sfogg Posted January 28, 2007 Share Posted January 28, 2007 Erik, The modification to add an 6/8 channel analog bypass to the Lexicon DC-1 is working out well so far. This is basically what the board looks like. I made a couple of small changes to the board for the next revision. Shawn Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 28, 2007 Author Share Posted January 28, 2007 Here it is trial installed in a DC-1..... Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 28, 2007 Author Share Posted January 28, 2007 Here are a couple of pictures demonstrating the analog bypass in action. This is a 10kHz SQUARE wave out of the DC-1. This is input into the Lexicon in non-analog bypass mode... in other words it is digitizing the signal and then reconverting it to analog. Because of the sampling rate of the Lexicon most of the harmonics of the 10kHz square wave are missing, this is why it looks like a sine wave and this is totally expected. Shawn Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 28, 2007 Author Share Posted January 28, 2007 Here is the same 10kHz square wave but with the DC-1 now in multichannel analog bypass mode. Because it is in multichannel analog bypass it no longer has the low pass filtering of the A/Ds-D/As so the harmonics come through and the square wave looks proper. There is a few dB difference in level between both modes. Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 28, 2007 Author Share Posted January 28, 2007 Here is a 100kHz square wave with analog bypass OFF. Well beyond the low pass filter so the signal is basically gone, again as expected. Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 28, 2007 Author Share Posted January 28, 2007 Same 100kHz square wave with multichannel analog bypass ON. Quote Link to comment Share on other sites More sharing options...
Deang Posted January 29, 2007 Share Posted January 29, 2007 Help me understand what this is for Shawn. What's the purpose of the mod? Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 29, 2007 Author Share Posted January 29, 2007 For high resolution multi-channel sources. Such as DVD-A, SACD and the various high resolution formats on HD-DVD and BluRay. For all of them they are output from the players as 6 analog channels from up to 96/24 sources. Additionally they can be output over Firewire and HDMI in some players/receivers/pre-pros. DC-1, DC-2 and MC-1s don't have firewire, HDMI or 6 channel analog inputs. So there is basically no way to hear these formats in their full multi-channel resolution. What the mod does is add a 6/8 channel analog bypass to the Lexicon's. That allows one to connect their high resolution multi-channel source to the Lexicon to listen to the music/soundtrack in full resolution. In Erik's case he has a DVD-A/SACD player. (Denon 2900) He was curious to know what DVD-A/SACD sounds like. This mod will let him hear that. He will configure one input on the Lexicon as the MC analog bypass and when he switches to that input the DC-1 will go into MC analog bypass mode. When he selects his other inputs the unit will function exactly as it always has. Make sense? Shawn Quote Link to comment Share on other sites More sharing options...
travisc Posted January 29, 2007 Share Posted January 29, 2007 so his dc-1 is dts ready?? or is that not neccesary, mine does not have the dts function though like Erik I have a denon 2910. Should I just keep my eye out for a dc-1 with dts and when I do is this mod gonna be available through you, how is it gonna connect to the denon? you would need 6 seperate inputs.....no? or does the denon downmix to two channels and Lexicon plays two channels with out the option of any processing like logic 7 im a little confused Quote Link to comment Share on other sites More sharing options...
travisc Posted January 29, 2007 Share Posted January 29, 2007 whats the back side of that board look like? Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 29, 2007 Author Share Posted January 29, 2007 "so his dc-1 is dts ready?? or is that not neccesary" The hardware level of the DC-1 is irrelevant as the multi-channel analog bypass is bypassing all the A/D, DSPs and D/As. The mod can be done on any DC-1. The one in the picture is a base level without DD or DTS decoding. "how is it gonna connect to the denon? you would need 6 seperate inputs.....no?" Yes, you need 6 (or 8) separate analog inputs. This will work just like it does on the MC-4,MC-8 and MC-12 actually in that when you configure the MC input you loose 4 pairs of regular analog inputs from the unit. In this case the VCR1, VCR2, VDisc and TV analog inputs on the back panel get utilized for the MC analog input. VCR1 becomes Front L/R Input, VCR2 is Center/Sub input, V-Disc is Side L/R Input and TV is Rear L/R input. "or does the denon downmix to two channels and Lexicon plays two channels with out the option of any processing like logic 7" Nope, the Denon would spit out the full multichannel high resolution 6 channel DVD-A or SACD music over its analog outputs and that would be played through the Lexicon. When the Lexicon is in analog bypass mode all processing is bypassed. It basically becomes an 8 channel analog pre-amp. Any bass management and time alignment would need to be configured in the player. The Lexicon would still handle speaker level balancing. "whats the back side of that board look like?" Just traces. Shawn Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted January 29, 2007 Share Posted January 29, 2007 Shawn: This is impressive to say the least. Very nice work! Is the board shown the second, slightly smaller one you mentioned? "Any bass management and time alignment would need to be configured in the player. The Lexicon would still handle speaker level balancing." I understood that all processing in the Lexicon is bypassed, but was wondering about speaker level/channel balancing. Thanks for addressing that here. I