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Edwar65 25th January 2013 09:11 AM

Arcam cd73
Hi all, I've read somewhere of mods done to the arcam cd73, I think these incur fitting of capacitors near the signal outputs of the dac and removing/ bypassing the opamps?. Does anyone know about these mods and whether it improves the sound quality from the player?
I know of a chap called lampizator, that fits some valves in the area of opamps,
But cannot find any other mods in this area of the CD player?

T Leung 31st January 2013 12:18 PM

See if this link help.
Anyone ever upgraded an Arcam CD player? (Arcam upgrade, not a mod.) | Steve Hoffman Music Forums
I typed "mod arcam cd73" in google and quite a list come out.

Xoc1 1st February 2013 11:38 PM

I have an Arcam CD72T
When I bought it home I was mildly disappointed that the bass was not as clean as My old cheap 100 Aiwa player that I had modified fairly heavily!
So taking it apart was a bit of a no brainer for me.
What I found with the cd72 was firstly finding the schematics was not easy.
Secondly the circuity was quite sensible The voltage regulators were LM 317 / 337 adjustable types not fixed voltage chips. The output muting circuit used a relay not transistors. Audio supply caps were bi-passed etc...
The one aspect that I thought could be easily improved was the output op amps these were cheap dual JRC parts but sneakily the output stage had been biased into class A by connecting a resistor from the output to a voltage rail.
So far I have totally recapped the entire player. I replaced the smaller value caps in critical areas with Elna Silmic and replaced all the reservoir caps with Panasonic FC This was fairly easy as the PCB is not over populated. The output dual op amps were replaced with pairs of single National SMD op amps on an adapter PCB, I bought the PCB adapters from DIYaudio member Peranders. The adapter pcbs had space for extra caps on the board so an extra pair of 100uF silmics were fitted on each.
The only issue I had was that one op amp failed as it did not like the class A biasing fitted as standard. Eventually I found and removed the biasing resistors.
Apart from that I have been happy with the performance of the Arcam CD player It has proved to be good enough to allow me to easily hear improvements in the rest of my system. I'm sure that more can be done, especially clock mods etc.
Regards Xoc1

PlasticIsGood 2nd February 2013 02:11 AM

JRC opamps are generally well-specified for purpose, with no nonsense. The 2114 for example was used in preference to 5532 by Marantz and others in some very good machines. Biasing for class A is common for 5532 I think, so possibly equally appropriate for JRC2114.

Xoc1 2nd February 2013 08:43 PM

The Arcam CD players are nicely designed.
Maybe that's why there are not that many documented modifications for them!
The LME49710 op amps were a definite upgrade.:)

stephensank 3rd February 2013 07:22 PM

I am very firmly of the belief that anything better than an old 5532 type of opamp will reveal too much of the wolfson dac's horribly metallic treble. The ancient opamps and grotty electrolytic coupling caps will gloss over enough of this to make it sound acceptable. Just my opinion, as one who can't see how anyone can stand those dac chips.

sutantoroy 26th September 2017 07:00 PM

Based on Arcam CD 73 circuit here, is there significant results to change the opamp of JRC 2114D and TL072CP on the digital to analogue conversion section? The service manual writes that audio output from dac is differential outputs which will have +/- offset respectively. The differential audio output are summed by JRC 2114D before driving into the output opamp which is also JRC 2114D, and then DC offset removed by servo opamp TL072CP providing DC coupled output.

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