rivers" wrote in message news:znr1100391373k@trad... Mr. Marketing here . . . How about presenting it as a two-channel preamp which, I suspect, is more in demand than an eight-channel preamp. Make a two-channel board with pads to mount components for phantom powering, the high-pass filter, and the additional components for the balanced output. Let the user decide what extra features he wants to add for more flexibility rather than what features he wants to leave out to save a few bucks. The power supply will handle up to eight channels worth of boards, so the preamp can grow as the users' needs grow. It's already a two-channel preamp if you only buy two preamp boards. And since the users are buying the parts, they get to decide what to leave out. I'll make it clear, if I market the boards, just what parts are mandatory and what parts aren't. The chassis, panel, and case will remain a stumbling block for many, however. But not all; I'm aiming this at folks who have had at least some experience with DIY. And I have a guy who's willing to make and sell panels and/or cases. If someone wanted fewer than 8 channels, they could always put plugs into the unused front-panel holes. Peace, Paul |
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#98
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#99
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#100
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#101
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#102
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#103
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#104
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In article writes: A good start for audio projects is a set of Greenlee chassis punches for male and female XLR connectors, about $40 a piece. I thought these punches were more like $200-250 each? You are talking about the ones with the slots for the mounting screws, right? No, punches that make 3/4" (male) and 15/16" (female) round holes. There's a 3/8" bolt that draws the punch through the die, so you have to be able to drill a 3/8" hole but that's easy enough with a Harry Homeowner electric hand drill - though getting it in the right place is a little tricky. Markertek sells the punches. Look in their catalog under C for "Chassis Punch" (at least that's how it's listed in the paper catalog I have here). Here ya go: http://www.markertek.com/SearchProdu...m=GL730A&off=1 And on the next page, they have a 2 space rack mount chassis that takes five of their panel modules front and rear (they come pre-punched for some things useful like XLR connectors, or blank). The chassis is $65. Panels are $6 - $10 and come up to triple width. I took a look at the Sescom web page as Monte suggested and they have a similar rack mount chassis with what looks like solid front and rear panels for around $40 that would probably accommodate the preamp. They also have chassis punches for the microphone connectors that are about half the price of those from Markertek. Sescom doesn't specify a brand name (Markertek's are from Greenlee who has been making them for about 50 years) so it's possible that the Sescom ones are Chinese. They're probably fine for a couple of projects, but may not last through a lifetime of building. -- I'm really Mike Rivers ) However, until the spam goes away or Hell freezes over, lots of IP addresses are blocked from this system. If you e-mail me and it bounces, use your secret decoder ring and reach me he double-m-eleven-double-zero at yahoo |
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#105
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In article writes: A good start for audio projects is a set of Greenlee chassis punches for male and female XLR connectors, about $40 a piece. I thought these punches were more like $200-250 each? You are talking about the ones with the slots for the mounting screws, right? No, punches that make 3/4" (male) and 15/16" (female) round holes. There's a 3/8" bolt that draws the punch through the die, so you have to be able to drill a 3/8" hole but that's easy enough with a Harry Homeowner electric hand drill - though getting it in the right place is a little tricky. Markertek sells the punches. Look in their catalog under C for "Chassis Punch" (at least that's how it's listed in the paper catalog I have here). Here ya go: http://www.markertek.com/SearchProdu...m=GL730A&off=1 And on the next page, they have a 2 space rack mount chassis that takes five of their panel modules front and rear (they come pre-punched for some things useful like XLR connectors, or blank). The chassis is $65. Panels are $6 - $10 and come up to triple width. I took a look at the Sescom web page as Monte suggested and they have a similar rack mount chassis with what looks like solid front and rear panels for around $40 that would probably accommodate the preamp. They also have chassis punches for the microphone connectors that are about half the price of those from Markertek. Sescom doesn't specify a brand name (Markertek's are from Greenlee who has been making them for about 50 years) so it's possible that the Sescom ones are Chinese. They're probably fine for a couple of projects, but may not last through a lifetime of building. -- I'm really Mike Rivers ) However, until the spam goes away or Hell freezes over, lots of IP addresses are blocked from this system. If you e-mail me and it bounces, use your secret decoder ring and reach me he double-m-eleven-double-zero at yahoo |
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#106
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#107
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#108
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Scott Dorsey wrote:
Kurt Albershardt wrote: Mike Rivers wrote: Actually that isn't too difficult. If you're going to build a $2,000 preamp, you're probably into building things and you don't have to start out by buying every tool that you need, because you already have a decent shop. A good start for audio projects is a set of Greenlee chassis punches for male and female XLR connectors, about $40 a piece. I thought these punches were more like $200-250 each? You are talking about the ones with the slots for the mounting screws, right? No, he is talking about round Greenless punches, without holes for mounting screws. You punch the hole, put in the connector, and then drill the screw holes. I can do that with a Unibit, unless it's a really thick panel. I did not know that there were ANY hand punches that will do all three holes in one operation! If you know of one, I would really like to know. I have used a small hydraulic press with custom tooling, a combination that cost a lot more than $200 and was not convenient to take into the field. A hand punch that would do all three holes would be wonderful for field modification work. At a place I worked in Hollywood, we used to have a set (one for each connector sex.) It was a single hole with keyways (notches) for the mounting screws. I don't know who made them. |
