Right, the capacitor thing looks as follows now:
D3 12
Kram 12
Jason 30
Jon 8
me ~46 (at the moment)
And Jon, you shold be more than fine with your trasformer setup like that, just make sure to keep your grounding all nice and clean (as I'm sure you have been told way too much already).
As far as FET's go, but me down for 36 for now (will these be pre matched at all, or just ones from a large order from some supplier?)
D3 12
Kram 12
Jason 30
Jon 8
me ~46 (at the moment)
And Jon, you shold be more than fine with your trasformer setup like that, just make sure to keep your grounding all nice and clean (as I'm sure you have been told way too much already).
As far as FET's go, but me down for 36 for now (will these be pre matched at all, or just ones from a large order from some supplier?)
FETS
Hi BP,
thanks for the GC advice - that is my 4 x GC monoblocks in one box (cos the tranny is so cheap). That'll be fed by my soon-to-be-constructed ESP P88 (with OPA627s - and quite possibly superregulated).
The FETs, I understand, are all going to be matched by Anders. Is that correct, D3?
So, running total for FETs is:
BP - 36
Me - 32
D3 - 50
Kram - 32
Is that correct??
Cheers!
Jon
Hi BP,
thanks for the GC advice - that is my 4 x GC monoblocks in one box (cos the tranny is so cheap). That'll be fed by my soon-to-be-constructed ESP P88 (with OPA627s - and quite possibly superregulated).
The FETs, I understand, are all going to be matched by Anders. Is that correct, D3?
So, running total for FETs is:
BP - 36
Me - 32
D3 - 50
Kram - 32
Is that correct??
Cheers!
Jon
Variable speed fan cooling
Not sure where i got the link from - try the "learning from PC overclockers" thread, but i saw some little pyramid style fan speed controllers - you put them inside your case and they increase the fan speed as the temperature inside your case rises.
Another trick is to use a thermal switch on the heatsink - feed the fan via a resistor or a chain of diodes (each diode drops 0.6v) to get a base speed, then if the thermal switch trips use it to short out the resistor/diode chain to supply full voltage to the fan. Very simple and cheap!
Not sure where i got the link from - try the "learning from PC overclockers" thread, but i saw some little pyramid style fan speed controllers - you put them inside your case and they increase the fan speed as the temperature inside your case rises.
Another trick is to use a thermal switch on the heatsink - feed the fan via a resistor or a chain of diodes (each diode drops 0.6v) to get a base speed, then if the thermal switch trips use it to short out the resistor/diode chain to supply full voltage to the fan. Very simple and cheap!
cans + heat
BP please increase my order to 14 cans! Thanks.
Many thanks.....for all the ideas....I am definately going to use forced air.......but only at low speeds....I recon it should double sink effiency even at pretty low air flows.........
Jason those pyramid controllers are pretty nifty...........I may well experiment on that...............the circuit you describe for temp control sounds interesting........any chance of a sketch????
Richard............. from sunny ''notlob''BP please increase my order to 14 cans! BP please increase my order to 14 cans!
BP please increase my order to 14 cans! Thanks.
Many thanks.....for all the ideas....I am definately going to use forced air.......but only at low speeds....I recon it should double sink effiency even at pretty low air flows.........
Jason those pyramid controllers are pretty nifty...........I may well experiment on that...............the circuit you describe for temp control sounds interesting........any chance of a sketch????
Richard............. from sunny ''notlob''BP please increase my order to 14 cans! BP please increase my order to 14 cans!
HI SPEED RECTIFIER??
BP take a look at this...........looks quite interesting....
what do you think??
http://home.swipnet.se/~w-50719/hifi/rfb01/index.html;)
BP take a look at this...........looks quite interesting....
what do you think??
http://home.swipnet.se/~w-50719/hifi/rfb01/index.html;)
Yeah, I have seen that before, but to be honest, I am pretty sure it would be possible to make something similar up myself and get about 50 made with a cost of about £4.00 per board (proper double sided boards with soldermasks and silkscreen). So although it may work out cheeper if you only want one or two, I think that if this was realy something people were interested in here we could come up with something a bit better suited for less money.
