View Full Version : AMP4-HV, it's alive!!
I am working on a high voltage modded AMP4 with STA517B. And it's going well!
I have changed:
-Removed R6 to feed the regulators for 5V externally in order to prevent them from generating too much heat.
-Changed all the ceramic 0.1uF SMD caps to 100V version X7R quality.
-Changed the feedback resistors to suit the higher voltage.
-Changed the R100 to suit the higher voltage.
-Used thicker wire on the inductors, similar to the AMP9, AMP5 and AMP10 inductors.
-Changed C102 and 103 to 50V version 330uF.
-Placed screw terminals on the tank cap positions to wire up external caps (four 10000uF 50V caps, like the ones used on an AMP5).
-Of course changed the STA505 to STA517B.
-Changed R54 to 330K to make the upper voltage limit 51Vdc.
More to try:
-Different value caps in the output filter to suit lower impedance loads for which the amp is more suitable now. (0.47uF instead of 0.22uF)
So a -HV BOM could look like this:
-R100 1K
-C10,C110,C112,C12,C14,C18,C2,C21,C22,C24,C3,C30,C3 1,C35,C4,C59,C60,C61,C62,C7 0.1uF 100V
-C1000, C1001 50v or 63V
-AMP9/5/10 cores and wire
-C11,C23,C25,C35 0.22uF 100V
-C102,C103 50V or 63V
-R54 330K
-R103,R107,R112,R114 20K
-U2 STA517B
-R42,R50 Maybe 2W instead of 1W
-Q10 Maybe LM317HVT with increased R6 value, but I would still prefer to remove R6 and feed it externally, or use PS4, but haven't yet tested this...
I think that sums it up! :)
It will be a complete module with heatsink attached, ready to place in a box or in a speaker as active module.
It will be roughly four times as powerful as the standard AMP4! :D:D:D
Sweet!
(Now we just need to make that miniSMPS + LDO combo to create a nice little power-efficient and cool 5V section ...)
I thought the STA517B could do upto 60Vdc, so why not 63 or 100V caps?
And I think that 2x 10mF 'tank'-caps will still be plenty.
It can do, but I am not going to. It's not going to make a major difference and will only make it run hotter and live shorter. 50V caps are considerably smaller...
2x10mF should do OK, but I like to stiffen the voltage up really tight, afterall it's half the ESR with four caps compared to two!
Sweet!
(Now we just need to make that miniSMPS + LDO combo to create a nice little power-efficient and cool 5V section ...)
Yep, the PS4, I want to build the two I have soon and try them out! But I also still have two more AMP11-HV to put to use, so maybe I'll keep the SMPS+LDO for that purpose. The solution of extra windings and rectifier, bulk cap works like a charm too and it's simple.... And it's isolated completely from the main supply...
Ok, it's playing now! It's UN BE LIE VA BLE!!!! How strong such a tiny chip can be, how superb the sound is and the incredible bass that is pumping out of this kit!
Now running it at 48Vdc...
I forgot to mention one of the necessary changes... R54 should be increased to 330K to be able to operate at higher voltages, with this value it will shut down at ~51Vdc and won't even start up at ~49Vdc...
I'm happy as a bird in the sky! :D
Great! When the first rush have settled :) it would be great to get your objective review of the amp!
When can we expect a kit?
/J
:D I don't know, I'm not in charge of that....
You can do what I did with a standard AMP4...
And seriously, I think I am being objective when I say this amp is a class higher in power! It's pretty serious, and I have a standard AMP4 here to compare with...
The STA517B is well available now.
The AMP11-HV will be there again soon, waiting for PCB's...
I have convinced Jan to sell the chip separately, and he will, even now you can just buy an AMP4 and choose "pay by bank" which will effectively puts the order on hold. Then send a support thread message to ask for the upgrade components for -HV and Jan will ship the goods! It's really that simple...
There will be more TK2050 amps in the future, they have the best sound (by very small margin though) and the lowest noise floor (also by a small margin) They are compact and with the STA517B they are in the league of the beastly powerful...
The STA517B is well available now.
Please stop teasing us V-bro. It is not available in the shop:
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The AMP11-HV will be there again soon, waiting for PCB's...
Agreed;
Item # 834
AMP11-HV kit (50V)
Price
$42.78
We're sorry, this item is currently out of stock! Please contact us for details.