really haven't worked with any of the multi-channel adjustment/bass management features of the Denon, so need to study that a bit. "In this case the VCR1, VCR2, VDisc and TV analog inputs on the back panel get utilized for the MC analog input. VCR1 becomes Front L/R Input, VCR2 is Center/Sub input, V-Disc is Side L/R Input and TV is Rear L/R input." Perfect. Until you suggested this modification of the Lexicon, and since I have become more and more interested in trying the multi-channel outputs of the Denon for SACD, I had been pondering a multi-channel tube preamp project in order to accomplish the same thing. The DC-1 has performed so well as a straight ahead linestage, though, that it would be very hard for me to improve on. What do things look like in terms of physically mounting the board? Erik Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 29, 2007 Author Share Posted January 29, 2007 Erik, "Is the board shown the second, slightly smaller one you mentioned?" Nope, that is the first version. The second version is only a tiny bit smaller few tenths of an inch really. I'm hoping the boards will ship this week so I will have the next week. "I understood that all processing in the Lexicon is bypassed, but was wondering about speaker level/channel balancing." Speaker balancing is done with the 8 volume controls in the Lexicon so that is still active with the multichannel analog input. The front/rear fader and left/right balance control will still work too. "Until you suggested this modification of the Lexicon, and since I have become more and more interested in trying the multi-channel outputs of the Denon for SACD, I had been pondering a multi-channel tube preamp project in order to accomplish the same thing. " The Denon can do both DVD-A and SACD so if you see any music you want to hear in either format you will be able to listen to it. An interesting comparison could be the Dark Side of the Moon SACD vs. the DVD-A for example. "What do things look like in terms of physically mounting the board?" It is going to be mounted roughly where it is in that picture. It isn't installed in that picture but the video board sits basically above where the board is and takes up roughly the top right quarter of the motherboard. The MC analog bypass board will be below that. Shawn Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted January 29, 2007 Share Posted January 29, 2007 Shawn: It looks great; thanks for posting these pictures, and for explaining test result expectations regarding your measurements. What are you planning to use to secure the board? Erik Quote Link to comment Share on other sites More sharing options...
travisc Posted January 30, 2007 Share Posted January 30, 2007 "I understood that all processing in the Lexicon is bypassed, but was wondering about speaker level/channel balancing. Thanks for addressing that here. I really haven't worked with any of the multi-channel adjustment/bass management features of the Denon, so need to study that a bit" Erik, the Denon(or mine atleast 2910) can adjust speaker levels as well for the multi out Shawn, please keep me up to date on price and availability Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 30, 2007 Author Share Posted January 30, 2007 "Erik, the Denon(or mine atleast 2910) can adjust speaker levels as well for the multi out" You won't want to do that though. The speaker levels you set in the configuration of the Lexicon are still valid for the multichannel input. If you wanted to tweak the levels slightly you could do that in the Denon if desired (so it only effects the MC source and nothing else) but the main level balancing would still be done in the Lexicon. For the MC source you would configure the bass management and time alignment in the Denon as in analog bypass the Lexicon can't do that. Does your 2910 have a DTS decoder in it? If it does you could use that to listen to DTS soundtracks if you desired. For movies I'd just use DD and let the Lexicon do everything. But if there were some DTS Music discs you wanted to listen to if the 2910 can *decode* them you could listen to that over the MC analog bypass. Shawn Quote Link to comment Share on other sites More sharing options...
travisc Posted January 30, 2007 Share Posted January 30, 2007 right easy way to get both worlds dts sample rate and multichannel Im game!! Are you gonna make this available for the likes of me? Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 30, 2007 Author Share Posted January 30, 2007 "Are you gonna make this available for the likes of me?" Yes, since I had to revise the prototype PCB slightly when I ordered the next batch I order extras as there was interest from others. I'm hoping to receive the new PCBs next week. Assuming they check out I will be ready to go with this. Thanks, Shawn Quote Link to comment Share on other sites More sharing options...
travisc Posted January 30, 2007 Share Posted January 30, 2007 Shawn, can you upgrade this one to version 4? Would it be worth buying and have it shipped to you and you could perform upgrade at you leisure? http://cgi.ebay.com/Lexicon-DC-1-Base-Version-with-THX_W0QQitemZ130074243180QQihZ003QQcategoryZ14978QQssPageNameZWDVWQQrdZ1QQcmdZViewItem Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 30, 2007 Author Share Posted January 30, 2007 Nope, that DC-1 would require both hardware and software as v4 only ran on DD or DD/DTS models. Both the hardware and software was discontinued several years ago by Lexicon and it is very difficult to find now. Are you concerned about down time of your system? I should be able to turn it around pretty quickly to minimize that. Also buying that DC-1 on ebay would cost more then the mod itself. IMO you would be better off putting that money into DVD-As or SACDs. Thanks, Shawn Quote Link to comment Share on other sites More sharing options...
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