Do It Yourself

So I recently picked up a couple of niche audio control modules. They're unusual passive summing boxes/mixers controlled entirely by midi. It's 8 inputs, 8 outputs, and then a summed out. The 8 inputs and 8 outputs are TS unbalanced, with a TRS out that's 1-4 TS and 5-8 RS. If I were to make an XLR patch panel that has 4 XLR inputs that send each channel to pins 1/2 and 1/3 as TS cables, would this result in a 4 channel balanced mono summing mixer?

So for a little while now my Sony DAS-R1 has had a problem with the left channel cutting out. It used to get better by itself after a minute or so, then it needed longer. Now I have the lid unscrewed all the time and give it a wee tap. While this cures the symptom it doesn't cure the disease and the wee tap is now turning into a prod, before I know it, I'll be using a frame hammer. I'd like to fix this myself however I only just know which end of a soldering iron plugs into the mains and which end you use to burn your fingers touch against things to heat them up. I've looked under the board and I cannot see any obviously broken connections. I am fairly certain that …

Man, I forgot to add 4 1000uF/50V Panasonic FM capacitors (P12393-ND) to my last Digikey order... anyone happen to have some on hand, or about to place an order and wouldn't mind shoving 4 parts into an envelope and sending them my way?

Quick question and likely an easy one, but it escapes me. If one were to have a power meter on the front of their amp, say, like the D'Agostino Momentum, what would it be connected to? I assume across the power supply...or would it be across the output? Thanks! Gratuitous picture for fun.

So birgir asked for this one, but truth be told, i have been working on it for quite a while, and i have a working prototype. Specs: DC to 200khz +0, -.2 db Slew Rate >350 volts per microsecond Thd < .01% Voltage Peak to Peak, Stator to Stator 2950 http://gilmore.chem....n.edu/togte.pdf This is not for the faint of heart. The amp actually can go higher in voltage by a bit, but anything over +/-750 for the power supply gets to be Very difficult to regulate well. The +/-250 is actually resistor dividers off the +/-750 Its the only push pull fully dc coupled electrostatic amp that i know of Since this schematic i have replaced the 2s3840 with…

So I was working on the torpedo top cover and left it outside the house for the paint to dry. Awesomely enough a fucking duck put dirt and shit all over it. I have access to home depot and limited funds. Is there anything that can be done to fix this so I can start over or did the duck fuck it all? Thanks

Well OK this one may be tamed, but it is indeed beautiful to behold. Naaman's casework (and all around attention to detail) sets him apart, along with a handful of amazing builders we have in our group. But this one in particular really hit a chord with me. Simple but eye catching at the same time. I've had my sights set on this DAC for some time now, as it seemed a natural progression from the Epic Opus ( Opus DAC w/Zapfilter output stage) I had from the Twisted Pear line. And this DAC had a surprise for me. Naaman built in a Mini³ amp into the case, so that it could be used as a stand alone system if wanted. That would be nice for desktop use, meets and for me a reason…

I am in need of a preamp with some gain and I was thinking about a DIY tube preamp. Doesn't need to have crazy high gain as the power amps will have voltage gain as well. Right now what looks attractive is the K&K Audio active output stage. The level 2 kit comes with most parts including the OPTs. Looks like a fairly good design to me? If not any other suggestions? Preferably something that is well documented.

So how difficult would it be to design an upgraded linear power supply for this unit? Something that might fit in a smallish Hammond case maybe.

I'm finally going to get back to some DIY projects. One that's been boxed away is the Bijou. Part of the reason is I want to get a case design going in my head before I get too far on the soldering. And the problem with this is I really am not seeing the kind of case I was hoping for. Oh well. Onward. My last ditch effort will be to use a fairly boxy-shaped HiFi2000 case. It is 12.20 x 11.02 x 3.14. My main concern, and the question for y'all: with this layout, am I going to pick up any RF with the transformer so close to the two amp boards at the front of the case? They will be about 6" away from a Hammond 370DAX . Here's a pic of the case size. Thanks! …

Recently I obtained a circa 1977 Technics SU-7300 integrated amp. The unit has several fuses (4), of which I have not been able to find the following: 3 Amp 125 Volt (Size 1.25" by 0.25") - need one 3.3 Amp 125 Volt (Size 1.25" by 0.25") - need two The closest I have found are: 3A 3AG FUSE | AllElectronics.com Would it work two replace the 3.3 amp fuse? Thanks.

So, I have some nice shiny TO-3 transistors. I'd like to make a PCB with these as output devices and some sort of way to transfer heat via flange that I can mount to a heat sink. I have to admit I've never used this package, so I'm curious.... assuming I cannot mount the can on the fin side of the heat sink (which would require way to much milling and effort), what sort of ways are there to deal with this? Second question, and not at all related to the above... any recommendations for a relatively low voltage CCS? Let's say 60V and 3A or so as extreme parameters. Thanks!