I have convinced Jan to sell the chip separately, and he will, even now you can just buy an AMP4 and choose "pay by bank" which will effectively puts the order on hold. Then send a support thread message to ask for the upgrade components for -HV and Jan will ship the goods! It's really that simple...
There will be more TK2050 amps in the future, they have the best sound (by very small margin though) and the lowest noise floor (also by a small margin) They are compact and with the STA517B they are in the league of the beastly powerful...
AMP4 is not listed with this chip yet.
To me, the biggest benefit to this chip is the increased current capability.
This means you can build a standard AMP4 (35V) and substitute this chip instead of the TP2050, and you would have a 4ohm capable amp.
Please stop teasing us V-bro.
Like I said, just order the AMP4 and delay the order by choosing "pay by bank" and add a wishlist via a support thread.... Jan will sell...
ONly replacing the chip sure is a great way to make it 4 ohm stable! Only I guess it is 4 ohm stable up to even much higher voltage, so changing some more parts would then make it even more powerful..
Okay, now it is a complete module, and tested thoroughly...
Looks like you've been busy V-bro:
http://www.zelfbouwaudio.nl/forum/viewtopic.php?f=7&t=10579
Ok, religion with exaggeration equals extremism... LOL! http://www.zelfbouwaudio.nl/forum/images/smilies/icon_lol.gif http://www.zelfbouwaudio.nl/forum/images/smilies/icon_lol.gif
Seems like this new chip has turned you into even more of a AMP4 zealot :eek:
This chip is just great!
The response there was directed to that guy there who is a total class A amplifier zealot, exaggerating about distortion figures, preaching like it makes a major difference to the sound experience when you go from 0.0001% to 0.00001%... He himself also preaching that there are many more important issues than distortion by itself, which I can only agree with, it's got to be something making Tripath amps sound so good! :D (not to say they present bad distortion, actually they show quite good performance figures, but not 0.000001% THD...) I can only say it has been proven several times in the past that good figures don't necessarily result in great sound.
His defense is rather exaggerated, often even rude. (where did I see that before?http://www.opel-forum.nl/images/smilies/hmmz.gif) I had made a remark about his first signature after which he changed it, now I felt like making a remark about his present one as well... All argumentation he is using in his defense is what he's most guilty of himself... Like I've also seen before...http://www.opel-forum.nl/images/smilies/hmmz.gif
Well, let's give that a rest and enjoy music! (That was what it was all about afterall wasn't it?!)
No need to defend yourself, I am in violent agreement with you.
I was merely Googling "STA517B" to see if I could purchase some of these chips elesewhere, when I found your post.
I have one AMP4 & 2 AMP11's still in their bags, and thought I could build them with the improved chip and toss out the TP2050s.
As we all know, running the AMP well below it's rated output keeps the THD figures even lower.
BTW, congratulations on your country's second gold medal in Speed Skating (http://www.vancouver2010.com/olympic-medals/medallists/index_cf-Ad.html?cat6=&cat1=ned&medal_searchSelect+drp_nojs=%2Folympic-medals%2Fmedallists%2Findex_cf-Ad.html&q=hm) yesterday!
Ah yes, another gold medal! Thanks!
If you contact Jan I'm sure will sell you a bunch.... If you have a hard time with this I shall contact him for you! :)
To me, the biggest benefit to this chip is the increased current capability.
This means you can build a standard AMP4 (35V) and substitute this chip instead of the TP2050, and you would have a 4ohm capable amp.
Only replacing the chip sure is a great way to make it 4 ohm stable! Only I guess it is 4 ohm stable up to even much higher voltage, so changing some more parts would then make it even more powerful..
It ought to be stable at ~41V (if 24V / 3.5A * 6A = ~41V is the right way to calculate it.)
Then it depends on the cost of the HV kit or modification, and the speakers you're using, what's effective ... 40V rails should give noticeably lower THD in some situations. Personally I'd go for the simple 32V-capable chip-swap Amp4 in most cases. But it definitely is tempting to build a 4-Ohm 40V "monster" Amp4!
(Edit: I guess that the main obstacle / disadvantage in going to 40V+ instead of 35V is that the bulk caps will need to be physically larger, have lower capacitance, more expensive, or off-board :) Plus regulator heat issues. Both issues are easily addressable, as V-Bro has shown.)
