Dashpuppy's Blog

YEP ! For Christmas present I bought my lab a new tool ! Almost every year I try to buy a new piece of equipment, slowly building up my equipment pile for the bench. ! Last year was my JBC Soldering Station !

This year we got a new QA401 Audio Analyzer from QuantAsylum ! I have been reading lots about what it can do, not sure how to use this device fully yet BUT that’s the best part, learn and have fun !

QA401 Audio Analyzer – QuantAsylum < I got mine used from a Good friend in Denmark.

I also creating a series of youtube videos on how to use the device from opening to final measurements !

Been working on my SSr project over the holidays and when I had downtime at work. I’d have to say 40% just looking at the screen figuring out how to make the board flow nice, look nice, and build nice.

I’m pretty happy with Revision 2.0, it allows to be mounted to a pair of binding posts & also be mounted off board ( oh look I need to add mounting holes ) BUT wait, there is a reason for this, Revision DUAl 1.0 is going to come out soon so, we can wait for that.

Going to order 10 boards soon, then test these, if all goes well, I’ll order more boards and possibly sell kits as blank boards OR fully populated.

A nice big SMD amplifier project!

Yep, a 800watt monoblock amplifier, utilizing 14 irfp9240-irfp240 drives with 90v rails.

First step is to build test boards and make any mods for final boards. Since this amplifier is a bit older, it’s suggested to do a few test boards first.

I do have a few really good ideas tho.

Alright I’ll start off with, it has one issue, took me a while to find out what I did wrong ! BUT, it works perfect and I accomplished my goal!

What was wrong ? I somehow missed a wire in the pcb drawing process and didn’t tie input sense to the speaker terminal, very important wire too!

After finding the issue and making the missed connection she came alive and worked perfectly ! Now onto revision 1.5, made a few changes and have a few more ideas for different versions for new applications.

Yes ! A new amp in the build, one of the guys I think is the best at Amplifier designs. I’ll go into depth about that a little, i’m not saying his designs are 100% the best because yes there are other ones out there that “could” be better BUT Nelson Pass puts more energy into helping people and contributing to builds and ideas on DIY audio.com more than any other designer I know of! AND THAT from my pint of view is the best !

Now I have’t built many class AB amps in years, most of my amps in the last 10+ years have been Class A, so this one is going to be pretty sweet! At only 100 watts, I’m pretty sure it will go over the 100watt mark, and to be honest do I need more ? ( we will find out )

Photo of the boards & a few nice 1% Dale resistors installed so far !

Been waiting years for one of these, it came on sale so I snatched one up!

“UPDATE” I created a Youtube Video :

After a few months of working on this project it’s finally into the next stage! the PCB stage 😛

I have to admit, I had some issues, but not because of the circuit issues, but because of the lack of looking at the CORRECT pin out’s on the “VOM” ic 🙂 Stumbled upon my issue when going through my notes & measuring every point with my DMM, after I realized that I wired the VOM backwards and then connecting it properly IT SPRUNG to life! DERP! Live and learn !

And I did a little Video of it too !

I’ve been working on this for a very long long time ! And first I would like to say Special thanks to Thomas Uhd Larsen, a good close friend of mine on Facebook for helping me and making this possible 😛

Now, what is a SSR ? A “SSR” is a Solid State Relay, in audio they are used on the speaker output of an amplifier to protect the speaker if anything goes wrong with the amplifier. When an amplifier has problems or is going to blow up or has blown up, it sends FULL DC voltage AKA rail voltage to the speaker terminals VERY BAD and this will COOK your voice-coils and spew out TONS of smoke 😛 Not something you want !

Tipically in amplifiers they use “relays” but this is much better and faster 🙂

Short story of the circuit is here : https://sound-au.com/articles/mosfet-relay.htm

But mine is a bit different 😛 Pictures below ! When the led is on, the FETS are on passing audio signals! When the led is off! it’s in protect mode !

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I have to admit, this is the sweetest pieces of software since sliced bread ! it’s not a super easy piece of software to learn BUT DAMN ! It sure can do alot !

Over the winter I plan to learn and do lots of experiments with this software ! In the screen shot below, I am learning to simulate sinewaves for a Class A Balanced amplifier !

Software can be downloaded for free at : http://www.spectrum-soft.com/index.shtm

Been working on this project for a few months now, just about to order the pcb. After months of working on this, I have come to the conclusion that it’s much easier and less hair loss when doing pcb designs.

However, to accomplish this near perfect “test” pcb, you need to make sure all pin out’s on the pcb for the components are proper IE ECB or GDS are all accurate and point to pint ! :p Let’s not go down that rabbit hole and explain what happens when you don’t 😛

Whats a “SSR” ? SSR stand’s for Solid State Relay, these are not anything new BUT starting to become really popular in amplifier designs instead of using relays. SSR’s are much faster & don’t wear out!

Picture of my schematic !

Here is a picture of my first Printed 1:1 on paper to make sure all the pins align & look correct for spacing !

And a picture of it in 3D mode from Kicad !

Hopefully next week I get a chance to order the pcb’s and start testing and making sure everything works !