Do It Yourself

I could use some help with a problem I have in my father's amp. It is an integrated tube amp, Sonic Frontiers SFC-1. The amplifier has a "direct" toggle switch, which sends the signal directly from the RCA input to the volume pot,and then has 4 inputs which go through an elna selector switch and a balance control. When using "direct" nothing is wrong, but when using any of the other 4 inputs there is audible distortion in the music. I went through the tubes, checked and replaced each one with some older ones and they seem to be fine, the situation continued. I've inspected the solder joints in the rca's and the elna switch andthey seem ok. the balance control is i…

Hey all, I am planning to re-case my Buffalo DAC using a 2U 300mm deep Pesante case from the HiFi2000 case group buy that is going on. For this case I was going to get some custom panels made from Front Panel Express or Cam Expert. Being my first set of custom panels, I am opening my designs up to any and all criticism for the cosmetic aspects...... and if anybody is really bored and has the time, some super-quick checks that I haven't borked any measurements (particularly for the mounting holes) would be greatly appreciated. Firstly, what the design is going to entail...... I will be buying the SPDIF Mux from Twisted Pear. This includes a 4 position switch detailed…

....so I bought one of these. They popped up on Massdrop while I was talking to Kevin who immediately called BS on this. My curiosity peaked, I had to get one. Here is the product page: https://www.bursonaudio.com/products/supreme-sound-opamp-v5i/ BS meter is tingling so I waited for it to arrive: Nice enough box and here are the internals: I forgot to take a picture of the top but it looks exactly as it did on the page. Here is the bottom though: The potting compound is pretty soft so here is what I found: So... the only thing in there is an opamp with the top markings sanded off and one small cap. There is noth…

Background: Just for fun, I'm going to build an energizer using a small Class-D power amplifier and a transformer. The inspiration was that I'm basically junking my recently-purchased and rejected Topping EHA5 and O can use the chassis and connectors. The rest I plan to junk. I bought a high voltage DC-DC converter for the bias voltage and a pair of toroidal transformers meant for a tube amplifier. The transformers are so big I may have to mount them on top of the Topping Chassis! For the amp I'm hoping that the Texas instruments TPA3116d2 Class D chip will do a good job. If I don't like the soun of this chip, I'm only out $10 for a populated board from Amazon!!! OK…

I finally stopped dicking around with psud and actually dead bugged this psu I've been mulling over. It's alive, and no parts were killed. Glad we don't have a cat anymore. Loaded it down, and it was pretty close to what psud predicted. Not knowing what the regulation of the transformer was, I adjusted the setting in psud until it matched the output, and it scales properly. Added a small resistor up front to bring the output down a bit, and I think I'm done. No electrolytics, with a shared C-L-C, then it splits into two channels, each having an L-C-R-C string. The output power tap is at the L-C jct, the gain stage tap is at the end. Rectifier is a 5V4GA I had on han…

Here a video guide I made on how to make a LOD, hope it will be of some help to some.

I just finished making the Wenge trim piece to overlay the damaged plinth on the Mitsubishi LT-30 that I bought a few months back. I'm happy with the way it turned out. There is a very slight lip that I milled that covers the top edge of the plinth where there were a few chips. Most of the damage had been at the corner of the plinth where something had struck it and crumpled the MDF. Here's a couple before and some afters...

my GF and I want to build a ferrofluid sculpture. We'll need a pretty damn powerful electromagnet to make it work. The problem is where the hell do we get a powerful but inexpensive electromagnet. I'm hoping that we can build one. Is this something that a total amature can pull off?

I would like to build my new balanced rig properly. Should a source have male or female XLR terminals, and again what should the amp have?

I'm trying to make a Super Symmetry Dynahi (not dynalo) the best possible way. (without getting in the ridiculous). Anyone could direct me to the up to date gerber files, a BOM, any other resources are also appreciated. Also if any of you previous builders have recommendation on best practices and what to avoid while making the susy please share ! Thanks

For the moment I have the beta and the EHHA amps, two boards each but only one Sigma. Until I get another sigma they are going to share. The sigma has four outputs, enough for the boards. Now, if I want to run both amps together is there any reason not to? I can switch on the heaters before the amps to warm up the EHHA. Any problems so far? Not ideal but I'm not worried about ideal at this point, just functionality. There's also the option of running the sigma output pairs through switches to turn one or the other pair off. Any thoughts on the best and safest way to do this or is what I suggested first fine?

BASS CAPACITOR Ok, someone explain what a digital capacitor is? Thanks.

