| Family_Dog |
Hi Carlos,
You lost me a little... ;)
I was referring to a local South African AV forum... http://www.avforums.co.za where this amplifier has received some discussion ;)
-F_D |
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| emmasdad |
Hi Nico,
I have been out of circulation for while.
I have ordered and paid for 1 set brds on your merchant site. I hope that is OK.
Humble apologies for the delay.
Regards
Emmasdad |
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| Nordic |
Hi there Peter, I saw your order this morning, have been doing too many things at once, and I have not answered you yet.
The last set of the first batch was sold the night before... If you can be just a tiny bit patient as the factories are closed for christmas, likely until Tuesday or so, then I will request the second batch, wich will be a bit faster than the first one as the screens are allready prepared.
Can you believe it? I sold the whole first batch!!!!!!!!
Also going to nag them to make sure the boards get bottom and top mask like the PSUs, to be nice and blue. Production run should take about 4 days from date of order.
Dog, yes you can order your boards directly through me, but as with Peter who allready requested boards months ago (but then dissapeared due to ill health), you will have to be patient for a week or so.
I will check to see when the factory will be available tommorrow, maybe we are lucky...
P.S. Peter it is nice to have you back with us. |
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| destroyer X |
Thank you because you had the kindness to upload those images for us.
I have watched each one of them, and in details...good work.
regards,
Carlos |
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| salesmonster |
I added a few more optional values for Cin as Billabong suggested.
I think at this point, any additional tweeks to the list just stray off into the esoteric...which is great for the individual. But this list's purpose is to help someone (me in particular) get a good starting point for the additional components that need to acquired.
I kept all items to one vendor's catalog. And all items are stocked by Mouser, and available in quantities as low as 1.
As always, let me know if you see any errors or ommissions...hope it comes in handy.
IMO: The productivity and sense of community in this thread are amazing!
:snowman: |
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| salesmonster |
I found a good supply of them @ my local electronics shop, Electronic Surplus.
They do mail order with a $15 minimum plus shipping.
I'm so excited, they are FINALLY re-opening their retail location...they have only been mail order for a few months now during a move across town. |
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| salesmonster |
Nordic,
Back in post #443 you show us how to assemble the servo board. With the tiny boards that are included in the kit, it looks to me (and that ain't saying much!) that the column the emitter is attached to is all one node. That would leave R29 as a short. Is there a cut in the trace on the back of the board pictured? Or am I even more confused than normal. :rolleyes:
Thanks, and I hope you are having a good holiday!
Dave |
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| Nordic |
| let me wake up a bit and I'll draw it for you... |
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| Nordic |
Sadly it took a while for my brain to kick in...
The first couple of packages went out with strips only 6 holes long. This can still be overcome if you follow the attached picture.
or if there is enough space infront of the first holes you can solder the transistor there and have the hole available...
I recommend you not soldering the transistor into the holes even if you have 7 holes, as it is hard to remove it afterwards. just solder it flat.
If you need to cut the trace like shown in the picture, under the resistor, cut it before soldering, and test with multimeter after soldering. If you have seven holes, you can clean the copper away around the hole and mount the resistor over that (more conventional way). |
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| destroyer X |
regards,
Carlos |
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| salesmonster |
Thanks!
:santa2: |
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| Nordic |
| after connecting it to PCB, adjust trimpot to read about 3K from servo+ to - points on PCB, before powering on. |
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| emmasdad |
Hi Nico,
Thank you for the info. Of course I am happy to wait for the next batch of boards. I am trying to catch up with all the stuff that I had to put on hold, such as speaker protection module, heatsinks,psu and a case for the amp so I have lots to do before I can begin to stuff the boards.
Thank you also for the welcome back and I echo the sentiment that the goodwill and co-operation in this thread are truly heartwarming.
Thank you also to Carlos who started the whole thing off.
Regards
Peter aka Emmasdad. |
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| destroyer X |
All i want is see you happy, having nice amplifier to build and having the joy of life listening good music.