I saw it as a challenge, but may have done more than necessary. On testing the AMP11-HV I noticed the LM317HVT (high voltage version) was still acceptable temperature up to around 42Vdc. This was with a small heatsink though!
Then you could increase the value of R6...
Then yes, the bulk caps, I also changed all the 0.1uF caps, but this would also probably not be that necessary up to 45Vdc. I have also found the same size bulk caps (as the original) in 6800uF 50V, which then would add up to 13600uF, which might be enough capacitance?
Since this discussion was about AMP4, my intent is to use the AMP4 with 24VAC transformer = 34VDC.
I just want to it to be 4 ohm stable without having to go to the trouble of upgrading a bunch of caps.
I also purchased 2 - 36V AMP11's last year, which I might consider upgrading to a higher voltage, but that belongs in another forum.
Since this discussion was about AMP4, my intent is to use the AMP4 with 24VAC transformer = 34VDC.
I just want to it to be 4 ohm stable without having to go to the trouble of upgrading a bunch of caps.
Interesting idea definitely. Perhaps an AMP4 for 4 ohm speakers with a 22VAC 160VA transformer...
Guys!!
http://www.41hz.com/shop/item.asp?itemid=833&catid=
Guys!!
http://www.41hz.com/shop/item.asp?itemid=833&catid=
Nice! Not too expensive ...
When will the amp4-hv be available in the shop? I could replace my 2 amp9 in my htpc box with 4 amp4-hv. The transformer is 650VA 2x18V wich I can use to get 36V!
36Vac is really high, the absolute max. of the chip is 60V. 36Vac will be about 55Vdc and maybe even more, this would be very risky. For a TA3020 amp (absolute max of the TA3020 is +/-70Vdc) this voltage is just about right...
I would not recommend to exceed 50Vdc for any STA517B amplifier.
The AMP4-HV could really best be a complete new design to be presented as a good kit. For the present board, which was really designed for the STA505 there are some problems, which can be worked around, but it's not a good fitting solution then. It will be a pioneers and adventurers option to sell a -HV upgrade kit.
Maybe when 13600uF in total is enough buffer capacitance the -HV kit could be presented with the present board, I have found 6800uF 50V bulk caps in the same size as the original 10000uF 35V. Still I would say, higher voltage means more need for higher capacitance too, so from that theory I would say it is better to have more than 20000uF in total... Which is what I did, apply four 10000uF 50V caps similar to the ones on an AMP5.
Well, according to my calculator 36x1,41 = 50,76.
Unfortunately I have 4 ohm speakers, and I guess that will fry the amp :-(. Or maybe swap my jordans for fostexes!
However, I have another project doing active 3 way speakers with isobaric 4 ohm woofers where I can use 2 amp4-hv. I guess I should use 40 V rail for these. A 28V rms transformer could be used.
As soon as the amp4-hv appears in the shop I will get 4 of them. Now you make this happen V-bro! :-)
Well, according to my calculator 36x1,41 = 50,76.
Yup, but then the mains voltage is specified to go up/down by some percent, and the transformer voltage rises when unloaded ... :/
Yup, but then the mains voltage is specified to go up/down by some percent, and the transformer voltage rises when unloaded ... :/
Yep and still was that 36Vac measured or specified?
I have seen these transformers datasheet specs the loaded and unloaded voltage:
http://docs-europe.origin.electrocomponents.com/webdocs/0028/0900766b800284be.pdf
http://nl.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2238948
And they are moulded in, which should make them nicely silent!
My 24VAC toroid transformers output over 36VDC when rectified and under no load.
You should add 10% to any transformer, even after the DC recitified voltage....
As soon as the amp4-hv appears in the shop I will get 4 of them. Now you make this happen V-bro! :-)
I can arrange some -HV upgrade kits for those who are interested? Then just buy the AMP4 and STA517B from 41hz and I'll compose the rest of the components and arrange a detailed description of the mods for you at cost prices. :)
I really want these in my htpc amp. Which rail voltage should I use for 4 ohm speakers? What will the output power be?
I would say max 42Vdc, then you should see about 135W per channel on a 4 ohm load.
That is about double performance compared to my current amp9! I guess att double price also :-)
That is about double performance compared to my current amp9! I guess att double price also :-)
And double sq! :) No, the AMP9 is ok, but yes the AMP4-HV is really that inpressive! And it has a lot more features to adjust feedback and gain and voltage sensing etc.etc....
