Do It Yourself

For the Carbon I am building, the user would like to be able to bypass the volume pot, but would like it switchable for when the source doesn't have a volume control. I had initially told him no problem, this will be easy. The more I thought about it, I realized it isn't quite as easy as I had surmised. Simply shorting the input to the output (wiper) would still result in potentially bad things depending upon where the pot was in its rotation. Since I had already done the pot adapter boards for the gb awhile ago, I started with one of those for pcb layout (the pot I am going to use is a TKD CP2500 4 channel). My initial thought was to take the pot completely out…

Group buy from PCBNet (same as Carbon and Circlotron Group Buy) for boards > 40. State your interest here A table and a modular graphic for easier overview of the various Golden Reference PSU boards and their function: The color scheme is the same used in the modular picture below. Options, each representing a full PSU everything needed for an amp (in the spreadsheet one can choose either): Option 1: Contains HV+/-, LV+/- and PRO BIAS. Option 2: As Option 1, but “Split” into two separate boards, making mounting more versatile. (Skinny and FAT contains the same, but Skinny is rectangular shape wheres FAT is sqarish) Option 3: Separ…

Has anyone had any experiences with the Furutech FP-682 or FP-681 http://www.thecableco.com/product.php?id=4201 I'm wondering whether the rhodium or gold version of these are any improvement over the Neutrik or Switchcraft alternatives. This is me window shopping connectors for a balanced Beta22.

Finally found a way to get cheap output transformers for my amp after reading this page. All resistors are 1/2W unless otherwise noted, coupling caps should be 250V or better. The power supply capacitors are all 240VAC motor run caps from Aerovox which I scrounged for $5 a pop from the surplus store, and the chokes are also cheap surplus store goodies. You don't have to go nuts on the PSU like I did, I just felt like building an amp with no electrolytic capacitors anywhere in it. The output transformer is actually a 50W toroidal power transformer from Amveco (~$20 each from Digikey). If you have high impedance 'phones or simply listen loud then connect the seco…

I'm building a Xono clone. I need to match 2SK170 JFETs and BC550 BJTs. I'm new to transistor matching - Google has left me a bit confused with the amount of "suggestions". Any clues as to the best / most convenient method, hopefully with a link to a tutorial?

Has anyone built this balanced beast and tried it out?Rightmove Kijiji Quizlet

I've building a preamplifier that also functions as a headphone amplifier. When no headphones are present, the gain of the internal opamps should be 1x (unity), so that the signal can be passed out the back of the device at line level for a speaker amplifier to further process. When headphones are inserted, the rear outputs disable, and the user should be able to select from no gain (1x), low gain (2x) or high gain (6x) to suit the impedance of the headphones. The entire operation will be controlled from an Arduino. I'm using a switched headphone jack to determine when a set of headphones has been plugged in. The gain should be selectable usi…

I'm interested in getting a (relatively) inexpensive USB computer rig at the moment, so I'm looking for advice on what to pick. At the moment, I have three choices in mind, of which I'm considering two: 1) DAC/amp combo at http://www6.head-fi.org/forums/showthread.php?t=185569 Which seems to be a NOS TDA1543 DAC, maybe similar to the Monica II (?), plus a PINT, in one PCB & enclosure. 2) Alien DAC + Go-Vibe 5 With the Alien DAC being a simple USB PCM2702 DAC, and then the Go-Vibe 5 apparently being a simple LM6172 deal with a DC jack. 3) Total Bithead At the moment I think the others will be a better value. Since while I don't have any electronics sk…

My beloved KGSSHV died, one channel went up in smoke. Tried to fix it but I cannot find the fault. Would you be willing to help troubleshoot? I’ll gladly pay for any help, want to get my amp back to work.

The part tested ok and seems to a 15 volt reg mc 7915ctg mc 7815ctg Bottom right is where the reg were Below the vishey 4700uf caps

Hey everyone, I am in the process of developing a headphone for the Brazilian market, and thought I could use some help of the many knowledgeable people here, especially regarding the acoustics. Some background info on it: it's not going to be a high-end headphone, but one that has style, nicer choice of materials and decent sound quality, compatible with the $150-200 price that we hope to sell it for when it's done. I think something like an M50 but more stylish and with better materials would be a good analogy for what we're trying to achieve. I'm not sure it's possible, but that's our goal. The problem is that we're just a group of 4 people, with no enginee…

Trying to make some DIY USB cable, but I cannot seem to find USB 2.0 type B male plugs anywhere in USA, only some from China on eBay with long shipping estimates. Found some type A plugs on Amazon. For type B, looking for something like these: http://www.ebay.com/itm/170578212079?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

How can I measure if my DAC puts out common mode DC from the balanced outputs?

