Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › Denon DVD-758 / DVD-1940ci mods
New Posts  All Forums:Forum Nav:

Denon DVD-758 / DVD-1940ci mods

post #1 of 6
Thread Starter 
I picked up one of these super cheap ($39) Denon DVD-758 universal players this week, and am looking forward to having some fun modding it. Denon seems to have, with the exception of the PCB that houses all of the digital components, made the design of this player pretty simple and mod-friendly. I'm creating this thread to share information for anyone else that might be interested in modding theirs. Anyways, here are some shots of the unit's internals:

Overview:


Digital / DA Section (top):


Digital / DA Section (bottom):


Power Supply Section:


Remainder of Power Supply and Components for Front Panel:


Analog Audio / Component & Composite Video Out Section:


5.1CH Analog Out Section:


I've only had this unit in my hands for ~18 hours at this point, so I've not done much yet. I discovered this morning that disconnecting both of the ribbons to the 5.1CH out seems to have added a bit of additional clarity to the stereo analog outs.

At a glance, the power supply section looks like an obvious candidate for improvement. Some larger caps and a higher quality transformer to replace that itty bitty stock part would probably make a difference. The op amp on the analog output section appears to be a TI RC4558 running at +10v/-10v. I think I may start there. I only have a spare OPA2227 on-hand, which would probably be an upgrade, but an OPA2604 might be more worth the effort.

If anyone else has any experience with modding this unit, advice would be appreciated. If anyone has any questions, feel free to ask.

--Matt
post #2 of 6
Thread Starter 
Here are some baseline RMAA Frequency Response, Noise Level, and THD results at 16/44.1.

--Matt
LL
LL
LL
post #3 of 6
Thread Starter 
Any more for 24/96 from DVD audio.

--Matt
LL
LL
LL
post #4 of 6
Thread Starter 
I acquired a service manual for the DVD-758/1940ci and have had a chance to review the schematics. It appears as though the op-amp on the stereo output is only running on 10v total, and there are lots of pieces in the signal path, so I think I'm going to bypass that section entirely and use an off-board solution from twisted pear for the I/V section. If anyone is interested in a copy, PM me and I can send it along.

--Matt
post #5 of 6
I have the 1940ci and I thought about just putting a Twisted Pear Buffalo in the open area. Maybe with the i2s. Will keep a eye on this.

Good luck.
post #6 of 6
Thread Starter 

Good luck to you too! It looks like you can pick up SPDIF on the outer leg of L618 or on pin 16 of the CN1601 connector. Pins 5, 7, 9, 11, and 15 on the same connector should be ground. I'm planning to tap into pins 12 and 14 on the same connector for Analog L and R channels, and 13 for ground. Both of the audio connections at that cable are direct from the DAC and untouched.

My bid on a house was accepted yesterday, so I'll probably have to wait on this for a while, but I'll try to keep it going since it should be a relatively low-budget process.

--Matt


Edited by mattkosem - 7/13/10 at 4:26am
New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › Denon DVD-758 / DVD-1940ci mods