Topping D30Pro Review (Balanced DAC)

[Lozanoa11]

what I'm saying is your dac could be putting out 2v and your preamp max input is 1.5 or whatever. wouldnt be surprised if the output was higher on the xlr out than the rca . easiest way to test is put it in variable mode and turn the volume down on the dac and see if the problem still exists

But the distortion is on the Unbalanced RCA output, not the XLR

 

[aka_Z]

But the distortion is on the Unbalanced RCA output, not the XLR

It's still good idea to lower the output, input to your preamp.

 

[MacCali]

But the distortion is on the Unbalanced RCA output, not the XLR

I think his suggestion is the first step to figure out where the issue is coming from. So give it a shot and see what happens. Then we can go to plan b.

But honestly it makes no difference if you use the dac or pre mode. The only reason they suggest that is so you can get fixed voltage. Performance is not hindered

 

[jamescarter1982]

is your preamp an older model ? sometimes they are not meant to take such a high input as modern equipment puts out . I've had this happen a couple times once I got a loud ticking crackling sound this time much more subtle the only thing gave the game away was on my preamp it flashed up in red 'over ' so . loads of things you could do . go dac straight to power amp see if distortion still there .

 

[Lozanoa11]

I think his suggestion is the first step to figure out where the issue is coming from. So give it a shot and see what happens. Then we can go to plan b.

But honestly it makes no difference if you use the dac or pre mode. The only reason they suggest that is so you can get fixed voltage. Performance is not hindered

Yea sure I'll give it a shot tonight. Of course the problem in intermittent so I'll have to just lower it and use it like that for a week and see if I notice any distortion.

 

[Lozanoa11]

is your preamp an older model ? sometimes they are not meant to take such a high input as modern equipment puts out . I've had this happen a couple times once I got a loud ticking crackling sound this time much more subtle the only thing gave the game away was on my preamp it flashed up in red 'over ' so . loads of things you could do . go dac straight to power amp see if distortion still there .

Yes both my Pre and power amp were built in 1976. I get what you guys are saying about too much input volume, and I'm going to try any suggestions, but wouldn't it be worse out of the XLR plugs due to the higher voltage?

 

[jamescarter1982]

I think mine was intermittent it only happened on bass heavy music hence why I thought I had a blown woofer .

 

[jamescarter1982]

Yes both my Pre and power amp were built in 1976. I get what you guys are saying about too much input volume, and I'm going to try any suggestions, but wouldn't it be worse out of the XLR plugs due to the higher voltage?

unless you know what your dac puts out over xlr vs rca it's a bit of guess work . I think that's one way inwhich hifi vs professional can be frustrating . having metering on an interface helps woth situations like this

 

[Lozanoa11]

unless you know what your dac puts out over xlr vs rca it's a bit of guess work . I think that's one way inwhich hifi vs professional can be frustrating . having metering on an interface helps woth situations like this

According to the manual, 2vrms for RCA and 4vrms for XLR. I have my volt meter with me I could check to verify

 

[Lozanoa11]

Also if you read the specs XLR is rated better, but is that amount even audible?

 

[Lozanoa11]

Actually how would you measure voltage with it plugged in? Because you should right? I guess could make a simulated load? I'm running it in pre-amp mode but turned all the way up, if I notice and distortion I'll try turning it down

 

[jamescarter1982]

I think red probe inside rca black prope to earth wherever that is . Don't quote me though I don't want you to blow something up . are there any internal jumpers that set diff output levels I know one of my days has them inside .

 

[jamescarter1982]

After that I'd be switching inputs round see where the problem goes perhaps something in the preamp is no longer working properly on the input that your dac xlr goes to

 

[Lozanoa11]

After that I'd be switching inputs round see where the problem goes perhaps something in the preamp is no longer working properly on the input that your dac xlr goes to

Yea I thought of that so I swapped them and the problem followed the RCA cable.
The problem is you can't see the inner pin when it's plugged in. I suppose I could open up the case and go right to the terminals on the board

 

[jamescarter1982]

so the problem followed the rca cable ? loose connection inside then I bought one online the other day and the end of the jack fell off inside the little bag before I got round to using it

 

[jamescarter1982]

maybe wiggle it a bit and see what happens lol

 

[Lozanoa11]

maybe wiggle it a bit and see what happens lol

If you read my post, you'd see that I've tried multiple cables, factory and homemade with Mogami cable

 

[jamescarter1982]

I did but that was hours ago I can't remember every detail . you asked for help so why get ****** when people reply don't be so ungrateful

 

[staticV3]

Actually how would you measure voltage with it plugged in? Because you should right? I guess could make a simulated load? I'm running it in pre-amp mode but turned all the way up, if I notice and distortion I'll try turning it down

No need for a dummy load when measuring a DAC's output voltage because realistically, they almost always see perfect voltage bridging (high load impedance). You can stick your voltmeter straight to the signal pins and get reliable results.

The XLR output can be probed directly (XLR Pin 2&3), while the RCA out is easily reached by plugging a Male to Male RCA cable into the DAC, then probing the other end.

 

[Atanasi]

The XLR output can be probed directly (XLR Pin 2&3), while the RCA out is easily reached by plugging a Male to Male RCA cable into the DAC, then probing the other end.

I think male 1/4" TRS may be the easiest common connector for probing, with its large surface area for poles.