Do It Yourself

just curious, has anyone tried using other tubes in the Blue Hawaii than the 6CA7/EL34? I ended up with a set of boards, and was looking at some datasheets over the weekend. I started looking at the 6BG6GE, 3D21A/WB/7403, 12E1, EL360, 6146, etc.... I started looking more at the 3D21A, but noted that the one major concern is that the transconductance is about half that of the EL34 which means that the gain will probably be about 6dB lower than the EL34, and depending on headroom in the cathode drive circuit this could result in significantly higher distortion. (Also, I might not get enough voltage swing without making other changes that would raise the source impedance …

Recently I purchased a B22 from Spritzer. The unit was built by Nate, so it's a nice Nugget Audio 3 boards + 1 Sigma 22, single ended, 8x gain unit, made to work on 230VAC. Apart from exquisite care to avoid hum and lower the noise floor, it features a dual input to select from two sources from a rear switch. Spritzer had changed this feature to a loop, so the switch was disabled and while one of the inputs is used, the other one works as an output. I point this because that switch resulted a handy addition. The amp works very well and sounds great with all of my cans, but as time living with it passed, I started to feel annoyed for the fact that being my so…

Some of you will remember my first turning on my new lathe that Vicki affectionately dubbed the Peppermill. Well the Peppermill has been repurposed, or should I say purposed. It's now part of a headphone stand for a Head-Fier that wanted a 4 phone stand. It's not finished yet, it still needs a few more coats of lacquer. I thought I'd post it though because it's rather unique looking.

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

I'm looking to get an inexpensive bench power supply, hopefully for less than $50. Can anybody recommend one. If not, please recommend the least expensive ps that will do the job. Thanks.

I remember reading in a post somewhere that Frank was nice enough to release his schematic for his DHT amp, the dynamic version not the electrostat version. I would like to take a look at it. I'll send him a PM at headfi as well.

hello people, i wanna build myself a decent headphone amp. so i thought maybe of building a supra. it uses 3 6sn7 or 6 (if you wanna do it balanced) did anyone do this before ? what are the costs ? does anyone has the schematics ? does anyone know a better amp for that price ? i know it is otl, and some are for otl, some are for trannies. i just don't know what i'm up to. i would use it on a akg 701 which i still have to buy. i need help guys, thanx a lot

I know some of the newer and cheaper Chinese digital scopes are all the rage (Keysight, etc.) I am toying with buying a refurbed Tek 2465A, completely working, for a decent price. I know these have a proprietary IC in them, that if it fails, turns these into a doorstop (though I seem to recall this IC being available now...). Good idea or bad? For some reason, I've always wanted one of these... Flail away.

Hi, Has anybody got a great idea for a really good power cable that's under about $50 in parts cost, including connectors? The new Woo needs a power cord. At the moment, it's attached to the wall with a spare 14/3 Belden. My past thoughts on power cords have been pretty basic - for-real adequately sized conductors and shield the living bejeezus out of it. I've had good luck with some nice star-quad plenum wire with the safety ground on the outside, a la the recipe on TakeFive Audio. I pulled one of those cords out of my living room system and tried it on the Woo. It was lovely. But nowadays everybody's into braiding everything. I've made some very nice soundin…

The left earcup snapped off. You'll see from the pics that there is a sort of ring or collar made of black plastic around a brass/metal part. That black plastic piece snapped. I'm not sure how modular these things are, but it looks like some Krazy Glue might do the trick. I welcome your suggestions.

Apologies if this thread already exists. I wonder if there are any experienced builders here, who would like to build an amp for me - for a good fee of course? I live in Finland, so EU location would be prefered. I am thinking about the current feedback amp, because I need to keep the physical size of the amp smallish.

Hello all, I'm working on a little project with my old SRD-6 energizer and a cheapo TA2020 amp. I'm trying to put together a compact transportable setup for my SR-5s. I have done a few modifications to this box already, such as wiring the transformers directly to the speaker taps on the back of the box and directly to the Stax socket on the front, completely bypassing the bias board and the loudspeaker switch. Those mods have done great things in terms of sound quality, but what I'm interested in now is modifying the bias circuit to operate as a self biasing one. As I understand it, Stax accomplishes this by tapping some of the output signal from one of the transformers, …

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…

As several people have asked for the PSU boards, and some whether caps are available lets probe the interest. Group Buy moving ahead - collecting payments, and then ordering. Please bear in mind that lead time is 12 weeks ... edit: added: "Group Buy moving ahead - collecting payments, and then ordering.", and price confirmation.

