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Post pics of your builds.... - Page 636

post #9526 of 9594
Quote:
Originally Posted by mwhouston View Post

Looking very smart. Nice build. Some technical info please?

 

It started as a Millett Starving Student hybrid amplifier. It uses 12AU7 tubes as voltage gain and MOSFETs as current gains. The MOSFETs are loaded using the heaters of the tubes.

 

The transformer has a 30-0-30 ouput, which is what made this project possible.

 

I built a voltage multiplier identical to the one in the SOHA II, giving me ~180V at its output. This rail is regulated down to 138V using a TL783 linear regulator and powers the tubes. Each triode operates at 70V/2mA. Each tube has its triodes paralleled.

 

I built a high-current 25V rail for the MOSFETs from the same transformer taps, regulated using an LM317.

post #9527 of 9594

My latest project, a fun little headphone amp based on the Bottlehead Quickie pre-amp.  It still uses a low voltage 40v supply, but with plate chokes and output transformers. Works great with Grados :L3000:

 

 

post #9528 of 9594

Neat

post #9529 of 9594
Quote:
Originally Posted by mcandmar View Post
 

My latest project, a fun little headphone amp based on the Bottlehead Quickie pre-amp.  It still uses a low voltage 40v supply, but with plate chokes and output transformers. Works great with Grados :L3000:

 

 

Nice Flooring... i like the color...

post #9530 of 9594
Quote:
Originally Posted by 2leftears View Post
 

I built this headphone amp back in 1992 when I was a student.  It was very loosely based on the NAD 1020 pre-amplifier high output/ headphone section, but I made a lot of major modifications (Darlington output stage, switchable bias spreader etc.) so pretty much completely my own design.

Handsome little unit, nice work! 

post #9531 of 9594

A simple "Curryman" DAC, with a CM6631a USB receiver from Diynhk. Case is a Galaxy GX247.

 

 

post #9532 of 9594
Very neat. Looks pro.
post #9533 of 9594

The amp is finally "complete". Just have to add one more ceramic in the regulator board when the order gets here, but it isn't required for operation. This baby started singing a little while ago. Driven from the y2 and going into the K1000's  :D

Front:

Back:

Inside:

Another angle:

Case is from eBay, I engraved the panels in my DIY CNC machine so this was quite cheap to do (although a massive PITA). Transformer is a 50VA 2x15VAC (series connected) AntekInc toroid, with a steel case. The IEC module includes the switch + fuse + line filter inside of it. A ToliRegV3 regulator (obviously :D) set to 30VDC with a current limit of 1.5A. There is an amplified zener set to 35V as a protection in case something goes wrong with the supply voltage. There's a ground loop breaker bolted to the case, I went for the one with the diode bridge mainly because its easier to mount :)
M3 with 2.5" high heatsinks set to 140mA bias, OPA627 for all 3 channels. Gain is set to 5, a compromise between driving the K1000 to sufficient volume and using it with my other headphones. I was pleased to see that with this gain I get sufficient listening volume with the K1000's even when playing a quite recording from my Sansa Fuse player (used it for testing since it has a low output level). When using the y2 I'm mostly around the 1-2 o'clock position.
e12 mounted on the center aluminum plate I've added to the case. It was slightly too sensitive when playing music with lots of bass at high volume levels, so I've replaced R5-R8 with 33K to lower the gain at low frequencies.
Since all the input wires are shielded, and the transformer (which is itself a shielded transformer) is placed inside a steel case, there's no hum. Plugged in a pair of PX100 and rotated the volume knob from minimum to maximum position, no hum/noise anywhere.

post #9534 of 9594

That, sir, is a fabulous piece of work.

post #9535 of 9594
KT88: great work.
post #9536 of 9594

And here's a dynalo to match the DAC above  :D

 

 

 

 

 

post #9537 of 9594

I'm starting to get my pics changed for the net so here is a bit of eye candy.

This is a mic and stand i made to go with an audio analyzer i had built to complete my home system at the time.

 The rods are from discarded printers and scanners. Each section raises and lowers like velvet. And it is as sturdy as any mic stand.

This mic pre-amp i got off the net and have duplicated many times as it preforms great. Using a quad op-amp 1-for precision DC supply, 1-for mic/amp, and 2-for pos and neg over excursion monitor and display. It also has high and low gain settings.

post #9538 of 9594

I guess I will shamelessly post my beta here as well even though I already posted pictures in the beta thread.  

 

 

 

 

 

 

It is a 4 channel fully balanced beta with upgraded large heat sinks, 2 sigmas, 2 epsilon 12's for relay delay and protection, and a goindpoint attenuator.  

 

Of course it has balanced and unbalanced inputs and outputs as well as preamp out and speaker taps. 

post #9539 of 9594
post #9540 of 9594

This is how my QRV-08 ended up looking!

 

 

 

 

 

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