Do It Yourself

For the bias voltage, I will be using a DC power supply I'm getting from Ebay: Bertan PMT-10C/N -1 kV 4mA Adjustable High Voltage DC Power Supply. Even though this supply takes in a DC input, the spec sheet says: "These fully enclosed modules are specifically designed with proprietary linear power conversion techniques to provide exceptionally low ripple and noise" Not sure how they can get a regulated high voltage from +24 VDC using "linear techniques", but in without using a switcher, but anyway, my question is: Is it necessary to ground one side of the bias supply? That is, connect it to chassis, U ground and audio ground? Is it necessary or useful for one …

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…

....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…

I'm just finished school about to be working as an electrician and my teacher swears by butane soldering irons. She's had the same one for 20 years. It looks like they can be used for melting heatshrink too. Does anyone have any experience with these?

For the Carbon I am building, the user would like to be able to bypass the volume pot, but would like it switchable for when the source doesn't have a volume control. I had initially told him no problem, this will be easy. The more I thought about it, I realized it isn't quite as easy as I had surmised. Simply shorting the input to the output (wiper) would still result in potentially bad things depending upon where the pot was in its rotation. Since I had already done the pot adapter boards for the gb awhile ago, I started with one of those for pcb layout (the pot I am going to use is a TKD CP2500 4 channel). My initial thought was to take the pot completely out…

I moved this from the build gallery thread cuz it was getting too far off topic. I am playing around with a Rotel 991 CD player and was going to replace the exisiting I/V stage with THS4031 and AD8599 buffers. My plan was to use Aries adapters and socket the opamps, with Pana FM 100uf caps as close to the V+/V- pins, and somewhere in the area of 1-3.3nf across V+/V-. I had removed the stock opamps, so I put a std. Mill Max socket in one of the I/V spots, and put the Pana FMs on the bottom, going from pins 7-3 (V+) and pins 4-3 (V-). The board has a top ground plane which would be a better spot to run these too than pin 3, but I felt I could get the caps closer to the …

A good friend of mine owns a McIntosh amp and pre-amp--both vintage, probably 1970s. My friend likes audio but doesn't know too much about the technical side of things (and no, my "friend" is not me). He needs some help with this McIntosh gear. My friend's apartment building caught fire and his apartment, though not burned, was totaled. His entire apartment was soaked through due to the fire hoses and smoked through due to the, well, smoke. The gear is now sitting at an audio store in NYC, and has been for a while. He has been quoted a "repair" of $2000.00 for the McIntosh gear and a Hafler amp. He does not have a good idea of what's going on with the gear, and he doe…

I'm still on my quest to build a large an powerful electromagnet. I'm wondering if I can put a non oscillating signal in one of the RCA jacks if my old crappy, "don't care if i blow it" amp will amplify the signal. Also how can I put in a non oscillating signal? Would a 1.5 volt battery work?

Looking for some one to build me 3 pin XLR's To Rca , or 1/4"'s to RCA to hook my Begringer DEQ2496 to my headphone amp. Can anybody help me out?

Hi all, Well silly me purchased a Dac Ah a year ago after reading some of the reviews over on HeadFi. http://www.pacificvalve.us/LTDACAH2.html I sent the DAC over to Reference Audio Mods for their full gundie mods and the experience has been less than satisfactory to say the least. The modded Dac Ah sat in my home office system and never got any serious play until recently and basically IT SUCKS! Any piano like Bill Evans or Monk sound very shrill, there is a noticeable suck out in the upper mids and bass is muddied. As I complained to another Head Caser it is as if the soundboard in the piano was replaced with ceramic tiles. Is there anyone out there who is willing …

Hi all, I purchased a KGSSHV recently, and whilst overall i'm very pleased with the sound, the pot installed is cheap and unfortunately has some balance issues at lower volumes. It looks to be a modular type pot, and bizarrely has 4 lugs per channel rather than 3. I've managed to get hold of what I'm told is a rather nice TKD 4CP 2500 pot, which has three lugs per channel. Can anyone offer some advice on the correct way to go about wiring it in? Looking at the old pot, there looks to be a set of bridged lugs on the far right which go directly to a piece of wire bridging the inputs at the back of the amp, as well as left/right input and output wires from t…

I think I'll ask santa for a good desoldering station this Christmas. It would be for through hole work, can anyone recommend one that works well for them?