I guess people could be intrested in this, and if I could get together say perhaps 20 definate board orders I could go ahead and try and get a design made up.
If people start to show intrest I guess I could come up with a preliminary design and see what features and conections people would be interested in having on it.
I guess people could be intrested in this, and if I could get together say perhaps 20 definate board orders I could go ahead and try and get a design made up.
If people start to show intrest I guess I could come up with a preliminary design and see what features and conections people would be interested in having on it.
Bridge rect
Mr Pass currently uses these:-
''We are currently using the ST Micro BYW99W-200, which is
a dual "high efficiency, fast recovery" 35 amp diode at 200
volts, and have been very happy with it.
It's remarkable for us to have converted to exotic rectifiers,
as we previously were very sceptical, but we did find a distinct
sonic improvement, and they also made it easier to meet
RF noise emission standards. ''
Mr Pass currently uses these:-
''We are currently using the ST Micro BYW99W-200, which is
a dual "high efficiency, fast recovery" 35 amp diode at 200
volts, and have been very happy with it.
It's remarkable for us to have converted to exotic rectifiers,
as we previously were very sceptical, but we did find a distinct
sonic improvement, and they also made it easier to meet
RF noise emission standards. ''
Right I have had a quick look about on the RS website and found that the ones nelson uses in his maps come in at about £1.89 each (for 25+, also each package contains two diodes, but it is only realy feasble to use them as a single unit hence the rather high cost), where as the MUR860 which is so popular with the gaincloners comes in at a whole 60p each (for 25+, 52p for 100+). So I think from my point of view here I would rather go for the cheeper MUR860's.
However, I also know that these things are only specced at about 8A, so for some of the more eager amngst us this would probably be a little on the pathetic side, so I guess I could do a design based around the BYW99W-200's (which could potentialy offer up to 70A when run in parallel if you can keep them cool enough) as long as people don't mind the minor extra expense this would cause.
However, I also know that these things are only specced at about 8A, so for some of the more eager amngst us this would probably be a little on the pathetic side, so I guess I could do a design based around the BYW99W-200's (which could potentialy offer up to 70A when run in parallel if you can keep them cool enough) as long as people don't mind the minor extra expense this would cause.
Right, I have sent off a request to BG micro now for three boxes of caps and hopefuly they should be getting back to me soon with a final price so I can go ahead with the order. I should have a rough idea of how much they will cost when I get the final price form BG, but I still think it will be best to weight untill I actualy have them before collecting money off people as I have no firm indication of how much the duty and tax will be when they arrive (and I'm sure my credit card company will love me for having all of those hundresd of dollars on there for a bit 
)
edit:
you may have noticed that I have orded quite a few for myself, mainly in case anyone else decides they would like some after it is all a bit too late, so if anyone does still want one or two (or more), let me know and I can probably srot someting out.
)edit:
you may have noticed that I have orded quite a few for myself, mainly in case anyone else decides they would like some after it is all a bit too late, so if anyone does still want one or two (or more), let me know and I can probably srot someting out.
Perhaps one of us could do this, as I can't imagine that matching the FET's requires much more than setting up a simple circuit with few crocodile clips and sitting taking measurements with a multi-meter for a couple of hours, and if we get all of the devices at the smae time t will be fairly likely they will com from the smae bathc nad be quite close in tolerances in any case.
BRIDGE, FETs etc
Hi All,
OK, first Kram is in for 32 FETs.
Secondly, understand that Anders cannot supply in the quantities we want. Now, what is it we need to measure on the FETs? (Noob Me! ). ISTR that there are small testers for passive and active components (also Cat 5 cables etc). Maplin have them on offer at the moment. If this is what we need, then I may be persuaded to make the investment.... I do have a reasonable DMM, though. If this is what we need, then I will be pleased to sit and make measurements to an agreed standard and sorting model.
