Do It Yourself

I am in need of a preamp with some gain and I was thinking about a DIY tube preamp. Doesn't need to have crazy high gain as the power amps will have voltage gain as well. Right now what looks attractive is the K&K Audio active output stage. The level 2 kit comes with most parts including the OPTs. Looks like a fairly good design to me? If not any other suggestions? Preferably something that is well documented.

So birgir asked for this one, but truth be told, i have been working on it for quite a while, and i have a working prototype. Specs: DC to 200khz +0, -.2 db Slew Rate >350 volts per microsecond Thd < .01% Voltage Peak to Peak, Stator to Stator 2950 http://gilmore.chem....n.edu/togte.pdf This is not for the faint of heart. The amp actually can go higher in voltage by a bit, but anything over +/-750 for the power supply gets to be Very difficult to regulate well. The +/-250 is actually resistor dividers off the +/-750 Its the only push pull fully dc coupled electrostatic amp that i know of Since this schematic i have replaced the 2s3840 with…

So how difficult would it be to design an upgraded linear power supply for this unit? Something that might fit in a smallish Hammond case maybe.

I'm finally going to get back to some DIY projects. One that's been boxed away is the Bijou. Part of the reason is I want to get a case design going in my head before I get too far on the soldering. And the problem with this is I really am not seeing the kind of case I was hoping for. Oh well. Onward. My last ditch effort will be to use a fairly boxy-shaped HiFi2000 case. It is 12.20 x 11.02 x 3.14. My main concern, and the question for y'all: with this layout, am I going to pick up any RF with the transformer so close to the two amp boards at the front of the case? They will be about 6" away from a Hammond 370DAX . Here's a pic of the case size. Thanks! …

I'm modding an Adcom CD player for a member here, installing a pair of Colin's I/V boards (player is balanced), and am debating on how and where to connect ground on these to the main board and power. These boards have on-board shunt regulators, so I am tapping power from the main filter caps right after the rectifiers for the 2 +/-15V power supplies for the analog section on the main board. AFAIK, it is usually not a good idea to connect more than 1 ground per board. The options I see are: Ground the boards through the power connector Ground the input of the boards Ground the output of the boards Currently, I am leaning towards #1, thinking that noise from the shunt r…

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

So, I have some nice shiny TO-3 transistors. I'd like to make a PCB with these as output devices and some sort of way to transfer heat via flange that I can mount to a heat sink. I have to admit I've never used this package, so I'm curious.... assuming I cannot mount the can on the fin side of the heat sink (which would require way to much milling and effort), what sort of ways are there to deal with this? Second question, and not at all related to the above... any recommendations for a relatively low voltage CCS? Let's say 60V and 3A or so as extreme parameters. Thanks!

A mate at Auriculares posted the link to this article which may be of interest for you DIYers. Not being a DIYer myself I found it interesting nonetheless.

hi! i'm new here.. i'd like to ask for some help. diagnosis and repair.. i have a A4tech hu-200 usb headphone. now it only plays the right channel.. but before that happened i noticed that the audio is like panning from left to right til it could only be heard in the right. i researched about repairing headphones and all i saw is that the problem could be a loose wire or something similar but when i open my headphone there were no loose or broken wires. what could be the problem? and how do i fix it? i don't wanna send it to a repair shop cause i wanna see if i could repair it myself.

I was not really planning on going into work next week, but this has changed my mind. http://gilmore.chem....n.edu/ebony.jpg 1500 grams, 8 x 2.5 x 3.5 inches about 50 years old.

I'v decided to build a balaced M3 and I would like to see how others may have implmemented swithchable gain and different component choices. Thanks

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?

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

So it turns out that the lme49830 is pretty much a dynafet on a chip, with diamond buffers driving the fets. SO... combine with the semelab-tt lateral audio mosfets, and the result is something super sweet, and easy to build, about $50 in parts per channel. Combine 4 channels with my balanced preamp, and have one serious kickass thing guaranteed to drive anything, he6's and k1000's included. At about 2 orders of magnitude less distortion than that other thing. And more than 10 times the available output current. at... 20hz to 20khz... .1mw .05% thd (most of which is noise) 1mw .01% thd 100mw .005% thd 1w .0003% thd many watts <.0001% thd …

This has been needed for a while. For those with problematic DAC's that put out a bit of DC, and balanced headphone amplifiers happy to amplify said DC and produce differential DC on the output... http://gilmore.chem.northwestern.edu/protector.jpg This is the one case where ti kan's protection board does not work, unless you want to use 2 of them.

