DIY PCB for dual mount TDA1541 (***Part-1***)

Could not resist getting this DIY PCB to attempt simplifying twin mounting the TDA1541/A since there has been quite a few notes of it being done by well-known manufacturers eg Accuphase, Nakamichi, to deliver better DAC processing resolution etc.

Have always deferred the "twin mounting" as preferred a less tedious or permanent solution ... until now!

Kit supplied components, top view

Kit supplied components, bottom view

Kit supplied components, with the row of pins slotted into position only

Kit supplied components, slot into place and straighten using DIP-24

Kit supplied components, slot into place and straighten using DIP-24 and held in-place by zip tie, before soldering

To be continue ...

Kenwood KT-5020 (***Follow-up***)

Was window shopping in town when I stumble upon this little gem.

Kenwood KT-5020

FMTUNERINFO rates the KT-5020 as a top-10 contender among all the devices it has tested over the years. Naturally pickup it up as it was too good an opportunity to pass over.

The tuner has a simple, intuitive and easy to use interface with auto-tuning and set of A/B memory presets for both AM and FM - really ... no manual required.

As per reviewed in stock form by FMTUNERINFO, the KT-5020 is indeed an excellent performer which delivers with confidence!

May consider recapping it at a later stage according to the suggestions in the MODS sections of FMTUNERINFO, once I have spend time listening to the KT-5020.

11Oct, 2022

Finally opened up the KT-5020 - no fancy capacitors in-sight (just brown ELNA;s) but yet able to attain a top-10 spot in the shoot-out performed by FMTUNERINFO!!!

Single motherboard of the KT-5020

DIY CDM-9 tray gear replacement

Was helping a friend replace the aging CD player tray gear on his Arcam Alpha 5 CD player ... did not expect I would need to dissamble the enitre machine to get the task done😩

The Arcam Alpha 5 uses a CDM-9 mounting mechanism and because the Arcam box is a solid part ....

New tray gear on LHS of the pix

There was really no choice as there was no release mechanism for removal of the CD tray itself, to simplify removal of the CD mount mechanism eg alike VAM12.1. The gear is secured by 2-torx screws on the bottom of the CD mounting mechanism. The CD mounting mechanism was in-turn then secured to the motherboard by 2 screws covered by hard plastic (after the threads)!!!

LHS is the new, vs, the removed CDM-9 tray gear on RHS

TIP - Remember to grease the shaft on the CD mounting mechanism before inserting the new gear into place ... use suitable grease which will not "eat-into" the plastic, available from electronics part shops

REVISIT#2 - DIY TDA1541A DAC

Recently retrieved the unit (REF: http://myoldvintagehifi.blogspot.com/2018/04/revisit-diy-tda1541a-dac-with-usb.html) from storage for a listen, only to discover that it did not sound as clear nor as precise as my Meridian 600-series DAC. I do not expect it to best the Meridian but the reproduction was clearly "more muddle" than it could have been.

Hence I Google-d for TDA1541A DAC schematics and upon review, discovered the capacitor values deployed in the output stage (where the opamp are) can vary drastically, depending on implementation - section encircled by yellow line in the pix below.

Output section with op-amps

Cross checking the Google-d information for the capaciitors deployed in the op-amp section, vs,  the values etched onto the op-amp section of  the PCB, these values differ drastically. And examining the capacitor themselves, again result in different values than the etched values on the PCB next to the capacitor itself!😒 Well, what can I say - I did buy it from a China based eBay seller....

For the record, all the blue capacitors deployed in that section are Vishay 1nF 100V. 

After some basic tracing of the PCB connectivity, I decided to try replacing the encircled capacitors in the pix below with Wima 100pf 100V.

1st Capacitor to be changed in op-amp section

Opon power-up, output clearity and realism (being less muddle-d) has been drastically improved ... will update after I have an opportunity to "run-in" the change.