The good music is the one touch your heart...and to make this magic comes true, me and Nico.... we're working for that..... and doing it gladly.
regards,
Carlos |
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| salesmonster |
If you need to cut the traces on the servo board, remember that the diagram is from the TOP! You need to mentally flip things over in your head before you start to cutting...or you will be making a trip to the shop that sells perf board. :rolleyes:
Dave |
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| Nordic |
| Oi, DAvid some people have blind luck, not you, it seems... I have connected the multiplier inverted once... luckily nothing died... :bfold: |
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| salesmonster |
My favorite "mistake" was when I worked for a company building X-Ray machines.
The power supply used 6 6900uF 500V caps wired in PARALLEL!
Once in a while, a cap would get put in backwards...BOOM!!!
They learned after the first explosion...they built a separate cinder block room to power up in, with REALLY LONG cables.
Good Times |
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| Nordic |
| hahaha grey confetti!!!!!!!! |
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| RKH |
Some advice please ...
I intend to go with the "standard" rail voltage of +/- 35 volts. That means zeners z1+z2, (as well as Z3+z4) give me 32 volts.
?Am I cutting it too close to have C3 (and C4) rated at 35 volts?
Thanks much,
Ryan |
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| meanman1964 |
| I always take 10% more,that would be 40 Volts caps or better 50Volts. |
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| RKH |
Thanks very much.
Ryan |
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| Nordic |
http://picasaweb.google.com/salesmo...275751666677938
It is best to take the point to the groundstar there by the bottom spade... don't use too thin wire, as the amp's power will runn trough it i case of some mallfuntctions and it can't protect your tweeters if burned off.
http://picasaweb.google.com/salesmo...397743153281554
Take this measurement with servo connected to PCB...
Well done with the pictures...
Some pointers for future constructions....
Start with smallest componenst first, wire links, small resistors, and work your way up, this makles it easier keeping the components in place while you solder upside down.
For zener diodes (and most other similiar packaged components), you get better dissipation (i.e. the power rateing goes up) if you allow a few millimeter air clearance under them...
It seems you are in the group that got only 4 small insulating pieces... one of those should be used for the bias servo to isolate it electricaly from the heatsink. Idealy you would have received 6 pieces, but clarity on actions normaly is higer on things done than those that are going to be done., use the other piese on the transistor by that resistor that is installed underneath the board.
Also if you want to try an output inductor in parallel with the 18R resistor on the board, you should bridge its holes and install the resistor and inductor offboard.. the inductor will be pretty large..
Thanks for keeping us updated
P.S. use 50V or preferably higher voltage caps please. |
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| salesmonster |
Nordic:
Just to make sure we are on the same page, you are talking about this little guy, aren't you? Link2?
Thanks!
Dave |
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| salesmonster |
Nordic, thanks for the input! The changes have been made (to both my boards, and to the slideshow)
http://picasaweb.google.com/salesmonster <- for those of you keeping score at home!
Dave |
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| Nordic |
Finish your amp, now, I am sitting on the edge of my seat waiting for your feedback...
Oh and clean the flux before power on.... I have seen nasty things with flux on a board... in the dark it would arch and would actualy burn black scorches into the blank PCB... and this was on a 12V supply only. |
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| salesmonster |
Does anyone have any opinions regarding what type of transformer to use with the power supply?
Does toroidial offer any significant advantage?
Any other thoughts? |
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| Nordic |
Main advantage for toroidal, is they tend to be small enough to fit in the case with the rest of the amp... and even if you want to house them seperately they tend not to stand so tall, so will fit in a cheaper lower profile housing.
Negatives; lets through a bit more noise from mains supply, larger toroids need some inrush limiting for power on surge.
EI transformer is roughly the inverse of the toroids... Large, My HRII PSU must clock in between 20 and 30kgs on its own at an estimate... You need your feet well planted before attemptimg to lift it. negligible inrush current, and lets through less garbage... |
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| salesmonster |
Nordic: Did you base your PSU off of the board assembly you are selling?
