Yeah, that's what it looks like, I first thought the buzzing was coming partly from my test speakers, but then I realized its all coming from the transformer itself.
Thanks for the help guys, I learned how to measure the bias current tonight!
Coreyk
Try connecting one channel to the transformer you already have, to get an idea of the improvement you will get by going with a bigger one.
Yeah just disconnect one channel, and have a listen.
Let us know what you think
Try connecting one channel to the transformer you already have, to get an idea of the improvement you will get by going with a bigger one.
Yeah just disconnect one channel, and have a listen.
Let us know what you think
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Some transformer sizes from harbuch electronics
625VA - Outside Diameter = 135mm
800VA - Outside Diameter = 160mm
1000VA - Outside Diameter =160mm
625VA - Outside Diameter = 135mm
800VA - Outside Diameter = 160mm
1000VA - Outside Diameter =160mm
I have one other concern now, I'm using MUR860 diodes without heatsinks right now, I didn't try and check how warm they are running last night. Should I sink them or maybe move to some heavier duty chassis mounted bridge rectifiers?
Did you try disconnecting one of the channels from the transformer.
Give it a go and let us know what you think?
From what I have read the mur860 diodes perform quite nicely. So I would stick with them since you already have them. You could add small heatsinks to them, although I think you can run them with out heat sinking (I am not sure though).
Give it a go and let us know what you think?
From what I have read the mur860 diodes perform quite nicely. So I would stick with them since you already have them. You could add small heatsinks to them, although I think you can run them with out heat sinking (I am not sure though).
Speaker currently - Ribbon 3 way hybrid /bi-amped 84 db 2.83 v /m
1.8 ohm 400-5 K 1 ohm 5-20 K
Yes i have looked at the F5, F4, Aleph -J , Alephj-X , not sure which would work for me , but I'm interested in getting my feet wet and playing with one ..
Have the schematics will take a look ....
This Post need PIcs ...................🙂
Use a separate chassis for the Supply , i like to use 2 chassis and get the transformer away from the Main Board..
Hi a.wayne
As soon as you finish your amp, do yourself a favour, build Nelson's (soon to be released) big open baffle speaker.
Then in the future, you can build any amp you like.
As soon as you finish your amp, do yourself a favour, build Nelson's (soon to be released) big open baffle speaker.
Then in the future, you can build any amp you like.
Ahhh, errrr, I was hoping Nelson would build my speaker instead , then we all would have an amp that could drive anything ...................😀
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Dats a lot of reading Mega 🙂
I will give it a looksie as i have never heard of this one , care to add any comments about it ? have you built one already ?
regards
I will give it a looksie as i have never heard of this one , care to add any comments about it ? have you built one already ?
regards
The problem is not finding an amplifier that will drive your speaker load to your requirements.
It is the cost involved to build it. I think you wanted as a bare minimum 160W into 1Ohm and 85W into 8Ohm.
Lets assume 85W average and 160W average.
You need 37 to 40 volt rails to get your 85W (170W pk) into 8 Ohms.
You need around 18A to drive 1Ohms to 160W (320W pk).
You will probably want around 6 to 8 A of bias current (for push pull topology).
Let us say 8A.
8A x (2x40) = 640W of heat per channel. the heatsinks will be huge something like 350mm long by 1200mm high per channel.
You will need something like 1.5kVA transformer per channel (as a bare minimum) in reality you probably want 3kVA per channel.
Capacitors probably, 2F per channel (thats 2,000,000 uF). You could probably do it with 1F if you use CLC but the inductor will be huge.
If you have that sought of money to spend I would probably spend $2000 on a new speaker design, and around $700 on the amp.
It is the cost involved to build it. I think you wanted as a bare minimum 160W into 1Ohm and 85W into 8Ohm.
Lets assume 85W average and 160W average.
You need 37 to 40 volt rails to get your 85W (170W pk) into 8 Ohms.
You need around 18A to drive 1Ohms to 160W (320W pk).
You will probably want around 6 to 8 A of bias current (for push pull topology).
Let us say 8A.
8A x (2x40) = 640W of heat per channel. the heatsinks will be huge something like 350mm long by 1200mm high per channel.
You will need something like 1.5kVA transformer per channel (as a bare minimum) in reality you probably want 3kVA per channel.
Capacitors probably, 2F per channel (thats 2,000,000 uF). You could probably do it with 1F if you use CLC but the inductor will be huge.
If you have that sought of money to spend I would probably spend $2000 on a new speaker design, and around $700 on the amp.
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No it was 20 watt @ 8 ohm , 160 @ 1 ohm..
MEGA ,
I took a look at the A75 material ........ I likey ... off to more reading this just might be the one.... 🙂
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Awayne,
An A-75 amp with 12 output devices per rail is a hulking monster. I know, I have one on my workbench right now. If it can not drive anything it will surely pull a train load of boxcars down the track.
Everyone who has built them has good things to say. I just with the boards I got were mono.
Tad
An A-75 amp with 12 output devices per rail is a hulking monster. I know, I have one on my workbench right now. If it can not drive anything it will surely pull a train load of boxcars down the track.
Everyone who has built them has good things to say. I just with the boards I got were mono.
Tad
Haven't built it yet, but its one of the many projects on my plate, its Class A up to 75 watts, beyond that it goes into Class AB up to 150watts, and will drive into 1 ohm quite happily. The design is scalable i.e. you can up the voltages and add more outputs beyond stock. From what I've read on this board, the sound is very nice, though not as smooth and refined as Aleph (purely subjective of course). To get an Aleph to go properly into 1 ohm, it'll have to be physically gigantic or water-cooled, with many many outputs, big supply, big everything. There are some Pass designs that will work with 1 ohm, but not with a lot of power, the A75 is the closest amp here to my knowledge that meets your requirements. That being said, if you haven't built anything yet, I wouldn't recommend that as a first project, its a bit complex, and requires a fair amount of hardware. A good example: Pass DIY Gallery: A75 - Alain If your ambitious enough, anything is possible!
Take a look here: scroll down to A75
Pass DIY: Project Gallery
Take a look here: scroll down to A75
Pass DIY: Project Gallery
Mega ,
😱
It looks precisely like what i had in mind and you guys hid this from me until now 🙂 Ahhh the sight what a Monsta ....
😱
It looks precisely like what i had in mind and you guys hid this from me until now 🙂 Ahhh the sight what a Monsta ....
Go for it.
However, I would seriously consider getting your feet wet with an F5 first, even if it is only one channel.
Then go straight to the A75.
You will probably need to buy at least 100 (make it 200) n channel mosfets and at least 100 p channel mosfets to get them matched.
I would start up a new thread for this project so people can help you along the way. I will be glad to help in any way I can.
Enjoy the ride. Once you start you can't stop.
However, I would seriously consider getting your feet wet with an F5 first, even if it is only one channel.
Then go straight to the A75.
You will probably need to buy at least 100 (make it 200) n channel mosfets and at least 100 p channel mosfets to get them matched.
I would start up a new thread for this project so people can help you along the way. I will be glad to help in any way I can.
Enjoy the ride. Once you start you can't stop.
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If you are into A75 amp, I still have those parts available (except for heatsinks): http://www.diyaudio.com/forums/swap-meet/20994-75-parts-sale-not-only.html