And double sq! :) No, the AMP9 is ok, but yes the AMP4-HV is really that inpressive! And it has a lot more features to adjust feedback and gain and voltage sensing etc.etc....
STOP PRAISING THE DAMN AMP4!
I want it so bad now, and I haven't even built my first amp yet.
I can't wait to built one.
STOP PRAISING THE DAMN AMP4!
I want it so bad now, and I haven't even built my first amp yet.
I can't wait to built one.
http://forum.zelfbouwaudio.nl/images/smilies/icon_lol.gif
Sorry...http://forum.zelfbouwaudio.nl/images/smilies/icon_rolleyes.gif
The AMP4 used to be not that powerful, but now that is solved I can't see why one would need anything else...
Well, I have 1,5 kW in my stereo and I actually use it :-). You cannot have too much power!
Can I get some more info and clarification?
I ordered and built an AMP6 and have been quite happy with it since, except that it'd be nice if I had more power (duh).
I looked at AMP4 and thought it'd be a good option but it's not a whole lot more power (than AMP6) and doesn't say it'll play nice with 4ohm speakers. So for awhile I wanted to save up for a truepath, than I saw AMP7 and thought that'd be it, that's what I need, but am waiting for the AMP7PS kit to be available. When is that gonna be out anyway? It says late 2009. Now you're talking about AMP4 option that may have more power or be more compatible with 4ohm loads. I just want a great sounding amp that puts out enough power that it's unlikely I'll ever need more. I'm pretty modest about this, I don't need 1KW+. 4ohm loads are pretty important, I do a lot of speaker swapping and 4ohm speakers are fairly common.
So you say this would have more power but can you give us an educated guess as to the RMS number out of both channels? 8ohm and 4ohm if possible at the higher voltages you're talking about. Or is it like another guy posted, this mod may just make AMP4 4ohm capable? What sort of RMS power output could I expect into 4ohms at the original supply voltage? Would I have to change as many parts?
Or should I just keep waiting for AMP7PS?
Thanks,
Bryan
Remember, AMP4 is all surface mount components...
All the other amps you mentioned are through-hole components.
I realize that, scares me a bit but I think I can handle it. I think that only reason I haven't gotten an AMP4 already is that it doesn't play well with 4ohm loads.
Bryan
So you say this would have more power but can you give us an educated guess as to the RMS number out of both channels? 8ohm and 4ohm if possible at the higher voltages you're talking about. Or is it like another guy posted, this mod may just make AMP4 4ohm capable? What sort of RMS power output could I expect into 4ohms at the original supply voltage? Would I have to change as many parts?
A rather technical answer... :) Hope it's enough ...
The Amp4 is OK with both 8 and 4 Ohm loads at up to 24V. At that voltage, into 4 Ohm, you get around 38 lowest-distortion Watts (http://www.google.com/search?q=60%+of+(45%25+of+((24+Volts)+squared+/+8+Ohms))) / max 65 Watts (http://www.google.com/search?q=60%+of+(45%25+of+((24+Volts)+squared+/+8+Ohms))). With an 8 Ohms load, you get 19 (http://www.google.com/search?q=60%+of+(45%25+of+((24+Volts)+squared+/+8+Ohms))) / 32 (http://www.google.com/search?q=45%25+of+((24+Volts)+squared+/+8+Ohms))) W.
The simplest mod: Change only the output driver chip to STA517 (or similar). The new output driver chip's much higher maximum current will allow the amp to feed a 4 Ohm load at the maximum voltage allowed by the stock components. I think that's 32V or thereabouts? That nets you 50 (http://www.google.com/search?q=65%+45%25+of+((32+Volts)+squared+/+4+Ohms))) / 115 (http://www.google.com/search?q=45%25+of+((32+Volts)+squared+/+4+Ohms))) W into 4 Ohms, 25 (http://www.google.com/search?q=65%+45%25+of+((32+Volts)+squared+/+8+Ohms))) / 57 (http://www.google.com/search?q=45%25+of+((32+Volts)+squared+/+8+Ohms))) W into 8 Ohms. There you will be limited by the voltage tolerance of components - the driver stage can take higher voltages into 4 Ohm loads.
