It’s an open design so I welcome people to build and enjoy it. Nice that Prasi made Gerbers available. If you want to use the amp as it was designed with ultra low impedance circuit traces and superb layout by JPS64, I would encourage you to try the XRK PCB. Just having the huge 100A Wurth flat copper coil inductor in it is nice eye candy.
Hi X
yes i know...that is the power monster...but i try to do step by step..
i ordered it on 8.10.2023 😉
Ho Ho Ho...
Merry Chrismas....
My little Amp is working. Sounds beautiful. Strong bass, cristal clear high frequency. The rails are set to +-37 volt. Biasadjusment is 80 mA. The heatsinks keep cool after an hour. The little case has weight of 3kG, not very much. I will try a higher bias adjustment, thinking about 100 - 120 mA. I decide of the heat on the heatsinks.
My delay is not working properly. Something is wrong. I wonder why, because i tested it before with an other amp....
I have built in a speaker protection at same same place.
A secondary fault is the circuit around the pot. My idea of switching of the pot. The relais is working but doesnt switch correctly...i have to search after.
Thats will be a small thing...
Many thanks for this wonderful amp to prasi and XRK...
Peter
Merry Chrismas....
My little Amp is working. Sounds beautiful. Strong bass, cristal clear high frequency. The rails are set to +-37 volt. Biasadjusment is 80 mA. The heatsinks keep cool after an hour. The little case has weight of 3kG, not very much. I will try a higher bias adjustment, thinking about 100 - 120 mA. I decide of the heat on the heatsinks.
My delay is not working properly. Something is wrong. I wonder why, because i tested it before with an other amp....
I have built in a speaker protection at same same place.
A secondary fault is the circuit around the pot. My idea of switching of the pot. The relais is working but doesnt switch correctly...i have to search after.
Thats will be a small thing...
Many thanks for this wonderful amp to prasi and XRK...
Peter
Hi...
i soveld the problem wit the circuit around the (my) pot. I need 4 relay openers. 2 for the RCA input and two for the pot output. I took a second relay. If the relays are switched, 2 normally open connect to the boards, the 4 openers disconnect. Works fine now....happy to solve it
Peter
i soveld the problem wit the circuit around the (my) pot. I need 4 relay openers. 2 for the RCA input and two for the pot output. I took a second relay. If the relays are switched, 2 normally open connect to the boards, the 4 openers disconnect. Works fine now....happy to solve it
Peter
Hi Peter
if i read correctly your SMPS connex 300RE is 300W and +/- 24V and you wrote in post 24 that you turn it up to +/- 37V.
really? that is a big adjustment range.......that is fine
if i read correctly your SMPS connex 300RE is 300W and +/- 24V and you wrote in post 24 that you turn it up to +/- 37V.
really? that is a big adjustment range.......that is fine
Hi Chris,
oh no...i built in a Connex 300 Watt +-36 Volt RE. You could only make a adjust of 5% up or down in the past. Connex seems to make new pcb's. Its only 3 % i could change yet. I get +-37 Volt now.
Perhaps you mean my test transformer ? 24x2 Volt ac to +-35 volt dc ?
To change something on the Connex Boards may possible, but to difficult for me.
This is the SMPS https://www.audiophonics.fr/en/smps-power-supply/smps300re-power-supply-module-300w-36v-p-6816.html
The picture is taken from on old one, not updated by audiophonics.
For the next FH9 amp i will order a Hypex SMPS 400/180. Built in speakerprotection and low ripple for a smps. In the past i built a amp with ucd 180 HxR. Not my amp...straight frequency over all and to harsh at high frequency..loveless...
The Hypex SMPS 400/180 will deliver +-46 volt. Its a good working alternative to connex.
Peter
oh no...i built in a Connex 300 Watt +-36 Volt RE. You could only make a adjust of 5% up or down in the past. Connex seems to make new pcb's. Its only 3 % i could change yet. I get +-37 Volt now.
Perhaps you mean my test transformer ? 24x2 Volt ac to +-35 volt dc ?
To change something on the Connex Boards may possible, but to difficult for me.
