Do It Yourself

I'm getting ready to build up one of Colin's tooleaudio I/V stages to put into my Rotel RCD-991. This is a dual PCM-63P player with pcm100 filter. I have currently been listening to it modded with THS4031s for the I/V stage and AD8599s doing the buffer/bal conversion. stock output stage: U302 is the single I/V opamp, U306 is the buffer/conversion opamp (dual) and U304 is an anti-aliasing opamp (socketed now, but not populated. I am trying to decide whether to Retain the AD8599s as buffers/conversion Replace the AD8599s with different opamps Use transformers? If so what? Other? I want to retain the muting relay functiona…

Is anyone familiar with this "hacker collective"? [url=http://www.nycresistor.com/]NYC Resistor

I'm not sure if this is the right place but I guess DIYers should understand better whats going on inside the DAC. Basically the Northstar doesn't lock with the upscaling activated and just blinks wildly, If I turn off the upscaling before it starts blinking it will play without a problem but if I let a few minutes with it on, it goes wild and won't let me deactivate the upscaling. When this happens if I connect any transport it immediately does that even without music. Any idea what this could be and if it can be fixed ?

I'm about to give my M^3 a major overhaul - new enclosure, sigma 11 to replace the current tread power supply, and a possible cap upgrade. I've never found myself using the bass control much and am considering removing it. It's removal would seem to remove 1 pot and a few caps from the signal path, which might be a good thing to do, especially if you don't see the need for constant bass adjustment.

OK, here's the schematic for my crossovers, including the APOC protection circuit (at the bottom), which is powered by my amp, and is not battery powered: http://www.bwgroup-support.com/downloads/techmanuals/bw/802-TM.pdf Photos of the crossover appear here: http://www.head-case.org/forums/do-yourself/9007-b-w-802-series-80-repair-5.html#post404176 and here: http://www.head-case.org/forums/do-yourself/9007-b-w-802-series-80-repair-3.html#post402352 and here: http://www.head-case.org/forums/do-yourself/9007-b-w-802-series-80-repair-5.html#post404221 I can see which points to connect on the PC board to bypass the relay; that's no big deal. My questi…

I wasn't really sure where to post this, a friend at work has a set of K701's whose cable has apparently crapped out, can anyone offer any advice on who he might contact to see about getting them recabled at a reasonable price?

I had a problem with the last amp i built with pcb mounted sockets where the tubes werent straight (probably because the sockets werent parallel to the board. anyone have any tips on how i can get the sockets all mounted level so the tubes can stick out straight?

This amp (plus the matching tuner and a Sony reel to teel) has been sitting at my parents house for as long as I can remember, completely untouched. I was finally curious enough to open it up recently and it is really something special in a vintage kind of way, a germanium SS amp with output transformers. I'm not sure how old this is but late 60's would be a good guess. Now it is about the same size as the larger Stax amps so no powerhouse but I'm a bit interested in hearing it. So here is what it looks like on the inside: Here is the back panel, DIN connectors everywhere plus the output transistors: It is a pretty neat layout and the assembly is bri…

Hi, n00b here. Please dont get out your shovels or hammers, i'm just asking a honest question. I've noticed that the term "sand" has been used a lot in the DIY Forum when referring to semiconductors. Does this mean something along the lines that transistors and diodes are made out of silicon, basically quartz "sand"? Therefore: sand = semiconductor? Since semiconductors are generally not considered "passive" devices, maybe it could be a fancy acronym for Silicon Active Node Device? I've searched high and low and could only find this totally geeked-out reference: Self-Assembled Nanodielectric. Could this explain "sand"? Or is it something else? …

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…

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 it looks like the old B&W speakers are ok, which leaves pretty much only the amp as the culprit. Specifically, it seems like one channel is problematic. The sound it puts out sounds very very muffled, distorted, and scratchy. I opened up the amp and didn't see anything that to my untrained eye appears to be obviously kablooey. However, I did note that one of the fuses on the board looks different than the others. It's not blown but could that be it? Anyone see anything else?

