Marantz cd 67SE HDAM Bypass question
The four resistors R651 - 654 supply the two HDAM circuits with +/- 12V.
R617 and 618 are the audio input resistors, these need removing to stop audio entering the HDAM.
RH23 and 24 are the output resistors from the HDAM, removing these prevents audio going backwards into the HDAM.
Resistors R619/620 bypass the whole HDAM (like in the CD43/53) my question is, instead of removing the said resistors, could one side be snipped at top of board? also, if i remember correctly, i have a resistor for R619 but, there is a label for R620 but no resistor present? Thanks for any help! 🙂
The four resistors R651 - 654 supply the two HDAM circuits with +/- 12V.
R617 and 618 are the audio input resistors, these need removing to stop audio entering the HDAM.
RH23 and 24 are the output resistors from the HDAM, removing these prevents audio going backwards into the HDAM.
Resistors R619/620 bypass the whole HDAM (like in the CD43/53) my question is, instead of removing the said resistors, could one side be snipped at top of board? also, if i remember correctly, i have a resistor for R619 but, there is a label for R620 but no resistor present? Thanks for any help! 🙂
I've been modding again 
This time I have removed the pre reg pcb to the two clocks and given them their own TX and caps direct to the regs.
The results are really good, bass is weightier with much better speed and timing.
Here are a few pics:-
You will see the 3.2VA tx mounted against the chassis with less than 1mm clearance on the mech + the pcb with schottky diodes and 4x Silmic caps for each psu. The regs are right up to the clocks!
Brent
This time I have removed the pre reg pcb to the two clocks and given them their own TX and caps direct to the regs.
The results are really good, bass is weightier with much better speed and timing.
Here are a few pics:-
You will see the 3.2VA tx mounted against the chassis with less than 1mm clearance on the mech + the pcb with schottky diodes and 4x Silmic caps for each psu. The regs are right up to the clocks!
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Brent
More transformers kicks backside!
Brent's current modlist:
http://www.eurolinkcourses.co.uk/simon/ROWEMEISTERS CD63 KI MODS.rar
Looking forward to hearing it again!
Brent's current modlist:
http://www.eurolinkcourses.co.uk/simon/ROWEMEISTERS CD63 KI MODS.rar
Looking forward to hearing it again!
Hi all, really nice tread is this🙂 Eventhough most of the stuff is too difficult for me; I'm a electronics n00b and hardly managed to build the hypex..
The thing is the following; recently I bought a modified CD67 which has been modified with inspiration from this topic. This player overclassed my professionally modified Marantz CD17 with tent clock and better caps & opamps (www.soundevolution.nl).
The CD17 has been sold and I'm really enjoying the CD67. There is one thing that's slightly bothering me. I'm using a 10k ohm attenuator for volumecontrol and a Hypex UcD400, with the attenuator at the lowest step the volume is already really loud.
The Cd67 has been equipped with LM4562 opamps, like many others in this tread. Do you experience the same thing, what could be the reason and solution?
- I found a voltage divider, but is this the best option?-
thanks in advance,
Paul
The thing is the following; recently I bought a modified CD67 which has been modified with inspiration from this topic. This player overclassed my professionally modified Marantz CD17 with tent clock and better caps & opamps (www.soundevolution.nl).
The CD17 has been sold and I'm really enjoying the CD67. There is one thing that's slightly bothering me. I'm using a 10k ohm attenuator for volumecontrol and a Hypex UcD400, with the attenuator at the lowest step the volume is already really loud.
The Cd67 has been equipped with LM4562 opamps, like many others in this tread. Do you experience the same thing, what could be the reason and solution?
- I found a voltage divider, but is this the best option?-
thanks in advance,
Paul
Hi Paul and welcome to the thread!
The problem is there's too much gain in your amplifier. You solution is either to reduce the gain there or attenuate it more with a larger value pot (e.g. 20k).
If you can find out how to reduce the gain do so as this will sound best (too much gain will harm the sound).
Regards
Simon
The problem is there's too much gain in your amplifier. You solution is either to reduce the gain there or attenuate it more with a larger value pot (e.g. 20k).
If you can find out how to reduce the gain do so as this will sound best (too much gain will harm the sound).
Regards
Simon
Hi Symon,
thanks for your answer, the reason for the question lies in the fact that the Hypex has not that much gain (20), also when I compared the Cd67 to my old Cd17 the Cd67 plays much louder....
(I had a non modified Cd67 for a while too, this did the same) So I'm still wondering why these players are so loud..
thanks for your answer, the reason for the question lies in the fact that the Hypex has not that much gain (20), also when I compared the Cd67 to my old Cd17 the Cd67 plays much louder....
(I had a non modified Cd67 for a while too, this did the same) So I'm still wondering why these players are so loud..
