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alexcp alexcp is offline

diyAudio Member

About Me

  • About alexcp
    Location
    Florida
    Occupation
    Finance
    Country
    United States

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Blog - My DIY projects
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  • Wiki Contributions: 0
  • Wiki Comments: 0
  • Recent Wiki Activity: alexcp has no recent wiki activity
General Information
  • Last Activity: 20th July 2016 09:21 PM
  • Join Date: 9th June 2009

Blog

View alexcp's BlogRecent Entries
Latest Blog Entry

Posted 9th April 2016 at 01:51 PM by alexcp Comments 0
The designer of Cambridge Audio A3i had talked about the amp in this forum and suggested some changes to the components that bring the performance of the amp to a new level.

When I saw a cheap A3i on eBay, I decided to try it out. One channel was DOA, but it did not matter as I was about to mod it anyway.

Here is what I've done:
  1. Replaced all rectifiers (D201-D206 on the schematic) with soft recovery diodes and removed the capacitors in paralell with the diodes;
  2. Changed the grounding scheme so that the protection circuit and the relay driver are connected directly to the star ground;
  3. Added a 30ohm resistor in series with the rectifiers of the protection circuit;
  4. Replaced the electrolytic capacitors in the amplifier (but not the protection circuit) with Nichicon KA and replaced the two large power supply capacitors with Nichicon LLS;
  5. Replaced all film capacitors with Kemet PHE426 or, where PHE426 wouldn't fit, with Kemet SMR;
  6. Replaced the rectifiers
...

Posted 9th April 2016 at 01:27 PM by alexcp Comments 0
When I saw the discussions of KSA-5 headphone amplifier on head-case.org and on this forum, I thought it may be a nice use for the bag of 1000uF capacitors I had at the time. This was the main motivation for putting this Krell KSA-5 clone together.

The main challenge was to drill the front panel. The 10mm aluminum panel that came with the enclosure is easy to work with, but I wanted it to be pretty and asked the people at Modushop to CNC it for me.

Although it works ok, I think it is not a very good power amplifier for loudspeakers. As a headphone amplifier, it is no match for my Musical Fidelity X-CANv8.

Posted 9th April 2016 at 01:20 PM by alexcp Comments 0
Ever since I heard about the Hypex NCore technology, I have wanted to build a power amplifier based on Hypex NC400 modules. Here is what I got. It works very well with the preamplifier from the previous post.

I used a spare Arduino to control the SMPSes. For now, it simply allows to use a momentary push button on the front panel. I may add remote control (12V trigger or similar) later.

Posted 9th April 2016 at 01:14 PM by alexcp Comments 0
Posted in Preamps
In April 2013, Linear Audio published in Vol.5 Bruno Putzeys' article "The G Word, or How to Get Your Audio off the Ground". Linear Audio included a free PCB for the demo project from the article: a balanced volume controller, or rather a minimalist balanced preamp with two pairs of balanced inputs.

I have been looking at balanced interconnects for some time and decided to use the free PCB and build the preamp. Here is what I built.

The enclosure used is Galaxy GX247 with front and back panels custom made by Front Panel Express. It was difficult to place a C14 power inlet on the back panel, as the space is quite limited due to the central placement of the six XLR connectors. An easy solution would be to fix the power cord permanently to the preamp, but I found a compact snap-in connector that fits the 3mm back panel of the enclosure.

I understand the article is available for download at the Hypex web site, and the PCB gerbers and a...

Posted 25th June 2015 at 08:05 PM by alexcp Comments 0
Posted in Uncategorized
For every hobbyist-built amplifier in existence there are probably one thousand amplifiers which are planned on being built and maybe one hundred amplifiers that have all their parts collected in a box waiting to be built and ten amplifiers that are partially built and collecting dust in a closet.

(see full post here)
Recent Comments
Nice B1! Where did you...
Posted 18th April 2016 at 09:13 PM by marc brown marc brown is offline
I've now got a PCB Layout...
Posted 8th February 2015 at 11:06 AM by SNAPEFU SNAPEFU is offline
very good! :cheers:
Posted 28th February 2014 at 11:46 PM by sjh327 sjh327 is offline
That is the most difficult...
Posted 2nd November 2013 at 08:46 AM by alexcp alexcp is offline
How does it sound Alex?...
Posted 1st November 2013 at 02:41 PM by udailey udailey is offline
Hide this!Advertise here!

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