Do It Yourself

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…

Sorry to pollute the forum -- does anyone have any Blackgate N 4.7u/50V or 10u/50V caps? I could use either 3 or 4 of the 4.7's (I have one) or 4 of the 10's. I am happy to pay the going rate, or I have lots of DIY stuff to trade (including some new WM8741 based DAC PCBs arriving in a couple of days). Thanks

hi all! I was wondering if anyone here would be willing to turn a wood motor pod for a project I am working on. I have a custom aluminum plate that I'd like to press fit into a simple, wood cylinder that would include a cutout for the motor itself that would run right down the middle. The outside diameter would be 120mm and the height would be just enough to accommodate my Nottingham turntable, so 4-5". If anyone is interested, I can supply detailed drawings for the top plate and we can talk price Thanks!

Just curious, does anyone happen to have a variac I could borrow for a bit? If not, I suppose I could go ghetto...

Hey gang- When I bought my Hagerman Bugle a while back, Jim set the gain high so it would work with the DL-103. While the sound was excellent, I found there was too much hiss present in my setup, and went to a SUT + MM phono combo. Today I was looking at the Bugle and thinking it would be nice to get the gain lowered so that I could run it from my SUT and compare it to my Bottlehead Seduction. Can any friendly DIYer give me a rough idea of what would have to be done to get the gain on this sucker back down to stock levels?

As Luvdunhill has a limit of 100 total for his mini-GB, and the the count was well above 100 not counting myself and luvdunhill, I've got a quote from Trendsetter at 5USD/ea, at minimum of 100, I've decided to organize a GB for those who still wants the LSK389B at 5USD/each, state your interest here At this point in time there are almost 100. Please be aware that the GB started as for SOIC-8 package alone. I have added the TO-71 to the spreadsheet. 20160120: GROUP BUY CLOSED

Hello Head-Case I am working on an amp using this transformer in a PP output from a 6h30 tube. I would like to know if anyone has had experience with wiring the secondaries in various series/parallel configurations as indicated on the datasheet for different stepdown ratios to drive different load impedances The schematics & articles I could find which use this transformer for headphone use (the Raven, and a few from Andrea Ciuffoli) dont make mention of using the secondaries this way, where other a few others with sowter & "unknown to me iron" do. I think its something worth exploring, but would like to know ahead of time if its a waste of time.

Does anyone happen to have info on the 4070 cups? What kind of wood it uses, other materials if any, dimensions (doesn't have to be exact), where the bass port is, how angled the drivers are, etc.

Here's the APC H15 I got recently: I wanted black, but I got the silver for $200 less. Is there an easy way to paint it black? The face plate is some sort of metal. Any ideas about how to make it, well, less silvery?

Cases and heatsinks are a problem for DIY builds. Front panels of thick alloy need machining and tapping as do heatsinks. These items are hard to get machined or the sizes the builder wants are not available. I devised a way of making cases, which eliminated these problems and made for easier case design, lower costs and quicker builds. Cases Made from sheet aluminium alloy of preferably 3mm so only single sheet of material needed. I get the parts laser cut by a company which will also supply the material. The case parts need holes to be countersunk where necessary and are then taken for surface finishing, (bead blasting and anodising in my cas…

I want to experiment with making some data only USB cables. Looking at the specs of the bulk USB cable by lcomm it shows 28awg twisted for the data lines. Is it ok to use stranded?

Anybody know what votage the Mapletree Ear+ runs at?

markl marce Mods Due to popular demand, I am now offering to perform the modifications I developed for the D5000 (and D2000) on your Denons. M

These caps are extremely transparent in the many uses I did. Both high voltage 600 and 1000 volts I’ve used them in dc blocking and seem to have a neutral sound has anyone tried these in Amps and pre amps I’m curious to know what others think I’m not a fan of anything oil as I feel they color the sound. In addition in stat amp builds 400 vdc seems on the edge of max range why don’t builders use 1000 vdc rated caps ? ABD0000C255.pdf

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?

I want to match some PRP resistors to 0.10% so I read tangent's blog on this and I need a meter with 10,000 counts or better. Is this worth doing or am I wasting my time? I was wondering what everyone else's experiences were?

updated Megatron schematic. If you manage to figure out what the stax mafia is doing, please let us know. We are having a hard time keeping track of it all

I have been thinking about parting with my Melos SHA-1 for a while. It was [url=http://www.stereophile.com/headphones/617/]Corey Greenberg

Does anyone have schematics for either the Gold (balanced?) or the unbalanced version of these? I told a person I dealt with (diyaudio user) that I thought they might be available (and told him why bother), but his interest is just in the front end section as a preamp). I saw what is available on the eservice info site, but can't remember my login there. The user says he has some incomplete schematics with pencil markings on them. I had the attached jpeg, but think this could be what he already has. Thanks for anything you can find.

Dear HC crew, I'm getting desperate and could really use some input on troubleshooting... First off I've been plugging away at this old thing for a while now, was always afraid to post up here for various reasons but at this point I don't have much to lose anymore. I do recognize I am still relatively new to DIY but I've been doing what I can with what I've got. I have a long winding thread with chronicle of the madness while it was working great; more than happy to remove the link if the admins do mind. There are links somewhere in there to the original schematic but it won't be of much help. http://www.superbestaudiofriends.org/index.php?threads/melos-s…

One of these rare amps stopped by for a visit: This one belongs to Stuart but I'm taking a look at it for him to sort out the unbelievably noisy CT2 stepper and do something about the very high gain. I was thinking about a simple voltage divider on the input instead of messing with the circuit. I might also change out the PSU caps as some do appear to be stock. Any further ideas about this beast? I did read Doug's thread on the SHA-1 but I doubt I'll do something as extreme. It very noisy though and quite frankly, doesn't sound very good with RS-2's and Mullard E88CC tubes. Very edgy and with crappy bass. There also appears to be a small channel imbalanc…

Memory Distortion Philosophies I have no idea what he's talking about... but the way his design blatantly goes against all "audiophile design philosophy" is rather intriguing

The part tested ok and seems to a 15 volt reg mc 7915ctg mc 7815ctg

I know that AMB has his Arduino-based system in the works, but I'm at a point in my EE education where I want to design something myself. I'm thinking of the following high-level scheme for a 4-input, 4-output audio switchbox. TI MSP430 microcontroller LCD display pushbuttons ADG1604 analog muxes My question to the other EEs on Head-Case is this: most all of the electronic switchers I've seen so far in the DIY realm use relays. Is there any major downside to using analog muxes that I haven't realized yet? Any reason that I shouldn't pursue this technique? I was wanting to try something that I haven't seen already, and this seems like a very do-able project for m…

Hey, I'm having a slot milled that will accept a piece of aluminum bar that is nominally 0.5" wide. How wide should I have the slot milled in order to ensure that the bar can be easily removed? I'm not sure what the tolerances are on aluminum bar and not really sure what extra width to account for that doesn't require a hammer to (re)move the piece.