JDS Labs C5/C5D (pg96) portable amp/amp+DAC

[jseaber]

Quote:

It is strange, but from JDS Lab's C5 blog post:
Looking more closely at the press release photos, all of the C5's have the switch in the up position.

 
The switch position was a choice of performance over aesthetic intuition. I wanted bass boost Up, and normal audio Down also, but that analog path used the longer set of legs on the switch. It's important to keep pathways short in this section of circuitry.

Bass boost is hardware from what I know

 
Correct. A switch also yields greatest performance. We did two prototypes with digital pots in place of the toggle switch, but there's no true "off" state. The wiper presents a small amount of resistance even at minimal position. Thus, bass boost could never truly be turned off in the chosen circuit, and you'd experience an extremely small amount of phase and frequency response manipulation. So we went back to a DPDT toggle to control bass boost.
 
We released firmware source code for the benefit of the DIY community. It's not intended to manipulate SQ.
 
 

Are all other JDS products shipping prolonged due to the preorder queue of the new C5?

 

No way! We stay on top of incoming orders. All in-stock orders placed through Friday afternoon have already shipped.
 
25% of C5 preorders have also shipped by now. The remaining 75% will be fully tested and ready to ship as soon as the second round of cases come back from the anodizer (Wednesday).

 

[miceblue]

Quote:

Quote:

It is strange, but from JDS Lab's C5 blog post:
Looking more closely at the press release photos, all of the C5's have the switch in the up position.

 
The switch position was a choice of performance over aesthetic intuition. I wanted bass boost Up, and normal audio Down also, but that analog path used the longer set of legs on the switch. It's important to keep pathways short in this section of circuitry.

Bass boost is hardware from what I know

 
Correct. A switch also yields greatest performance. We did two prototypes with digital pots in place of the toggle switch, but there's no true "off" state. The wiper presents a small amount of resistance even at minimal position. Thus, bass boost could never truly be turned off in the chosen circuit, and you'd experience an extremely small amount of phase and frequency response manipulation. So we went back to a DPDT toggle to control bass boost.
 
We released firmware source code for the benefit of the DIY community. It's not intended to manipulate SQ.

Sounds great! It's cool to hear that you did try it out, but opted out for performance instead of aesthetics.
 
As for re-programming the C5, on the blog it mentions that a 6-pin header and an ISP programmer are needed. The SparkFun webpage that is linked mentions that the 6-pin cable is included with the ISP programmer. I haven't used Arduino before (first time learning experience! ), so I'm wondering how does one connect the C5 to the Arduino? I can't really tell from the photo on the blog how it's connected.

 

[ClieOS]

It starts to get weird when people are concerning which direction of the switch is bass boost or not

 

[luisdent]

It starts to get weird when people are concerning which direction of the switch is bass boost or not

Yeah, we're not particular about things at all here at head-fi are we?

 

[jseaber]

Quote:

Sounds great! It's cool to hear that you did try it out, but opted out for performance instead of aesthetics.
 
As for re-programming the C5, on the blog it mentions that a 6-pin header and an ISP programmer are needed. The SparkFun webpage that is linked mentions that the 6-pin cable is included with the ISP programmer. I haven't used Arduino before (first time learning experience! ), so I'm wondering how does one connect the C5 to the Arduino? I can't really tell from the photo on the blog how it's connected.

 
The 6-pin ISP header is unpopulated. See "JP1", near the bottom left corner of the battery:

 
 

Spoiler: Warning%3A%20Off-topic%20engineering...

 
There are two ways to interface an Atmega chip:
1) ISP, via 6-pin header
2) Serial pins, usually via FTDI (USB-to-serial bridge)
[size=1em]Atmega's latest AT90USB series microcontrollers have onboard USB support for direct programming via USB (no FTDI or ISP required). But, they dropped I2C support pins on the equivalent 16K microcontroller, and we need I2C to interface the digital potentiometers.[/size]
Since firmware should never need to be flashed on a C5 amp, we decided not to implement FTDI, as it would be a waste of money to most users.
The 6-pin ISP header had to be omitted on production units due to physical height. A standard 0.1in, 6-pin header simply will not fit in the C5 case. You can still solder in the header; pins can be slightly trimmed to fit. All well within the capabilities of a DIY'er.
 

