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and now for something completely different part 3


kevin gilmore
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  • 2 weeks later...
On 2016/2/27 at 10:18 PM, kevin gilmore said:

depends on how much heatsink you have.

150mv is a good starting point

Finally decided switching to Uber3+CFA2 set. got some question for uber3

what is the use for J1 Jumper and can we apply +-24V directly to uber3?

thanks :)

Edited by ang728
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9 minutes ago, kevin gilmore said:

jumper J1?   on what?

+/-24V is going to be pretty low for uber2.  Should work, but much lower power.

The J1 placed in the middle of uber3 ubal to bal.

UAeunXI.png

 

Thanks ! now I can comfortably share +/- 24V supply with CFA2 

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  • 2 weeks later...

Ahh so the +/- 40V, +/-D, FB, and GND terminal block connections serve only to connect the two boards together.  I had thought the +/-40V from the golden reference power supply went there...  Thanks!

Edited by chiguy
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  • 2 weeks later...
  • 2 weeks later...
On ‎2016‎年‎1‎月‎21‎日 at 5:48 AM, kevin gilmore said:

plus a very large transformer, a pair of 25 amp diode bridges and some really honking large power caps and mass quantities of heatsinks.

different 25 amp diode bridges, different sound. some may sound poor. how do we choose then?
as for the the power caps, is 10,000 uf overkill?

Edited by mtoc
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my head's spinning for a few hours or so, still can not figuring out how to connect the three uberamp2 and gr boards. don't know where's in and where's out. so many ins and outs. unreg + in, unreg + out, + reg drive, - reg drive, +d, -d, fb.

still don't know which part is called pass transistor... could someone just provide an example. and where are the power caps, power caps is unregulated caps' another name as far as i know. and where is the often mentioned pre-reg stage, pre-reg stage = pre regulated stage as far as i guess. the caps previous mentioned are called unregulated caps, isn't this pre regulated stage thingy located in the area of the unregulated caps? pre means before, so pre-reg stage's existence is before gr because gr has diode bridge to do the regulation.

and uberamp2 needs one gr with 30v and one gr with 40v, how to make them 30 and 40, there are labels ac25v, should or should not input 25vac when you need 40v or always input 25vac into gr and changing the resistors and then still get the 40v and 30v or what we need?

uberamp2 actually is more than 3 boards, what i mean above is three different kind of boards. what're their names, input board, x board, and amp board or output board. 

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6 hours ago, mtoc said:

uberamp2 actually is more than 3 boards, what i mean above is three different kind of boards. what're their names, input board, x board, and amp board or output board. 

only names I see are 1,2,3 on the files.

Uber3 is the balanced/unbal/cast   input board

Uber1 is what I call drivers, as they drive the output transistors.

Uber2 would be the output boards

On this page there is a picture showing where the six pin connectors go...

you will need to build your own unregulated suppy.   Large transformer(s) into 35A diode bridge(s) into large caps

and that can feed the rest of the parts - the unreg in, I also use it to feed my GRLV set for +-40v which goes to Reg in  +-

How many sets of boards do you plan to use?  2 driver/outputs for stereo and one GRLV at 40v

for Balanced outputs you will need to double  everything and add the input boards

 

Edited by congo5
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1 hour ago, congo5 said:

you will need to build your own unregulated suppy.   Large transformer(s) into 35A diode bridge(s) into large caps

and that can feed the rest of the parts - the unreg in, I also use it to feed my GRLV set for +-40v which goes to Reg in  +-

I hadn't considered using the unregulated supply to feed the +/-40V GRLV... it would eliminate one of the needed transformers.  Are there any downsides with this approach?

Would you mind sharing your unregulated supply design?   

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don't really know of any downside, just using an amp or so for the grlv..

no design here just transformers into bridges into a pair of caps.

the center of caps +&- are connected which is GND

I read First watt articles to learn and get ideas. He has lots of class A unregulated power supplys. With the Uber...  the 8 pass transistors per board do most of the work so we don't need resistors to get rid of ripple.

At DIYaudio they say for class a amps we need 6-10 times the Class A output power.

http://www.diyaudio.com/forums/pass-labs/207103-f5-turbo-builders-thread-425.html#post4625793

I'm starting with 1000va 36VAC trans and two 47000uf 80v caps.

which is probably not enough, but leaving room to add the extra trans & caps.

 

Edited by congo5
wrong numbers
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On Sunday, April 24, 2016 at 5:10 AM, congo5 said:

you will need to build your own unregulated suppy.   Large transformer(s) into 35A diode bridge(s) into large caps

and that can feed the rest of the parts - the unreg in, I also use it to feed my GRLV set for +-40v which goes to Reg in  +-

genius! now i can understand a little more of this science stuff, your tranny is 36vac, and we hook it up with a diode bridge, 36*1.4=50, and this 50v (vdc, right?) going like a river through these caps, and it becomes a liitle less than 50v now, but it keeps going, bump, into the +/-40v gr, my question is, this nearly 50v thingy goes into this +/-40v psu, actually how many relations are there between 50v and +/-40v? Does this +/-40v gal also accept 80v since 40-(40)=80? btw, have a look at the gr circuit, like the goldenreference7, the stock version is +/-20v, how could they achieve +/-3/40v? and have a second look at the circuit, there is a diode bridge on the gr board, i ain't no sure it's diode bridge or not, but it 50% is the diode bridge, that is a 4-pin molex shape sits besides the big cap on the gr board. we do this unregulated supply, and feed our unregulation into +/-many vs gr board, so the diode bridge on the gr board should be removed, right? the unregulations which go beyond the unregulated supply is already dc and dc into gr board so we no need diode bridge anymore.

Edited by mtoc
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yes the diode bridges are not needed, doesn't hurt to have them there, I didn't use them in picture above

the GRLV needs to be configured to +-40v so I used two 4.5k feedback resistors in place of the 1500R (R8, R9)

Some Caps need to be higher voltages, Large inputs @ 63v and the output caps at 50v or so, check schematic.....

also change opa134 to opa445

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@congo5

Did you have any issues getting the Xicon resistors to fit on the output board?  The ones available at Mouser are 49mm and the board is only able to support ~45mm.

On a similar note to everyone else, what resistors did you use (or recommend)?

Edited by chiguy
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17 hours ago, chiguy said:

Did you have any issues getting the Xicon resistors to fit on the output board?  The ones available at Mouser are 49mm and the board is only able to support ~45mm.

yes but  You can bend the legs under a bit and I think they will like a bit of air under themselves for cooling

17 hours ago, chiguy said:

Are there insulating pads

used mica 20x25mm

I ordered these: http://www.ebay.com/itm/311071328876?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Just checked the board files and Kevin added a set of holes for longer resistors, they are 49.53mm

I think that was done before the GB, if not just bend under.................

Edited by congo5
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