I was wondering about the 4700uF caps, or if I would see improvement with more capacitance. I know some of the biggest improvements I would get with commercial gear was beefier PSUs. The one that comes to mind would be Naim. They will sell you a really nice product for an arm and a leg...but if you want to unlock the real character of the equipment, that'll be another arm and leg. And for that price, what you got was the PSU they should've sold you to start with. I love the free market system. |
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| Nordic |
The 4700uf caps are sufficient for 50W into 8ohms at least...
I have 1 pair 4700uf and 1 pair 10000uf caps in mine (I had some 10000ufs spare after getting the Panasonic's that fit on the amp PCBs).
Free market is a wonderfull thing, i was looking at using only 'boutique' resistors for some completed modules of the new Precision model... erm well $22 per channel... |
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| destroyer X |
For instance....one Precision channel have 2 amperes consumption each channel, full power (166 watts over 8 ohms)....this means 2 amperes each rail...and into 8 ohms.
Into 4 ohms you will have 4 amperes each rail.... or something around that..... so.... 20000uf each rail to one channel only.
Having two channels into a single supply, value goes higher... near 40000uf each rail....but this is into 4 ohms.
So.... 20000uf each rail use to fit our needs into Precision.
How this works:
You inject 5 hertz and go with the oscilator volume up till you have unclipped maximum power into 5 Hertz....usually this is very near the maximum into the amplifier i use to make.... 5 Hertz is infrasound.... infrasonic frequencies are not audible...but if you have small condensers...you will listen the hummm into the moments the speaker is into the maximum forward excursion and backward excursion (movement...maximum amplitude)... this means we gonna listen the supply noises...the mains frequency will modulate, will be listened, will be together the maximum power peaks.... i could find that 4700uf each ampere can control that.
But when you increase the voltage... the need will be reducing.
Into 35 volts it is 4700uf...but into 63 i could see it is 3300uf or something around that.
Minimum, to Precision, into 8 ohms... really the minimum to feed two channels using a single supply is 14000uf each rail.... going to 28 or 30 thousand microfarads (uF....means 30 milifarads) each rail to 4 ohms operation.
Is my method precise?
No!...but works.... try and you will see.
regards,
Carlos |
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| destroyer X |
Having a single supply feeding two channels, and using 35 to 37 Volts as the supply voltage, you will need 20 thousand microfarads, or 20 milifarads (20.000uF) each rail as minimum!
Of course, increasing it you will have better supply.
This is when you are using a single supply feeding two channels..there are more economical sittuations, for instance, operating with 8 ohms only you will need 10000uf each channel.
When you have series inductor into the supply, you cannot add the condenser you have into each rails, say, inside the supply...because the inductor you will not have those folks added..so.... some overkill, while using inductors in series into the rails are a very good idea.
The reference i am giving you folks...because doing that for long time...and you can check my ideas doing the tests with 5 hertz into the input (big condenser will be used into the input while doing that, because normally 5 Hertz are into -3dB).
1 ampere, till 45 volts will need 5000 uf (4700uf)
1 ampere, from 45 to 63 volts will need 3300uf
1 ampere, from 63 to 100 volts will need 2200uf
Not precise..but works...try it by yourself..never trust me or other folks... the best sittuation for you is to check everything folks say to you...this way you will learn deeply the subject, will never forget and will "really know the whole thing"
Complementary information, about the Dx Standard supply into this adress:
http://www.diyaudio.com/forums/show...655#post1386655
regards,
Carlos |
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| destroyer X |
Very impressive.... very good.
regards,
Carlos |
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| salesmonster |
When choosing the electrolytic caps for this amp (and power supply), is the amp very sensitive to what type of caps are used?
I'm considering the Nichicon VR and VZ series. I have heard good things about the Panasonic caps as well. Is this even worth worrying about for this amp? Also, as I build up the power supply, I'm looking at the possibility in using it to feed the Dx Precision.
Dave |
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| destroyer X |
In my point of view they are all the same.
My choice is how they look, how big they are and how much they cost.
But, i can be wrong.....so... go to Panasonic, a lot of people say they are excelent.... some folks said they sound good...i have put one into my ear and i could hear nothing..ahahahahahah.
