dsavitsk

Guys -- I could use some help putting together a new living room computer. This started out as thinking a mac mini running win32 would be OK, then thinking that new Dell thing would work, and as always happens, has devolved into building a system myself. I am basically looking for small and silent -- totally fanless if possible. Probably a solid state drive, though the dvr already makes enough noise that this might be an unnecessary luxury. This will get used for watching Netflix and other downloadable TV, playing music, and RMAA testing. It will also be used as a headless workstation via remote desktop -- in order to avoid digging through and updating 100K lines of old code that I maintain, I basically need to be able to run two different versions of Python, and the easiest way I have found to do this is to just have two different systems, one of which I can run remotely. The video stuff probably requires a decent video card, but nothing spectacular (it will connect to a 32" 780p TV). It is conceivable that a USB Blu Ray drive might be added someday, so enough power for Blu Ray playback would be useful. Music will be via winamp mostly, and the files all reside on a NAS in another room. Optical drive of any sort is sort of optional -- all it would get used for is installing software (for which an external drive is fine) and ripping CDs, which can be done on another computer. For RMAA, a decent soundcard would be useful (probably an audiophile 2492 or 192). Built in sound that would just be for TV might also be a possibility as I can use a USB card for music/RMAA. I'll probably run XP as I have extra licenses and no real reason to "upgrade". I also think keeping the PS outside the box would also be good. I think this might mean miniITX, but I am lost in all the different models and specs, which is why I need the help. For cases, I found this review of the Coolermaster's Fanless TC-100 mini-ITX case | silentpcreview.com but the cases don't seem to be for sale anywhere. They also make a "Cube" and a TC-100A that both look pretty good, but are also unfindable. More available are the Serener Fanless Cases For those, I am not sure what I am looking for in terms of mobo - they mention heatpipes for Via motherboards, but not whether those work with other motherboards. And, I don't know whether Via's are worth trying, or if they are even fast enough. Any suggestions?

Yeah, well, I doubt there is anything that will work with every amp. But, you can probably come close. Pretty much any off the shelf amp can drive a 300 ohm headphone. So, with a 300:32 step down and you can probably get decent results.

I take that back. It looks like power transformers on both sides, and tubes in the middle? Does it really take 2 power cords? Odd. Anyhow, it looks like a solid state bridge rectifier sunk on the side and a CRCRC filter for B+. It also looks like AC heaters. Either of those could cause hum. To lower B+ ripple, you could add a choke -- it will not only reduce ripple, but it will also take some edginess off the sound. Heaters are a little harder as the 6080's draw a lot of current which means big diodes and a lot capacitance. It is also tricky to get 6.3VDC out of a 6.3VAC winding. Honestly, I'm not sure I'd bother.

It looks like it's already transformer coupled. The proper solution is to just fix the hum. It could be power supply noise, heater noise, grounding, or magnetic coupling.

Why? That's all a parafeed amp is. Or the Maple Tree stuff. Or the L'espressivo. It's just a matter of using the right transformer.

I think you listened to an amp of mine using this sort of pot at the Chicago meet, if that helps you believe that it works.

The spikes that came in my old B&W's were the same spikes I used to put in the bottom of my shoes when I ran CC -- they helped me run faster, so I assume they'll make your speakers respond faster, too ...

It's called a Gaincard Amplifier

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

Nothing magical from me -- I've used these but I can't vouch for the quality. Realm of Excursion - Audio Downloads I've also downloaded tone generation software and used it to make tones -- but I can't remember which software. Oh, and I have one of these:

Immigration Lawyers: Find Attorney, Lawyer, Attorneys, Law Firm, Law Firms

Maybe this will help

Ryan is borrowing Asr's Ayre, and since he was over to pick up an amp last night, we gave the Ayre a quick listen. Basic impression was that it was OK but not great. It was a little flat sounding, and there was an overall fuzzy and unfocused nature to the sound. Bass was there but mushy. At it's price point, I'd guess that it is an OK deal. To be fair, we didn't do any special computer optimization. Just plugged it in and played FLAC files through Winamp. Though, another USB DAC that just uses a simple USB to SPDIF converter sounded better. That isn't to say that the digital signal was better, but rather that IMO the analog is more important to the overall sound, particularly when there are plenty of easy ways to clean up jitter. So overall, while it didn't sound bad, if I'd just built a DAC that sounded like that, I'd probably keep working on it.

Yes, a glob of epoxy will fix that, and probably make it stronger than it was to begin with. But, use a 24 hour epoxy -- not one of those quick set types. Also, don't be tempted by the Gorilla glue as it expands as it cures. Finally, get a small clamp to hold it while it sets -- it will need to be held firmly for a long time (hours) to make a good bond.

They look a little like the headphones used for hearing tests when I was in elementary school.

This one was there which I hear was very nice

Welborne hasn't actually sold those cases in years. I once posted to AA that I was looking for someone to make a few wood cases for me and ended up getting about half a dozen emails of willing builders.

The Straight Dope on Dr. Bronner

Most datasheets list a max plate voltage above which arcing may occur. Indeed Question #1. What is the major error in that article? -d

Other than that little green wire being suspicious, I'd doubt that the DAC is the issue. Maybe the USB to spdif converter? what happens if you connect to the dac with a usb to toslink connection instead? Is your wall grounded properly, and does everything, including the dac, have a connection to safety ground?

I've seen this with improperly grounded input connections to a spdif receiver. Can you post a picture, or a schematic, of the dac's input section?

sure -- use carbon comps. Either vintage from AES or Ohmite Little Demons from Digikey. replace the first 1K5 resistor with something like a hammond 154G err, well, there is an issue which is that the Z out of the preamp is like 50K and won't likely do a good job driving the transformer's inductance. I think you should either work another tube in there (6T4 perhaps?) to lower the Z out so it can actually drive something like a cable, or the next stage, or you should switch from the 12ax7 to something with a lower rp -- maybe a 12ay7 or 12at7. The former will increase the signal a bit -- more than the 6db you were looking for, while the latter will lower it. You'll need to make some other changes to do the latter, however. Oh, and a 0.1u coupling cap will be too small in either case But, assuming you do lower the impedance, on the primary you would connect out to + and - to ground (or the cathode if you like), and leave the input ct unconnected. For out, the "right" way to do it is to connect the + and - transformer taps to hot and cold, and connect the chassis (now grounded to safety ground) to the "ground" pin on the xlr.

Tubes and caps are the most likely. It is possible that resistors have drifted, but it is doubtful they have drifted that much. Really, I'd guess you are just used to the sound and that it is not as good as you once thought Or, maybe your pickups are dying a slow death. But, the schematic is too small to see clearly. If you want to quiet the noise, replace one of the resistors in the PS with a cheap choke -- it'll do wonders. particularly since you plug an instrument that you touch in to this, that should be fixed asap. You have a misunderstanding of what "balanced" means. All those amps and cd players that give you an extra 6db when balanced do so because they are really bridged which doubles the circuit. If you want 6 db more from this, buy another one and use them both at the same time. If you want a balanced output, use an output transformer -- Edcor would be good here, something like the XSM10K/10K would likely work well and could just be bolted to the output. The best guitar amp forum I know is http://www.ax84.com/ Diyaudio tube section is also pretty good.

Jam On It