A friend asked me to come up with a phono stage that is of reasonable quality but not too over the top. Here's my first go. Basically, it is a hybrid cascode gain stage followed by a passive RIAA filter and a cathode follower. The idea is that the single gain stage should not only provide enough gain, but it should be reasonably quiet. The Zout is also governed by the plate resistor which keeps the filter stable even as tubes age. In a sense, it is much like Pete's pentode phono, other than that the cascode should be a bit quieter than a pentode. That's a lot of should's, so it remains to be seen whether it actually works. The only really tricky part I anticipate is se…

To all the owners of a transistor amplifier V3.0 from http://www.high-amp.de out there in the world. Here is a support how to update your amplifier to the version 4.0 that will be coming out soon. The items below are refered to the following schematic: http://high-amp.de/html/transistor_v3_schematics.html - replace the four resistors R07x and R08x with 51K/1W resistors to increase the current in the second stage to 4mA - replace the two resistors R11x with 200 ohm resistors to increase the current in the last stage to 15mA - replace the resistors R56, R57 by a constant voltage source as shown below (one per chanel) - If you are using the 2SC5466 in the last stage r…

Hey everyone, To make a long story short, some damage occurred to a b22 that I sold internationally during shipping. I know absolutely nothing about fixing it up, but from the pics he sent me I'm guessing it should be a relatively easy fix. Is there anyone with experience with b22s(it's a 2channel board) in the area of quincy MA (or anyone in general) who would be able to help him fix it (either in person or by talking him through it?). I would be grateful for the help, as the situation is starting to turn sour. Thanks for reading.

I normally use FMs in most cases, but I see that they have come out with the FR series which are supposedly lower ESR, higher ripple current and longer life? Anyone use these, or are FM good enough? Or other? Use for now would be in PSU filtering for an I/V stage.

ujamerstand had his university make up some of my version of the stax jacks, maybe he is willing to sell a few. I have 3 of the 6 pin teflon versions that i make left, i'm not going to make any more jacks this year due to lack of time. You could always plug the center pin with an appropriate teflon rod if you wish. Someone needs to organize a group buy and find someone in china to make a large batch of them, with REAL teflon.

I find myself in need of a sub - not room shaking high level bass but responsive low end. I have seen a few really good options about but they are all big cubes which have zero aesthetic acceptance from my better half. I thought of placing a low profile unit below the media rack and found a 3 inch long throw ( xmax still limited at 5.5mm ) and a horn loaded design which in theory should produce decent bass 25-100Hz. Anyone have any experience with subwoofers? My instinct tells me I need max surface area with large excursion to reliably produce decent low end but with the trend of things getting smaller in the modern world, I am open to accept that technology has succ…

Maybe keeping such things in one place will prove helpful? Maybe not. Anyway, to get the ball rolling, does anyone have a technique for removing a snapped off 4-40 tap from extruded aluminum side rails? Maybe the sort of kit one uses for removing stripped screws would work, but there is no head, essentially. Any other thoughts?

Ok, I have a quick question. So, I have some of these sockets, with brackets: I need to somehow embed a nut into the bracket, so I can then secure them to the top of the chassis. I won't have access to the bottom of the socket. I don't know much about PEM nuts, but I was wondering if something like that might work. I'm leary to try an adhesive, or soldering, etc. but maybe it might work, but I'd prefer a better solution. If someone wants to make me a bracket, that's a different story, but let's assume that's not a viable option either.

Just wondering if anyones tried Craig's teflon, pressure adjustable tube sockets? They're very $$$ ($70) but if I was building a 300B/2A3 amp using "the good stuff" parts, it wouldn't be totally out of line. http://www.eddiecurrent.com/Tube_Socket.html

Now that the PCBs are finding their ways to us -Balanced Dynahi Builders-, I think that it's time for starting a build discussion thread for this beloved amplifier. The purpose of this thread is to create a place for builders to discuss all topics related to the build of this amp (parts, constructions, troubleshooting...), to share experiences and to consolidate the information and discussions about this project. Schematics of the Balanced Dynahi and the associated Power Supply by KG. Background information about the original KG Dynahi can be found here. Based on the preliminary BOM posted by Lil Knight earlier, an updated version for the Dynahi and the assoc…