Pass Monster + 34" Monster Subwoofer sound like a good match 
http://www.betteraudio.com/geolemon/AWT34
..
I haven't followed this story, is the Pass Monster amp going to be published for DIY'ers?
http://www.betteraudio.com/geolemon/AWT34
..
I haven't followed this story, is the Pass Monster amp going to be published for DIY'ers?
thylantyr said:
That is the plan! Nelson will publish it with specs etc once it is completed. But this will be a slow moving project. we will drop updates and info as we get things solidly nailed down.
I think the general concesious is that the 6 prototype amp channels will be finished sometime mid next summer!
We have some basics down. Power supply schematic is finished, w are just waiting on the final parts list.
Basic chassis layouts are nearly finished and are just waiting on the final parts list to finalize the Power supply and Capacitor chassis layouts.
Preliminary Amp Chassis concept is in the works.
Zero
Is it just me, or are the capacitors in the picture of that Madrigal amp not connected to anything? And it's no wonder Madrigal amps cost so much, there's no efficient way to step-and-repeat that ridiculous cactus-shaped circuit board!
As for those power supplies you guys are building: holy crap! How are you gonna explain that to the department of homeland security?
PS Vishay now owns everybody. Dale, BC, Röderstein, Ford, Volvo, Bentley, Airbus, Gazprom, etc.
As for those power supplies you guys are building: holy crap! How are you gonna explain that to the department of homeland security?
PS Vishay now owns everybody. Dale, BC, Röderstein, Ford, Volvo, Bentley, Airbus, Gazprom, etc.
Zero Cool said:
I take that as a promise, my current insane project fully occupies my ball book.
Most will need some time to find economy parts.
I just managed to acquire a quadruple of 5000VA/110V toroids, getting a large bunch of +170V caps will not be that easy.
Cant wait to see what the cooling arrangement will be.
Any reason why Casey reminds me of Clintwood Eastwood as
Josey Wales ?
OK, well the CES show is 6 days away!
Casey and I are planning on getting together at the show and
hammer 
out some details on the mechanical aspects of the design.
things have slowed due to the holidays but we are still moving forward.
We have found the inductors are going to be harder to get then first thought. a company we are wroking with has come up with some preliminary figures for the 2mh 20 amp inductors! Imagine 2 inductors made from 6ga wire, 6" in diameter and weighing in around 20lbs each! and they will STILL be dissapating 35watts each in heat! so we are still exploring our option swith those....
If any of you will be at the CES show and would like to get together and Buy Casey and I Dinner or Drinks! SPEAK UP!!! hahahahah But seriously Folks, if your going to be at CES and would like to hang and chat audio. email me and lets see what we can do to put together a mini DIY/CES get together!
Zero
Casey and I are planning on getting together at the show and
hammer out some details on the mechanical aspects of the design.things have slowed due to the holidays but we are still moving forward.
We have found the inductors are going to be harder to get then first thought. a company we are wroking with has come up with some preliminary figures for the 2mh 20 amp inductors! Imagine 2 inductors made from 6ga wire, 6" in diameter and weighing in around 20lbs each! and they will STILL be dissapating 35watts each in heat! so we are still exploring our option swith those....
If any of you will be at the CES show and would like to get together and Buy Casey and I Dinner or Drinks! SPEAK UP!!! hahahahah But seriously Folks, if your going to be at CES and would like to hang and chat audio. email me and lets see what we can do to put together a mini DIY/CES get together!
Zero
I would suggest using a nice large stack of iron laminations and a foil winding for the inductors. 35W dissipation is way too much. No matter which way you do it, there things are going to be big...
