shit, I'm making a portable amp with NO volume control. gunna be thin son.

I have seen his prototype, people. Radical new technogly uses an inner gyroscope. To turn the volume, you simply tilt the amp left or right to lower or raise the volume accordingly.

Mac users would be on that like Mac users on Mac products, including some of the third party ones.

You should make a thermistor sticking out of the amp so you can stick the amp on different parts of your body for different volumes according to their respective temperatures.

Best idea yet -- then add a thermochromic element to the casing. And then add a chaotic factor for opalescence.

...because I feel a lot of hand holding is going to be needed to get people comfortable with the words 'digital volume control'.

I'm in.

..because I feel a lot of hand holding is going to be needed to get people comfortable with the words 'digital volume control'.

Which is a pity, when you look at the specs/performance of chips like the PGA2310 PGA2311 PGA2320 PGA4311

Imagine one of those on the GS-X (or a

Apparently the Crystal chips (discontinued) were much better sounding than the PGA23xx series, partially (or mainly) because the PGA series has a built in opamp which is essentially an OPA2132/4. I had a Coda preamp with a PCA2310 (IIRC) in it, and I thought a TKD pot was more transparent.

Apparently the Crystal chips (discontinued) were much better sounding than the PGA23xx series, partially (or mainly) because the PGA series has a built in opamp which is essentially an OPA2132/4. I had a Coda preamp with a PCA2310 (IIRC) in it, and I thought a TKD pot was more transparent.

Those kind of chips require a microcontroller and a 5V supply, so I think they're unlikely to be the ones used here. There are a few that will work with pushbuttons/toggle switches on 3V, no uC needed, so that seems most likely. But they're limited to 32 or 64 steps and don't offer more attenuation than a typical small volume pot

(or a

Naaman, what is that?

Three channel B22. Just waiting on the back panel from Cam-Expert to finish it up.

It's a beaut!

Three channel B22. Just waiting on the back panel from Cam-Expert to finish it up.

Any link or info on the controller setup used?

Any link or info on the controller setup used?

diyAudio Forums - New project : R-2R Attenuator With Remote Control V2 - Page 1

Nice thing is that it also can turn the amp on/off with a press of the source knob or remote control. Pretty slick at a really good price.

Three channel B22. Just waiting on the back panel from Cam-Expert to finish it up.

I was talking about the fancy display.

Thanks for the link and as usual, nice work!

I'd be very curious to hear your thoughts about that kit and how it performs. Reading that thread has always left me with kind of a mixed bag of impressions.

Edited May 12, 200917 yr by n_maher

diyAudio Forums - New project : R-2R Attenuator With Remote Control V2 - Page 1

Nice thing is that it also can turn the amp on/off with a press of the source knob or remote control. Pretty slick at a really good price.

Wow, that's a rather sweet price for the kit. The remote is included in the price?

At best, he can be using the same thing that I am, because nothing better exists.

Justin, glad you solved this one

Why did you decide against using the Silonex LDRs, with a thumb wheel pot, for example? Very compact and not "digital" and sounds fantastic.

remote is included in the price?

It is. The remote is just a large universal one. I plan on just programming my Harmony.

As for the price I do think it went up to $75 but it's still a really good deal. Another $40 or so gets you a balanced set up.

Very nice! I'm planning on trying my hand at creating something similar to the functionality of the twisted pear audio AC1. I reckon it should be an interesting experience learning to use the arduino platform.

Perhaps its time we start a misinformation campaign regarding new products.

I am personally thinking about "leaking" a new trend were people want larger amps. Maybe building a battery powered amp into a garden cart type set up. A rickshaw amp.

Then we wait.....

Justin, glad you solved this one

Why did you decide against using the Silonex LDRs, with a thumb wheel pot, for example? Very compact and not "digital" and sounds fantastic.

I've never heard of that before. I just looked at it, I doubt it would fit in this size enclosure and the current use is probably too high. I could have used a thumb wheel, but those have only been used in much cheaper portable amps (like the Airhead). Hard to convince someone to spend up to $400 on an amp with a thumb wheel, even if its just being used for a digital volume control

I've never heard of that before

I don't see why they wouldn't fit, the optos are around 6mm by 5mm or so. All you need other than that is a crappy pot, so a thumbwheel would work great, since it's not in the signal path. That's what I'd do at least. As for current draw, it's no different than powering a few LEDs... shrug. Same thing as the volume control in the higher end Melos amps of old, I'm surprised you haven't heard of it before.

I don't see why they wouldn't fit, the optos are around 6mm by 5mm or so. All you need other than that is a crappy pot, so a thumbwheel would work great, since it's not in the signal path. That's what I'd do at least. As for current draw, it's no different than powering a few LEDs... shrug. Same thing as the volume control in the higher end Melos amps of old, I'm surprised you haven't heard of it before.

Are there specs on max attenuation and channel matching? I know a thumbwheel would work as good as anything else, but it lacks the visual appeal thats needed. The Iq of the Pico Slim is 12mA so a few mA is significant

I think thumb wheels suck.

Are there specs on max attenuation and channel matching?

Depends how close you match the devices. 0.5dB is pretty normal, and 0.1dB is definitely possible for stereo operation. Attenuation, take your pick, -70dB is a reasonable amount.

Are there specs on max attenuation and channel matching?

60dB if your lucky, channel matching is totally conditional on how well the parts are hand-matched.

LDR's sound great, but they are fiddly as hell and probably require better system matching than most people will do. Melos used hand-selected parts for their success. The photentiometer used a full-on automotive dome-light bulb for light source: it could be replaced with an LED sure, but it would still be drawing tons of current to get a high attenuation.