Re: Re: Re: Almost done...
If you end up running warm, you could try quiet undervoltaged fans on each side to create wind tunnels.
How did you do the light (power button?) on the front of the case?
I've gotten similar heatsinks for similar price on eBay, and there's a very simple solution and is what I did: I cut them across the fins and arranged the pieces side by side, with fins running vertically. Cutting is simple if you have or borrow a circular saw, as the hardware store has specialty wheels you can use to cut metal for like $10.syn08 said:
If you end up running warm, you could try quiet undervoltaged fans on each side to create wind tunnels.
How did you do the light (power button?) on the front of the case?
Re: Re: Re: Re: Almost done...
You can ask the eBay guy to cut the HSs for you in two 6" pieces, its free. This is what I would do today if I would order them. About machining, it should be avoided here like plague (due to costs). I'd rather wait and buy my own circular saw for $100 from Canadian Tire rather than paying $40 for slicing two pieces of aluminum.
The switch is purchased.
http://www.bulgin.co.uk/PDFs/CatNo82/CatNo82pages/Page_183_2005_Cat.pdf
Its an antivandal momentary pushbutton. You need to add a circuit to convert it to toggle operation and of course to have provisions in the power supply electronics for a control input. My control input enables the +/-55V supplies via on board relays, everything else (+/-12V and +5V) is powered via the back panel rocker switch.
abzug said:
You can ask the eBay guy to cut the HSs for you in two 6" pieces, its free. This is what I would do today if I would order them. About machining, it should be avoided here like plague (due to costs). I'd rather wait and buy my own circular saw for $100 from Canadian Tire rather than paying $40 for slicing two pieces of aluminum.
The switch is purchased.
http://www.bulgin.co.uk/PDFs/CatNo82/CatNo82pages/Page_183_2005_Cat.pdf
Its an antivandal momentary pushbutton. You need to add a circuit to convert it to toggle operation and of course to have provisions in the power supply electronics for a control input. My control input enables the +/-55V supplies via on board relays, everything else (+/-12V and +5V) is powered via the back panel rocker switch.
Re: Re: Re: Re: Re: Re: Re: Re: Cmcl
You may want to change C1 to 100nF/400V, U2 has to hold 600V (but preferable 800V), something like the OnSemi MAC12SN. Depending on the comparators you are using, C1 may need some further experimenting/adjusting. 220nF (or 100nF for 220V) would work for MAX972 and TLC352.
Note that the triac has also to be sensitive, with a gate trigger current lower than 5mA. If you can't get such a triac, you need to further increase C1.
You may also want to increase R9 to 47ohm/10W wirewound but then you have to (again) experiment this value anyway, to match your amp power requirements. The idea is to have (at power on) only 50% or less of the AC voltage across the load (toroid, modelled as R10). The triac will need a decent on board heatsink of about 10-15C/W (I am using a 10C/W but the current is larger (and so is the forward drop) at 120V).
AndrewT said:
You may want to change C1 to 100nF/400V, U2 has to hold 600V (but preferable 800V), something like the OnSemi MAC12SN. Depending on the comparators you are using, C1 may need some further experimenting/adjusting. 220nF (or 100nF for 220V) would work for MAX972 and TLC352.
Note that the triac has also to be sensitive, with a gate trigger current lower than 5mA. If you can't get such a triac, you need to further increase C1.
You may also want to increase R9 to 47ohm/10W wirewound but then you have to (again) experiment this value anyway, to match your amp power requirements. The idea is to have (at power on) only 50% or less of the AC voltage across the load (toroid, modelled as R10). The triac will need a decent on board heatsink of about 10-15C/W (I am using a 10C/W but the current is larger (and so is the forward drop) at 120V).
Re: Re: Re: Re: Re: Almost done...
I'm using antivandal pushbuttons as well, but I haven't seen ones with lights here... I love the ring of light looks yours has.