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#109
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Scott Dorsey wrote:
Kurt Albershardt wrote: Mike Rivers wrote: Actually that isn't too difficult. If you're going to build a $2,000 preamp, you're probably into building things and you don't have to start out by buying every tool that you need, because you already have a decent shop. A good start for audio projects is a set of Greenlee chassis punches for male and female XLR connectors, about $40 a piece. I thought these punches were more like $200-250 each? You are talking about the ones with the slots for the mounting screws, right? No, he is talking about round Greenless punches, without holes for mounting screws. You punch the hole, put in the connector, and then drill the screw holes. I can do that with a Unibit, unless it's a really thick panel. I did not know that there were ANY hand punches that will do all three holes in one operation! If you know of one, I would really like to know. I have used a small hydraulic press with custom tooling, a combination that cost a lot more than $200 and was not convenient to take into the field. A hand punch that would do all three holes would be wonderful for field modification work. At a place I worked in Hollywood, we used to have a set (one for each connector sex.) It was a single hole with keyways (notches) for the mounting screws. I don't know who made them. |
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#110
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Mike Rivers wrote:
From: Bob Cain come up with a battery operated unit at $50/channel. At a trade show a couple of years back, Dan Kennedy sketched something out for me on a yellow legal pad. I still have the sheet. I built up a channel and it looked like it would work out fine, but I never packaged it. Same old story. What I'm dying for is a four channel as per above but with a form of gain control that will allow any number of channels to be ganged and operated with a single control. Some kind precision voltage controled pot on each channel if such a thing exists. Check out the Burr-Brown PGA2500. It's a digitally controlled mic preamp chip. I'm not sure if I've heard one, but it's what Mackie is using in the mic preamp module of their new dxb console. That module appears to have a component made of unobtanium, maybe it's the PGA2500. $16.58 in single unit quantities from Digi-Key. Surely this ought to find its way into some affordable remote digital preamp packages soon? |
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#111
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Mike Rivers wrote:
From: Bob Cain come up with a battery operated unit at $50/channel. At a trade show a couple of years back, Dan Kennedy sketched something out for me on a yellow legal pad. I still have the sheet. I built up a channel and it looked like it would work out fine, but I never packaged it. Same old story. What I'm dying for is a four channel as per above but with a form of gain control that will allow any number of channels to be ganged and operated with a single control. Some kind precision voltage controled pot on each channel if such a thing exists. Check out the Burr-Brown PGA2500. It's a digitally controlled mic preamp chip. I'm not sure if I've heard one, but it's what Mackie is using in the mic preamp module of their new dxb console. That module appears to have a component made of unobtanium, maybe it's the PGA2500. $16.58 in single unit quantities from Digi-Key. Surely this ought to find its way into some affordable remote digital preamp packages soon? |
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#112
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#113
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#114
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#116
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Mike Rivers wrote: Check out the Burr-Brown PGA2500. It's a digitally controlled mic preamp chip. I'm not sure if I've heard one, but it's what Mackie is using in the mic preamp module of their new dxb console. That module appears to have a component made of unobtanium, maybe it's the PGA2500. Wow! That certainly is the ticket for my app. Cascadable too for ganging. Only problem I see is the need for a PIC to convert an analog voltage from a gain pot to the digital gain control for the chips. PICs are cheap, but there would certainly be a learning curve and development investment for progamming one to do the job. At $16.50 for the PGA2500 and a buck for a PIC, this certainly should offer the low cost channel that many people have been wanting. The -128 dB noise Ein isn't stellar by any means but certainly usable. This might just be worth kitting. Thanks, Bob -- "Things should be described as simply as possible, but no simpler." A. Einstein |
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#117
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Mike Rivers wrote: Check out the Burr-Brown PGA2500. It's a digitally controlled mic preamp chip. I'm not sure if I've heard one, but it's what Mackie is using in the mic preamp module of their new dxb console. That module appears to have a component made of unobtanium, maybe it's the PGA2500. Wow! That certainly is the ticket for my app. Cascadable too for ganging. Only problem I see is the need for a PIC to convert an analog voltage from a gain pot to the digital gain control for the chips. PICs are cheap, but there would certainly be a learning curve and development investment for progamming one to do the job. At $16.50 for the PGA2500 and a buck for a PIC, this certainly should offer the low cost channel that many people have been wanting. The -128 dB noise Ein isn't stellar by any means but certainly usable. This might just be worth kitting. Thanks, Bob -- "Things should be described as simply as possible, but no simpler." A. Einstein |
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#119
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(Mike Rivers) wrote in message news:znr1100380037k@trad...
