Digitally controlled preamp/headphone amp

Status
Not open for further replies.
Jump to Latest
#283
Russ,
Nice work, I received my kit and assembled in 1 ½ hr no problems. I will test in a day or two. I am inspired by Doggie’s case work; I am planning to use your selector board in completed unit and would like to build case in advance. I was wandering if the vandal illuminated switches would be compatible with the selector’s interfaces.

Thanks Bill
 
#284
wirewiggler said:
Russ,
Nice work, I received my kit and assembled in 1 ½ hr no problems. I will test in a day or two. I am inspired by Doggie’s case work; I am planning to use your selector board in completed unit and would like to build case in advance. I was wandering if the vandal illuminated switches would be compatible with the selector’s interfaces.

Thanks Bill
Click to expand...


Hi Bill, Thanks for the kind words, I am glad it went smoothly so far. 🙂 Lets hope it stays that way. 🙂

As for the source selecttor it is too ealry for me to comment on which parts will work, because the design is still being developed, but as it is currently any momentary normally open switch would work.

I will post more details as that project progresses to completion. 🙂

Enjoy your preamp. :drink:

Cheers!
Russ
 
#285
almost finished

Phew! Don't think I want to do any soic chips; at my age they are getting hard to see. Also exactly what is the purpose of the jumper? my preamp wouldn't work without it. I still have do get a better switch but itis playing well. I will let it burn in for a while.

cheers
doggy:drink: :xmastree:
 

Attachments

  • 2005_1211kookaburra0007 (custom).jpg
    2005_1211kookaburra0007 (custom).jpg
    26.4 KB · Views: 1,072
#288
Re: almost finished

doggy said:
Phew! Don't think I want to do any soic chips; at my age they are getting hard to see. Also exactly what is the purpose of the jumper? my preamp wouldn't work without it. I still have do get a better switch but itis playing well. I will let it burn in for a while.

cheers
doggy:drink: :xmastree:
Click to expand...


Which jumper do you mean? 🙂

If you are referring to the 0R JGND that is simply used to provide a very slight resistance between the audio ground plane and the digital ground plane as per the PGA2311 datasheet. 🙂 You can also use something like a 1R to 10R resistor there which I have tried with success. The noise is so low in any case using the 0R jumper is an excellent option.

There are two more jumpers, but those are omitted if you are using the input buffer. 🙂

I am glad your preamp is working well. Enjoy it. 🙂

Your case is nicer than mine. 😀

Cheers!
Russ
 
#289
case

I learned something on this last case: bronze is tough but also very ductile

I also cut it with my table saw. The forming, to get those nice corners, I cut a groove with the carbide saw blade on the backside 1/2 the thickness of the 1/8" plate. Then I clamped the plate in my workmate and bent it by hand.If I say so, the bends and corners turned out perfect; better than a press brake could do, plus no damage to the front face. Just wanted to pass this along; I am still learning!

The preamp sounds really good and it can only improve. Thanks for this gem.

Any interest in a R.W. phono stage?

Cheers
doggy🙂 🙂 🙂
 
#292
Finished Preamp

Well it's finally done. It tested the limit of my soldering skills. I used AD8620's for the input and output buffers; getting them soldered into place was really interesting.

My original setup was Sony CDP ES series (using the volume control line out) to BrianGT LM3886 power amp to modified Thor speakers. The sound was very good indeed. Then I used the non-volume controlled line out on the CDP to the "DC" Preamp. It's only been playing for about two hours, but I am amazed at the brightness, detail and the sound stage; not tremendous change, but definitly better. IMHO it is well worth the effort and $ to build this gem!

Thanks to Russ and Brian D for all the help.

Ps The only thing I would do differenty would be to use a ParMetal enclosure rather than a Hammand; the ParMetal has more utility and I think looks better.

Bob
 
#294
Hi Troy,

I used Vifa D25AG-35-06 metal dome tweeters instead of the Seas. I modified the xover using 2nd-order Linlwitz-Riley; corner frequency of 1800Hz to take advantage of the Vifa's specs. The enclosure is traditional Thor, not fat-Thor. It's been playing for a couple months now and I'm very satisfied.

Bob
 
#299
-> Russ White
I found those connectors at a fleamarket a long time ago, i think it is Stöckli-brand.. (German make?) too bad my supply is running low..

Here is my setup to finish up my picture-spamming with 😎
 

Attachments

  • setup.jpg
    setup.jpg
    58.5 KB · Views: 1,032
#300
Russ/Brian-

Is my AD op amp oriented correctly?

If not just send me another board (and invoice) and I will start again from scratch.

I got my Rev_C back yesterday and went to install my Kookaburra(*) and realized I have the voltage regs backwards... 🙁

I removed them and figured I better ask about the op amp before I go any further.

Edit: * I recently found out the "locals" of the Kookaburra call it the "Laughing Jack-***". No joke!
 

Attachments

  • picture 028 (medium).jpg
    picture 028 (medium).jpg
    99.5 KB · Views: 1,020
Status
Not open for further replies.
Top Bottom