Those STK2038IV's!!!
Here's a 2 X LM3886-to-Stk Retrofit board I made on perf-board. I designed, built, and installed it in a Technics SA350, a few months ago. I have it out for modifications while I'm doing other maintenance on the receiver. The board has snubbers, but no main filter caps, as its made to replace an STK in receivers and amps. I'll probably have FAR Circuits run a few for me in a couple months. It's the first GainClone amp I've ever built and I'm delighted at how great they sound! 2 123VA toroids and a pair of 15,000uf caps on my +/- 32V rails probably help the sound.
Here's a 2 X LM3886-to-Stk Retrofit board I made on perf-board. I designed, built, and installed it in a Technics SA350, a few months ago. I have it out for modifications while I'm doing other maintenance on the receiver. The board has snubbers, but no main filter caps, as its made to replace an STK in receivers and amps. I'll probably have FAR Circuits run a few for me in a couple months. It's the first GainClone amp I've ever built and I'm delighted at how great they sound! 2 123VA toroids and a pair of 15,000uf caps on my +/- 32V rails probably help the sound.
Attachments
heatsink
Nah like i said im sure they are well too small,or so i thought. It runs fine at low to moderate volume. It is after all open chassis. Ive done some very rough testing of heatsinks on this chip, using 22-0-22 quality traffo, quality wires (i dont mean trendy i mean short, stiff, twisted copper!) and basic techniques which often get forgotton.
The result after 8 months of v.loose testing more just monitoring temperature against volume. Even at high volumes, driven hard into 6ohm each side ive not had a thermal cutout trip ever. admittidly with theses sinks i just dont push it nd usually have a fan running.
But it is a concept piece! 😎
Nah like i said im sure they are well too small,or so i thought. It runs fine at low to moderate volume. It is after all open chassis. Ive done some very rough testing of heatsinks on this chip, using 22-0-22 quality traffo, quality wires (i dont mean trendy i mean short, stiff, twisted copper!) and basic techniques which often get forgotton.
The result after 8 months of v.loose testing more just monitoring temperature against volume. Even at high volumes, driven hard into 6ohm each side ive not had a thermal cutout trip ever. admittidly with theses sinks i just dont push it nd usually have a fan running.
But it is a concept piece! 😎
fans make a huge difference. I ran without one into 6R speakers with similar sized sink and it got soooo hot. I turned it off before anything started screeching though and upgraded sinks. I am sure a fan would have done a great job.
Uriah
Uriah
Just finished a pair of dual-mono LM3886 amps with boards from BrianGT. My unique take on them this time is that they are built into the lower enclosure on a set of Zaph ZDT3.5 speakers. Setup is simple, 200VA toroidals, and a simple pot for volume control. The heatsinks are adequate for home listening, but after blasting them at the workshop at full volume into a 3.2 ohm load, they got uncomfortably hot... No thermal trip, however.
The enclosures for the speakers and the rear panel were all CNC cut. All in all, I'm very satisfied! The amps are a good match for the speakers, and let me use the pre-outs on my receiver to their best. The rear speaker terminals allow the amplifier section to be separated from the speaker section, if desired - that way the amps could run other speakers, and the speakers could be driven by other amps, if I ever get the desire.
Rear of speakers by phidauex, on Flickr
Painted cabinets by phidauex, on Flickr
-Sam
The enclosures for the speakers and the rear panel were all CNC cut. All in all, I'm very satisfied! The amps are a good match for the speakers, and let me use the pre-outs on my receiver to their best. The rear speaker terminals allow the amplifier section to be separated from the speaker section, if desired - that way the amps could run other speakers, and the speakers could be driven by other amps, if I ever get the desire.
Rear of speakers by phidauex, on Flickr
Painted cabinets by phidauex, on Flickr
-Sam
I decided to take the comments above and make my own heat sinks.
For this one I am using LM3875's and made my own PCB's again.
Here is my latest version of a simple chip amp. (unfinished)
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An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I was just about to say the same thing about yours! I love the CLEAN design - no component out of place. I like the solid copper bus bar, too!
You say you made the heat sinks yourself - meaning you cut them on a lathe? They look fantastic.
-Sam
-Sam,
Yes I have a little bench top lathe I use to make the heatsinlks.
Your speakers are stunning. The finish is amazing.
DIY Rules!
-Bill
Yes I have a little bench top lathe I use to make the heatsinlks.
Your speakers are stunning. The finish is amazing.
DIY Rules!
-Bill
bbm3, the only thing I'd change is the sharp edges on the wood. I like a round radius, personally. other than that, I love the rest!
BBM3----WOW
BBM3..... I don't want you to think I'm stalking you ( 😀 ) but I did find the pics of your build in this thread!
Wow--great work. I love the straightforward simplicity of your designs!
(Makes me want to go back, and strip all the "bells and whistles" out of my Pass F5 DIY.....)
BBM3..... I don't want you to think I'm stalking you ( 😀 ) but I did find the pics of your build in this thread!
Wow--great work. I love the straightforward simplicity of your designs!
(Makes me want to go back, and strip all the "bells and whistles" out of my Pass F5 DIY.....)
Thanks linuxworks,
It is a work in progress that I plan to duplicate as gifts for my fiends and family.
Thanks for your input.
-Bill
BBM3..... I don't want you to think I'm stalking you ( 😀 ) but I did find the pics of your build in this thread!