Hey y'all, I've lurked around here for a few years but now I'm planning on getting started building amps, and I could use a bit of assistance. I've never soldered anything and I've probably stripped a wire once, so I'm gonna need to ease into this. From what I've read here and on Innerfidelity the Bottlehead Crack or Torpedo would be good places to start, as they're simple builds and pair well with my HD650s. Any other suggestions? I read this plan on getting the Hakko FX-888 as my solder 'gun' and 63-37 eutectic solder. According to tangentsoft I need small screwdrivers, small cutters and pliers, and a wire stripper. Are any other supplies needed? After this…

As somewhat of a learning experience, I decided to build a PSU using the kgbhultraminipsV4 board (KGBH). All seemed to go well in assembly, and I tested every adjacent solder point for proper continuity, and ensured no cold solder joints. Used proper heat sinks on the silicon devices wires while soldering to avoid overheating them. Cleaned the board with 99.99 alcohol. I set the board up with 2x100v and 1xs150V zeners to output 350V. I plugged it into a 300V x2 transformer (smartly using a very long extension cord in the garage) it I got a HUGE pop. I was using 5W zeners, and when they go, they really go! It was the Positive side of the PSU. One zener totally evap…

Here's the APC H15 I got recently: I wanted black, but I got the silver for $200 less. Is there an easy way to paint it black? The face plate is some sort of metal. Any ideas about how to make it, well, less silvery?

I have my little lathe on order and it's a cheap POS cos I'm broke so the question I have is..... If you too were a broke cheap-ass, what would be the one chisel you'd buy for doing stuff like woody cups and the like? I can't afford much so It needs to be small enough for detail and tough enough for roughing out the basic shape. Suggestions?

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…

Hi All, I would like to mod my SRM007Tii so that it can use 6S4A tubes. However I am almost new in messing around with electronics circuit. Need some guidance from you all. Pictures below show my 007Tii board with re-routing & termination labels (Incomplete). I took quite sometimes to compare snapshots available online posted by Spritzer & Justin. All of them have slightly different wirings. The one I understand the most is the one Spritzer posted for the first time, so my preliminary outcome is similar to his one although it is still incomplete. Therefore I would like to clear my doubts before I start messing around with the PCB. This i…

Does anyone have or know where I can find a board that would let me mount a single or side by side Amveco PC mount low profile toroidial transformers? I'm just looking for a board that would have AC in and out going to terminal blocks and allow the use of standoffs. Amveco PC mount low profile 50VA toroidial transformers https://talema.com/wp-content/uploads/datasheets/70000K-72400K.pdf If not, I'd gladly pay someone for their time to lay out a board for me. Something like the pic in here

Frigate

http://nervenet.info/HT_delay/ I bought 2 of these to delay the HV startup of the megatron, I'll let you guys know how they turn out. Seems like a pretty nice drop-in

I did search but I couldn't find a dedicated thread about DIY electrostatics so in the spirit of getting the discussion started, here is something I've been working on. Well over a decade ago I bought up all the spare Sennheiser HE60 parts to assemble new headphones. The first thing to go out of stock was the main housing so to assemble the last pair, I had to adept a HD650 housing to take the HE60 drivers. Ever since then it has stuck in my head to make my own drivers for those housings and well... here is version 2.0: I bought a ratty old HD650 and completely stripped it apart. Headpad, earpads and cable went into the trash while the rest went for a l…

As many of you know, I for one have stopped releasing all new designs for a few years now after I got fed up with people building crap and claiming it was somehow connected to Kevin or I. Now this also means I don't release the PCB's for many of the older projects as I want to change something and often... make them smaller. So this hasn't stopped people selling crap with our circuits but at least they don't get any of the updates. Now here is an amp I saw come up for sale in Japan a while ago. The new owner contacted Kevin to try and trouble shoot it but yeah, we don't offer any real help with these things. Something about the PSU did peak my interest so when …