If the light switch is a dimmer switch, it will thow out a lot of RF interference. If I plug in an electric guitar in a room with a dimmer switch, the noise will very easily be heard through the amp. Now that's an extreme case, but illustrates how much noise some electric devices can radiate...

Very nice panel on that amp. Looks classy and professional.

Advocates of high-end power cables can offer plenty of scientific reasons why they can potentially improve the audio of a system and you can find countless testimonials that insist they do in fact improve the sound. That doesn't necessarily mean that there is a measureable audible improvement...

Sonically, perfboard construction would be equal to PCB although you can do things like ground planes with PCB and in some cases make a smaller circuit with PCB. If you're getting into surface mount components, then a PCB is pretty much required although I've seen it done with perfboard. Also...

I was thinking along the lines of a noise gate type circuit but the configuration you need has one signal acting as the trigger to attenuate the other signal. It's actually called 'ducking' in the recording biz. The circuit is not all that simple and requires a chip called a compander. If you...

Sure you can! The disassembly and soldering is not going to be the difficult part though. Finding a suitable replacement jack is. If you can open up the remote without breaking any plastic tabs, you can measure the existing headphone jack and pin spacing. Get a hold of Mouser and Digi-key...

Shouldn't be too complicated to wire up a pair of 9v batteries in series to double your voltage. An easy troubleshooting method for the rest of the circuit is to remove the opamp from the socket and make two little jumpers out of clipped resistor ends to connect pins 1 to 3 and 5 to 7. This...

Congratulations! The problem solving and resoldering are part of what makes DYI satisfying for me. If everything went together perfectly the first time, you would never appreciate all the work that goes into a handmade amp. Sounds all the more sweeter because of it.

I second the recommendation of a benchtop drill press if you have the space for it. They can be found for under $100 and are very useful for DIY projects and all kinds of other things. Many come with a vise as well. And if you are into making your own PCBs, they make short work of the drilling...

FET = field effect transistor. It's just a different type of transistor used inside the opamp. The FET input opamps have a slightly different sound, but whether they are better or worse, is subjective. I would think that the PA version is perfectly suitable for a CMOY amp and since you're...

I wouldn't jump to the conclusion that the jacks are bad unless somehow one of the pins was shorted to ground. That's easily checked with an ohmmeter. "not loud enough" can be cause by either an input shorting straight to the output, bypassing the opamp, or by a problem with the feedback...

The pinout on the pot looks correct, but I would look closely at the two adjacent pins, R-out and R-in to make sure they're not bridged. Use a multimeter to make sure. That would surely result in the symptoms you describe. It certainly should be loud, so chances are you may have some other...

I know how tough it can be selecting the right capacitors, I spent a few hours myself browsing Digikey's catalog selecting just the right caps for my next projects. You really have to look at the voltage, capacitance and size numbers carefully to find the right part. I ended up choosing the...

Very informative and written in a way that's easy to understand. Those Pultec EQs are highly desired in professional studios and fetch a high price on Ebay. No better reason than that to make it a DYI project! Thanks for the links.

I like gloss spray polyurethane for coating enclosures. In your case, you sand down the enclosure, don't touch it with fingerprints but immediately clean it with alcohol or something to remove grease and spray with polyurethane. I get the spray polyurethane at Home Depot or any hardware store...

Well, it's easy to replace if you are fairly at all with desoldering and soldering parts on circuit boards and if you can obtain a suitable replacement jack. You should feel confident that you can disassemble and reassemble your iPod properly before you even think of repairing that jack. I...

That's a very clever idea. I would be very interested with your results. A pocket-sized heafphone amp is an ideal companion to an iPod, so matching the curves with a custom amp case seems like a winner. How do you plan on making a shell rather than a solid block? If you don't mind me asking.

Quote: Originally Posted by hottyson BTW, It was very satisfying to hear the successful results from my first try. And that's exactly why it's all worth it no matter how much you spent. Would a commercial amp have brought you as much listening enjoyment? Only a DIYer can really...

My current project is a mini cmoy where the enclosure will be too small for a proper volume pot (much smaller than a mint tin) and the only pot I can see that might possibly fit the space would be one of those mini thumbwheels. The problem is that I am having trouble sourcing a dual ganged...

The 'hum' is caused by RFI (radio frequency interference) which is a term that represents any kind of energy within the frequencies we typically use raio in. Since radio waves can be picked up by the electrical wires and circuit board traces much like the antenna on a radio can pick up the...

I've had fairly good success with the toner transfer method. You need to make a PCB layout with thick traces and I even make the solder pads larger in diameter with a smaller hole than the PCB software normally allows (Express PCB) by modifying the artwork in Adobe Illustrator. I thought the...

Very nice looking amps you have there, I have been eyeing that smaller Hammond case also, I think it's a great case to use with an external PSU. And the contrast between the regular aluminum color with the black anodise body is a nice touch as well as the hex head screws. A tip on the...

I always wear safety glasses when drilling and using a Dremel tool, but I have to admit that I don't always wear the glasses when soldering even after having some close calls as I tend to flick excess solder off the tip of my iron. Clipping leads doesn't worry me as much since I hold the...

You're really not supposed to try and send a low level signal over that kind of distance. Way better off amplifying it at the source and running the speaker wires over the 70 feet. That's the way it's generally done for the in-wall speaker setups. Throw enough amps behind it and you can pretty...

I like the idea of using CAT5 cable for the long run, just use one of the twisted pairs to carry the L/R signals and use another pair for the grounds. If you can amplify the signal at the source, it would be even better. If you can go from unbalanced input at the source to balanced over the 70...