They will say i am deaf and idiot...no problems, i use to say they are crazy!!!
regards,
Carlos |
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| Nordic |
Well I guess you can use anything... the limit is basicaly the cap's diameter... I am useing Panasonic TSUP 10000uf, as it was one of the few caps I found to fit in the space... (25mm)
They were about $30 for 4. (i.e. more expensive than the PCBs)
You could do like Carlos, and build it with smaller caps... it will still work... |
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| Francois G |
As a former tube amp builder I have a practical question for the experienced HRII builders. How are you gents/ladies mounting your power transistors to the heat sink?
I started drilling and tapping 4-40 screw thread into the sinks, but it takes a long time! Is there an easier technique I'm not aware of?
Thanks,
Francois |
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| meanman1964 |
| I always use self-tapping srews. |
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| Nordic |
Lucky man...
I also do the drilling and tapping... but it does not take that long.
Not familiar with imperial sizes unfortunately. For me its a 2.5mm drill bit and metric m3 tap for the m3 screws I can readily get... |
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| Francois G |
Thanks meanman - I will give self-tapping screws a try.
Nordic - are you using a cutting fluid when you drill? I find that the fluting on the drill packs so easily. I think I will try some form of cutting fluid.
Francois |
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| Nordic |
I give it a squirt with WD40...
I read somewhere that because the cut threads don't fragment as fast as other metals it is beter to give a small twist back for every quarter revolution.. to break the threads and allow it to get in the exhaust grooves of the tap... I just spray the tap... otherwise the little loose peices don't want to come out of the holes when I'm done... |
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| meanman1964 |
| quote: | Originally posted by Francois G
Thanks meanman - I will give self-tapping screws a try.
Francois |
If you gonna use them don't try to turn them in at once.Turn them in a bit and then turn them out a bit and take your time don't let them get warmt up or they can break. |
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| es44 |
| quote: | Originally posted by meanman1964
If you gonna use them don't try to turn them in at once.Turn them in a bit and then turn them out a bit and take your time don't let them get warmt up or they can break. |
And a little bit of "Never seeze" won't hurt ( Silver coloured grease, used in the automotive bussines to avoid bolts to get stuck )
I still prefer threads, or even better, a clamp to hold transistors pressed against the cooling fin.
Edit: Self tapping screws tend to let the material "rise" a bit around the hole, remember to check that, or the heat won't get transferred fast enough.
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| Nordic |
I stack some washers in increasing size under the head of the screw to spread the presure zone a little over the transistor...
Makes me less scared of cracking one... |
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| Family_Dog |
| quote: | Originally posted by Francois G
Thanks meanman - I will give self-tapping screws a try.
Nordic - are you using a cutting fluid when you drill? I find that the fluting on the drill packs so easily. I think I will try some form of cutting fluid.
Francois |
I was told to use methylated Spirits as a cutting aid with aluminium. Tried it once, worked well enough for me.
-F_D |
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| Francois G |
A sincere thanks to all! A most helpful group!
Francois |
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| destroyer X |
More pictures and details into the Dx amplifier thread.
regards,
Carlos |
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| destroyer X |
hard and freezing in Washington DC.
Here is the supply.
Picture is bad because camera is defective.... but supply is good
regards,
Carlos |
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| EvilYoda |
I've been away for a while and just stumbled upon this GB...I don't suppose there are any full kits available (or were they ever?)? Other than that, maybe someone has some extra boards and pieces they'd like off. Aside from that, I guess that ordering through the webpage is my main option right?
I'll read through things in the morning...the text is starting to get a little fuzzy :p |
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| Nordic |
Hi there... the kits are pretty comprehensive... you just need to buy a few capacitors realy... and the output transistors...
I have 3 paid for backorders allready and we are just waiting for the factory to reopen on monday, to get our next batch out... |
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| EvilYoda |
So I should just go through the website and order the 4 "parts"? amp PCB, PSU PCB, resistor pack and transistor pack?