Twisted Pear Audio (Russ and I) are holding a raffle to raise money for Doctors Without Borders relief work in Haiti. I have set up a page on our site here: Relief Raffle for Haiti The Grand Prize for the raffle is a complete kits to build a Buffalo II-based digital preamp. This consists of a BuffaloII module, IVY-II I/V Stage, Placid power supply kits for both, an S/PDIF Mux kit, a Volumite Kit for the BuffaloII, and a pair of transformers. We are also giving away the following runner-up prizes: An Opus S/PDIF (or USB) Dual-Mono DAC Combination A COD S/PDIF (or USB) Dual-Mono DAC Combination A Ventus Headphone Amp Kit Each raffle ticket is $10. 100…

Just been auditioning the Asus Xonar Essence One, and they sent me some of these Muses 8820 op-amps to replace the stock 5532s. My, this amp/DAC sounds pretty damn good for $599, and with the Muses ($899 is the price with these installed) it sounds very nice. Articulate, punchy, smooove! I likey. Anyone used these parts? Linky

Folks, I replaced all the electrolytic capacitors in my SRM-600. I can't say for sure if this has happened before, but this (photo) capacitor at 10V 4700uF is heating up. Not very much, around 55C. The headphones aren't plugged in. Can you tell me if this capacitor is in normal operation? Does it have to warm up? My SRM-600 for 230V voltage. First, I supplied a cheap Jamicon TKR472M1AJ26 capacitor. It was heating up.Then I decided to place EEUFR1A472L Panasonic Low ESR capacitor. However, it's warming up, too. I checked the diodes next to it - they're not broke. On the cap about 7V. Any other caps running cold. Only 4700uF/10V run…

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

So for various reasons that i won't exactly go into, i'm about to have a bunch of surplus stuff looking for an application. A bunch of programmed test sources signal generators. computer controllable. All phase coherent to the master reference source. http://www.programmedtest.com/pts500.html 3 x 1 mhz to 500 mhz generators 1 x 1 mhz to 620 mhz generator with dual outputs that can be inter-modulated 3 x 1 mhz to 300 mhz generators one with dual outputs that can be inter-modulated And some CW capable class A RF power amps 2 x 200mhz to 500mhz 50 watts 3 x 10mhz to 200mhz 300 watts As i said, looking for an application. So i contacted craig who is on…

I have a 30" Monitor that is awesome, but the Video Controller chip has issues with the Lead Free solder joints going cold and causing Video issues. The fix is for the board to be re-balled with Leaded Solder. Anybody know someone who could do this? Here's pix of the board: It's the Altera chip with the issue

I'm trying to learn MAGIC which seems to be the most popular open source VLSI layout program. Feel free to post anything relating to VLSI layout in this thread, perhaps something you bring up will be of use to me and others. Currently wondering if there are any other good programs, open source or not, and if there is something more GUI than command line based. I'm currently trying to run MAGIC off an SSH connection to my school's Unix server and it's giving me troubles so I'm going to go home and try it or just install MAGIC on my computer. Any good tutorials or examples would be nice as well, I'm currently following a set of tutorials by John Ousterhout.

Anyone else get the following email this weekend/today? modu Case made in Italy by Hi-Fi 2000 We would like our kind customer to know that the Galaxy, Slim and Dissipante series are now available in full aluminium see here modushop.biz and it is already possible to customize them. Click here modushop.biz Modu Staff A bit expensive, more of a jump from the standard pricing than I would have thought. Oh yeah, I got this email 3 times yesterday, and once (so far) today

I need to pick up three sets of tube sockets for my Dared 845 amp and I assume I need 2 pcb mount 12ax7, 2 6sn7 pcb mount (do they make a 7n7 pcb mount?) and a pair of 845 bayonet type sockets. I really prefer high quality over saving a few bucks. Any ideas on where to buy also ceramic and teflon is one better than the other? The reason I ask is I found a local tech here in the East Bay (SF area) that will do the work if I source the sockets. Great older guy who grew up in the radio and recording industry. Thanks in advance for any help that you can provide.

Hi: I just placed an order to have 10 sets of KGST boards made. A few of them are already spoken for but I should have 5 sets available to those interested. Here are some details: 1. The amp board is KGST6S4CASCODE (120mm x 135mm), the PSU is KGBHULTRAMINPSV4 (105mm x 134mm). 2. The boards are all 2mm thickness, 2oz copper, green silkscreen with white lettering. I wanted the thicker board that can better sustain the mounting and dismounting of the tubes. 3. I am using a PCB fab house in Taiwan which was recommended to me but I have no prior experience with them. 4. JimL has traced the cascode CCS part of the KGS…

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…

I've been messing around with a Counterpoint preamp I have owned for several years on and off. It's always had a slight amount of hum, not real bad, but it bothered me. Over the years I've managed to make it worse, and then much better, but never quite gone completely. After dealings with a couple of former service techs on diyaudio, I finally decided to try once again to rectify this. I was prodded to look at the PSU, particularly the heater supply (I'd already done some work and parts replacement in the HV section). Looking at the heaters, I had recalled seeing some ripple on them back when I rewired the umbilical (both before and after). About 50mV of r…

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