If you do the full Amp4-HV mod, you can take the amp to 41-42V into 4 Ohm. (And near 50V into 8 Ohms ...)
How far you need to go is really dictated by the efficiency of your speakers. (I'm running Amp11's into, what, 89dB/W speakers?, 6 Ohm, at only 20V, and am perfectly happy - they do go quite loud thank you!)
But doing the output-stage mod is really a no-brainer. And I wouldn't advise doing the full mod the first time you build an Amp4. (I can only speak for myself, but having too many variables make me uncomfortable when building, which delays the build.)
And also to make use of the extra-high-power stuff, you need a higher-voltage, higher-current power supply - which is more expensive of course, perhaps slightly harder to find, and a liiiitle more dangerous.
So order the kit and ask for one chip change and I can run the regular voltage into 4ohms? How does the power output of AMP4 at 30-32V compare to my AMP6 with the regulator set where ever it is stock?
Thanks,
Bryan
In to 4 ohms it'll be more than 100 watts per channel...
Compared to the AMP6 it is MUCH more dynamic and quite a bit louder...
And in my opinion quite noticeably more magical.
I wonder why the mono AMP-11-HV is available, but the stereo AMP-4-PS-HV is not. Should be the same 'mod'?
Well, maybe he's busy with it. IF he has time for it.
Guess 2x AMP-11-HV is still easier to build than a Truepath (or something like it)...just 1 single voltage needed.
But most are served with 2x100W of HQ-music from a AMP-4-PS-HV.
There's a good reason, the AMP4 has an on board rectifier and bulk caps and this power supply section is not really designed for such power. The AMP11 is by nature more over-dimensioned a design and it works from DC voltage, so you can build any external power supply with any rated power.
We could thicken the PCB-lines with tin/wire, and make the PS off-PCB, like the AMP-11-HV.
The PCB isn't so much the limit, it's the capcitor footprints and amount of. What I did is basically what works really well, but then with the caps placed externally. I do think that perhaps the capacitance can go down unpunished, still in the game to try that out. Yet the best -HV option is to design a new board.
Usually on a 50hz supply you would want to have 3500uF for each Ampère of current. Given that the power stage alone is doing 6A per bridge we can assume that plenty of capacitance is never going to fit on the board. In practise however we may experience no down sides from this, but I would just not feel comfortable about it. Especially not when the amp would have to drive large woofers or a low frequency filter with large capacitors in it....
The 40000 is really not that over dimensioned...
Hi,
what would I need to change on the amp4 if I would use a 25V toroid?
Will it be only the 35V caps 50, 51, 102, 103, the big 'power caps' (can't see the number on the pcb) and the STA517?
I am not sure, but I think that the idle voltage of the torroid would be too high for the caps?
Best regards
Christian
Hi,
what would I need to change on the amp4 if I would use a 25V toroid?
Will it be only the 35V caps 50, 51, 102, 103, the big 'power caps' (can't see the number on the pcb) and the STA517?
I am not sure, but I think that the idle voltage of the torroid would be too high for the caps?
Best regards
Christian
Hi, for such a voltage see the first post in this thread.... I made a modification BOM there....
You see, this is a bridged amplifier, so some parts see a voltage that is double the rail voltage....
felixcollins
08-Dec-10, 01:08
What gauge wire would be recommended for the output inductors?
Thicker wire with the same size toroid means fewer turns and less inductance.
You would have to use larger toroids to maintain the same inductance with thicker wire.
Amplifiers like AMP9 which can drive more current (lower impedance speakers) have a different output filter. This means lower inductance toroids... You can basically copy this output filter design for the AMP4-PS-HV... This would also mean the 0.22uF caps can be 0.47uF...
hello,
i'm gonna buy an amp4, and will put an sta517b in it, so i can get more power out of it.
i see on the first post that a lot of parts have to be changed for operating on a high voltage.
i wonder what maximum voltage the parts have in the kit ? if the caps are 35v then that's a pitty.
is there gonna be a kit for high voltage ? or do you supply a kit-parts V-bro ?
thanks a lot
ps i have looked for smps vs trannie. as i thought before and found on the site of meanwell: smps lifespan is normally determined by capacitor-failure; they state that for big psu's (i suppose more then 100w) they can run 11 years 24/7. i run my smps already 4 years 24/7 and it still performs great. i doubt that within 11 years i will still ahve the same amp; still a trannie should outlast the builder.
bye
For this kit I would recommend an SMPS because the board doesn't really have place for enough bulk capacitance to get optimal results from a linear power supply.
