Hi D3,
Is that £100 for both monoblocks or just for one?
If its for 2 then i think that is quite a good price especially considering the thickness of the sheets you are using.
Will this contact also be cutting the sheets to size for you or are you gonna have to do that your self?
Bigparsnip.
have you orderd your parts yet? I think it was you that posted a parts list in excel.
What is this Welbourn Labs place that you are getting your Dale V4 resistors from? does it have a website? what tolerance are these resistors?
what about these Meggit ER58 resistors from RS, they are only 5% tolerance, should we be looking at some other resistors with a higher tolerance?
I think that will do for now.
Mark 🙂
Is that £100 for both monoblocks or just for one?
If its for 2 then i think that is quite a good price especially considering the thickness of the sheets you are using.
Will this contact also be cutting the sheets to size for you or are you gonna have to do that your self?
Bigparsnip.
have you orderd your parts yet? I think it was you that posted a parts list in excel.
What is this Welbourn Labs place that you are getting your Dale V4 resistors from? does it have a website? what tolerance are these resistors?
what about these Meggit ER58 resistors from RS, they are only 5% tolerance, should we be looking at some other resistors with a higher tolerance?
I think that will do for now.
Mark 🙂
hi, I still haven't gotten round to placing the orders for the parts, although I do still want to try and get it done soon, I guess it would be nice if those of you who did want to get some of the parts together would let me know soon though, so people don't miss out if I place the order without their parts.
If you want to have a look at the welborne labs hompage, you should click here although their sight is an absolute nightmare to navigate, so if you only want the dale resistors (1% tollerence, but if enough of us get some I can match them to potentialy better than 0.05% before I send them out to people) you could try this link insted.
The Meggit resistors from RS are specified as 5% parts, but as these are the larger power resistors (6W from memory) it is quite difficult to find anything in a much tighter tollerence without spending a lot of money on them. And I'm sure in the positions they are used in the circuit 5% tollerence will be more than sufficient (although again, I can match these before sending them out).
Also, as people will onmly need the IRF9610's in matching pars for each board, it would be quite easy (I presume) for me to match these up when I get them and sned them out as matched pairs as well for the differential pair inout stage.
So, if people do want to join in, just let me know that you are definately intrested, and I will hopefuly be pesstering you as to what parts you want soonish.
Andrew.
If you want to have a look at the welborne labs hompage, you should click here although their sight is an absolute nightmare to navigate, so if you only want the dale resistors (1% tollerence, but if enough of us get some I can match them to potentialy better than 0.05% before I send them out to people) you could try this link insted.
The Meggit resistors from RS are specified as 5% parts, but as these are the larger power resistors (6W from memory) it is quite difficult to find anything in a much tighter tollerence without spending a lot of money on them. And I'm sure in the positions they are used in the circuit 5% tollerence will be more than sufficient (although again, I can match these before sending them out).
Also, as people will onmly need the IRF9610's in matching pars for each board, it would be quite easy (I presume) for me to match these up when I get them and sned them out as matched pairs as well for the differential pair inout stage.
So, if people do want to join in, just let me know that you are definately intrested, and I will hopefuly be pesstering you as to what parts you want soonish.
Andrew.
Sure, as I said above, I will be matching my own up in any case, so it makes sense to just do all of the ones that I order all together that way we should get better matches without needing to order so many extras (I would proabbly say, if there are three of us, all wanting three for each board, and with four boards worth each then ordering about 75-100 between us should give enough to get plenty of close matches).
And I should hve plenty of time to start matching things up in the evenings soon, when I start my summer job in a few weeks time.
And I should hve plenty of time to start matching things up in the evenings soon, when I start my summer job in a few weeks time.
Hi Andrew,
could I please join the parts purchase for 2 boards worth? As I am going with the flow on my AX spec, I will be happy with whatever parts are the popular choice 😎
I can help out with the anti-static bags and mail-lite envelopes if you'd like.
Cheers
Jon 🙂
could I please join the parts purchase for 2 boards worth? As I am going with the flow on my AX spec, I will be happy with whatever parts are the popular choice 😎
I can help out with the anti-static bags and mail-lite envelopes if you'd like.
Cheers
Jon 🙂
Hi, if you want to let me know what you are aiming for in terms of your rail voltages and power output (number of output devices too) I should be able to help prodd your shopping list in the right direction. I take it you already have the power supply sorted (at least the ddesign anyway) so if yo let me know I will check off what you will need as I'm going through and finalising my own list.
