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Modify Denon AVR-X1800H with preouts

cobby

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I consider buying a Denon AVR 1800H and modify its preamps, or to be more specific its lack of it.
Its just a thought, might some have views and infos to share.

The 1800h would be nice for me, if it had propper Front preouts.

Basically its no big deal to open the case find the amp board, check which cables are for the fronts and then solder a wire in parallel, even better would be to disconnect the amp stage, but this is recognized by the amp and its shuts down, so amp stage prob need to stay connected.

i could imagine to make a small pcb with some op amps to go symetric from this point, just a rough idea so far, might skip that, or skip the idea completly.
 
I consider buying a Denon AVR 1800H and modify its preamps, or to be more specific its lack of it.
Its just a thought, might some have views and infos to share.

The 1800h would be nice for me, if it had propper Front preouts.

The NA version does have front left and right pre puts but the European version apparently does not.


Basically its no big deal to open the case find the amp board, check which cables are for the fronts and then solder a wire in parallel, even better would be to disconnect the amp stage, but this is recognized by the amp and its shuts down, so amp stage prob need to stay connected.

i could imagine to make a small pcb with some op amps to go symetric from this point, just a rough idea so far, might skip that, or skip the idea completly.
 
that would be perfect, unfortunately i am in europe.

i bet there are no closeup pictures or one ho knows if there is maybe a jumper or some solder pads on the european version.
i dont get why they offer not the same features, a reason to not buy any of their recievers, still tempting to mod such a x1800h.
 
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that would be perfect, unfortunately i am in europe.

i bet there are no closeup pictures or one ho knows if there is maybe a jumper or some solder pads on the european version.
i dont get why they offer not the same features, a reason to not buy any of their recievers, still tempting to mod such a x1800h.
Yeah it is strange, the NA version even includes the option to set it to pre out only, like a preamp mode for 2 channel stereo use. No idea why the made different for Europe. The service manual for the x1700h is available so you can take a look to see how to potentially do a mod.
 
so true, not a great move from Denon.
Best i could find is this
Denon_AVR_X1800H_inside-scaled-1.jpg

i will look for that service manual, or simply take another aproach.
Dont want the amp of the x1800 to be connected, but might a small resitor connected in parallel giving a small load would solve any noise issue for the cost a few mA burned.
On the other hand connected over a buffer there should be any sorrow either i would guess.
There are might be easier ways to skin the cat and i would need to spend 400€ o na receiver just to open it after unboxing.
 
I have installed pre-outs to my AVR-X1500H - with RCA unbalanced connectors. THD+N is up to -100 dB (0,001%)

Signal is taken from C2101 and C2102 (via new bipolar caps) - see the pic.
Denon_pre_out.png


THD - Toslink input, 0 dB volume:

Denon_pre_out_THD.png
 
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Wow, very nice info and very nice results, thats encouraging looks clever to go over a cap.
Would need a bit myself to get into the topic.
Your THD measurements are looking good, i allready considered a Marantz C70s for its preout section and okish DAC but looks like it could be worth to mod a Denon, well done!
 
I have installed pre-outs to my AVR-X1500H - with RCA unbalanced connectors. THD+N is up to -100 dB (0,001%)

Signal is taken from C2101 and C2102 (via new bipolar caps) - see the pic.
View attachment 393008

THD - Toslink input, 0 dB volume:

View attachment 393010
I'm going to do that, but there are warranty concerns. I decided to make this modification after the warranty expired.

Today's AVR is garbage in sound processing, and tens of times the price to barely keep up with FOSI's small box, which is ridiculous!
 
regarding a dummy load, i would bet you guys have a opinion.

in the case we have AV receiver with preouts who dont switch of the amp stage when activated, simply run in parallel.
would it make sense to ad a dummy load to the amp outputs?
just so it stays stable and predictable may distorting less.
 
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I'm going to do that, but there are warranty concerns. I decided to make this modification after the warranty expired.

Today's AVR is garbage in sound processing, and tens of times the price to barely keep up with FOSI's small box, which is ridiculous!
true, see no need for these old darlington AB class ams anymore too, but looks there are not many options for AV processing elsewhere.
 
regarding a dummy load, i would bet you guys have a opinion.

in the case we have AV receiver with preouts who dont switch of the amp stage when activated, simply run in parallel.
would it make sense to ad a dummy load to the amp outputs?
just so it stays stable and predictable may distorting less.
I would break the track to the input of the C2101 and C2102 and connect them to GND and take the signal before the break of the track.

Denon_pre_out2.png
 
thats probably the cleanest way, i saw in a youtube video one trying to disconnect the whole amp board and replacing it with preamp outputs, didnt worked as there is some check from the mainboard preventing startup in that case.
not sure if that be the same above.

you have a opinion on a dummy load? its easy to apply, thought of may 0.5 to 1k, just a minimal defined load when using the preouts in parallel.
 
you have a opinion on a dummy load? its easy to apply, thought of may 0.5 to 1k, just a minimal defined load when using the preouts in parallel.
If you mean the speaker output, you can leave it without the load.
 
thats probably the cleanest way, i saw in a youtube video one trying to disconnect the whole amp board and replacing it with preamp outputs, didnt worked as there is some check from the mainboard preventing startup in that case.
not sure if that be the same above.

you have a opinion on a dummy load? its easy to apply, thought of may 0.5 to 1k, just a minimal defined load when using the preouts in parallel.
I don't see a reason for that, I had used AVRs without such dummy load and never experienced any issues. Even without disconnected the power amp section, I have never seen SINAD dropped below 75 dB at 2 V and higher, based on Amir's test results of the Denon AVRs. Are you planning on installing a relay to implement your own preamp mode?
 
in some kind it would had some lets say forced manual mode preamp mode if you want to call it like that.
the 1800x is almost half the price of the cinema 70s so its a consideration, on the other hand the cinema would be ready to go,.
The Cinema 70 do use relays in preamp mode and offers 12V out to switch the amp.
when modding such a denon i would prob go for symetric outputs, why not.
atm i favor a way simpler idea.
i do have a marantz 1606 which works just the network connectivity is broken, no matter what i do.
prob stick with that for a while and build me hacksaw automated stereo system.

streaming mini pc > dac > aiyima a70 amp > speakers
marantz AV > same speakers

the aiyima amp i may connect over its sub out to a dsp before the sub, to get the cutoff right and eq a bit,
the other input of the sub i could connect to the marantz.
the a70 have a 12v trigger in, so the 12v signal whos there would serve me 2 functions, amp on/off and speaker relay switching.

the speaker cables i could simply switch with a 12V relay between AV and stereo, pretty painless solution.
kind of a "super pure direct mode" for the marantz.
same would be true for any cheap av receiver in the future too.
 
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