An F5 is born!
I recently rebuilt several Rawson amps for me and a friend - 2 Stereo Aleph Mini J's, 4 Aleph J Mono blocks, and a PSU on another F5. All had missing safety earths. IIRC, all but one had a single rectifier. Some wiring was scary. They're all fixed up now. You can see the pic of the old PSU boards from the bone pile. I learned a ton in the process.
The newest project I completed last night was taking a Rawson Gainclone and using the chassis to make a nice F5. Only original parts are chassis, feet, RCA's, LED, and binding posts. Thanks to this site I learned several things incorporated into the build. I used a quasimodo jig to measure snubbers. I used Jeff Young's PSU board design to make a dual rail decoupled power supply. And I have to give a huge THANK YOU to Jim "6L6" for the support over the past months. And yesterday, he was a huge help in demystifying the F5 Biasing process. It's a bit tricky, but he made it easy for me.
The amp sounds fantastic on the test speakers. Next I'll put it in the main system.
I recently rebuilt several Rawson amps for me and a friend - 2 Stereo Aleph Mini J's, 4 Aleph J Mono blocks, and a PSU on another F5. All had missing safety earths. IIRC, all but one had a single rectifier. Some wiring was scary. They're all fixed up now. You can see the pic of the old PSU boards from the bone pile. I learned a ton in the process.
The newest project I completed last night was taking a Rawson Gainclone and using the chassis to make a nice F5. Only original parts are chassis, feet, RCA's, LED, and binding posts. Thanks to this site I learned several things incorporated into the build. I used a quasimodo jig to measure snubbers. I used Jeff Young's PSU board design to make a dual rail decoupled power supply. And I have to give a huge THANK YOU to Jim "6L6" for the support over the past months. And yesterday, he was a huge help in demystifying the F5 Biasing process. It's a bit tricky, but he made it easy for me.
The amp sounds fantastic on the test speakers. Next I'll put it in the main system.
Attachments
Pass DIY Addict
Joined 2000
Paid Member
Yes, Well done again! In a sad sort of way, there seems to ALWAYS be a market for cleaning up the messes that others make 😉
Do the heat sinks work in this orientation? enough Ventilation? Do you have a hole in the Bottom plate under the sinks?
I also thougt About this way to mount the heatsinks. but be worried they may get to warm.
I also thougt About this way to mount the heatsinks. but be worried they may get to warm.
Pass DIY Addict
Joined 2000
Paid Member
Sharp looking set of amps you have there! A pile of these small and great amps is great for so many uses...
Thanks, Eric. These are just the stock kits, but these builds give me confidence to do more. Now I need to build a preamp and speakers for these new ACAs.
And you are right, so many uses, I'm impressed with how the v1.6 ACAs are so flexible - can be used as stereo, monoblocks, bridged, balanced. Good stuff!
You have done AMAZING work fixing all the issues built into them and making them safe and perform well. Bravo!!
rhthatcher,
Wow, you have been busy... and probably gained a few pounds of muscle! Quite a stack of Class A amplifiers there.
Wow, you have been busy... and probably gained a few pounds of muscle! Quite a stack of Class A amplifiers there.
Nice work Rhthatcher! You seem to be a magnet for these rawson pieces and it's
great that you've successfully rehabilitated them. 🙂
Dennis
great that you've successfully rehabilitated them. 🙂
Dennis
I finished the Aleph Mini Left / Right and psu boards off today and now just waiting on the toroidal to roll up this week so I can start testing!
Do you like my attempts at artistic photos with my phone and a led strip [emoji1787]
Do you like my attempts at artistic photos with my phone and a led strip [emoji1787]
M2x build
Hey Everyone
Love this site and especially this pass dedicated category. I had a couple Thule amps that I just didn't want to repair. class G type 5 channel. the amps sounded amazing when they were young but some underrated supply caps and other stuff caused them both to die an early death. I decided to reuse as much of them as possible to build a pair of M2x mono's.
the transformer had way too much voltage so I ran the primary's in series to get 19-0-19 volts AC. I used the pi design on the filter supply and with no draw it came out to only 1 mV of ripple! I have lots of those hard to get fets in another project I just could never get to work properly so I just pulled a couple out.
The amps are done and tested on my bench, I plan on putting them in my stereo next weekend. I think in total I spent about $250 CAD on building them if you don't count all the stuff I already had. the output looks really clean and there is only 1 mV of ripple on the output with no signal applied. that's nice and quiet for my speakers which are about 94 dB efficient.
There are 2 sets of outputs, one for full range and the other >60Hz
Some pics
enjoy
Hey Everyone
Love this site and especially this pass dedicated category. I had a couple Thule amps that I just didn't want to repair. class G type 5 channel. the amps sounded amazing when they were young but some underrated supply caps and other stuff caused them both to die an early death. I decided to reuse as much of them as possible to build a pair of M2x mono's.
the transformer had way too much voltage so I ran the primary's in series to get 19-0-19 volts AC. I used the pi design on the filter supply and with no draw it came out to only 1 mV of ripple! I have lots of those hard to get fets in another project I just could never get to work properly so I just pulled a couple out.
The amps are done and tested on my bench, I plan on putting them in my stereo next weekend. I think in total I spent about $250 CAD on building them if you don't count all the stuff I already had. the output looks really clean and there is only 1 mV of ripple on the output with no signal applied. that's nice and quiet for my speakers which are about 94 dB efficient.
There are 2 sets of outputs, one for full range and the other >60Hz
Some pics
enjoy