Aleph-x stuffing!
Hi Bp........right my power supply is as you advised earlier
a CRCRC giving me a target voltage of 20v this supply will be used in all the amps.....
I am building 2 monoblocks and one stereo amp.
The monoblocks have 16 IRFP044N each ......... each amp is to be biased to 8 amps. This should give around about 100w into 4 ohms
The stereo amp will have 8 fets per Aleph-x board running @ 4amp bias. This should give approx 40w into 4 ohms.
Hope you can help with ordering components........particularly with the sensative driver transistors.
by the way my aluminium calcs were wrong......it's going to cost £180 for 3 cases thats with aluminium cut to size and bent
using 6mm material.......not too bad.....£60 a case....just sounds alot when you add it up!
Hi Bp........right my power supply is as you advised earlier
a CRCRC giving me a target voltage of 20v this supply will be used in all the amps.....
I am building 2 monoblocks and one stereo amp.
The monoblocks have 16 IRFP044N each ......... each amp is to be biased to 8 amps. This should give around about 100w into 4 ohms
The stereo amp will have 8 fets per Aleph-x board running @ 4amp bias. This should give approx 40w into 4 ohms.
Hope you can help with ordering components........particularly with the sensative driver transistors.
by the way my aluminium calcs were wrong......it's going to cost £180 for 3 cases thats with aluminium cut to size and bent
using 6mm material.......not too bad.....£60 a case....just sounds alot when you add it up!
Hi BP
I am using the same PS that you suggested for D3 so my rail voltage will also be 20V.
now the next part I am a little unsure of still.
Do you guys think that a heatsink temperature of 57.4C is too high, I really dont know if that is hot, cant remember the last time i toutched something that was 57.4C so i have no reference.
Anyway i am planing to have a bias of 6A and use either 16FETS or 12FETS.
Using 16 will give .75A through each one with a junction temp of 76.4C.
Using 12 will give 1A through each FET and a junction temp of 82.7C.
I seem to remember that there was some kind of 'sweet spot' with reguard to voltage and current that the IRFP044 opperated at which would limit distortion. Any one know if either of my proposed number of fets falls within that range?
Thanks BP for the link to the welborne labs hompage.
Thanks
Mark
I am using the same PS that you suggested for D3 so my rail voltage will also be 20V.
now the next part I am a little unsure of still.
Do you guys think that a heatsink temperature of 57.4C is too high, I really dont know if that is hot, cant remember the last time i toutched something that was 57.4C so i have no reference.
Anyway i am planing to have a bias of 6A and use either 16FETS or 12FETS.
Using 16 will give .75A through each one with a junction temp of 76.4C.
Using 12 will give 1A through each FET and a junction temp of 82.7C.
I seem to remember that there was some kind of 'sweet spot' with reguard to voltage and current that the IRFP044 opperated at which would limit distortion. Any one know if either of my proposed number of fets falls within that range?
Thanks BP for the link to the welborne labs hompage.
Thanks
Mark
Hi, I think you should be safe with those heatsink temps (although it does depend a little on what ambient you are thinking about when you are saying that) as mine will be running at just over 61 assuming an ambient of 25 degrees (and a junction temp of about 90 degrees, which is hot, but should be ok).
As far as the optimum current oges, I can't quite remeber now, although I do vaugely rmeber some disscussion about that too, so perhaps there is some information out there on the topic. Although I think my setup will end up with about 1.5A in each FET so there may not be a lot I can do to change this in my amp.
As far as the optimum current oges, I can't quite remeber now, although I do vaugely rmeber some disscussion about that too, so perhaps there is some information out there on the topic. Although I think my setup will end up with about 1.5A in each FET so there may not be a lot I can do to change this in my amp.
temperatures
Hi Kram.....just to let you 45deg you can just about tolerate to keep your hand on without scoulding.............57.4 is pretty hot.....enough to scould.....if you kept your hand on it for more than a few seconds.
However.... is this temp. including ambiant air temp???
you should allow for 25deg.
That could push things to 83 deg....ouch....
I have increased my sink area by nearly 50% using a special chassis...........and some fan assistance....
Getting temps of around 50 deg. inc ambient.
Hi Kram.....just to let you 45deg you can just about tolerate to keep your hand on without scoulding.............57.4 is pretty hot.....enough to scould.....if you kept your hand on it for more than a few seconds.
However.... is this temp. including ambiant air temp???
you should allow for 25deg.
That could push things to 83 deg....ouch....
