Digitally controlled preamp/headphone amp

[BrianDonegan]

Sure, send me an email.

The pot we are shipping in the kits is a cheapo Alpha 5K linear (single). It's quality isn't that important, as it is just a voltage reference for the PIC.

 

[Russ White]

So are any of you builders making any progress? I would like to hear some "reviews" of the preamp.

 

[hayenc]

Since you ask

Russ,

Finally got things packaged this weekend and will have some time to listen. Also just got a Benchmark DAC1 and am learning no amp is better than the source feeding it. Will let you know after some listening.

 

[hayenc]

And the Front view.

Sorry for the bad camera. Maybe Santa will be nice.

Cocobolo.

 

[earsandeyes]

the housing

As allways with these projects the right housing is the challange.
As things look now, with Sinterklaas behind us the coming weekend will be listening time.

E&E

 

[Russ White]

Re: Since you ask

Russ,

Finally got things packaged this weekend and will have some time to listen. Also just got a Benchmark DAC1 and am learning no amp is better than the source feeding it. Will let you know after some listening.

Good job Craig! I like it. I hope Santa brings your wish.

 

[hayenc]

One other little note. I replaced the kit pot with a 10 turn from BG Micro. No problem with sensitivity in setting the volume now.

 

[Russ White]

One other little note. I replaced the kit pot with a 10 turn from BG Micro. No problem with sensitivity in setting the volume now.

Wow! That should allow for ultra fine adustments. In reality though, there are 256 steps, so you will get 25.6 steps per turn.

 

[hayenc]

Yes, a bit of overkill with about 15 degrees per step, but it was what was available at a reasonable (under $10) price.

 

[troystg]

Mine is built and sitting on my desk awaiting the return or my Rev_C from Reputes house where he was testing it.

The Rev_C blows away his pre and amp combo in EVERY way except low end control. Bass is better on his amp but I think the small toroids in mine are the reason. I have a set of 400va 23v that I will drop in and try..

I was supose to get my Rev_C back this past weekend but it won't be until this weekend.

 

[troystg]

And the test speakers...

From this thread:

http://www.diyaudio.com/forums/showthread.php?postid=770636#post770636

 

[Algar_emi]

Hi Russ. Do you have the Eagle PCB file of the latest PCB. I would like to do my own.

Thanks in advance...

 

[Russ White]

Sorry Algar, I will not be sharing the eagle files yet, perhaps in the future.

 

[doggy]

update

Just got the preamp kit from the mailman this morning. I actually flagged him down on another street. If you are not home to receive the package; they make you go to the P.O. later after 6:00 pm to get it. All going well, hope to be assembled and in use soon.

cheers
doggy

 

[doggy]

chip direction

Just want to make sure about the direction of the chips on the pcb; does this look correct? Concerned about the op amps especially.

thanks
doggy

 

[Russ White]

Re: chip direction

Just want to make sure about the direction of the chips on the pcb; does this look correct? Concerned about the op amps especially.

thanks
doggy

:EDIT: no you don't, sorry had to look at mine. The opamps are reversed.

Cheers!
Russ

 

[Algar_emi]

No problem Russ. You shared your program with us and that is very kind of you. I'll do my own PCB using your PCB image.

Thanks again for all your work.

 

[Russ White]

Re: chip direction

Just want to make sure about the direction of the chips on the pcb; does this look correct? Concerned about the op amps especially.

thanks
doggy

Doggy, I spoke too soon. Your opamps appear to be reversed. I had to dig my prototype out of its case and look. The dot/indent on the opamp indicates pin 1, and the should match the "1" on the PCB.

 

[doggy]

Thanks for the speedy reply. There has been a lot going on lately in this forum. I hope to see you post frequently about your projects. I for one have not felt to happy about recent events here.

all the best
doggy

my next project: my mini-amp-planning of using lm3886 chips

 

[doggy]

Ah-ha!! I have erversed op-amps before, and guess what? poof!

cheers
doggy