The speaker protection i have uses 2 relays for stereo channel (1 relay for each channel). But I'm thinking of using it in "mono-mode" and shorting the R+L input and R+L output to make it more "robust". Will that work? (this would mean I would need 2 devices for 2 channels.) Thanks again

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So, I have never really found a good quick connect that I like... I used to buy some insulated parts and stick them on the end of an old power inlet that uses quick connects and try and pull the plastic part away quick enough to separate the metal from the plastic, then feed the wire through and solder then reattach the plastic and heat shrink the thing... that's not working with the last few ones I've tried. So, any recommendations? I'd really prefer solder types to crimp and they must be insulated. Thanks guys!

So I don't make mistakes in my latest build I was wondering what is reccomended most. Should I twist the AC power leads on a torroid being used in a DAC? Should I twist the DC power hookup wire that will go from the PSU to the DAC board? I'm assuming I should always twist the signal wires...

Hello, I would like to inquire about "caps in the bias supply" for Stax headphones. Spritzer and others said several times that "caps should not be used after the ballast resistor" (for example here: ) In this quoted case it refers to a cap in parallel after the ballast resistor. In other places the same is said about the cap in series, after the ballast ( What problems does the cap cause exactly, in that position? May I ask an opinion about the attached "blinker" circuit (with a series cap...), of which I read a long time ago; I have used one like this for a long time "without adverse…

ok, I'm finishing up a Twisted Pear Buffalo DAC using the soon to be released Legato III I/V output stage. I intend to use the BAL/SE stage in the beginning since all of my headphone amps are single ended. However I want to build a balanced headphone amp. It will be the balanced dynahi or M³ and I'm concerned about the statement below from Twisted Pear. What does this mean if I build a balanced M³ or dynahi rev2?

Is this the new product for high voltage transistors ofr electrostatic headphone amplifiers? https://www.akhansemi.com/company.html

I've been doing some Google searching and also on diyaudio but I can't seem to find a nice answer to which pins are connected to what on Quad 5-pin and 4-pin DIN interconnects. Anyone here know? -think ive got it now-

I have have an old Dynalo power supply that I never got working properly, but I'll make another attempt. It's headamp.com PCB layout and I've used the parts list that was suggested at that time, except for the 5 uF caps. The suggest 5 uF caps were Epassives MKS4475J63-6, but I don't think these are available anymore. Instead I used Solen caps. Maybe that was the problem. Anyone here built the Dynalo power supply and could share a parts list? In particular, info on the 5 uF caps would be helpful. I'll also try some high slew rate caps. Digi-Key has Cornell Dubilier 940C6W4P7K-F with a slew rate of 105 V/us. These are quite large and won't fit the board properly, so thi…

just got this for free from the good folks upstairs. nothing beats a free soldering iron (the one i have a cheap one from home depot) but is it any good? has a nice little slider for temperature control. cant find too much info on it online so i thought i would ask. the guy who runs the electrical engineering labs is cleaning house so is giving away a crapload of stuff (transformers/old drivers/test equipment/anything under the sun). i already called dibs on anything audio and surprisingly he hasnt had any requests for the stuff i put my name down for so should be nice. he used to work for bendix back in the day and has some 600 tubes in pristine condition he is t…

Can't seem to find any info or examples of these in use, but someone here must have tried them. I have found that buffers on the output of a Muses electronic volume control works very well and had good results with Sjöström Audio diamond buffers but Kevin's little PCB's might be even more compact. Can anyone remember a thread or post where these were introduced? They are a very simple circuit and could possibly do with some extra PSRR with caps right on the power pins, they are so compact I have found a neat way to stack them, in the pics below is a quad channel balanced stack, all the PBCs are connected through the power pins, leaving the i/o's separate. E…

I have the boards from Justin (KGSS and BH power supply). I'm having some trouble locating a BOM for both, a circuit diagram and a parts overlay image. So far, all I can find is this: http://gilmore2.chem.northwestern.edu/projects/showfile.php?file=gilmore2_prj.htm Any kind souls care to point me in the right direction?