In article writes: I have some general opinions on magazine-published DIY projects, and this is aimed not only at Mr Stamler but also Mr Dorsey and everyone else that do these things. First, I want to be able to get ALL parts at once from one place, and that must include the chassis. That's really nice, but unless someone is willing to put together a complete kit, it really can't be done. Paia used to do this but they don't seem to be quite so active in that area these days. Understand that this requires a substantial investment when it comes to metalwork. They can often use resistors, capacitors and op amp chips for multiple products but they can't punch a chassis for an 8-channel mic preamp and use it for a compressor. Scott Hampton seems to manage just fine. Of course there isn't a decent business in doing kits, but Mr Dorsey et al arn't making any money on the kits as it so... As a naive end-user/reader it's hard to see the difference in not making much money on "hard to get parts for and then I have to slave away on housing"-kits and not making much money on "yummy it's just one package to order for off-hours soldering goodness". Just add the extra labor costs onto the cost of the full package to take you from "losing money" to "not making much money". Second, I don't think anyone is interested in merly "decent" or "servicable" projects. I think most readers have too much of that already. We want "really good" or even "outstanding". This is why I didn't think Paul's project would be a smashing success. On the other hand, a project like Scott's Oktava mic modifications that involve a simple circuit board that he can provide, a handful of parts, and only small hand tools are pretty popular. Yes it's an examplary mod. Unfortunately he does in fact NOT provide replacement circuit bords as you say, which I kind of whish he did since he mentions about a million times how easy it is to wreck the board. I wonder, would there be enough room to make it have a truly balanced output if one redesigned the board? To keep price down I think you need to make costly features optional. Many people couldn't care less about HP-filtering, phase switches, metering and balanced outputs in a preamp for instance. I wrote an article in Recording a while back about developing your own DIY project (using a monitor switcher as an example) in which I explained exactly that concept - but the point of my article was that YOU could make those decisions. It's not difficult to find application notes for transfomrers and op amps that will get you a decent mic preamp and you can make it "really good" or even "outstanding" by the way you apply what's in those application notes. If you want someone to make those decisions for you, you have to accept his take on what's good for you. The problem is that "DIY" is not a good term for what we are discussing. It's not so much "Do It Yourself" as "Someone Else Did Most Of It For Me And Now I Just Paint By Numbers" (SEDMOIFMANIJPBN). The reason why me and my ilk have to read your articles is because we are in fact NOT skilled enough to concieve and design these things. We can however build them. But since we are already pampered rather heavily it feels ardenous to have to make the final set of decisions ourselves (housing). This is a perfectly good example of a project that you could develop yourself. All you need to do is understand what you need to accomplish. Package it as pretty or as ugly as you wish. But I don't want to develop it myself. I want to pay YOU to do it. I want you to guide me through the design in the assembly notes, explaining what each thing does, why this is good design practice etc. So that at the end of assembling I may have learnt something. That's ALL I want. If I wanted to become an audio equipment designer of such a caliber that I could design these things myself then I would study to become one and not waste time trying to deduct something from a paint by numbers DIY project. |
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#120
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Kurt Albershardt wrote:
Scott Dorsey wrote: I did not know that there were ANY hand punches that will do all three holes in one operation! If you know of one, I would really like to know. I have used a small hydraulic press with custom tooling, a combination that cost a lot more than $200 and was not convenient to take into the field. A hand punch that would do all three holes would be wonderful for field modification work. At a place I worked in Hollywood, we used to have a set (one for each connector sex.) It was a single hole with keyways (notches) for the mounting screws. I don't know who made them. That is exactly what I want! Where do I get them? A couple hundred bucks each is doable if they last. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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