Finally I received the pair of LME4970HA op-amps from Farnell. In they went and at the same time I bypassed and disabled the HDAM.
Wow! what a open and detailed sound. This is a great mod.
But the op-amps run very hot - can feel it when touching for few seconds. Is this normal? Does any of you use heat-sinks on these?
Wow! what a open and detailed sound. This is a great mod.
But the op-amps run very hot - can feel it when touching for few seconds. Is this normal? Does any of you use heat-sinks on these?
Yes the Metal CAN 49720HA works quite hot and for peace of mind I put a heat sink on it
Attachments
My laser has annoyingly decided to be very selective about which tracks and discs it plays. I have cleaned it but this makes no difference. Based on what I have seen on here, I understand that it is likely that the laser needs replacing.
Does this mean I need to replace the whole of the plastic assembly on which the laser and tray sit, or will the laser come out on its own?
I have a second machine bought on ebay for spares (thank goodness, for times such as these) so all options are open to me. Those who have done this before: what would you suggest?
Thanks in advance.
Does this mean I need to replace the whole of the plastic assembly on which the laser and tray sit, or will the laser come out on its own?
I have a second machine bought on ebay for spares (thank goodness, for times such as these) so all options are open to me. Those who have done this before: what would you suggest?
Thanks in advance.
It's LME49720HA (Missing the digit "2" in my post)
LME49720HA/NOPB - TEXAS INSTRUMENTS - IC, AUDIO OP-AMP, 55MHZ, TO-99 | Farnell United Kingdom
Its wonder me, the LME4910HA/LME4920HA sounds better than HDAM?
Otherwise some use discrete OPAs like the OPA-line from audio-gd
Audio-gd Discrete OPA
Are this for a Marantz SA 7001 KI recommendable?
I suggest before the laser dies you may try trimming the laser voltage by adjusting the small VR at the back of the laser unit. This may sometime help to extend the laser life.
Higlander, can I ask how much you paid for these discrete opamps? Obviously I would need 2. There is no price on the site, just an 'ask for a quote' option.
Thanks
From my experience 49720 is definitely sound better than the stock HDAM. In lieu of 49720 someone prefers using discrete opamps like Burson or Audio-GD. Personally I like discrete opamps and they sound more smooth and analogue. But to get the most out of it the +/- 15V source supply to the opamps MUST be of very low noise.
Alternatively you may install DOS but I have no experience with it.
Thanks very much for this. I have no idea how to do this, but I am seeing my guru next week and will ask him. (As an aside, I'm assuming 'VR' means 'voltage regulator', and 'trimming the voltage' means putting a resistor in circuit or inserting a lower value regulator?)
If you refer to Audio-GD they did post the price on their web, see below:
Price:
OPA-EARTH Dual OPA USD22.5/1 unit (24*24*40)
OPA-EARTH Single OPA USD12/1 unit
OPA-MOON Dual OPA USD25/1 unit (24*24*40)
OPA-MOON Single OPA USD13.5/1 unit
OPA-SUN Dual OPA USD30/1 unit (24*24*40)
OPA-SUN Single OPA USD16/1 unit
(Without Postage)
I think the postage to UK is USD20 using DHL (very fast and good service - you can get the item in a week)
I have tried all three kinds of opamps. Earth is warm while SUN is more neutral and give more clarity. It depends on your personal preference.
For Burson it costs about £50 each in the UK but it sounds very much like Earth. DEXA also produces discrete opamps costing £30 each but I have not tried it.
Not really. Yes VR means variable resistor. Trimming means you just use a small screw driver to turn the VR.
Sorry, I must have missed the pricing on the Audio-GD site. 'Sun' is the one, I think. As always I will discuss this with my guru. Thanks again!
Apart from trimming the VR you can also try adjusting the height of the rotating magnetic clamping disc on the laser unit. In most cases a small adjustment of the distance can solve the cannot read disc problem
Apart from trimming the VR you can also try adjusting the height of the rotating magnetic clamping disc on the laser unit. In most cases a small adjustment of the distance can solve the cannot read disc problem
If I have time, I'll pop the lid tonight and have a look for this adjustment + look for the VR and maybe have a fiddle (and probably screw things up!).