If you have trouble finding parts I can source them, sure, but Jan can probably also...
thanks V-bro,
the problem with the caps-psu: i can always put a few on hardwire, and then te last two on the board. i don't build into very small enclosures anyway, i build in old 43cm hifi devices.
so V-bro i can order an amp4 at 41hz and ask immediatly to supply the parts for a high voltage version ? or i can ask you ?
that would be great.
thanks a lot
Sure, but do place them as close to the board as possible, every millimeter counts!
You can order it here in the shop, then put the payment on "Pay by bank" which basically puts the order on hold and then add a note to Jan to supply -HV parts. Then you shall receive the final price from Jan and get the stuff and you can still pay whichever way you like best....
aha, that's a nice service, pitty that you just cannot buy it as a kit straight from the shop. but offcourse, they offer like 20 different designs already. i just cannot see the justification to offer a 20watt version when you can get 60watt out of it with a few parts in exchange. (not that i'm gonna use the 60 watt right now, but maybe on an open baffle i will need more than 20watt). and like you said V-bro, desoldering is not a pleasent job. lot's of time you damage the print...
i know to put the caps close to the board, i even soldered a few straight on the pins of my ta2020, they are sanyo oscon (they supopsed to be the best in digital domain).
i'll sent an order to 41hz, and see what they can offer.
great thanks
Lower power means you need a smaler power supply, which is cheaper. So if you don't need the power it's nice you're not stuck with it.... Plus the capacitors of a lower voltage are also either smaller or have larger capacitance. Trust me, Jan has thought this through quite well.
I love the Sanyo os-con caps, over at where I work we have lots of HP workstations which are laced with them. Only down side is they don't come in very high voltage and the higher voltage ones are very low capacitance. Plus they are extremely expensive. And I don't find the operation life span that spectacular. The ripple current capability and ESR are though...
That is mostly the case. And mostly with toroids (copper/steel).
But with SMPS, economics of mass production come into play.
Therefore laptop-smps's are becoming real cheap, and the Meanwell-type 350W version is, for it's size/powwer, very cheap.
But, indeed, cheap. I do not expect it to last for 10+ years.
The 41hz amps though, are low-cost, not cheap, I DO expect them to last for 20+ years.
Problem is, do -I- last that long?
But, with this forum, it feels OK.
Lower power means you need a smaler power supply
Happy new year to you too. I pulled the trigger and bought this kit and asked Jan to add the cost of the upgraded parts. I don't know how many of the parts he has, but worse case can source the rest from Mouser or DigiKey. I originally thought of doing a dual amp11 but then I saw this thread. :) The amp4-hv makes more sense since I would need to add the PS rectifier and speaker protection for the other kit separately, anyway.
What is the maximum diameter for the big caps - they are the only ones which wouldn't fit, no?
The caps look like they are 25x50mm but someone can verify. For the LM317HVT in Q10, could we mount it upside down (on the bottom of the PCB) with the pins bent at a 90-degree angle to mount a small heatsink on it? I assume the concern is that there's not enough space to get a TO-220 heatsink on the top, correct? I don't know if you can use a single large heatsink (or the amp case) if you do this, though...
I found these here, is the 10mm lead spacing is OK? I'd put one on each side if possible and use an extra heatsink for the IC.
Mouser # 598-SLPX223M050H9P3
link: http://at.mouser.com/Search/ProductDetail.aspx?qs=tRzVlScAa5ocMXiD6CyeXQ%3d%3d
edit:
The board is 50mm wide, so the caps are probably 20mm?
I found these here, is the 10mm lead spacing is OK? The board is 50mm wide, so the caps are probably 20mm?
The assembly instruction page (http://www.41hz.com/forums/content.php?32-AI-AMP__4-PS) talks about terminal blocks with 5.08mm lead spacing. Its in the "additional compoments" section, second bullet point. You might be right on the caps. I tried to look them up in the BOM and the assembly page, but saw no info on their sizes. I don't physically have the kit yet so can't measure them. ;)
Hm, but isn't tha only about the power connectors? I'll see, what 'll do when I get my boards then. :)
Ah, ok. I just clicked on the mouser link again and saw the caps. It didn't work earlier for some reason. Sorry to not answer you question. I thought you were talking about the terminal blocks...