Aside from that, just whatever inexpensive/expensive caps I want to stick on there, the xformer and usual connectors.
More thinking tomorrow. |
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| Nordic |
| You're a fast learner :D |
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| Harry3 |
Hi Nico,
did you recieve the email I sent you in regards to my boards?
Regards
Harry |
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| meanman1964 |
Hi Nordic,
At your website you're talking about an earth-disconnect network,I was wondering can you use a thermistor for that like the CL-60 or other like Pass Aleph amplifiers? |
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| Nordic |
| Hi, it is not an essential part... first check to see if you can wire your unit up without any groundloops... |
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| Nordic |
| Ok just want to confirm for the backorder groupbuyers, that I got hold of the owner of the PCB factory, got a bit worried as it seems they had an extended holiday... The order for your boards have been submitted and will be processed asap... |
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| salesmonster |
Newbie question:
The kit contains silicon washers for the 2sc5200/2sa1943 output devices. Is this the preferred method for attaching these transistors to the heatsink, or is a thermal compound (Arctic Silver?) considered better?
Do the heatsinks for each channel need to be electrically isolated from each other? Or can 2 boards share one long heatsink?
Sorry for such basic questions. I got so confused going through the different threads, and the talk about the variants of the DX, then the HRII, HRIII, Precision I, Precision II...my eyes have gone buggy! :bigeyes: So I decided to post here in this thread.
Thanks from the frozen wasteland that is Ohio,
Dave |
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| Francois G |
| quote: | Originally posted by salesmonster
Newbie question:
Do the heatsinks for each channel need to be electrically isolated from each other? Or can 2 boards share one long heatsink?
Dave |
Each transistor needs to be electrically isolated from the heatsink - that's the job of the pads. If well isolated it is not a problem to put one or more channels on a heatsink, because the heatsink is at chassis ground.
But since heat must be conducted away from the transistor you also need low thermal resistance - that the reason for using thermal compounds. Sanding and polishing the contact surfaces is recommended by some -- helps lower the thermal resistance. Thermal compounds are not insulating and must be used in a very thin film, it only fills microscopic uneveness in the mating surfaces.
Before using arctic silver as thermal compound check its properties - I think it is electrically conductive. You don't want to use a conductive material here.
Hope this helps,
Francois |
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| Nordic |
Artic silver is fine with those pads.. have combined them before...
Arcticsilver is not conductive to the point that I'd worry about it... it can act capacitive (bit of a problem if you decide to use them on some videocards' memory chips), but I have used it with great success.. take multimeter and find which pin is connected to the transistor's tab... after installing transistorcheck for no continuity between the tab and the sink...
P.S. prefer Mica pads and thermal goop above the silicon ones..
burs on the drill edge of holes can for instance cut through the silicon and cause a short... |
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| salesmonster |
Thanks for the information. I'm much clearer now.
Play safe! |
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| Nordic |
Thanks mr boss people!!! ;)
Now how about some feedback..? you guys are either the slowest or most polite builders... |
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| jacco vermeulen |
Het u dan wel eens last gekry met die pos ?
Mail from SA to old boer country is slowest. |
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| Nordic |
Het jy nie jou goed gekry nie?
Will look up tracking later when I'm on my regular harddrive.... just swap to this one for work stuff. |
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| Family_Dog |
Hi Nordic,
I have emailed you directly.
I am busy collecting bits and pieces for the construction of this amplifier, has there been any discussion on suitable enclosures for it? What size enclosure should I be looking at?
-Eric |
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| jacco vermeulen |
Bare knuckle enclosure fight.
All-in-One 7-incher, 1/2" heavyweight=> |
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| destroyer X |
stuff needed to order boards.
I have friends in brazil that want me to provide them HRII and Precision 1 amplifiers, so, i have to order boards in my country.
Because of that i am asking you those files as soon as possible.
panzertoo@yahoo.com
regards,
Carlos |
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| cwujek |
| If anyone wants to get a HDII kit, I'm selling two stereo sets in the trading post. I just don't have the time....:( |
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| Nordic |
Come one guys, help Chris out over there.... Those are realy nice amps, not average by any means.
