Skip to main content

Quad 405 Amplifier Restoration & Upgrade Using MJ15022 As Final Transistors (Part 2 Final)

Continuing from the part 1, now this amplifier will be assembly with the boards and rewiring the power supply cables. Let's take a look on the progress.



As you can see, the capacitor on the board has replaced with Elna Silmic, then the MJ15022 will also install in this board.


Apply the thermal paste when attach to the heatsink, this high quality paste will keep stick on the heat-sink and not dry by times.





The finished board with some components been replaced to the higher quality parts.



I still adding the current limit board on the speaker terminals. I believe this board can be remove completely without any effect. But for now, let it be there.


The next steps is measure the size of the board for the new power supply components.




I make a bigger hole and marking the polarity. This would be a complicated job.


Adding 100nF old stock Phillips MKT for snubber capacitors. This will lead for extra smoothing on ripple cause by rectifier.


The connection between board and transformer is now begin. Of course with the new wiring cables.


The configuration is dual mono, means it will require more cables. It is quite messy right now. And for sure, this upgrade is not for the beginner.


Now the magic happened, when the board flip to it's place, tadaa... the messy cables are now disappears.


Very tidy isn't it? You don't see much cables around now.


I am using direct connection with solder instead of the sockets. This is high voltage amp. Each channel will accept 110 volt DC from the power supply. Loose contact a little bit will lead to produce heat on the connector itself. Not a good sign for efficiency and performance.


When the power cables are completely connected to the board, then it is time for the input connection using coaxial cable. Note that this high quality interconnect cable is from Canare and actually very suitable for this kind application due to it's internal shielding and bigger cable diameter.


The components upgrade is all in place.


The rest is assembly the remaining body parts, such as side panel and lower panel of this amp.




Right now this restoration process is completely done.


This amp is now running for an initial test for next several hours. It sound promising on this test. Next time I will try to have an audition with this amplifier. I will check the sound performance and improvement of this little mighty amplifier after this upgrade.


Disclaimer: Any statement and photos in this article are not allowed to copy or publish without written permission from the writer. Any injury or loss from following tips in this article is not under writer responsibility.

Comments

Popular posts from this blog

OPA1622 Vs. OPA627 High Performance Op-amps Comparison

This op-amps comparison topic is actually boring, but at the same time, many of us still curious about what others think about it. The reason is simply because of the op-amps variation are hundreds and they are depends by the implementation. The op-amps are considerably cheap and an interchangeable electronic components but they are not built for the same function. So in this discussion, I will focus on the modern Vs. vintage high performance op-amps in the simple non-inverting pre-amplifier gain stage.

Vintage Multibit R2R DAC Tier List

At the very beginning of this year, I committed to explore the best multi-bit R2R DAC. This is simply because I have plenty of the resources (from broken old unit CD player of course) and ability to build them up. If you think this kind a recycle from old un-used unit to become something useful, than I should stated myself giving contribute for greener world:) After all DAC that I built in this year, I think it is better for me to list them up again in one single page like this. Then I will rank them up in a simple tier list. The reason for this, so you all know what my opinion about of those vintage multibit R2R DAC especially in the sound quality.

What Mazda Bose Centerpoint Does to The Music?

It has been a month since I bought and use this brand-new Mazda CX-5 as my daily cars. No doubt for the car performance, this is one of the most reliable, yet very comfortable car to drive. This Mazda CX-5 is the Elite version with 2.5-liter engine and package with Bose  audio system as a "bonus" features. This is car is very interesting, I will try to explain it from my own perspectives as a casual user, especially for the Bose audio system. Early disclaimer, I listening to this Bose audio system and in my opinion, the overall sound quality is not very special. Surprise, surprise! The sound quality is average but for sure better than most cars with non-audio brand collaboration. Let's deep down to it.