It may also be interesting to look into the largest powdered iron E core that Micrometals manufactures to see if it will work. You will get some benefit from the upward shift of permeability of powdered iron with AC excitation. What you might also want to do if you use steel lams is to use a fairly large stack of keeper laminations. These will bridge the gap and provide high inductance at low power levels to help prevent peak charging for a low load situation. When a substantial load is drawn, they will saturate, and the inductance will then be defined by the gapped laminations. 20mH does sound rather hign for a 20A filter, and any dodge you can pull to reduce the inductance at max load will help the design a lot. Another possibility would be to wind an inductor using a stack of ferrite and powdered iron. This will accomplish the same effect. This type of trick was done a lot in the old tube days, and it is known as a swinging choke. I haven't looked, but maybe the Radiotron Designer's handbook would have more to say about this technique.
It may also be interesting to look into the largest powdered iron E core that Micrometals manufactures to see if it will work. You will get some benefit from the upward shift of permeability of powdered iron with AC excitation. What you might also want to do if you use steel lams is to use a fairly large stack of keeper laminations. These will bridge the gap and provide high inductance at low power levels to help prevent peak charging for a low load situation. When a substantial load is drawn, they will saturate, and the inductance will then be defined by the gapped laminations. 20mH does sound rather hign for a 20A filter, and any dodge you can pull to reduce the inductance at max load will help the design a lot. Another possibility would be to wind an inductor using a stack of ferrite and powdered iron. This will accomplish the same effect. This type of trick was done a lot in the old tube days, and it is known as a swinging choke. I haven't looked, but maybe the Radiotron Designer's handbook would have more to say about this technique.
Dave and Casey,
I suppose it's possible you did not get my email, what with the
world-wide plague of viruses bearing my email address, but
I indicated that the 2 mH was a strictly nominal value. I would
happily work with 1 mH at 10 amps - and I know that Ersin will
sell that to you for less than $10. We can make up any shortfall
with MORE CAPACITANCE (emphasis means echo canyon effect).
In any case, I don't want to get hung up on inductors. I want to
see this project move along. As I see it, we have a need for a
really coherent multi-chassis design (or give up any pretense
toward that and build it in wood crates). Either is OK by me.
I suppose it's possible you did not get my email, what with the
world-wide plague of viruses bearing my email address, but
I indicated that the 2 mH was a strictly nominal value. I would
happily work with 1 mH at 10 amps - and I know that Ersin will
sell that to you for less than $10. We can make up any shortfall
with MORE CAPACITANCE (emphasis means echo canyon effect).
In any case, I don't want to get hung up on inductors. I want to
see this project move along. As I see it, we have a need for a
really coherent multi-chassis design (or give up any pretense
toward that and build it in wood crates). Either is OK by me.
That was my mistake. I looked back at the earlier post, and 2mH was the target value. This is not too far off for operation at 20A, and should be doable without the 35W dissipation. I would suggest using a foil winding as before with steel EI laminations. This will give a good value of inductance per unit volume, as silicon steel has a pretty high saturation flux density. If you do an EI butt stack, with the airgap between the I bar and the Epiece, then you can do a swinging choke by reversing a small stack of Es and Is so that the reversed E laminations bridge the gap bridge the gap. This will result in a high inductance value for low excitation current, tapering off to the nominal 2mH at high current. It may also be possible to do the inductor with a large powdered E core. Check out the Micrometals web site for details on their product line (www.micrometals.com). Their type 26 material is suitable for 60Hz operation.
Nelson,
I did get your email, i was just stating where we are currently at. with the holidays and all, we slowed down a bit. Casey and I are looking forward to meeting and hammering out all the rest of the details so we can start the CNC machines grinding out our chassis!!!
We will be back on track in no time im sure.
Zero
I did get your email, i was just stating where we are currently at. with the holidays and all, we slowed down a bit. Casey and I are looking forward to meeting and hammering out all the rest of the details so we can start the CNC machines grinding out our chassis!!!
We will be back on track in no time im sure.