Finally, the bridge issue:
I have a couple of bridge PCBs from Avondale Audio
http://www.users.zetnet.co.uk/avondale/
and plan to get some more for my 8-bridge 4-channel gainclone. Now, I also have a very nice tube of 50 MUR860 diodes from my friends at OnSemi. The Avondale Bridge is described as:
FWB1 - Schottky Full Wave Bridge Rectifier
** ".....what a superb improvement for so little effort" - BL Manchester
A jolly quick amplifier upgrade indeed
Comprises 4 x 20A @ 200V Dual Schottky Diodes, with non - ferrous fixings - overall size 68mm X 33mm
Drop one into your power amplifier or pre-amp for an instant upgrade. All 'push on' connectors.
Ready built Price: £22.00 - Bare Silk Screened PCB: £4.50
As you see, it's not too expensive. I will call Len and see if there is a price break - if there is enough interest. Perhaps less hassle than making out own board, but we could customise it with heatsinks, more space etc........... Anyway, here's a pic:
http://www.users.zetnet.co.uk/avondale/Bridge.jpg
Looks nice, n'est-ce pas? I can vouch for the quality. Len can supply the 3mm hex-head fixings, but I found stainless equivalents at my local fastener suppliers. I could make up fastener kits if anyone wants. Or, if we do our own board, I could put kits together............... (with or without the diodes!!).
Cheers!
Jon
Hi All,
OK, first Kram is in for 32 FETs.
Secondly, understand that Anders cannot supply in the quantities we want. Now, what is it we need to measure on the FETs? (Noob Me!
). ISTR that there are small testers for passive and active components (also Cat 5 cables etc). Maplin have them on offer at the moment. If this is what we need, then I may be persuaded to make the investment.... I do have a reasonable DMM, though. If this is what we need, then I will be pleased to sit and make measurements to an agreed standard and sorting model.Finally, the bridge issue:
I have a couple of bridge PCBs from Avondale Audio
http://www.users.zetnet.co.uk/avondale/
and plan to get some more for my 8-bridge 4-channel gainclone. Now, I also have a very nice tube of 50 MUR860 diodes from my friends at OnSemi. The Avondale Bridge is described as:
FWB1 - Schottky Full Wave Bridge Rectifier
** ".....what a superb improvement for so little effort" - BL Manchester
A jolly quick amplifier upgrade indeed
Comprises 4 x 20A @ 200V Dual Schottky Diodes, with non - ferrous fixings - overall size 68mm X 33mm
Drop one into your power amplifier or pre-amp for an instant upgrade. All 'push on' connectors.
Ready built Price: £22.00 - Bare Silk Screened PCB: £4.50
As you see, it's not too expensive. I will call Len and see if there is a price break - if there is enough interest. Perhaps less hassle than making out own board, but we could customise it with heatsinks, more space etc........... Anyway, here's a pic:
http://www.users.zetnet.co.uk/avondale/Bridge.jpg
Looks nice, n'est-ce pas? I can vouch for the quality. Len can supply the 3mm hex-head fixings, but I found stainless equivalents at my local fastener suppliers. I could make up fastener kits if anyone wants. Or, if we do our own board, I could put kits together............... (with or without the diodes!!).
Cheers!
Jon
Atlas Component Tester
Here is the info from Maplin. This item is 50 GBP.
RQ87U - Atlas Component Analyser
·
Automatically identifies transistors, darlingtons, diode-protected transistors, resistor shunted transistors, enhancement mode and depletion mode MOSFETs, junction FETs, low power triacs, low power thyristors, diodes, diode networks, LEDs and bicolour LEDs
·
Automatic pin-out identification for above components
·
Connect the component any way around!