This is the SMPS https://www.audiophonics.fr/en/smps-power-supply/smps300re-power-supply-module-300w-36v-p-6816.html
The picture is taken from on old one, not updated by audiophonics.
For the next FH9 amp i will order a Hypex SMPS 400/180. Built in speakerprotection and low ripple for a smps. In the past i built a amp with ucd 180 HxR. Not my amp...straight frequency over all and to harsh at high frequency..loveless...
The Hypex SMPS 400/180 will deliver +-46 volt. Its a good working alternative to connex.
Peter
Hi Peter
yes i see on the photo...its written with a blue pen 36.
thanks
i did the smps journey with the class D amps in 2017...maybe i try again...will see...
chris
yes i see on the photo...its written with a blue pen 36.
thanks
i did the smps journey with the class D amps in 2017...maybe i try again...will see...
chris
If you need a unique and low cost heatsink and chassis for the FH9, try a griddle amp. That’s how I built mine.
https://www.diyaudio.com/community/...-a-budget-conscious-heatsink-solution.355302/
https://www.diyaudio.com/community/...-a-budget-conscious-heatsink-solution.355302/
hi X,
i know that crazy idea. i am old fashioned...i need a "classic" housing...especially if i borrow the amp to friends.
i know that crazy idea. i am old fashioned...i need a "classic" housing...especially if i borrow the amp to friends.
I understand, good friends can’t be electrocuted by your hobby. 🙂
I am getting ready to install a 40W class A amp into a “soon to be classic” custom chassis I designed.
Custom aluminum brackets for trafo donuts too. This would work for a 300W class AB I think.
Prototype screws for test fit are wrong color. Black hex drive all the way.
I am getting ready to install a 40W class A amp into a “soon to be classic” custom chassis I designed.
Custom aluminum brackets for trafo donuts too. This would work for a 300W class AB I think.
Prototype screws for test fit are wrong color. Black hex drive all the way.
Thank you XRK for the tip. I will have a look to she shop.
The griddle amp was a nice idea, but to big for my application. Your case i find extremly beautiful....👍
The griddle amp was a nice idea, but to big for my application. Your case i find extremly beautiful....👍
pre installation done...
to install the donut like this i have to adjust more then once... 🤣
back panel looks not so nice...a lot of holes and not in the same line....but it was an AVR 😉
to install the donut like this i have to adjust more then once... 🤣
back panel looks not so nice...a lot of holes and not in the same line....but it was an AVR 😉
Attachments
Nice case repurposing. It’s amazing how much retail audio was sold in thin stamped sheet steel cases. No one complained.
Happy new year to everybody and best wishes....
I have built a second FH9 with more power in a bigger case. Not tested yet, follows in the next days. The Connex SMPS works with +-45 Volt, 500 Watt.
Don't need to buy a 400/180 Hypex SMPS, because I found this SMPs at home. I was not sure if the SMPS will work correctly at the Aux Voltage. By a stupid mistake i damaged the negativ aux output....fixed it with new smd diodes. Working again correctly... 🙂
Perhaps i have to drill some holes in the ground plate. The top plate has vents already. The smps touches the top plate with its heatsinks.
greetings
Peter
I have built a second FH9 with more power in a bigger case. Not tested yet, follows in the next days. The Connex SMPS works with +-45 Volt, 500 Watt.
Don't need to buy a 400/180 Hypex SMPS, because I found this SMPs at home. I was not sure if the SMPS will work correctly at the Aux Voltage. By a stupid mistake i damaged the negativ aux output....fixed it with new smd diodes. Working again correctly... 🙂
Perhaps i have to drill some holes in the ground plate. The top plate has vents already. The smps touches the top plate with its heatsinks.
greetings
Peter
![IMG_20240103_142949[1].jpg](/community/data/attachments/1162/1162846-1f49b4d2bf82f3b502c7ec4f663eb792.jpg?hash=H0m00r-C87)
![IMG_20240103_143005[1].jpg](/community/data/attachments/1162/1162848-3db61c7f4a1b51a3c3ac94c66545f133.jpg?hash=PbYcf0obUa)