Sorry Erric, I have been working like a slave today...I would say aim for standard rack mount componet size... height will likely be determined by your transformer and or heatsinks, but I think a sink of about 10cm x 4cm x 20cm should be fine for 8 ohm loads driven pretty hard... your speakers are verry efficient anyway, and will not need to be driven very hard.
I have the prices for you... will sit and type it up more uniformly for you when I get up... and return by e-mail for you |
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| RKH |
Chris,
You have PM. Edit: Meant to quote two messages above, kits for sale...
Ryan |
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| Harry3 |
Hi Nordic,
just received the 4 power amp boards you shipped by surface mail in mid November on tracking number RD100854639ZA, order number 21. Thanks for the connectors etc that you also included.
As I did not receive the 4 power supply boards and because you did not declare these on the above package I take it that you have shipped these in a seperate parcel. What date was order number 42 shipped?
regards
Harry
Sydney
Australia
PS next time charge me extra for air mail as surface mail takes too long. |
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| Nordic |
Harry if there was an ommision it was my error...I will ship it at no further cost to you.
The post office put your parcel on seamail for some reason,as you can probably tell from the stamps etc I paid for airmail, which is normally about 12 days down to where you are...
Unfortunatly some people at our post office are holding affirmative action posts which leaves large gaps in the quality of service..
I will ship your boards tommorrow when I go to the post office again.
Thanks for the update though... and a sincere apology, I outsmarted myself, your package was one of the first I did, and I even held it back when I got the PSU order after it... |
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| suds |
hello,
I just finished with DX HDII Clone PCB Design.
I Used Original schematics, but the Amplifier PCB is redesign.
Power Supply PCB Layout is slightly changed (As shown in figure.
Here I am posting DX HDII Power Supply Board images, tomorrow I will post Amplifier PCB images.
-suds |
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| meanman1964 |
Nordic;
I've 2 toroids with 2x25VAC/160VA can I use them for the HDII? |
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| salesmonster |
Suds:
I'm certainnly not speaking for Carlos, but I would think one of the design elements of the snubbers (let's use C3 as an example) across the electrolytics (C7) is to be as close to the actual pins of the big caps as possible. I can see why you would move them around cosmetically, and you did a very good good with the boards. But, personally I think you should at least move any snubbers back to their close-up positions with their mates. In this case, it could mean mounting them on the bottom of the board.
Just my 2 cents.
:) |
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| Nordic |
Should be ok for 8 ohm loads... I would however swap the 16V zeners for 15V ones just to keep the regulation headroom.
Feel the transformers for overheating over a period of time and see how they handle it...
Worst case scenario you sit with a working amp and a transformer that needs an upgrade at some point in time... I think for average listening levels it should work fine.
just to give you an idea of scale one 180VA transformer is normaly good for a 20W x 2 amp, maybe a smidgen more if the amp is reasonably efficient. |
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| meanman1964 |
What voltage and VA do I need to get the best out of the amp for each channel?
I would use 1 toroid per channel. |
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| Nordic |
I am getting good enough results from 2 300VA 26VAC x2 transformers...
For a single I would go for 500VA+
Slightly higher rails wil also not be bad, say maybe a 2 x 28VAC transformer... (once again all youwould need to adjust is the zener.. although the kit ones will work fine, there is a bit more power to be had if you then switch the two 16V ones out for a 33V zener.... you can just bridge the position of the second zener.
Sorry for the delays in comming back to you, electricity supply is erratic here to say the least... (what happens when governments buy submarines for kickbacks rather than power stations). My dinner tonight went straight from the oven to the bin as the power went off midway through preperation...
Guess its peanut butter sandwitches tonight... and it would not suprise me if we go without power for another 2 hour session... |
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| meanman1964 |
I have 2 toroids of 2x30VAC/300VA,is that to much volts for this amp?
