Pitchfork pre-amplifier

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#21
i will follow along to see what you guys decide, see what I can add.
i should throw out there that others have expressed that they prefer the cirrus cs3318 vol control over pga2311. Some have reported pga2311 latch up. i have no experience with that problem.
i posted my pre-amp design in the other thread, so no need to post here again.
Slewmaster - CFA vs. VFA "Rumble"
I see you settled for the 1794A , Jeff wants the mobile 5102 ...
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well that was choice back then, not sure if I'd chose it now, but there are good reasons to stick with TI parts.
I usually do not design nor recommend to design something new with a part that has a "NRND" status!! unless ther is absolutely no other option.
LME49600 looks to be a nice part to use as well for a headphone buffer. does anyone find a need for a separate vol for the headphone amp/buffer vs the main pre o/p?
my idea for my pre-amp was all one pcb, no or minimal wires. once your start adding chinese pcb assemblies to the equation I lose interest really fast.
so lets see what feature sets everyone can agree upon.
 
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#23
rsavas said:
i will follow along to see what you guys decide, see what I can add.
i should throw out there that others have expressed that they prefer the cirrus cs3318 vol control over pga2311. Some have reported pga2311 latch up. i have no experience with that problem.
i posted my pre-amp design in the other thread, so no need to post here again.
Slewmaster - CFA vs. VFA "Rumble"

well that was choice back then, not sure if I'd chose it now, but there are good reasons to stick with TI parts.
LME49600 looks to be a nice part to use as well for a headphone buffer. does anyone find a need for a separate vol for the headphone amp/buffer vs the main pre o/p?
Click to expand...

I could ask the moderators to move that post here. They were most gracious
to rename my thread title screw-up.

I'll look at the cs3318 , and who listens to the headphones / main system
at the same time ? :scratch1:

OS
 
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#25
a really cheap solution is a maxim max9723, i used the now obsolete max9729 in my portable, it works really well but might be too much low-fi for the purists 🙂 the specs and performance say differently.
I could as the moderators to move that post here. They were most gracious to rename my thread title screw-up.
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sure, good idea or i can just re-post it again that is if you think it is of use.
could even consider max14778 as cost effective analog mux, another low-fi solution 🙂
okay pcm5102a is the replacement, i will take a look at it tomorrow.
 
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#26
rsavas said:
a really cheap solution is a maxim max9723, i used the now obsolete max9729 in my portable, it works really well but might be too much low-fi for the purists 🙂 the specs and performance say differently.

sure, good idea or i can just re-post it again that is if you think it is of use.
could even consider max14778 as cost effective analog mux, another low-fi solution 🙂
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Nope , a OPAxxxx buffered by the 49600. Only the best !

That combo "blows" the blowtorch ! 😱😀

I looked over your DAC. I (we) only need coax/toslink , and maybe usb.
Don't need 8 (maybe 2) ... to switch between digital sources.

I also notice some novel ways you embellished the power supply using
two LM317's in series to get better performance.

PS- you won't see no Chinese integration here ... all "in-house".

OS
 
#28
I'm down for whatever DAC you think will work. I just prefer to use something easily available to everyone. I have my doubts there will be an audible difference in any of them. PCM1794A looks neat with the output buffer. They aren't terribly expensive so the dual mono option might be worth looking at too if you want to go for the ultimate specs. It will depend more in the implementation than parts selected.

I've seen SS signal relays somewhere. I'll do some digging and see if I can find them.
 
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#31
I looked over your DAC. I (we) only need coax/toslink , and maybe usb.
Don't need 8 (maybe 2) ... to switch between digital sources.
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sure, the cs8416 is 8 ch so i used them all. the whole design can be scaled

Nope , a OPAxxxx buffered by the 49600. Only the best !
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agree, if i was to go at the pre-amp design again, i'd use this solution instead of what i used. my headphone amp design was taken from this pre-amp design featured in audioexpress a few years back
http://www.a-and-t-labs.com/K12_Preamp/index.htm

I also notice some novel ways you embellished the power supply using two LM317's in series to get better performance.
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i never did test it out, remember walt jung talking about pre-regs to get better psrr.

i find when i design these projects, the mechanical design is a big challenge. it can get costly and difficult to get a pro look. i did a rough design of the front/rear panel in frontpanel express, but they are costly to use.

As for the display, i used the newhaven 4x40 character lcd with blue backlight in the portable
NHD-0440WH-ATMI-JT# Newhaven Display | Mouser.

PS- you won't see no Chinese integration here ... all "in-house".
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that's the spirit 🙂

another newer option, more expensive, is a FT800 graphics LCD
FT800 Embedded Video Engine (EVE) - FTDI | Mouser
one heck of a lot more coding too.
 
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#33
i thought that lumex are more expensive and less available than the newhaven. the blue backlight is nice and i even have the encoder leds lit up for dark room application.
i have my newhaven running off 3.3V as i used a xmega.
i used the bottom row as my menus for the 6 encoders, it makes life so much easier. i am displaying rbds radio information amoung other stuff like temp/humidity, air pressure, stuff i forgot to mention as additional features.
 
#35
#36
I just have one of these laying around here.
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sure that makes sense. i put my info out there as to what I have done and what i got working reliably. it really depends if you want to cobble something together with what you have on hand or something that everyone can do.
There's an Arduino library already written for a 2x16 display with a Hitachi driver. Saves a ton of coding.
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I am aware of this too, I wrote my own asm code to use the busy bit to speed up the display routines. I am using MCS bascom-avr compiler, it works like a charm. I bypassed ardunio hw/sw for many reasons. i would not recommend to design using mega or other lower grade parts, esp if you want to add internet connections, you want a path to the largest and fastest mcu, xmega is where it is at using 3.3V logic. everyone has choices to make in there design decisions, it is hard to get conscensis esp with many people stating what they want as far as feature sets go.

you have to wonder about a company like ESS for DIY stuff, when they make designing with there parts difficult. like where are the datasheets and app notes? I have to sign an NDA with them to get any info, what's with that?
 
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#37
The fortune cookies say this project will fly.😀

I'm not a fan of dropping bits for volume control either. It makes the music go lifeless. I'd rather attenuate analogue.
 

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#39
rsavas said:
sure that makes sense. i put my info out there as to what I have done and what i got working reliably. it really depends if you want to cobble something together with what you have on hand or something that everyone can do.

I am aware of this too, I wrote my own asm code to use the busy bit to speed up the display routines. I am using MCS bascom-avr compiler, it works like a charm. I bypassed ardunio hw/sw for many reasons. i would not recommend to design using mega or other lower grade parts, esp if you want to add internet connections, you want a path to the largest and fastest mcu, xmega is where it is at using 3.3V logic. everyone has choices to make in there design decisions, it is hard to get conscensis esp with many people stating what they want as far as feature sets go.
Click to expand...

I suck at coding so I go with what's easy. I've got a Chinese PGA3211 pot with a 2 line display that does all I want to see and control but it starts up on and loud when power is first connected and it's really a POS.

These 16x2 displays are only a couple bucks now. I personally don't like big displays and flashing lights on my audio equipment. The little screen should light up and show any adjustment I've made, then a couple seconds later the backlighting should shut off and stop annoying me. If I were to put a larger display on, I would want it to be a touch screen so there wouldn't be any switches on the front at all.

I'm not sure what OS has in mind. We'll have to wait and see.
 
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