Hi All,
I did not see a similar thread anywhere, so I figured it would be OK to start this. Sorrt for any redundancy.
I have a pair of Grado SR-325s, which are very nice. But I don't really have anything to drive them with. I was using my computer / ipod, but as soon as I turned up the volume even slightly, the bass became distorted. I have a Sansui AU-719 integrated with headphone outs, but its location is very inconvenient for me to use as a headphone amp.
I primarily listen to rock and jazz. Occasionally, I put on NPR's classical radio station.
What can I build that would put some life into the Grados? I would like to spend about $50. It must have easily obtainable parts, which are luckily the cheap ones in most situations. It also can't be incredibly difficult to build because I am a total noob. At the same time, I thought this would be an easier project than a DIY amplifier or crossover network.
Thanks, Jim
I did not see a similar thread anywhere, so I figured it would be OK to start this. Sorrt for any redundancy.
I have a pair of Grado SR-325s, which are very nice. But I don't really have anything to drive them with. I was using my computer / ipod, but as soon as I turned up the volume even slightly, the bass became distorted. I have a Sansui AU-719 integrated with headphone outs, but its location is very inconvenient for me to use as a headphone amp.
I primarily listen to rock and jazz. Occasionally, I put on NPR's classical radio station.
What can I build that would put some life into the Grados? I would like to spend about $50. It must have easily obtainable parts, which are luckily the cheap ones in most situations. It also can't be incredibly difficult to build because I am a total noob. At the same time, I thought this would be an easier project than a DIY amplifier or crossover network.
Thanks, Jim
Under $50, you're not going to get much further than a decent CMOY variation.
I suggest the tutorial on Tangents website (How to Build the CMoy Pocket Amplifier) or, if you'd like something easily portable, the AMB labs Mini3 (The Mini³ Portable Stereo Headphone Amplifier). Read the documentation for both and you'll have a good start.
A good CMOY with a decent pot and a high quality opamp will get close to $50 by the time you've put it in a case.
I suggest the tutorial on Tangents website (How to Build the CMoy Pocket Amplifier) or, if you'd like something easily portable, the AMB labs Mini3 (The Mini³ Portable Stereo Headphone Amplifier). Read the documentation for both and you'll have a good start.
A good CMOY with a decent pot and a high quality opamp will get close to $50 by the time you've put it in a case.
Hi,
I also have a pair of 325's. I have been pretty happy with my PIMETA amp, with AD825 opamps. The CMOY is probably not quite as good as the PIMETA for grados, as the PIMETA has a buffer circuit, and is therefore better at supplying current to the relatively current-hungry Grados.
For $50, you'll have to go with something like the CMOY. You'll probably want to do it 'Grado RA-1 style', meaning you'd use a JR4556 opamp, which is pretty good at delivering current.
You might be able to get away with using a simple no-gain buffer circuit, e.g. something that isn't an 'amp', only a current driver. The JISBOS buffer ought to be pretty good: JISBOS - overview
I also have a pair of 325's. I have been pretty happy with my PIMETA amp, with AD825 opamps. The CMOY is probably not quite as good as the PIMETA for grados, as the PIMETA has a buffer circuit, and is therefore better at supplying current to the relatively current-hungry Grados.
For $50, you'll have to go with something like the CMOY. You'll probably want to do it 'Grado RA-1 style', meaning you'd use a JR4556 opamp, which is pretty good at delivering current.
You might be able to get away with using a simple no-gain buffer circuit, e.g. something that isn't an 'amp', only a current driver. The JISBOS buffer ought to be pretty good: JISBOS - overview
Bought a Grado-clone/ripoff off the auction. 2 batteries and a box keeps you under your budget. Remember ,the Grado's are very low impedance. Their amp ( and the rip-off) have a very high current op-amp. A plain MCoy is really taxing a standard op-amp. The above solutions with higher current drivers would be a better match. National publishes an op-amp/driver tech note. If you can do it from batteries, (rechargeable, low Z of course) that keeps the cost way down. A really nice power supply is not cheap. I run my rip-off from 2 9volters at the risk of if one dies first, there is a possibility of DC offset. Not good. Better to use the artificial ground circuit.
This will get you under $50. It will provide plenty of drive as well.
