The discrete TC-7520(SE)(+) line output

[Frizzup]

Count me in for 1 board please Stan, 30 quid seems reasonable to me.

Cheers
Frizzup

[Canetoad]

+1

[StanleyB]

I have asked my sourcing manager to get me a quote on the bill of material and the cost of a nice small foam padded box to put the finished PCB in. The PCB blanks manufacturer normally only accepts orders of 250 or more. So I'll make 250 blanks and populate 100 of those into fully working boards.
I'll know more next week, which will give me a chance to let you guys know the expected time of arrival/availability of the finished PCB and if the £30 price is about right. I am not looking to make a profit on any of my mods, which is why I give them away for free. But I have to at least cover the cost of manufacturing in this case.

In the meantime I'll PM a few people to see who might have the time to try out my PCB for a day or so in their system.

[Covenant]

Could you give a bit more detail about the method of fitting?
At this stage you can put me down for two boards please Stan.

[StanleyB]

1. Undo the 4 screws at the bottom of the DAC case.
2. Remove top cover of the case.
3. Remove existing audio PCB by holding it at the edges and pulling it upwards. Not an easy job since the audio PCB is stuck with a bit of glue to the headphone socket underneath. I use a scalpel to carefully cut away the glue.
4. Fit new PCB in the exposed sockets on the main PCB. Check that all the pins on the new PCB fit exactly inside the holes of the connector on the main PCB. No pins should be left exposed, otherwise the PCB is not fitted properly.

[Covenant]

Thats confimed it-two boards please Stan!

[StanleyB]

OK Jerry. I'll make a spreadsheet so that nobody is overlooked .

I'll probably offer a fitting service for those who are worried about swapping the PCB by themselves.

[Gazjam]

Hi Stan, just to double check.
(I'll ask then Jerry )

just one opamp...?
Is this for headphone use only?
(Probably not listening to common sense , but just checking!)

Also, do you see this sounding better than the "less is more" approach of the Passive Output Mod, which removes the opamp board all together?

I ask this as I found quite a difference in sound putting in different coupling Cap types in place of the original opamp board, which would seem indicate the Dac is sensitive to whatever is plugged into the PCB output socket.


thanks!

[StanleyB]

Hi Stan, just to double check.
(I'll ask then Jerry )

just one opamp...?
Is this for headphone use only?
(Probably not listening to common sense , but just checking!)

Also, do you see this sounding better than the "less is more" approach of the Passive Output Mod, which removes the opamp board all together?

I ask this as I found quite a difference in sound putting in different coupling Cap types in place of the original opamp board, which would seem indicate the Dac is sensitive to whatever is plugged into the PCB output socket.


thanks!

I refer my learned friend to the opening line of this thread, "I drew up a discrete output stage for the TC-7520 and Caiman to hear how it would sound. Leo built a prototype of it on stripboard and I did one as a 'proper' PCB. I wanted to find a solution for the low output of the passive mod and preserve the headphone output capability, but didn't want to go overboard with a complex discrete opamp type design. "

In other words, if you are happy with the passive mod and it's output level, and don't need the headphone output, then you don't need this upgrade.
As for caps and opamps for this PCB: feel free to improve on my choice.

[Getgaff]

I'd like to register my interest for this upgrade