Maybe I could wirewound some turns of 3volts or 4 volts so I could lower the output voltage. |
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| Nordic |
| You are looking at 42V rails, suspect that may require a parallel set of extra transistors with emitter resistors, I will ask Carlos later when we speak again and let you know. |
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| destroyer X |
But, to be more safe, avoid the use of 4 ohms loads...you can use 6 ohms or 8 ohms speakers.
regards,
Carlos |
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| meanman1964 |
What about I add a few turns on the toroid of let us say 3 Volts?
So I could deside what voltage 27 Volts or 33 Volts. |
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| salesmonster |
I just wanted to share my progress to this point.
I received some electrolytics today from apexjr. Really nice buy @ $2 each for 12000uF 50V caps. I sure it's overkill, but that's one of the things that makes this hobby so much fun!
http://picasaweb.google.com/salesmo...rSupplyPSUBuild |
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| meanman1964 |
| quote: | Originally posted by Nordic
You are looking at 42V rails, suspect that may require a parallel set of extra transistors with emitter resistors, I will ask Carlos later when we speak again and let you know. |
Nordic or Carlos
Can it be done with extra transistors and emitter resistors to be safe for using a 2 x30 VAC toroid? |
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| Nordic |
Hi man, sorry, I was a little cut off from communications... no power = no computer = no coms...
Will give you feedback today.
Wait I see Carlos allready replied
"It is all rigth..... 42V is the upper limit to a single pair Post #584
But, to be more safe, avoid the use of 4 ohms loads...you can use 6 ohms or 8 ohms speakers.
regards,
Carlos" |
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| meanman1964 |
Is it not better to play safe and use 2 more transistors?
If yes do I've to make some changes of some values of components? |
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| Nordic |
you will as far as I know just duplicate the output sections...
Will draw it for you in a little while..
2 extra resistors and the transistor each side...
With that much voltage you also need to modify the regulation to the front end by adjusting the zeners on the side with one or 2 in series, to drop about 5V.
say in the region of 38V for the zeners.
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| meanman1964 |
| quote: | Originally posted by Nordic
With that much voltage you also need to modify the regulation to the front end by adjusting the zeners on the side with one or 2 in series, to drop about 5V.
say in the region of 38V for the zeners.
[/B] |
wich one do you mean Z1-Z4 these ones? |
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| Nordic |
Yep, the ones at the side. The only other zener is the 12V that sets up the CSS for the front side. That one stays standard...
In fact the amp could in theory work without the transistor and zeners there on the sides, simply bridgeing the transistor with a 82R resistorso voltage can make it to the front side...
Will have more power but less quality in sound...
The benefit of the higher voltage is that you can use a large margin of it to regulate the front end and keep power output higher...
Of course without the regulation, full power is available to the amp... the 42V.
With the regulation, the outputs are only driven by the amount of volts you let through to the diffirential and voltage multiplier...
The Output transformers just supplies the current the output load needs to follow the instructions to keep the output voltage at whatever the voltage multiplier tells it to be at any instant, over said load. |
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| meanman1964 |
| So if I understand it correctly,instead of 32V zeners(2x12V) I need 38V zeners.And also need two more output-transistors and resistors? |
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| Nordic |
you meant 2 x 16....
You can use less or more regulation so the 38V is not set in stone...
You can use any 2 voltage zeners in series to make up approximately that amount of voltage.
And yes, 1 extra output transitor for each rail
1 extra 4.7 resisor to the base of each of those
and one 0R33 emmiter resistor for each. |
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| meanman1964 |
Yes 2x16V
Can you make a drawing for me just to be shure where those extra transistors are coming? |
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| Nordic |
| Tell me if it does not make sense... |
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| meanman1964 |
Thanks Nordic.
It's an idea why not making an other layout where you can mount 4 output transistors and the needed resistors.I think there are a lot of people having tranies of 2x30VAC or 2x35VAC.What do you think? |
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| Nordic |
The 2 x 35 trannies could be used on the P1 if you have more than one...
The P1 started off as a 4 transistor unit and grew to 6 for the sake of safety.
But it is not a bad idea. |
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| Nordic |
| Here is how to wire them into the HRII |
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