Has anyone modified a Rotel 1072 or know someone who may want to give it a shot, From my readings, it seems prime for upgrades , good drive, good power and architecture.
I have the basiv skills and desire but little experience on anything other than tube amps.
I am knew here and at the DIY thing but have been in Audio for over 20 years and am currently running a 300B setup.
Thanks
Scott
I have the basiv skills and desire but little experience on anything other than tube amps.
I am knew here and at the DIY thing but have been in Audio for over 20 years and am currently running a 300B setup.
Thanks
Scott
I modified an older Rotel amplifiers (power and integrated) . I belive they have same topolgy as new ones. First of all Rotel amplifiers (and Cd players) have very good base for upgrade. If you have knowledge about electronic components I will try to give you some advices. It is not expesive upgrade but sonic improovements are quite large. First thing you can do here is to replace resistor that connect output stage and inverted input of power amp section by 30-50% larger value resistor of higher quality(Vishay/Dale 1>% tolerance). That one is in negative feedback rail and with larger value the amp works with smaller NF , but have larger gain and smaller damping factor. Secound thing is to replace all Black Gate (F type) caps in signal path, with BG-NX HI-Q types or MKP type of capacitors 2,2uF . Now when power amp section have greater gain , you can bypass line preamp section wich is made with OP amps (BB OPA-2604 I think) and connect power amp directly to volume control pot. If you succeed to do that , theres a chance that you use only one bypass cap between pot and power amp input. PS in Rotel is quite good so here is a little thing to do, exept to change rectifier bridges(greatz) with some fast power diodes. This is it. There are no big shanges in topology and makeing a new circuit boards . This is all about cleaning the signal path and makeing power amp section to produce less tehnical and more musical sound.
. OK latter i will try again 
You forget to write >RCD< before 1072
This is my Rotel RCD990, but the same principle of upgrade is in your cd player. You only must find points in layout where these components are. Picture: Sanyo OS-CON caps(puple)(6,3V 150uF) instead of Black gates/Wima MKP in digital filter and D/A converter chip PS rails +/-5V
Attachments
If you want to buy some more os-cons, and you can find your values there:Gasho said:
http://hk.geocities.com/wkchenghk2000/orderformEng.htm
go for them. I bought 3 times from him and everything was perfect, very fast shipping and all.
Gasho, thanks
Thanks so much for the info, I will shoot you some digital photos of the interior layout of the RCD 1072, when I get it open.
Parts Connexion of Canada said they would be happy to mod it, but the cost may be pretty high. I would like to take advantage of the part that is good that applies to the review from Absolute Sound magazine.
Scott
Thanks so much for the info, I will shoot you some digital photos of the interior layout of the RCD 1072, when I get it open.
Parts Connexion of Canada said they would be happy to mod it, but the cost may be pretty high. I would like to take advantage of the part that is good that applies to the review from Absolute Sound magazine.
Scott
This is the reply when I asked Reference Audio about a diffrent Opamp chip.
Curious why it got such rave reviews in absolute sound? I do see some of the virtues that were pointed out in the review in absolute sound. I was hoping for better dynamics and bass slam and a bit fuller bottom end. It is dead quite and hase nice wide deep soundstage.
Thanks
Scott
"Hi Scott,
There is alot of mods and upgrade potential for this unit.
For starters, the stock toroid is pretty weak in my opinion and could be definitely replaced with a M6X version from Audio Consulting. This may be too large to fit in the stock chassis, thus requiring a seperate wooden box, but none the less the performance will be significant.
The Stock power supply design is basic and needs upgrading with Ultra Soft Recovery diodes and Jensen 4-pole caps. There are also a couple voltage regulators that can be replaced with the Audiocom Q-powers. These regulators power the DAC chip and the analog opamps.
The DAC Chips are the PCM1732 and I beleive they are located on the bottom side of the circuit board. The Stock op-amps might be good enough to not necessitate a change as the amount of performance will not be worth the actual costs, I dont know though since I have never done this change on this unit.
