[Reactcore]

Sorry to bump this but I have some questions. I have the 400i and my USB input went out and I just seen this. Currently I have a Topping D10 using S/PDIF out then going into 400i just to give my PC connectivity. As you probably know Questyle's support is horrible, like send it in to get repaired and never see your unit again horrible. So this has led me into using it way, and I think I could be the fix I'm looking for plus give me a better DAC. What features are lost? Can you switch to the pre-amp with Function button?

Sorry for replying this late.. if u still have this unit.
All digital part is functional. U can just bypass it feeding a analog signal straight into the amp section. Btw u might can fix the usb input part by replacing 4 diodes.. see my post on the CMA400i thread.

 

[DreamMan]

Very good manual, but I have to say that since I'm only a hobby worker (soldering etc. no topic), I don't dare to go there with my Questyle 12.
Unfortunately this is too much.

It would be a pity to have such analog connectors to test another DAC. But this is simply too much for me.


In addition, there is no space at all for the connectors on the back of the 12 to place them.

With the 400i I had before, there was room for it. Unfortunately I don't see one on the 12.

 

[Reactcore]

Very good manual, but I have to say that since I'm only a hobby worker (soldering etc. no topic), I don't dare to go there with my Questyle 12.
Unfortunately this is too much.

It would be a pity to have such analog connectors to test another DAC. But this is simply too much for me.


In addition, there is no space at all for the connectors on the back of the 12 to place them.

With the 400i I had before, there was room for it. Unfortunately I don't see one on the 12.

I imagine the 12 must sound superb too!!

The amp section sounds awesome with analog gear!

 

[Nayyte]

I am currently in the middle of adding analog input to my own CMA400i. My unit started cutting in and out rapidly through every digital input and I would prefer not to use the digital section at all. I'm thinking that as long as I don't solder anything to the right two PCB holes of the potentiometer then I shouldn't have any issues? Is there a way to cut power to the DAC section entirely without the AMP section freaking out? I'm not sure yet if I can make this work without tearing apart the new pot housing. The photo below is the underside of the pcb.

Old pot not reading good at all. I have a new alps pot to replace.

 

[Voxata]

I believe the pot controls line level signal to the amp section, but if your all is shutting off from DAC section going bad you may struggle. See if it stays on with nothing connected to the DAC side.

 

[Nayyte]

I believe the pot controls line level signal to the amp section, but if your all is shutting off from DAC section going bad you may struggle. See if it stays on with nothing connected to the DAC side.

I'm going to trust my instinct. It doesn't make sense to me that the unit would shut off output if there is no signal from the digital section. All the controls on the front are simple. This dac/amp doesn't auto seek through inputs to find a signal and there are no relays that trip when nothing is playing. I think I should be safe to just reroute the input pins on the pot to go straight to the rca's and block off the PCB connection from the DAC. There is a error light but I have never seen it error. If I have to feed a dummy signal then I will figure that out.

 

[Voxata]

I'm going to trust my instinct. It doesn't make sense to me that the unit would shut off output if there is no signal from the digital section. All the controls on the front are simple. This dac/amp doesn't auto seek through inputs to find a signal and there are no relays that trip when nothing is playing. I think I should be safe to just reroute the input pins on the pot to go straight to the rca's and block off the PCB connection from the DAC. There is a error light but I have never seen it error. If I have to feed a dummy signal then I will figure that out.

Since the unit is defective there isn't really anywhere else to go but up right?

 

[Nayyte]

She's alive!
Oh boy, when I say this was a headache, I really mean I wanted to stick a nail through my head every step of the way. While I did manage to get the alps pot to fit, I had to make several adjustments and sacrifices to do so. Since I covered the input holes from the DAC with adhesive heat shrink tube, the pot sits too high on the PCB. And because of this, the rear pins didn't have enough length to ideally sit in the PCB, so the pot is also pointed up at an angle. It works fine, the knob is sticking out of the case, but I still have a functional unit. I had to move a few pieces to the underside of the board to make it fit and mill away a significant amount of aluminum from the casing. What a pain, not recommended. But I still have a functional headphone amp.

No issues with audio coming through and no new hiss or pops. I'm listening to it now and letting it warm up. This unit was defective anyways but I really just did it so I could see if anything else from questyle (with analog input) would be worth switching to. Results are promising so far. A very articulate and engaging sound. Will have to test for a while. I'm still probably not going to make this a permanent piece on the desk; more of a momento or point of reference for the future. I have heard better amps than this, as is the curse of hearing high end gear after living in midfi land for so long.

 

[Voxata]

You did this in a rather unique way. I laid the pins flat and soldered from the bottom of the board when I modded an alps pot into the 400i. Really happy to see the life extended on this unit!

 

[Reactcore]

She's alive!
Oh boy, when I say this was a headache, I really mean I wanted to stick a nail through my head every step of the way. While I did manage to get the alps pot to fit, I had to make several adjustments and sacrifices to do so. Since I covered the input holes from the DAC with adhesive heat shrink tube, the pot sits too high on the PCB. And because of this, the rear pins didn't have enough length to ideally sit in the PCB, so the pot is also pointed up at an angle. It works fine, the knob is sticking out of the case, but I still have a functional unit. I had to move a few pieces to the underside of the board to make it fit and mill away a significant amount of aluminum from the casing. What a pain, not recommended. But I still have a functional headphone amp.



No issues with audio coming through and no new hiss or pops. I'm listening to it now and letting it warm up. This unit was defective anyways but I really just did it so I could see if anything else from questyle (with analog input) would be worth switching to. Results are promising so far. A very articulate and engaging sound. Will have to test for a while. I'm still probably not going to make this a permanent piece on the desk; more of a momento or point of reference for the future. I have heard better amps than this, as is the curse of hearing high end gear after living in midfi land for so long.

Wow you squeezed 27mm Alps in there.
I did see a smaller Alps placed by others before.

Did you tried disconnect the 8v line to the digital part and see if the amp section kept working?

 

[Nayyte]

Wow you squeezed 27mm Alps in there.
I did see a smaller Alps placed by others before.

Did you tried disconnect the 8v line to the digital part and see if the amp section kept working?

Nah, I was unsure if the headamp/preout toggle switch would be disabled as well. I didnt know there were smaller alps pots lol! I just picked the first 50k pot I could have shipped quick on Amazon.

 

[Nayyte]

Just updating anyone that's interested. I've been listening to my cma400i fed through a r2r DAC and the result is a really gaintkilling sound. This amp is performing much like something above the $1k price range. The frequency response is not neutral. The upper bass/low mids is noticably recessed but still present. Very cool highs and a easy listening amp. I've never heard a ss this good yet. My headphones are 40ohm and this amp is outputting over a watt for that range. 100-300 ohm is less than 500mw so not the best for those cans. Considering this amp frequently listed for under $400 used, and the mod cost me $80 in parts, this is a slam dunk. Makes me wonder if it's worth ripping out the PCB, putting it in a bigger chassis, and upgrading all the other components around it.

 

[Reactcore]

Just updating anyone that's interested. I've been listening to my cma400i fed through a r2r DAC

Try it with a Chord Mojo. (€250 used)
I found the combo having superb synergy