Smaller Leach Amp V1

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If it doesn’t fit on the main board I would leave it out then, don’t want people mad at me for removing the diodes.

WorkingAtHome,
I had envisioned it as being part of the main board, that way you don’t have to fill in the parts if you don’t want to and there are only the two leads for the led coming off the board.
 
Personally I will not use the smt diodes (at least I think so😕 ) . Maybe you can use the space for something else Jens. WorkingAtHome's thoughts seems good to me:smash:

Tomorrow is 12th of May at last!!!!
Jens would you post a components list for this version? I know,
it's similar to the 10version but......it is more practical in my opinion, separate documents for certain projects.
 
I hate SMT/SMD's !

Anyway, anyone something groovy to say on groupy components buys ?
Someone interested in sharing some 15032/15033 rails from Digikey ?

Brian, read the MT200 mica thread ?
 
I did. I got some free Bergquist samples, and have been cutting up Sil-Pad K10 (kapton-based) for use with my Tosh 2565/1095's.

I am also using them with my 4780 amp, and they work great. No mess.

I'll probably be finishing up my Aleph30 and the Nikko rebuild before I build this Leach. I also have another half built leach I might finish up first.
 
jacco vermeulen,

I am going to need 8 of each 15032/15033. I can send you some.

Are you going to modify this one for the Sanken/Toshiba output devices too?
 
hmmmm, let's see: surface mount diodes or clipping indicator?

ding, ding!

easy decision: clipping indicator

🙂

mlloyd1

JensRasmussen said:
I guess I could make room for a small board with the clipping indicator on board....

What does the rest of the you think about the idea?

\Jens
Click to expand...
 
gengis said:
Are you going to modify this one for the Sanken/Toshiba output devices too?
Click to expand...

I bought 100 Toshiba 2SA1301/2SC3280 devices, 24 of them will go on these boards.
Same size as the 1302/3281, but the 120 watt version.
Bandwidth is very high too, so same changes as the first Leach boards.
These boards i am bridging, with lower voltage on the output stage, making it fully symmetric.
Means high current capability and very high slewrate.
Probably drop the voltage on the voltage gain stages too.
i know i am silly.

Thinking of making 2 fully chromed chassis for these, each containing 2 bridged channels.

My needs for 15032/15033's are like 50 all, which includes the number i need to send to JonDoe in Romania.
 
If you want a clipping indicator I would suggest the one in the APT Model 1, it is much better than the one at the Leach site.

It is comparator based and has a pulse stretching circuit so the
LED stays on long enough to see, and doesn't require adjusting for ±V changes.

Actually, I think it would be better off on its own board.
 
Passive parts will almost certainly (excluding the short circuit protection) be the same as the extended version or the original. The transistors are the same, so the only change will be in the short circuit protection.

The list is so far unproven, but if someone wants to be prototype the list, it will be most welcome as I have to start to put my diy-stuff into boxes very soon, so after this weekend I am unable to perform any tests at home.

Also the clipping indicator is new to me; I will need some time to sort out the layout and find out how to arrange the small boards in order to minimize the PCB area used.

Is the clipping indicator worth waiting for or should we go ahead as planned?

\Jens
 
Jacco,
My needs for 15032/15033's are like 50 all, which includes the number i need to send to JonDoe in Romania.
Click to expand...
Maybe i can contribute some $$$ in advance to buy more of these since they seem quite scarce and it's nice to have some more at hand when needed instead of going like crazy over the net to find them.
I like the leach so much that i might just even buld more (i'm kinda crazy you know, my dream beeing like 5.1 with all active speakers, like 1 speaker has 1mid+1hi each with it's own amp so that makes like 11 amps, oh wait, 12 because i'll use 2 subs ).:clown:

As for thr clipping indicator, i have nothing against it.
I was planning on building one anyway, just a more fancier one. Think of a vu-meter like clip indicator. The longer the clip goes, the more the vu goes.

CU
 
Hey Jens i was just wandering if you still had any of the 10 transistor version pcbs left for sale, i was thinking of buying a couple of them as well so i can make a sub amp as well.Please let me know of cost and stuff. oh by the way do these boards come with BOM and component placements??

Regards

Bowdown
 
djk said:
If you want a clipping indicator I would suggest the one in the APT Model 1, it is much better than the one at the Leach site.

It is comparator based and has a pulse stretching circuit so the
LED stays on long enough to see, and doesn't require adjusting for ±V changes.

Actually, I think it would be better off on its own board.
Click to expand...


Can you post a schematic of this indicator?
 
"Can you post a schematic of this indicator?"

If I can find it (I just moved).

Probability seems low for now, I haven't seen it since before the LAST time I moved in 1998.

Maybe someone else has a copy?
 
It may be similar to the Bryston indicator, which you can find on there web site. I assume the leach indicator works by detecting when the output comes up to the rail. There is one case it which it may not work. If the load impendence is very small the protection circuit may be activated before this point. So if we wanted to make the leach circuit better the clipping indicator should connect to the SOA protection circuit as well, so it can detect if it is tripping. Have an idea of how this can be done, however I’m at work right now so I don’t have the time to draw it.
 
djk:
an excellent suggestion! i think i actually have the little module from my APT 1 from years ago. it WAS a very good design.

where did i put that schematic ...

mlloyd1

djk said:
If you want a clipping indicator I would suggest the one in the APT Model 1, it is much better than the one at the Leach site.

It is comparator based and has a pulse stretching circuit so the
LED stays on long enough to see, and doesn't require adjusting for ±V changes.

Actually, I think it would be better off on its own board.
Click to expand...
 
Picture of the final version of the 10 transistor board.

I will cut this to become the 6 transistor version

Please note that there will be no gnd plane under the driver transistors. This should make heatsinking easy with diy alu sinks.

PIC is 300k

http://www.delta-audio.com/temp_jens/Leach.gif

Schematics here:

http://www.delta-audio.com/temp_jens/Leach ver 6.6.10.pdf

Please give your :yes: or :no: to this data

Clipping indicator is out - sorry I don't have time at the moment to work on the layout.

\Jens
 
My needs for 15032/15033's are like 50 all, which includes the number i need to send to JonDoe in Romania.
Click to expand...

Jacco,

price become more attractive w/ increase #.
It can be done. How about trading some of Toshiba to me?
 
Hi Jens.
something odd happening when I try to download the schematic.
the PDF starts to download (dial up) and then after about 20 seconds locks my computer. When I (ctrl+alt+del) & end the download the computer closes the internet explorer as well??
 
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