Hi,
They're a touch louder than the industry standard 2v RMS I believe. The most likely reason is to win an A-B comparison in a shop.
Before I made a preamp I used my CD63 straight into my power amp (gain = 28 I think) with a 10k pot inbetween. That worked ok, but of course a pot has more variability than a stepped attenuator (if that's what you use). There was a channel balance problem at low listening levels (typical of a cheap pot) but I can listen at any levels now (Alps Blue pot) and it's perfectly correct.
Simon
They're a touch louder than the industry standard 2v RMS I believe. The most likely reason is to win an A-B comparison in a shop.
Before I made a preamp I used my CD63 straight into my power amp (gain = 28 I think) with a 10k pot inbetween. That worked ok, but of course a pot has more variability than a stepped attenuator (if that's what you use). There was a channel balance problem at low listening levels (typical of a cheap pot) but I can listen at any levels now (Alps Blue pot) and it's perfectly correct.
Simon
Hi,
I had a similar problem with my ZAPpulse based amp. To be honest, I didn't find that switching between a 10k and 50k pot made that much difference. I'm now using a 50k pot and 18db attenuation (voltage divider on amp input) to get a useable volume.
Regards
Pete
I had a similar problem with my ZAPpulse based amp. To be honest, I didn't find that switching between a 10k and 50k pot made that much difference. I'm now using a 50k pot and 18db attenuation (voltage divider on amp input) to get a useable volume.
Regards
Pete
Mornin' Fellows,
I've modded a friend's CD53 this weekend, quite few (PSU caps, diodes, key caps (Dac...), opamps (LM4562)and their caps, bypassed CD blocking caps...) and have listened to it when OEM : it sounds so harsh compared to mine ! No way to listen to it too long or loud... Now him and his wife find it more natural and more detailled.
About the loudness of these players, won't it be better to lower the gain at opamps? Some did it? Of how much?
Thanks.
I've modded a friend's CD53 this weekend, quite few (PSU caps, diodes, key caps (Dac...), opamps (LM4562)and their caps, bypassed CD blocking caps...) and have listened to it when OEM : it sounds so harsh compared to mine ! No way to listen to it too long or loud... Now him and his wife find it more natural and more detailled.
About the loudness of these players, won't it be better to lower the gain at opamps? Some did it? Of how much?
Thanks.
Malefoda said:
Good job on the player, spreading the old Marantz wellness...
As for cranking down the gain in the player, I wouldn't want to do it like that. 2v RMS is standard, so unless you're going to take it down to exactly 2V then I wouldn't bother. Clearly a lot of people have too much gain in their amps and this should be addressed to achieve a more natural sound with no volume control problems.
Simon
SimontY,
is there any topic or anything about your pre amplifier?
For now I will make a voltage divider because working with the digital volume control on the cd67 isn't that nice, sounds very held back.
is there any topic or anything about your pre amplifier?
For now I will make a voltage divider because working with the digital volume control on the cd67 isn't that nice, sounds very held back.
Paulus1981 said:
No topic about my preamp, I didn't think it was interesting to anybody. I will think about starting one though as perhaps some others have used the Rod Elliot project 88 preamp board.
The instructions were good but you need to change a lot to make it useable and sound good!
I agree the digital volume control isn't great. I've accidentally left it turned down before and wondered why it sounded so soft and lacking in detail.
A strong signal to the amp is good and then at the amps inputs the attenution is needed. If you attenuate at the cdp end you will get a loss of bass information.
The CD63/67 has 2V output and most amps have an input sensitivity of 150-300mV. As you can see there is a big difference.
I use a Russ Andrews attenuated lead on mine -11db, I have also tried the Golden Jacks atts at -10db and -14db. Both working perfectly well.
The attenuation removes the harsh edge to the music.
For -11db you need 10K inline res and a 6.8K res after the 10K to gnd. Use 0.1%tol res if you can. If not 1% will be ok.
Brent
The CD63/67 has 2V output and most amps have an input sensitivity of 150-300mV. As you can see there is a big difference.
I use a Russ Andrews attenuated lead on mine -11db, I have also tried the Golden Jacks atts at -10db and -14db. Both working perfectly well.
The attenuation removes the harsh edge to the music.
For -11db you need 10K inline res and a 6.8K res after the 10K to gnd. Use 0.1%tol res if you can. If not 1% will be ok.
Brent
Well the attenuated leads work wonders in Brent's system, but it would make even more sense to reduce the power amplifier's gain if you can.
Simon
Simon
SimontY said:
Good idea! I am thinking of building a p2p version and would welcome a chance to discuss how to make it sound good.
Oh, and Brent, where do you get those self adhesive standoffs? I have now run out of places to drill and could do with some. Can't find 'em anywhere tho'.
Lee.