I have increased my sink area by nearly 50% using a special chassis...........and some fan assistance....
Getting temps of around 50 deg. inc ambient.
I used a 23C room temp.
i have actually just come back from town where i was planning to have a look at some digital thermometers in Maplins only to find that it is closed due to it being refurbished and made twice as large. Hopefully now they will carry more stock as they never seem to have what i go in for.
I think what im going to do is try out a version with 12 fets at 1A 1st and just see how it goes. I can always change it later.
Just a quick question.
The current the circuit runs at is controled by the source resistors of Q1, Q2,Q10, Q11 (and the source resistors of the extra Fets i am adding) so to change the bias I only have to change these resistors. Are any other changes needed?
Mark 🙂
i have actually just come back from town where i was planning to have a look at some digital thermometers in Maplins only to find that it is closed due to it being refurbished and made twice as large. Hopefully now they will carry more stock as they never seem to have what i go in for.
I think what im going to do is try out a version with 12 fets at 1A 1st and just see how it goes. I can always change it later.
Just a quick question.
The current the circuit runs at is controled by the source resistors of Q1, Q2,Q10, Q11 (and the source resistors of the extra Fets i am adding) so to change the bias I only have to change these resistors. Are any other changes needed?
Mark 🙂
hi, I think you'll probably find that changing the values of the source resistros has little effect on the the current draw formt eh circuit, as Q1 (and the corresponding device on the other side) is set up as a constant current source which is varied by means of the attached circuitry and trimpot. So, if you want to change your bias you should just need to alter this rather than the source resistors.
Parts
Hi Bigparsnip
have you gotta your drukin...parties out the way??? Hope all went well with the dratted exams!!!!..................any news on the group order for parts for stuffing boards????????
.............I am looking to start in the next few weeks...........
I am getting everthing together here......I bought an 8amp variac....I intend to gently bring the boards on line......I don't wana fry anything.......
Hope you can find time to get back to us..........
D3
Hi Bigparsnip
have you gotta your drukin...parties out the way??? Hope all went well with the dratted exams!!!!..................any news on the group order for parts for stuffing boards????????
.............I am looking to start in the next few weeks...........
I am getting everthing together here......I bought an 8amp variac....I intend to gently bring the boards on line......I don't wana fry anything.......
Hope you can find time to get back to us..........
D3
Ok well after a bit of prodding I'm about to start looking at what people will need in terms of components to build up their boards (a tailored version of the excell sheet I posted a while back).
So, if anyone would like to get in on the group buy of parts if you post up here which parts you would like and I'll see what I can do.
Alternatively, if you let me know what spec you are aiming for I can work out what I would use in each case and sujest a parts list for people individualy.
So, far I have the following ones which should definately be going through:
Bigparsnip: 18V, 5.5A bias
D3 (big ones): 20V, 8A bias
D3 (little ones): 20V 4A bias
Kram ?: 20V, 6A bias (how many output FET's 12 or 16?)
Jon Clancy: easy (but not in that way 😉 )
So, if there is anyone else who would like to try and join in (SineEra?) then just post what you want, or if you are on the list above and shouldn't be let me know as well.
Andrew.
So, if anyone would like to get in on the group buy of parts if you post up here which parts you would like and I'll see what I can do.
Alternatively, if you let me know what spec you are aiming for I can work out what I would use in each case and sujest a parts list for people individualy.
So, far I have the following ones which should definately be going through:
Bigparsnip: 18V, 5.5A bias
D3 (big ones): 20V, 8A bias
D3 (little ones): 20V 4A bias
Kram ?: 20V, 6A bias (how many output FET's 12 or 16?)
Jon Clancy: easy (but not in that way 😉 )
So, if there is anyone else who would like to try and join in (SineEra?) then just post what you want, or if you are on the list above and shouldn't be let me know as well.
Andrew.
Ok, I have been through the four configurations sugguested so far and (I probably should he guessed this before) most of the parts are the same with the exception of the source resistor values (and quantities of some parts).
One small consession I did have to make however was to replace the 220uF caps on the board with 180uF parts, as I couldn't find any caps that would fit in the board with a suitable voltage ratting at that size.
All of the prices I have included in the speread sheet below don't have any VAT or delivery charges (or duty where it applies) included yet, and may change depending on the size of the order. So, if people want to say what sort of thing they are after I should be able to come up with a final shopping list and a more accuract costing of everything.
Anyway, hope this helps for now, and I would appreciate it if people could get back to me on this quite soon, as I would like to have this sent of before the end of next week now that II've got back into doing things.