Wow--great work. I love the straightforward simplicity of your designs!
(Makes me want to go back, and strip all the "bells and whistles" out of my Pass F5 DIY.....)
Hey CanAm,
It's all good.
I'll send you a PM
-BB
Both of you, great work.
I have to say those are some of the most beautiful cabs I have seen on this site.
I have to say those are some of the most beautiful cabs I have seen on this site.
The VAMP (V-twin amp).
Just like to say that thats some craftsmanship there folks, stunning
Here some pics of my girlfriends converted disco light V-Twin amp!! build diary in seperate thread.
gems amgems V-Amp front.JPGp backGems Internal.JPG.JPG
gems v-amp insivamp.JPGde.JPG
Just like to say that thats some craftsmanship there folks, stunning
Here some pics of my girlfriends converted disco light V-Twin amp!! build diary in seperate thread.
gems amgems V-Amp front.JPGp backGems Internal.JPG.JPG
gems v-amp insivamp.JPGde.JPG
Attachments
8 Channel GainClone
After watching this forum for a while I decided to build my own amplifier. Actually I'm building a complete home cinema system! The mediacenter is up and running. It can handle 12 2.5" harddisks. Just because it's possible 😛.
Mediacenter:
Now I'm busy with the amplifier. It will contain 8x LM3875 and 2 250VA transformers (1x 25V 10A each). Volume controll will be handled by the pre amp (wich I still have to build). The amplifier is getting the same housing as the mediacenter. Size (including heatsinks) is 380mm wide, 50mm high and 300mm deep. It all just fits...
Complete layout on a piece of MDF. I made 4 modules with 2 channels. Each module has 2 50V 10.000uF capacitors (except 1, still waiting for 2 capacitors). All the resistors are 1% 0805 SMT and soldered onto the bottom:
Closeup of the rear (I know, connectors are realy close to eachother, but there's no more space...). Here you can also see the 2 relays and the thermistor to power it on. Each transformer has its own fuse. The diodes are on the bottom of the power pcb. I used SMT versions for this (45V 15A). In the real case they make contact with the aluminum bottom plate:
Here you can see how precise it fits. There is about 1mm between all pcb's. I putted 6pin molex connectors between the powerboard and the amplifier modules, so I can easily replace them if necessary. The 3pin headers will be changed for the same headers as they use for computer fans:
Next is to put this all into a nice case.
After watching this forum for a while I decided to build my own amplifier. Actually I'm building a complete home cinema system! The mediacenter is up and running. It can handle 12 2.5" harddisks. Just because it's possible 😛.
Mediacenter:
Now I'm busy with the amplifier. It will contain 8x LM3875 and 2 250VA transformers (1x 25V 10A each). Volume controll will be handled by the pre amp (wich I still have to build). The amplifier is getting the same housing as the mediacenter. Size (including heatsinks) is 380mm wide, 50mm high and 300mm deep. It all just fits...
Complete layout on a piece of MDF. I made 4 modules with 2 channels. Each module has 2 50V 10.000uF capacitors (except 1, still waiting for 2 capacitors). All the resistors are 1% 0805 SMT and soldered onto the bottom:
Closeup of the rear (I know, connectors are realy close to eachother, but there's no more space...). Here you can also see the 2 relays and the thermistor to power it on. Each transformer has its own fuse. The diodes are on the bottom of the power pcb. I used SMT versions for this (45V 15A). In the real case they make contact with the aluminum bottom plate:
Here you can see how precise it fits. There is about 1mm between all pcb's. I putted 6pin molex connectors between the powerboard and the amplifier modules, so I can easily replace them if necessary. The 3pin headers will be changed for the same headers as they use for computer fans:
Next is to put this all into a nice case.
Udden, Udden!
Cool amp!!! It has the distinctive look of a "V" type motorcycle engine!
Udden, udden, imitative sound of a motorcycle engine. "Coy, don't answer the phone "udden, udden" Ray Stevens
Just like to say that thats some craftsmanship there folks, stunning
Here some pics of my girlfriends converted disco light V-Twin amp!! build diary in seperate thread.
gems amgems V-Amp front.JPGp backGems Internal.JPG.JPG
gems v-amp insivamp.JPGde.JPG
Cool amp!!! It has the distinctive look of a "V" type motorcycle engine!
Udden, udden, imitative sound of a motorcycle engine. "Coy, don't answer the phone "udden, udden" Ray Stevens
Attachments
Very creative Tom.
That is a perfect example of thinking outside of the box.
Nice DP.
Can we have a look at the bottom of your boards?
That is a perfect example of thinking outside of the box.
Nice DP.
Can we have a look at the bottom of your boards?
Nice MOD job. What's funny is that I used to own a Technics SA-450 many years back. I'm curious as to what other modifications you are making to that receiver.
It's always good to see another fellow modder like me. I myself am working on a MOD project. I am heavily modifying a Memorex MP3851 boombox. So far my modifications on it make this little, what used to be a cheap sounding boombox, into a truly phenomenal sounding boombox that always gets jaw dropping responses when even audiophiles hear it. Gotta love 8-18v chip amps that put out amazing high power. And yes my little modified boombox can easily put a Bose wave radio to serious shame. Since I can't really find the right forum on this site for MOD projects like mine I am thinking of posting my pics here in this thread, showing my detailed modifications, which there are several. Let's just say the only thing untouched is the CD player. Lol