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Old 8th March 2007, 07:01 PM   #5901
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Especially the American ones (n'est ce pas?) So answer my question someone please!
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Old 8th March 2007, 08:38 PM   #5902
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Default 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!
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Old 9th March 2007, 01:38 PM   #5903
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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!

Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.

Brent
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Old 9th March 2007, 01:50 PM   #5904
SimontY is offline SimontY  United Kingdom
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More transformers kicks backside!

Brent's current modlist:

http://www.eurolinkcourses.co.uk/sim...0KI%20MODS.rar

Looking forward to hearing it again!

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Old 9th March 2007, 01:51 PM   #5905
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Cheers matey

Brent
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Old 10th March 2007, 11:13 PM   #5906
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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
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Old 11th March 2007, 10:15 PM   #5907
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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
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Old 12th March 2007, 11:27 PM   #5908
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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..
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Old 12th March 2007, 11:42 PM   #5909
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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
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Old 13th March 2007, 09:00 AM   #5910
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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
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