A mate at Auriculares posted the link to this article which may be of interest for you DIYers. Not being a DIYer myself I found it interesting nonetheless.

hi! i'm new here.. i'd like to ask for some help. diagnosis and repair.. i have a A4tech hu-200 usb headphone. now it only plays the right channel.. but before that happened i noticed that the audio is like panning from left to right til it could only be heard in the right. i researched about repairing headphones and all i saw is that the problem could be a loose wire or something similar but when i open my headphone there were no loose or broken wires. what could be the problem? and how do i fix it? i don't wanna send it to a repair shop cause i wanna see if i could repair it myself.

I'v decided to build a balaced M3 and I would like to see how others may have implmemented swithchable gain and different component choices. Thanks

will there be another run of the dynahi and psu boards? im in the market for a bablanced set

A friend asked me to come up with a phono stage that is of reasonable quality but not too over the top. Here's my first go. Basically, it is a hybrid cascode gain stage followed by a passive RIAA filter and a cathode follower. The idea is that the single gain stage should not only provide enough gain, but it should be reasonably quiet. The Zout is also governed by the plate resistor which keeps the filter stable even as tubes age. In a sense, it is much like Pete's pentode phono, other than that the cascode should be a bit quieter than a pentode. That's a lot of should's, so it remains to be seen whether it actually works. The only really tricky part I anticipate is se…

Anyone's got experience with this multimeter? I'm getting into DIY and I have the possibility to acquire a used unit in mint condition for 135$. From what I've read, Fluke dmm are generally a safe bet, but I was wondering if anyone had some feedback to give about this particular model.

To all the owners of a transistor amplifier V3.0 from http://www.high-amp.de out there in the world. Here is a support how to update your amplifier to the version 4.0 that will be coming out soon. The items below are refered to the following schematic: http://high-amp.de/html/transistor_v3_schematics.html - replace the four resistors R07x and R08x with 51K/1W resistors to increase the current in the second stage to 4mA - replace the two resistors R11x with 200 ohm resistors to increase the current in the last stage to 15mA - replace the resistors R56, R57 by a constant voltage source as shown below (one per chanel) - If you are using the 2SC5466 in the last stage r…

Hey everyone, To make a long story short, some damage occurred to a b22 that I sold internationally during shipping. I know absolutely nothing about fixing it up, but from the pics he sent me I'm guessing it should be a relatively easy fix. Is there anyone with experience with b22s(it's a 2channel board) in the area of quincy MA (or anyone in general) who would be able to help him fix it (either in person or by talking him through it?). I would be grateful for the help, as the situation is starting to turn sour. Thanks for reading.

I normally use FMs in most cases, but I see that they have come out with the FR series which are supposedly lower ESR, higher ripple current and longer life? Anyone use these, or are FM good enough? Or other? Use for now would be in PSU filtering for an I/V stage.

I find myself in need of a sub - not room shaking high level bass but responsive low end. I have seen a few really good options about but they are all big cubes which have zero aesthetic acceptance from my better half. I thought of placing a low profile unit below the media rack and found a 3 inch long throw ( xmax still limited at 5.5mm ) and a horn loaded design which in theory should produce decent bass 25-100Hz. Anyone have any experience with subwoofers? My instinct tells me I need max surface area with large excursion to reliably produce decent low end but with the trend of things getting smaller in the modern world, I am open to accept that technology has succ…

Hi all, I'm going to do a board run for Dr Gilmore's latest projects (KGSSHV, Dynahi Rev A and DynaFET) so if anyone is interested, please sign up here. The KGSSHV will be the latest revision. Board set would be 2x amp boards and 1x PSU board. The amp boards are now mounted on side heatsinks. http://gilmore.chem..../kgsshvps8e.jpg http://gilmore.chem....gsshvampv7s.jpg The Balanced Dyhahi Rev A and DynaFET will share the same PSU. One PSU is enough but due to the symmetry, 2 would surely look better Board set would be 2x amp boards and 1/2x PSU board(s). http://gilmore.chem....u/dynahibal.jpg http://gilmore.chem....ynahifetbal.jpg http://gilmore.chem....…

Ok, I have a quick question. So, I have some of these sockets, with brackets: I need to somehow embed a nut into the bracket, so I can then secure them to the top of the chassis. I won't have access to the bottom of the socket. I don't know much about PEM nuts, but I was wondering if something like that might work. I'm leary to try an adhesive, or soldering, etc. but maybe it might work, but I'd prefer a better solution. If someone wants to make me a bracket, that's a different story, but let's assume that's not a viable option either.

Just wondering if anyones tried Craig's teflon, pressure adjustable tube sockets? They're very $$$ ($70) but if I was building a 300B/2A3 amp using "the good stuff" parts, it wouldn't be totally out of line. http://www.eddiecurrent.com/Tube_Socket.html