The PCM1732 is a SINGLE ENDED OUTPUT D/A CHIP. This means that a Coupling Capacitor on the outputs (Pins 13, 16) needs to be the highest quality of your likings. I would try some Rubycon ZA in this application and see how you like them. It wont run more than a couple dollars each and peel the plastic off them for better sound. Mark the negative on the top of the cap with a sharpie. Blackgates N series can be used here and sound good, but I like the rubycons better.
Instead of using the opamps. You could run the outputs from these coupling capacitors directly to a set of isolated high quality RCA jacks. Run a 10kohm resistor from each signal on the output of the cap to ground. Just use a basic resistor for this purpose. This should bring a load more resolution and transparency. The opamp may be needed for more drive, and in this case I would use the Burr Brown BUF634 High speed buffers, which do NOTHING wrong to the sound but plainly pass the music and add current for drive in the signal. The BUF require a +/- power supply here.
I know this is alot to follow but this player can definitely be hotrodded to sound very good. It will never sound GREAT because the DAC chip does not use the most optimal topology.
In addition, a set of copper or silver signal coupling transformers can be used in the output from the cap or from the output of the op-amp or buffer to further increase performance by a wide margin.
Adding a Superclock 3 w/optional PSU will also be a nice change for this player.
I have had one here and have gone through it almost fully but the owner backed out and I returned it to him, he sold it and he sent me a Denon 2900 to mod, which will sound superior to the rotel any day in its fullest modded stage.
Please reply, email or call for more info and if you have questions.
Thanks!
_________________
Doug
Reference Audio Mods
East Location
Curious why it got such rave reviews in absolute sound? I do see some of the virtues that were pointed out in the review in absolute sound. I was hoping for better dynamics and bass slam and a bit fuller bottom end. It is dead quite and hase nice wide deep soundstage.
Thanks
Scott
"Hi Scott,
There is alot of mods and upgrade potential for this unit.
For starters, the stock toroid is pretty weak in my opinion and could be definitely replaced with a M6X version from Audio Consulting. This may be too large to fit in the stock chassis, thus requiring a seperate wooden box, but none the less the performance will be significant.
The Stock power supply design is basic and needs upgrading with Ultra Soft Recovery diodes and Jensen 4-pole caps. There are also a couple voltage regulators that can be replaced with the Audiocom Q-powers. These regulators power the DAC chip and the analog opamps.
The DAC Chips are the PCM1732 and I beleive they are located on the bottom side of the circuit board. The Stock op-amps might be good enough to not necessitate a change as the amount of performance will not be worth the actual costs, I dont know though since I have never done this change on this unit.
The PCM1732 is a SINGLE ENDED OUTPUT D/A CHIP. This means that a Coupling Capacitor on the outputs (Pins 13, 16) needs to be the highest quality of your likings. I would try some Rubycon ZA in this application and see how you like them. It wont run more than a couple dollars each and peel the plastic off them for better sound. Mark the negative on the top of the cap with a sharpie. Blackgates N series can be used here and sound good, but I like the rubycons better.
Instead of using the opamps. You could run the outputs from these coupling capacitors directly to a set of isolated high quality RCA jacks. Run a 10kohm resistor from each signal on the output of the cap to ground. Just use a basic resistor for this purpose. This should bring a load more resolution and transparency. The opamp may be needed for more drive, and in this case I would use the Burr Brown BUF634 High speed buffers, which do NOTHING wrong to the sound but plainly pass the music and add current for drive in the signal. The BUF require a +/- power supply here.
I know this is alot to follow but this player can definitely be hotrodded to sound very good. It will never sound GREAT because the DAC chip does not use the most optimal topology.
In addition, a set of copper or silver signal coupling transformers can be used in the output from the cap or from the output of the op-amp or buffer to further increase performance by a wide margin.
Adding a Superclock 3 w/optional PSU will also be a nice change for this player.
I have had one here and have gone through it almost fully but the owner backed out and I returned it to him, he sold it and he sent me a Denon 2900 to mod, which will sound superior to the rotel any day in its fullest modded stage.
Please reply, email or call for more info and if you have questions.
Thanks!
_________________
Doug
Reference Audio Mods
East Location
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.