Andrew.
One small consession I did have to make however was to replace the 220uF caps on the board with 180uF parts, as I couldn't find any caps that would fit in the board with a suitable voltage ratting at that size.
All of the prices I have included in the speread sheet below don't have any VAT or delivery charges (or duty where it applies) included yet, and may change depending on the size of the order. So, if people want to say what sort of thing they are after I should be able to come up with a final shopping list and a more accuract costing of everything.
Anyway, hope this helps for now, and I would appreciate it if people could get back to me on this quite soon, as I would like to have this sent of before the end of next week now that II've got back into doing things.
Andrew.
I GOT MY DEGREE & A JOB AND COMPANY CAR ALL IN THE SAME WEEK!!!
Sorry - just had to let everyone know! Hope all other exam bearers have done well too! 🙂
Gaz
Sorry - just had to let everyone know! Hope all other exam bearers have done well too! 🙂
Gaz
Hi BP
i need everything (except the IRFP004s) to populate the 2 pcbs that i have.
I will be going with 20V 6A bias with 12fets per board. i also need the resistors for the CRC power supply that was designed a while back for D3 I think.
just to let you know i am going on holiday on the 14th july to 5th august and i doubt I will have net access whilst i am away so if u would like some money before i go then let me know. And dont worry about posting stuff to me as someone is still at home.
congratulations gaz, jammy git.
Mark.
i need everything (except the IRFP004s) to populate the 2 pcbs that i have.
I will be going with 20V 6A bias with 12fets per board. i also need the resistors for the CRC power supply that was designed a while back for D3 I think.
just to let you know i am going on holiday on the 14th july to 5th august and i doubt I will have net access whilst i am away so if u would like some money before i go then let me know. And dont worry about posting stuff to me as someone is still at home.
congratulations gaz, jammy git.
Mark.
UK parts
Hi all..... well done Gaz......all you need now is her in doors and 2.4 kids!!!!!
Bp........thanks for the graft with the Spreadsheets.....fantastic....
Right I am up for:
2 lots of parts for 20v 8A 16 fets
2 Lots of parts for 20v 4A 8 fets
I make this £100.94.............do you want a cheque........or can I do a direct bank jobby.........+ could you email your address......
Kind regards
Richard
Hi all..... well done Gaz......all you need now is her in doors and 2.4 kids!!!!!
Bp........thanks for the graft with the Spreadsheets.....fantastic....
Right I am up for:
2 lots of parts for 20v 8A 16 fets
2 Lots of parts for 20v 4A 8 fets
I make this £100.94.............do you want a cheque........or can I do a direct bank jobby.........+ could you email your address......
Kind regards
Richard
Hi, D3, as I said above, the prices in the spreadsheet are without any VAt or postage included, so the price you have there is likely to go up a bit when you add these onto the costs (but may drop a little on some of the parts as some have price breaks at reasonable quantities).
Again, I will add up all of the bits tomorrow afternoon and work out what the total costs should be including the postage so can give people a better idea of what the price should be.
Again, I will add up all of the bits tomorrow afternoon and work out what the total costs should be including the postage so can give people a better idea of what the price should be.
Parts Order
Hi Bp........no worries......I realised that....the final cost would be more... Duties + postage....
I will pay you the amount you are requesting.....just let me know what any extra will be..... + I will add some for your troubles.......
these group buys can be complex......I know I have been caught up in it.....but hey its worth it!
Thank you for your help........I will look forward to your posting.
One thing that may be possible....if you get the sender to register that amount sent as under £75..........it would come in duty free...
(from states)
I have not checked....does the order include driver transistors????
These need real real close matching......I think it would be good to buy say 100 and split the cost proportionately......that way we stand a chance of getting a close batch match.....but that could cost say each person 20-25quid each......
Regards
Richard
Hi Bp........no worries......I realised that....the final cost would be more... Duties + postage....
I will pay you the amount you are requesting.....just let me know what any extra will be..... + I will add some for your troubles.......
these group buys can be complex......I know I have been caught up in it.....but hey its worth it!
Thank you for your help........I will look forward to your posting.
One thing that may be possible....if you get the sender to register that amount sent as under £75..........it would come in duty free...
(from states)
I have not checked....does the order include driver transistors????
These need real real close matching......I think it would be good to buy say 100 and split the cost proportionately......that way we stand a chance of getting a close batch match.....but that could cost say each person 20-25quid each......
Regards
Richard
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