I have an XP portable amp from MisterX that I got a while ago. It's set at a gain of 2 (I think) and its not powerful enough to listen to classical music with the im716s. Can anyone change the gain for me?

I got to thinking, that my source outputs PLENTY of voltage, so I could possibly get by with a headphone amp in unity gain, only suppling additional current. Is it possible to properly operate the dynahi this way? I am aware of how to change the gain, and fortunately dgardner socketed the gain resistor for me. My understanding of gain tells me that this resistor would essentially be bypassed to run unity gain, correct? The unusual nature of that setup is what made me wonder if it were possible. Certainly I could stick in a 100ohm resistor to get to a gain of 2, right? At any rate, is there any point to this? I figured that lower gain would equal less noise, since the v…

I know almost nothing about capacitors, but have it on fairly good authority that the frequency correction network on my old ESL63's uses an old Electrolytic-type capacitor which is not particularly good for this function, and should be replaced with a Polypropylene version at the same capacitance (220uF). Excepting the vast difference in size between these two types, what brands am I looking for? This cap is in the signal path, so quality is of the utmost importance. Voltage rating shouldn't be lower than 250V. It doesn't necessarily have to be a single 220uF cap - two 100uF caps will do the trick, and might be easier to place in the housing. Thanks for your help …

A friend and I are both building Pearl IIs. A sizable portion of the cost is capacitors. I don't have enough experience to have a well developed gut feeling for value or any favorite brands. There are basically three flavors we have to chose: big-ish electrolytics that smooth power, caps in the RIAA network that are between the signal and ground and two coupling caps, smack dab in the signal path -one is two paralleled film caps of small-ish value and right at the output we have what is specified to be a 22uF electrolytic, bypassed with a film cap. There's an armload of these things, so just buying the fanciest boutique brands all the way through doesn't seem like …

Hello, I would like to inquire about "caps in the bias supply" for Stax headphones. Spritzer and others said several times that "caps should not be used after the ballast resistor" (for example here: ) In this quoted case it refers to a cap in parallel after the ballast resistor. In other places the same is said about the cap in series, after the ballast ( What problems does the cap cause exactly, in that position? May I ask an opinion about the attached "blinker" circuit (with a series cap...), of which I read a long time ago; I have used one like this for a long time "without adverse…

Does anyone have measured dimensions for the Cardas GRFA DBL RCA jacks? I am trying to do a PCB and case layout, and Cardas doesn't give quite enough information away to actually accomplish this. Even better, anyone have an Eagle part library for these? Drawings for an alternative part from another manufacturer (Vampire?) that is of decent quality would be fine, too.

Per the drawing below, where's the best place to solder the ground wire?

Anyone ever tried them? If so, what setup worked best and how quiet were they? I've been thinking up logistics of the SRM212 I'm recasing with the new HV power supply. Thinking about using a small 40mm fan since the heatsinks I will be attempting to use (same ones as what I'm attempting to put in the mini Dynalo) aren't that big and I want to crank it to 10mA. I'll be using one per channel so 2 total and each will be dissipating around 11-12W. Guesstimating 4C/W rise on the sinks (no specs stated in the listing) that's around 75-80C on its own If it's 5C/W then it's really bad times.

I did a front panel and i want to order a case with it. I opened the order program and selected the Housing Profile 1. It only allows me to define the length. Does that mean FPE will follow the width and height of my front panel? Is that the true price of the casing? Anyone tell me how to get the case? I'm exploring my options. I have lots of solid wood and i was thinking of casing my b22 with it but im worried about the heat dissipation. I've been putting the casework off for a long time and i want to finish it before the bijou comes.

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

Where do I get started with case work? Obviously you get a case, drill necessary holes, and mount everything, but how do you pick cases and what kind of tools are necessary for plastic or metal?

Hey all , so this is my first post here so sorry if its not up to par. Recently i bought a Srm-006t amp 404 signature combo . I loved the sound but it seriously lacked volume . I replaced the tubes with a new set of EH tubes .. but aside from a uptake in tone .. I didn't get any extra volume . I started searching Google for mods to this energizer and came across a post by Kevin about a cascade mod for this amp and mention of an article in Audio Express July 2017 edition by James Lin. In the thread i was reading i saw that a board had been designed (im really not a fan of point to point electronics) and messaged Kevin Gilmore about it , He said he was all out…

I'm looking for something that adds basic control functionality to a computer IDE drive (pause, previous track etc). The front buttons are just eject and play/next track. Is there a simple solution for this?