·
Gain measurement for transistors
·
Gate threshold measurement for enhancement mode MOSFETs
·
Semiconductor voltage drops for diodes, LEDs and transistor junctions
·
Shorted, missing and faulty component detection
·
2 line scrollable display
·
Coloured, gold-plated universal probes
·
Auto power-off
·
Battery and detailed manual supplied
·
Free technical support
Here's a pic:
http://www.maplin.co.uk/media/largeimages/31538i0.jpg
Cheers!
Jon
Here is the info from Maplin. This item is 50 GBP.
RQ87U - Atlas Component Analyser
·
Automatically identifies transistors, darlingtons, diode-protected transistors, resistor shunted transistors, enhancement mode and depletion mode MOSFETs, junction FETs, low power triacs, low power thyristors, diodes, diode networks, LEDs and bicolour LEDs
·
Automatic pin-out identification for above components
·
Connect the component any way around!
·
Gain measurement for transistors
·
Gate threshold measurement for enhancement mode MOSFETs
·
Semiconductor voltage drops for diodes, LEDs and transistor junctions
·
Shorted, missing and faulty component detection
·
2 line scrollable display
·
Coloured, gold-plated universal probes
·
Auto power-off
·
Battery and detailed manual supplied
·
Free technical support
Here's a pic:
http://www.maplin.co.uk/media/largeimages/31538i0.jpg
Cheers!
Jon
I'm not too sure I would trust that bridge to run with the sort of curents that will be used with this project as it is. This is mainly because of the heatsinking or lack there of, as even with a lowly 5A bias curent, with a minimum voltage drop of 0.8V (that's for a 100V schottkey, I believe this would be higher for a 200V type) you would be looking at a total of 16W from all four diodes, which is quite a lot to dissipate just by using the PCB as a sink.
I think in this case I would be far happier going for something which had individual heatsinks for each of the power devices so that they could be happily run up to or over 10A continuousley.
If I get the work I was supposed to do this afternoon finished I might try and see what I can come up with before I head off to bead. I take it people would be happy with the spade lugs for conecting, as these will allow much larger cables to be used compared to any clamp mechanism? Plus, what would people consider a reasonable total cost when the diodes and heatsinks are figured in as well? Less than £20, a bit more, or a lot less?
I think in this case I would be far happier going for something which had individual heatsinks for each of the power devices so that they could be happily run up to or over 10A continuousley.
If I get the work I was supposed to do this afternoon finished I might try and see what I can come up with before I head off to bead. I take it people would be happy with the spade lugs for conecting, as these will allow much larger cables to be used compared to any clamp mechanism? Plus, what would people consider a reasonable total cost when the diodes and heatsinks are figured in as well? Less than £20, a bit more, or a lot less?
OK, I have had a bit more of a look about and I have found a few interesting components, and I reakon that a fairly beefy rectifier could be assembled for less than £20 using a custom PCB, the same BYW99W-200 diodes as Nelson uses in his amps, some snubber caps (and resistors?) as well as the rather nice heatsinks shown below (one for each diode). Using this configuration I think you should be able to run at up to about 20A RMS before the diodes start to overheat, which should be more than enough for this project.
edit: sadly I don't think that that component analyser will be up to the job (although I can check at work on sunday as I think there is one in the shop). It would probably require the setting up of one or two simple circuits to apply a set voltage/current to the device and then allow for certain measurements to be taken with a multimeter.
I believe there is a good article about this up on either the PASS website, or the pass DIY site so I guess these would be a good place to start looking.
An externally hosted image should be here but it was not working when we last tested it.
edit: sadly I don't think that that component analyser will be up to the job (although I can check at work on sunday as I think there is one in the shop). It would probably require the setting up of one or two simple circuits to apply a set voltage/current to the device and then allow for certain measurements to be taken with a multimeter.
I believe there is a good article about this up on either the PASS website, or the pass DIY site so I guess these would be a good place to start looking.
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