Zero
I just took the trouble to look all the way through this thread and find the proposed schematic for the power supply, so I now have some background on you guy's needs. Depending on the design philosophy (peak power only, or a solid RMS power rating), you may want to consider changing the power supply topology somewhat. If sustained RMS power rating is required, then there are going to be issues with transformer and first stage filter capacitor ratings. The first cap before the inductor will see a lot of ripple current, and this is passed right down the line to the rectifiers and transformer. How much everthing really sees will depend to a large part on line impedance, transformer leakage incuctance, etc. Suffice it to say, if you put a decent current probe at the transformer output, you will be shocked by the peak current coming out of the secondary when the rectifiers conduct at the peak of each AC half cycle. If you keep with this approach, you will want to size the transformer based on sustained power and the actual power factor it presents to the AC line, so the VA rating of the transformer should be Pout/PF. A PF of about 0.6 would be a good starting point for a nasty capacitive input filter such as this. The derating also applies to the switch and the fuse. The first filter cap will need to be sized to withstand the ripple current. Some sort of active inrush protection may be in order to prevent all sorts of mayhem when you turn on the power switch. I don't like seeing the lights in the room dim when I switch on an amplifier......
An alternative approach would be to shift things around somewhat and use an inductive input filter. This would definitely calm down the peak current through the transformer and rectifiers, and result in lower output ripple as well. The down side is that you will need a higher voltage transformer for the same output voltage, as the filter is now averaging rather than peak detecting the rectified AC waveform. This is what I had in mind when I was suggesting a swinging choke for the filter, as an inductive input filter will tend to peak detect when the amp is idling unless you have a high value of filter inductance or a swinging choke. An alternative to a swinging choke would be a couple of series chokes, one that is ungapped or has a very small gap, and one that is gapped to withstand the entire output current. The first choke would provide high inductance for idle conditions, and saturate when substantial output current is drawn, leaving the lower inductance choke to carry the load. All this is amenable to simulation using SPICE once you decide on the amplifier idle current and sustained power delivery. The design techniques for inductive input filters can be found in the Radiotron Design Handbook. I am planning on using an inductive input filter for my Class A amp that I have in the works. My initial bench testing has been very encouraging so far. Of course with a Class A design, the choke selection is simplified due to the high idle current.
My basic point is that there are a lot of things you can get away with in terms of power supply design when the output power is only a couple of hundred watts, but if you want to deliver a solid kilowatt, a change of design philosophy may be in order to make things easier for the poor unsuspecting components as well as the power line that has to service them
An alternative approach would be to shift things around somewhat and use an inductive input filter. This would definitely calm down the peak current through the transformer and rectifiers, and result in lower output ripple as well. The down side is that you will need a higher voltage transformer for the same output voltage, as the filter is now averaging rather than peak detecting the rectified AC waveform. This is what I had in mind when I was suggesting a swinging choke for the filter, as an inductive input filter will tend to peak detect when the amp is idling unless you have a high value of filter inductance or a swinging choke. An alternative to a swinging choke would be a couple of series chokes, one that is ungapped or has a very small gap, and one that is gapped to withstand the entire output current. The first choke would provide high inductance for idle conditions, and saturate when substantial output current is drawn, leaving the lower inductance choke to carry the load. All this is amenable to simulation using SPICE once you decide on the amplifier idle current and sustained power delivery. The design techniques for inductive input filters can be found in the Radiotron Design Handbook. I am planning on using an inductive input filter for my Class A amp that I have in the works. My initial bench testing has been very encouraging so far. Of course with a Class A design, the choke selection is simplified due to the high idle current.
My basic point is that there are a lot of things you can get away with in terms of power supply design when the output power is only a couple of hundred watts, but if you want to deliver a solid kilowatt, a change of design philosophy may be in order to make things easier for the poor unsuspecting components as well as the power line that has to service them
That fine I guess, but if I'm ever foolhardy enough to design my own kilowatt amp, I'll think twice about using a straight capacitive input filter. One other thing I didn't think of at the time would be that the power factor of a straight capacitive input filter would make it impossible to get the full kilowatt out of a 15A outlet. A 20A outlet or 220V input would be needed to meeet safety codes. That's all I'll say about the subject, and the last I'll contribute to this thread.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.