My parents have an old pair of B&W 802 Series 80 speakers. I've read that these are still considered pretty decent, but I'm concerned about the condition these are in. I'd like to replace parts like the binding posts and maybe parts of the crossovers. How difficult is this type of thing? Could an advanced beginner DIYer do it? The speakers look like this (these aren't the actual speakers):

I have a powered USB hub that I'd like to get up and running. However I don't have the wallwart for it. The input is marked DC 7.5V 2.1A. If I can't located the original wall wart, what rating range would be acceptable to use with this thing? Or does it have to be specifically 7.5V 2.1A?

Hi Gents, I

Nobel Prize on physics caught my attention this year. I've been reading about graphene and its peculiar proprieties. According to Yu

I didn't find anything in search, which was surprising. Maybe I suck at searching. Anyway, a couple q's for those that own one or more: 1) How do vintage ones hold up? How often do they need recalibration? I'm not talking about serious vintage, with 50 tubes inside, but 1970s to 1980s solid state stuff. 2) Specific brands to look for/avoid? 3) What's the cheapest decent digital oscilloscope that can be hooked up to a PC? This or something close to it is what I'm used to using in the labs (yes I know it's a couple thousand... used): Digital Phosphor Oscilloscopes: TDS3000C Series > Data Sheets : Tektronix Specifically TDS3012B. 4) How useful/not useful has i…

I think that I'd like to get some flux to make things like tinning wires (in a solder pot) and soldering to connectors, etc. more easy. So could you please answer the following questions: 1. Do you use flux? 2. If so, in what form factor? Paste? Pen? Other? Thanks for putting up with my total DIY ignorance and for helping me out.

ok, I have plenty of stuff that needs to go. Perhaps you do too. I'm open to all offers and if you're patient, I'll probably just give it away. Once this stuff goes, I have another list... so.. no prices, please make an offer. Pair of unopened, and unused ports. These are the best ports money can buy I suppose: Measurement Mic Preamp boards and Zen Headphone amp boards: A collection of Brown Dog adapters: Turntable motor pulley: Random component video cable: Mogami headphone cable: Onzow Zerodust, barely used: Twisted Pear Audio Ballsie, first generation I believe: Chinese Softstart Board, works great: A pa…

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.

I'm in the process of putting together an Elenco XP-720K bench power supply kit. The kit has 3 ICs and 1 transistor in T0-220 package format. The instructions have the builder bending the legs 90 degrees and then mounting the devices on the heat sink. This seems normal enough. However, to hook wires up to the devices, the instructions instruct the builder to tin the wire and solder it to the correct leg. The instructions are here: Elenco XP-720K manual To me, this approach seems likely to result in a fragile device. Is this a normal thing to do? I assume that there are connectors I could use. Would it be better to use connectors. Or can you suggest yet anot…

My b22 has felt feet and is in dire need of something, anything better that will provide some lift. Also what version of loctite is safe to use on nuts, bolts, screws, pots inside the amp? Things were pretty loose when I got it and have been tightened but I'd like it to be a one time thing

Any easy way to remove the magnets from speakers? I have some little 4 and 5" drivers I replaced in one of my cars and would love to keep the magnets.

I just bought a 1lb reel of Kester 245 solder online and the date of manufacture is 11/30/04. The website says that their leaded solder 'goes off' after 3 years. Given this is almost 6 years old, should I return it or not worry about it and just use it? Slightly reluctant to return it as Kester is not so easy to get locally here in the UK and I wanted to buy a decent/premium product for my first forays into serious (non-disastrous) soldering.

I recently got a Nugget B22 that had been around so I gave it a good tightening and put it to work. Sounds great no issues there. However I have noticed that like the consumer PC speakers I have at work, it picks up Blackberry traffic and passes it through to the headphone. Has never happened to my KGSS in the four years I've had it. So the question. What causes that and is there any way to fix it?