DVD player output mod, help needed

Mr. Sharpe

I have a Denon DVD-2800 I want to add a balanced output stage to with a separate switched power supply. I already know where to attach the extra power supply to have it switch on and off with the player.

I'm looking at simple unbalanced/balanced output boards on eBay that have power input and signal inputs on them. No problem, Those are easy to understand. What's more difficult to get is how to use a supply with these boards. Would I use an actual power supply or just a transformer? I know input and output voltage is not high at all so I don't think I need a regulator. And using the players supply would be too easy. His doesn't have to amount to anything really fancy because I'm not spending much on it.

If you're wondering why I want to do this to the player is because I hate seeing all the extra space in there go to waste and i want a cool project to do:)

FTGV

The simplest way to derive a balanced output would be by adding an op-amp configured as a unity gain invertor buffer. You would just need one op amp per channel, preferably the same type as the one's in the analog output section. You could power them from the same power supply. There is a better way but it is somewhat more involved.

Mr. Sharpe

Ok, what is the more involved way?

FTGV

A complete redo of the analog stage following the dac chip's.

pitdogg2

Well That player had all kinds of chroma bug problems from the start. That is why there is a 2800II and that one didn't last long either as the 2900 came out on it's heels. I sure wouldn't dump much money into it IMHO. Why not look for a player that already has that section?

Mr. Sharpe

FTGV wrote: »

A complete redo of the analog stage following the dac chip's.

Lol ew

pitdogg2 wrote: »

Well That player had all kinds of chroma bug problems from the start. That is why there is a 2800II and that one didn't last long either as the 2900 came out on it's heels. I sure wouldn't dump much money into it IMHO. Why not look for a player that already has that section?

I wasn’t planning on spending much more than $30 or so. I know about the chroma issues but the player works and I don’t really want to get another one. The only way I see this one going is though the garbage or a thrift store.


So using something like this https://www.ebay.com/itm/Assembled-DRV134PA-dual-channel-single-ended-balance-board/222441370583?_trksid=p2504926.m5232.l9681 hooked to the players supply and signal output isn’t really an option?

FTGV

Mr. Sharpe wrote: »

So using something like this https://www.ebay.com/itm/Assembled-DRV134PA-dual-channel-single-ended-balance-board/222441370583?_trksid=p2504926.m5232.l9681 hooked to the players supply and signal output isn’t really an option?

You should be able get that to do what you want. It's more complex then need be but should work.

Mr. Sharpe

Haha I’ll try it. I may even try one of the others that don’t have the plugs on them already. Then maybe try the supply thing later on

FTGV

That board already has a full power supply minus the transformer. You simply need to feed it an appropriate AC voltage. Powering it from transformer powering the analog section should be doable. Or feed it an unregulated DC from the analog supply.

Mr. Sharpe

FTGV wrote: »

That board already has a full power supply minus the transformer. You simply need to feed it an appropriate AC voltage. Powering it from transformer powering the analog section should be doable. Or feed it an unregulated DC from the analog supply.

Oh cool that’s what I was hoping you’d say to begin with:-) since I could use the players supply I see four wires going into the analog board, which should I use? When using my multi meter there are three wires with voltage but one is ever changing and the other two are something like 6 and 8v and then there’s ground, are those the ones I connect to this board?

FTGV

You need either two wires with 12-18 volts AC or plus and minus DC >15volts or so.
If not then you are out of luck. The meter is likely fluctuating because your measuring AC with the meter set to measure DC. I will try to find a schematic later this evening.

Mr. Sharpe

That’s where I get lost:( my meter only has a dial for volts, not either ac or dc so that sucks. I haven’t attempted this project yet because I did t want to do it and fry my preamp or something lol

Man everything you could help me with on this I am extremely appreciative!

mhardy6647

Mr. Sharpe wrote: »

That’s where I get lost:( my meter only has a dial for volts, not either ac or dc so that sucks. I haven’t attempted this project yet because I did t want to do it and fry my preamp or something lol

Man everything you could help me with on this I am extremely appreciative!

Guarantee that there's a selection for AC vs. DC voltage.
OK, I'd be very, very surprised if not.

Show us a photo or give us a mfgr name & model number.

Sometimes the AC vs. DC are represented graphically, thus.


(random. borrowed image )

AC voltage(V) and, on this meter, current (A) is indicated by the "tilde" (squiggle), ~

DC is indicated by the solid line over the dashed line.



We're here for ya, buddy!


edit: OK, it looks like some meters nowadays may auto-detect AC vs. DC Who knew?!?

FTGV

Ok it looks like there is + and - 12 volts DC feeding the analog section. Assuming your using the PC board you linked to,this is a bit too low of voltage to allow the regulators on the balanced board to operate correctly. I would remove the two 12 volt regulators on the new balanced board. (the black 3 pin transistor looking things.) Then you would need to feed the regulated voltages from the analog output board or from the power supply board to your new board. There should be an easy access point somewhere.

Mr. Sharpe

Here’s the mere I have. I have another one that takes a 9v but not sure if it works, it’s old.

Sounds simple enough and again I really appreciate you helping me out, I hate to seem lazy too, I think I just needed pointing in the right direction I.e away from the service manual 😂

txcoastal1

Put it on “A” then pushing the range button should toggle you between AC/dc

Should see a symbol change on screen

Also, when was the last time you changed the battery

Low batteries will give you false readings

Mr. Sharpe

I’ll do just that, I don’t think I’ve ever done it before and can’t recall if I had a instruction book.

Oh no they’re old lol you can turn it on and it’ll read an almost constant change in bolts without putting it to anything haha