OMG Alert not headphone related I added a subwoofer to my system ages ago and since then have played with various ways of integrating it with my main speaker system and now I'm plain out of ideas. - I've crossed it over really low, but my main speakers are weak in their bass, - I've...

I heard a snipet of this album on the radio last week and decided to check out the rest of it, so grabbed parts of it off the net. I liked the style and singing a lot and was thinking of buying the album, but there's something annoying about it. In all the tracks I have there's a tone in the...

The above circuit is actually the answer but I am trying to derrive it without SPICE using phasors. Call the top one R1, C, and the resistor to ground R2. What i'm trying to find is: H(w) = Vpre/Vin = (1+jw*z) / (1+jw*p). This is the actual simplification where Z and P are functions of R1 R2...

I have a perspex pannel on my amp which has been spraypainted on one side. Unfortunately a non-secured part rubbed against it during transit and caused it to bubble slightly. I think the only way to really get this fixed would be to strip the paint job and repaint. The problem ofcourse is...

Some of you may have noticed that I have talked a lot about DACs recently, having built one a while ago but never actually posted the design. I was going to post when I was finished but the DAC became a proto-design for anything DAC related. It now has 3 other boards hanging off it (usb, I/V...

Ok I designed it a while ago. I got around to etching the boards today, and I took a look at the ground trace. Something about the design does not smell good, just a hunch really. The basic idea originally was to make a TL431 based shunt supply. Then the idea was made to split it so I get +/-...

Ok finally it is done. I have always been a disbeliever of isolation in general, however for a turntable it did make perfect sense. I built the platform based on an article on TNT-Audio with some slight modifications for astetic reasons. Sides are pine with about 9 coats of black spraypaint...

Ok forgive me if this is plainly obvious but I am still sick so not working at 100% and yet not willing to let my DIY obsession rest for a week My new DAC output stage need +/-30V and I am trying to pull that without having to buy a new transformer. So Since the current transformer has 2x...

I have been wondering recently what some of the advantages of multiple opamps in a stage would be. What I mean is like an OPA134 followed by another OPA134, not by a dedicated buffer. I can only think of a few which is allowing higher order analogue filters, multiple feedback loops, biasing...

Ok for years I cringed while looking at threads like this, but every so often someone stepped up to the plate to help out, and now I am in a similar fix with parts. I need to order a Digikey part thats $2.50 and fits easily in a padded envelope. Asside from the handling charge the total cost...

I used to clean records with isopropyl alcohol however I've lost my only source of pure isopropyl. The only thing left alcohol wise is things like isocol which are only 70% pure and are filled with other things like antibacterial lotion and fragrances. I tried it once and the disc smelled like...

This isn't strictly headphone related but I've seen a few people here playing with bass boost / treble cuts so I may get a decent response. I've just built a subwoofer that I'm having difficulty integrating into my system. The sub is a standard sealed box with a linkwitz transform filter to...

I've got 2 projects on the way and I'm researching the best way to get a lovely gloss finish on both of them. We are talking almost pianogloss type finish, so really shiny. The Pine is standard shelving pine so it's untreated and very porus. I was actually thinking of staining it black, and...

I remember a discussion here a while ago about absolute phase. Well currently i'm in the process of building a subwoofer. It occured to me that a ported speaker will have a dramatically altered phase at the tuning frequency, and asside from a slight group delay this sounds almost identical to a...

A friend donated a "dead" 2x250watt poweramp to me the other day to "fix". I use the inverted commas simply because I undid the changes he made that caused the breakage in the first place. He really couldn't be bothered fixing it and just went out to buy a proper one. Anyway I replace the...

I've googled this a while now and I can't seem to find anything. What i'm looking for is a variable phase control circuit using an opamp, pot, and ofcourse any other components required. This will basically be part of a preamp for a subwoofer so a simple 0/180degree phase switch is...

I've been searching high and low both google and on this forum where i think i first got linked to it for a specific website. The entire website was dedicated to raising awareness of hot recordings, that is the modern method of squishing the dynamic range to get every last bit of loudness out of...

I've had my DAC fully working for about a month so it's time to start playing with it. I should really build the powersupply first but it's taking ages to get the parts. In the meantime I was thinking of playing with the output stage (currently and OPA627 + 2sc1815 follower), and I'm...

I've built a DAC which is currently running from my bench supply but obviously it needs some real power supplies built and I was thinking of customising each rail to it's needs. I need 3.3VL, 3.3V (for a PLL therefore very low noise), 5VA for the DAC, and +/-15VA for the output stage. I...

Forgive me if this has already been posted by I rarely venture into this forum. There's a viral advertisement going around via email. It has a lovely picture with 72 bands hidden (some more then others). It can be found here: http://pub.virgindigital.com/content...Area=S&ver=1.0 Some are...

Ok i'm not looking for anything like the Guido Tent XO-DAC. What i'm looking for is actually more like the XO-3's S/PDIF reclocking circuit. Something that takes S/PDIF in, reclocks it and sends it on it's way. Does any such things exist in the DIY world? I found the Kwak clock but that only...

Ok in 100000 words or less name all the sources of noise you can. GO. I'm trying to locate the source of a noise in my current balanced amp. The noise extends back to my main amp but I don't think it's a ground loop. Cases for ground loop: Main amp only makes ground loop type noise when...

I've just finished my DAC and as smooth as the midrange is there's still something a bit bitey about the treble. Since i've ruled out jitter (75 ohm coax properly terminated into Jocko's 74hcu04 input buffer took care of that) i'm begining to think it's something still on the output stage. Fair...

Ok there's 50ohm and 75ohm. I'm looking at the nonname brands that my local shop has. They have nothing written to say they are 75 ohm or not, so the question is how do I identify them?

I'm still trying to get my digital volume control working properly. It's based on 2x DS1802, controlled by a Rotary Quadrature encoder, and an LS7083 which converts the quadrature signal into low going pulses down and up on different pins. Fairly simple really encoder feeds A/B pins, as it...