 

[miceblue]

Quote:

Quote:

Sounds great! It's cool to hear that you did try it out, but opted out for performance instead of aesthetics.
 
As for re-programming the C5, on the blog it mentions that a 6-pin header and an ISP programmer are needed. The SparkFun webpage that is linked mentions that the 6-pin cable is included with the ISP programmer. I haven't used Arduino before (first time learning experience! ), so I'm wondering how does one connect the C5 to the Arduino? I can't really tell from the photo on the blog how it's connected.

 
The 6-pin ISP header is unpopulated. See "JP1", near the bottom left corner of the battery:

 
 

Spoiler: Warning%3A%20Off-topic%20engineering...

 
There are two ways to interface an Atmega chip:
1) ISP, via 6-pin header
2) Serial pins, usually via FTDI (USB-to-serial bridge)
[size=1em]Atmega's latest AT90USB series microcontrollers have onboard USB support for direct programming via USB (no FTDI or ISP required). But, they dropped I2C support pins on the equivalent 16K microcontroller, and we need I2C to interface the digital potentiometers.[/size]
Since firmware should never need to be flashed on a C5 amp, we decided not to implement FTDI, as it would be a waste of money to most users.
The 6-pin ISP header had to be omitted on production units due to physical height. A standard 0.1in, 6-pin header simply will not fit in the C5 case. You can still solder in the header; pins can be slightly trimmed to fit. All well within the capabilities of a DIY'er.
 

Okay I see what you mean now. This sounds like a fun project; I haven't had to solder header pins before, but it looks doable. Thank you for the heads up!

 

[rckyosho]

Okay I see what you mean now. This sounds like a fun project; I haven't had to solder header pins before, but it looks doable. Thank you for the heads up!

I recommend using an angled 6 pin header rather than straight up making for easier access due to the battery near jp1 and might even be able to fit in the case and might save you the trouble of cutting the pins(even if you do need to cut it up to fit the case it will be easier) since this is your attempt at doing it.

 

[audionewbi]

Ordered mine via noisymotel, cant wait.

 

[808Ronin]

Anxiously awaiting a comparison review between C5 and C421 w/ 8260 opamp before i can finalize my deision to buy or not.. The wallet will remain on lock down till then.

 

[Vanquiz]

So, which color has bigger sound stage? Lol

The red is super hot, but the slate is nice and match my Ed.8 better... Hmm tough decision...

 

[DMinor]

The red sounds more intimate if that matters to you. The color may have a placebo on your perception to sound and the slate may well be sounding dark.

 

[drachen]

Quote:

So, which color has bigger sound stage? Lol

The red is super hot, but the slate is nice and match my Ed.8 better... Hmm tough decision...

The red is more likely to get you tickets, where i hear the slate is rock-solid.  The gray is pretty neutral on things, though it was only implied by gray...

 

[miceblue]

The bass boost sounds pretty rockin' with the K 701, but way too much for a much bassier V-MODA Crossfade M-100 (although it does remind me of a live concert kind of bass).
The volume lever is really smooth, and I mean REALLY smooth. I'm still playing around with it. Having no channel imbalance at low listening levels is great for low-volume listeners such as myself.
The gain toggle takes some time to get used to since it's hard to push in, you have to push it right in the center, but it works well.
 

 

 

 

 

 

 

 

 

 

 

[drachen]

Quote:

The bass boost sounds pretty rockin' with the K 701, but way too much for a much bassier V-MODA Crossfade M-100 (although it does remind me of a live concert kind of bass).
The volume lever is really smooth, and I mean REALLY smooth. I'm still playing around with it. Having no channel imbalance at low listening levels is great for low-volume listeners such as myself.
The gain toggle takes some time to get used to since it's hard to push in, you have to push it right in the center, but it works well.

Spoiler: I%20am%20an%20image!%20%3AD

 
 

 

 

 

 

 

 

 

 

 

 

Red is definitely faster!  Miceblue has his already!   Mine is sitting at home waiting for me.  Guess who is clocking out early today?    /me points at himself

 

[miceblue]

Initial comparisons between the C5 and the O2, to me at least, the O2 has a larger soundstage with better instrument separation, the C5 has more bass (though I admit it is hard for me to properly volume match).