You can use two 9V batteries for power.
DIY IRF610 MOSFET Class-A Headphone Amplifier Project
You can use two 9V batteries for power.
DIY IRF610 MOSFET Class-A Headphone Amplifier Project
Not sure of your ability, but if your willing to stretch a bit, don't think you can beat this for the price.
ecp.cc
Tubes though, high voltages of course, B+, etc...so may be too difficult, but that will drive your grados with aplomb. I know Doug and some others might be doing some kind of board for it to be even easier.
ecp.cc
Tubes though, high voltages of course, B+, etc...so may be too difficult, but that will drive your grados with aplomb. I know Doug and some others might be doing some kind of board for it to be even easier.
you're going to blow through $50 quickly in batteries if you try to combine battery power and SE Class A output
cheap power is most readily had from sealed "wall wart" or brick modules - you should be able to find them for free - my last dead ink jet printer had a 12Vdc 800mA brick that could just be snapped out of the printer for easy recycling
depending on the amp circuit as little as 200mA rating could work, with SE Class A + active gnd requiring 800mA (assuming you'd like > 100 mWrms capability into the Grados)
another cost saving measure would be to go for fixed gain without a volume pot on the amp - just use the digital attenuation in the sources you have now - certaily will track better than a cheap audio taper pot
cheap power is most readily had from sealed "wall wart" or brick modules - you should be able to find them for free - my last dead ink jet printer had a 12Vdc 800mA brick that could just be snapped out of the printer for easy recycling
depending on the amp circuit as little as 200mA rating could work, with SE Class A + active gnd requiring 800mA (assuming you'd like > 100 mWrms capability into the Grados)
another cost saving measure would be to go for fixed gain without a volume pot on the amp - just use the digital attenuation in the sources you have now - certaily will track better than a cheap audio taper pot
jimwit, I don't know what your location is. Around here a lot of people discard old CRT monitors and old computers. You would be able to get a lot of good parts out of them, such as mosfets and bipolar transistors, capacitors, etc. The only thing you'd be left to buy would be a few resistors and the opamp if you choose to do an opamp based amp. I get a lot of good parts this way which sometimes I use for prototyping and testing ideas. Good way to save a buck.
Cannot forget about Pete Millett's Starving Student, can be made for about $35 if you scrap some kind of chassis. Hybrid design.
Starving Student hybrid
Starving Student hybrid
Don't get too outside of the box on your first build. Build something with a lot of documentation and support. AMB offers fantastic designs and boards, and kits are sold through glassjaraudio.com (I think that the mini 3 kit is around $80 for everything). if you don't want to source the parts yourself (don't known where you are in the world). Getting the parts yourself from digikey, mouser, newark, etc is a good thing to start doing though, because you begin to familiarize yourself with their catalogs, and the parts that they have available, which is great later on when you're building or repairing something that doesn't have the same detailed documentation that AMB does.
Keep in mind that if you only intend to build one amplifier, you are better off buying one, either from a builder, or a commercial product. By the time you purchase all the necessary tools to build, soldering iron, multimeter, desoldering tools, solder, solder wick, drill bits, pliers, clips, holders, etc, you will spend many times your initial figure of $50. (and if you are anything like me, you can expect to break a few things too). This is a great hobby, and I have definitely saved money over what I might have spent on similar commercial products, but it is not the cheapest way to get good sound all the time.
So, check out AMB.org. Start with a project that offers a circuit board that is well documented and supported. You can also look on the amb website for builders who don't charge much for their services and offer his products already made.
Have fun in your search!
Aaron.
Keep in mind that if you only intend to build one amplifier, you are better off buying one, either from a builder, or a commercial product. By the time you purchase all the necessary tools to build, soldering iron, multimeter, desoldering tools, solder, solder wick, drill bits, pliers, clips, holders, etc, you will spend many times your initial figure of $50. (and if you are anything like me, you can expect to break a few things too). This is a great hobby, and I have definitely saved money over what I might have spent on similar commercial products, but it is not the cheapest way to get good sound all the time.
So, check out AMB.org. Start with a project that offers a circuit board that is well documented and supported. You can also look on the amb website for builders who don't charge much for their services and offer his products already made.
Have fun in your search!
Aaron.
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