kevin gilmore

The only difference between the he60 and the he90 headphones is the stator material. the he60 uses fairly standard fr4, and the he90 uses some kind of plated glass. But otherwise identical in every way. Same size and shape stators, same diaphrams, same distances etc...

all the servo parts in exactly the same place hooking up to the same point. Should work fine. Any 1.7 or 1.8V LED will be fine.

kerry's multiamp boards are a bit different than the production boards.

sometimes mouser is out of stock on some caps, so I switch to in stock items. very little real difference between ceramic and mlcc

http://gilmore.chem.northwestern.edu/dynahibal4.zip in case you have not already found it

dynahibal4 was the last version with all Toshiba parts dynahibal5 has Motorola transistors and tosjiba jfets and Toshiba duals

back when I was in college, Yamaha was selling an integrated amp that had a class A switch on the front. In class A about 18 watts into 8 ohms. Otherwise 60 watts. filled with jfets. Would love to get my hands on one again in working condition. The tracking power supply thing has been done over and over. Not saying there is anything wrong with it, but it has to be done right otherwise it sounds like crap.

headinclouds has his kgst working now, I assume he will post pictures. had to decrease the cathode resistor to 1.1k and is running 10ma to the tubes.

here is the ubaltobal board with the fets http://gilmore.chem.northwestern.edu/dsc_0597.jpg you can do the same thing with the fets to the multiamp and then you can have a higher input impedance and you can do the same thing to the ss dynahi. Now that the fets are available thru diyaudio in small quantities, this is an option again. the boards are 5.47 x 3.02 inches to get it much smaller everything would (and could be) surface mount but the multiamp does do about 3 watts pure class A and the output transistors dissipate a total of 4 watts, so if smt they would have to be heatsinked I tested turnon/turnoff thump and there just is not any

there is a picture of the ubaltobal board with the jfets. will post board size later

edit: all of my chips are ti made A versions work fine

There are a number of parts to the complete preamp/everything solution. One is this http://gilmore.chem.northwestern.edu/baseboardbal3.jpg (low res for now) Which is the balanced input switch board. For unbalanced you use the neutrik rca to xlr converters. Next is the unbalanced/balanced to balanced converter http://gilmore.chem.northwestern.edu/ubaltobal2.jpg although there is a new rev of this board. you build it with the jfets because the that340 has significant bias currents. Now here is the thing about this part, its completely NO feedback ultra low distortion (<.001%) extremely fast, and gain is controllable by one resistor. (very similar to ayre kx-r only lower distortion and otherwise better) Next is the smt step attenuator http://gilmore.chem.northwestern.edu/attenuator5.jpg 256 steps, .5 db per step, two for balanced which includes a balance control http://gilmore.chem.northwestern.edu/ssdynalobal.jpg Finally is the multiamp as the output board, and also unbal/bal headphone board All the pieces put together comprise a seriously kickass preamp/headphone thing. Verified recently with amb/linuxworks lcduino and standard code. i made a change in the input board to get this to happen. But i really want a production version with touchscreen, and wifi so if anyone wants to step up and help... use any or all of the pieces seperately as needed its sweet i tell ya

The way the servo's is currently done results in +/-1.5mv of dc output. If what you want to do is the se to bal conversion you want the specifically designed thing i did instead of this. And build it with fets to keep a high impedance.

i need to know what the version numbers are for the boards you have. way to many, and no idea which boards were the first GB. I switched to the motorola parts because in general the toshiba parts are not available, and they are not pin compatible.

happy birthday tyll

http://gilmore.chem.northwestern.edu/kgdynalobalssproduction.pdf r38 and r39 on my version its 255 ohms i think 200 ohms should be about right for 20V

on +-15V power supplies it will do about 30vpp balanced on +/-20v power supplies it will do about 40vpp balanced on +/-15v power supplies its 200ma per channel. would need to adjust the bias resistors to reduce the current for 20v. works out to at least 2.5 watts rms pure class A into 50 ohms

http://gilmore.chem.northwestern.edu/ssdynalobal2.jpg loving it with he6

you are missing the most important, and least important amplifiers!

Fine, I will squeeze the expensive 4.7uf film caps in... done

Those pictures are fakes and dalbani knows it. Don't ever buy from them. 2sa1967 real things have the cutouts at the bottom of the transistors just like the 2sa1967. Only difference is that the 2sa1967 has an exposed tab and the 2sa1968 has plastic tab. I have some real ones, which I may dig out later and take pictures of.

this is the production version http://gilmore.chem.northwestern.edu/ssdynalobal.jpg

only one set of input devices. this is unbalanced/balanced in, balanced out

if you are going to buy a bunch of transistors the dy294 from ebay is what you need and cheap

which chassis is that?