Topping DX7 DAC & Headphone Amplifier Review and Measurements

[amirm]

Yes, it would be good to see prior efforts. So thanks for looking for it.

 

[SpeedyRodent]

Here is the information. This mod came from nwavguy himself. He went by a different user name on other forums.

OUTPUT IMPEDANCE MODIFICATION: I tried several ways to reduce the output impedance. I ultimately found some specific 0805 chip ferrites that seem to provide sufficient reactive load isolation and stability while providing a near zero ohm output impedance. The ferrites are from Laird and the part number is HI0805O121R-10 (DigiKey 240-2393-1). These are rated at 120 ohms at 100 Mhz and 3.5 amps DC with a 20 milliohm DC resistance. I tried several ferrites and several inductors including 0805 chip inductors, conventional through hole inductors, and an air core inductor. The ferrites provided the best square wave performance, and perhaps more important, offer easily reproducible results. Any “off board” solution would be more prone to implementation details, and where stability is concerned, that can make a big difference. The ferrites are simply paralleled and soldered on top of the 10 ohm output resistors R10 and R22 as shown in the photo to the right (click for a larger version). The 10 ohm resistor remains to provide damping for the ferrite’s resonance. There are, however, some trade offs to reducing the output impedance this way. I discuss them in the measurements below.

Part: https://www.digikey.com/product-det...-products/HI0805O121R-10/240-2393-1-ND/806753

Source: http://nwavguy.blogspot.ca/2011/06/qrv09-diy-headphone-amp.html

 

[amirm]

Ah, most excellent!

 

[Jimster480]

Here is the information. This mod came from nwavguy himself. He went by a different user name on other forums.



Part: https://www.digikey.com/product-det...-products/HI0805O121R-10/240-2393-1-ND/806753

Source: http://nwavguy.blogspot.ca/2011/06/qrv09-diy-headphone-amp.html

That is a pretty cool mod. I wonder if I could do it to my A30....

 

[amirm]

What is a reasonable low-impedance headphone people like to see tested with this mod? Need to make sure it does not oscillate with that.

 

[L0rdGwyn]

What is a reasonable low-impedance headphone people like to see tested with this mod? Need to make sure it does not oscillate with that.

If you're looking for cheap, an entry level Grado might fit the bill, SR60e is $80 ($50 used), 32Ohm impedance.

 

[amirm]

Ah, used to have Grado and liked it very much. Got handed down to my kids. Didn't know it had low impedance. Will get one. Thanks!

 

[Jimster480]

What is a reasonable low-impedance headphone people like to see tested with this mod? Need to make sure it does not oscillate with that.

Any cheap headphone?
Denon AH-MM400, you can find it for around $275
Also 1More triple driver IEM (BA IEM w/ 1 dynamic) you can find for $70

 

[stunta]

Is 40 Ohms low enough and $16 cheap enough?

https://www.monoprice.com/product?p_id=8323

This is one of the most popular headphones out there.

 

[PurpaSmart]

I recommend the status audio cb1, it goes on sale under $60 a lot

 

[amirm]

Is 40 Ohms low enough and $16 cheap enough?

https://www.monoprice.com/product?p_id=8323

This is one of the most popular headphones out there.

Thanks. I bought the Grado already. Do I need to get this one too? I don't think the people buying this are also getting the Topping DX7s.

 

[PurpaSmart]

These are way better than the Monoprice
https://www.amazon.com/Tascam-TH-02-Closed-Studio-Headphones/dp/B00B1N06PO

 

[amirm]

I recommend the status audio cb1, it goes on sale under $60 a lot

That one looks pretty nice! Do I buy more headphones or save the money for more DACs???

 

[PurpaSmart]

That one looks pretty nice! Do I buy more headphones or save the money for more DACs???

Buy all the headphones and return the ones you don't like

 

[amirm]

I am not buying the headphones to use. I already have my Stax headphones for that. I am buying these for testing with headphone amps.

 

[PurpaSmart]

I am not buying the headphones to use. I already have my Stax headphones for that. I am buying these for testing with headphone amps.

You gotta start collecting them

 

[amirm]

I have been! I have 3 Stax systems, Sennheiser HD60, HiFiman HE 400i, Sony MDR-V6, and etymotic SR4 (?). And now Grado SR60e.

 

[Toppings]

At this point I'm not sure whether Amir is upshilling Topping by downshilling Schiit or if SBAF/Head-Fi is trying to censor the truth because I don't know enough about audio science to know whether the measurements are accurate or really mean anything and I can't trust anyone to be unbiased in this forum war

I guess I'll just get my Topping DX7S next month and hope it sounds significantly better than my PC's onboard audio.

EDIT: If anyone would like to loan me a Schiit Jotunheim with the DAC module I can do an uneducated unbiased subjective no-measurements comparison between the two.

 

[Thomas savage]

At this point I'm not sure whether Amir is upshilling Topping by downshilling Schiit or if SBAF/Head-Fi is trying to censor the truth because I don't know enough about audio science to know whether the measurements are accurate or really mean anything and I can't trust anyone to be unbiased in this forum war

I guess I'll just get my Topping DX7S next month and hope it sounds significantly better than my PC's onboard audio.

EDIT: If anyone would like to loan me a Schiit Jotunheim with the DAC module I can do an uneducated unbiased subjective no-measurements comparison between the two.

Neither, he’s measurement shilling

Have fun with your topping.

 

[Wombat]

Neither, he’s measurement shilling

Have fun with your topping.

Whatever, here the shilling was only worth 10 cents when it was replaced. BE currency.