Running at over 40-45Vdc will make even a heatsinked LM317-HVT pisshot.
The voltage drop to 9V is just gigantic for an LDO reg. Better then take a PS4 switchmode reg from 41hz. Or create an extra voltage for the LDO circuit with less voltage drop. Something like 9Vac or 12Vdc is excellent.
Running at over 40-45Vdc will make even a heatsinked LM317-HVT pisshot. The voltage drop to 9V is just gigantic for an LDO reg. Better then take a PS4 switchmode reg from 41hz. Or create an extra voltage for the LDO circuit with less voltage drop. Something like 9Vac or 12Vdc is excellent.
Was looking at the PS4 (http://shop.41hz.com/shop/item.asp?itemid=317&catid=). Looks good and is just as small as a TO-220. What did you use to step down the voltage for your apm4-hv mod? Sent a mail to Jan to add the PS4 to my order.
PS4 is very nice. Hard to find, so it's great of Jan to make one and offer it. Use it.
I think it can power 2x amp4 (= 2x TC2001), so for that only 1 is needed (future...maybe)
The LM317 is very low-cost, so I mostly use that for stuff, but if the PS4 could give 1-1.5A and cost ~2 euro, I'd take 10 for stock.
Maybe it'll be cheaper in future.
Always comes in handy.
Was looking at the PS4 (http://shop.41hz.com/shop/item.asp?itemid=317&catid=). Looks good and is just as small as a TO-220. What did you use to step down the voltage for your apm4-hv mod? Sent a mail to Jan to add the PS4 to my order.
Exactly what I posted above, create an extra voltage from my transformer to feed the already present regulator circuit, but being lower voltage it's not running that hot. All you need is roughly 10Vac and a rectifier with a capacitor. If you use a toroidal transformer you can simply wrap some extra wire around it and you've got what you need....
sleepyhead
02-May-11, 18:54
Hello. I have successfully built two amp4s and am ready to tackle the hv version. I placed an order (pay by bank to delay) and started a support thread to request -hv parts swap. Is that how I was supposed to do it or did I mess up?
That's the way indeed... Only I know Jan has been extremely busy with keeping up the load of support questions. All I can say is don't keep posting there because you will only delay things more and if you need to know anything that can be answered on the forum then post here instead.
If it takes a load of Jan's and your back I can help you with the -HV parts too....
sleepyhead
02-May-11, 22:36
Okay, thanks V-bro. I only made one post and then edited it a couple days later.
All I can think of atm is to say I'm planning to run it off 52v battery, strictly 8 ohms. I guess that means I don't really need bulk caps or can get by with small ones if that helps. Also was wondering if the amp11 -hv "issue" had an effect on my order but I see the 517 power stage chip still available.
Also on the modulator gain I calculate 1.1k and 13.1k resistors for RFBB and RFBC. RFBA of 1k is not used. So if I use 13.1k is that fine? Or should I use 20k as per your BOM? I'm using equations presented in the TC2001 datasheet. I'm sorry to create confusion, just curious as to where I went wrong or if 20k is really correct.
I included the ps9-p in my order. I also ordered the amp1, amp5 t80 core torroids out of the shop. Do I need to buy these? Or will the -hv parts swap include alternate torroids already?
So...I'd like to buy the Amp4 with all the necessary parts swapped. I understand the process if Jan fixes me up but how does it work if you swap the parts? Does my order get sent to you and then you send to me?
It'd be far less complicated if Jan indeed supplies the parts. It'd be far less complicated if Jan stopped stocking 50V ceramic caps, but 100V ones instead for all amps. These are hardly more expensive and would make confusions diminish quite a bit.
For a dedicated 8 ohm amp you don't need to swap the inductors, though bigger cores are always better to some extend.
You need about 24K total feedback on the amp for 52V operating voltage, this consists of two resistors in series.
Jan will swap any faulty 517 chip if one bad specimen might slip through. Desoldering it is easy just by putting a small gas torch (costs €3,50) on the roof of the chip. This should work with no damage to the board at all... As soon as Jan knows which batch number of chips is bad they won't be supplied any more. That might already be the case...
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