I didn't say take it for machining--I cut them myself. Machining at home is fun. Even small amounts of milling can be done with a tabletop drill press (I used it to even out heatsinks' backs that weren't level), though it needs arm strength and is dangerous, and wears the bearings down fast.
I'm using antivandal pushbuttons as well, but I haven't seen ones with lights here... I love the ring of light looks yours has.
Done.
Now testing...
No significant issues, the only strange things are:
1. At -121 dB, S/N seem to be a little higher than what was measured before putting two channels in the case. It is therefore very hard to measure the THD20.
2. A slight drift of the THD20 value. After 1 hour warmup, THD20 floats around 1ppm with a period of about 15 minutes.
After a few hours of running at 187W/4ohm, the case temperature is about 55C, heatsinks are at about 70C. The fans kick in every 10 minutes for about 2 minutes.
Now testing...
No significant issues, the only strange things are:
1. At -121 dB, S/N seem to be a little higher than what was measured before putting two channels in the case. It is therefore very hard to measure the THD20.
2. A slight drift of the THD20 value. After 1 hour warmup, THD20 floats around 1ppm with a period of about 15 minutes.
After a few hours of running at 187W/4ohm, the case temperature is about 55C, heatsinks are at about 70C. The fans kick in every 10 minutes for about 2 minutes.
Attachments
Case closed 
- Site updates starting next week.
- Auditions scheduled to start next weekend with a group of friends contributing with a pair of B&W 801 speakers, a Mark Levinson No.32 preamp, a Rega Planar 5 turntable with a Dynavector MC cartridge and a Krell SACD player.
Still looking for a cheap option to oxidize the aluminum front panel...
This was the most complex project I've ever completed.
- Site updates starting next week.
- Auditions scheduled to start next weekend with a group of friends contributing with a pair of B&W 801 speakers, a Mark Levinson No.32 preamp, a Rega Planar 5 turntable with a Dynavector MC cartridge and a Krell SACD player.
Still looking for a cheap option to oxidize the aluminum front panel...
This was the most complex project I've ever completed.
Attachments
Hi,
Wow! Looks fabulous!
For anodizing, you can try gun barrel bluing. The front must be extremely clean for this to work (just like when doing a gun barrel). Practice on some scrap first. The longer you leave it on, the darker it gets. Finger grease will damage the finish, but that is repairable.
Try another preamp. The ML tends to sound a little "edgy", as does a Krell. Some day I would really love to hear this amp. It looks great on paper.
-Chris
Wow! Looks fabulous!
For anodizing, you can try gun barrel bluing. The front must be extremely clean for this to work (just like when doing a gun barrel). Practice on some scrap first. The longer you leave it on, the darker it gets. Finger grease will damage the finish, but that is repairable.
Try another preamp. The ML tends to sound a little "edgy", as does a Krell. Some day I would really love to hear this amp. It looks great on paper.
-Chris
anatech said:
Unfortunately, I don't own any high end sources, preamps or speakers. That's why I have to rely on what others are willing to provide for testing.
I'll look into the gun barrel bluing thing. I've found this company in Etobicoke http://www.brimacanodizing.com/ and I'll call them tomorrow for a quote.
I'll give you a call about listening to this amp ASAP.
Sites are updated
Both sites are preliminary updated with new pages, images and data (Gerbers, schematic archives, etc...). There are more details to follow in the next days and potentially some bug fixes. Edmond's web site currently seems to be very difficult to update via FTP (the FTP client crashes when updating files in batches) so I hope they are in good sync.
Feedback is welcomed. If you think I should add anything else regarding this project, just drop a me line.
Both sites are preliminary updated with new pages, images and data (Gerbers, schematic archives, etc...). There are more details to follow in the next days and potentially some bug fixes. Edmond's web site currently seems to be very difficult to update via FTP (the FTP client crashes when updating files in batches) so I hope they are in good sync.
Feedback is welcomed. If you think I should add anything else regarding this project, just drop a me line.
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