allFET circlotron

[kees52]

I am good with double sided board. Same cost as single sided for me.
Thanks find the work on the design. It's starting g to look like a real amp!

I do always use double sided boards when make power amp, there I have one side as a gnd.

this is a circlotron and has some strange crossed voltages, so then is the pcb more troublesome to make, or we have to make two boards, a front end driver section and the amp section, but these do work also.

it is quite difficult, need lot thinking and such, but traces are chort for where it matters. maybe later we can try smt to see where it end but now I do not need vias except through the components pins.

Ohh yes it is smaller then 100 mm.

regards

 

[joshvi]

Hi Kees 52,

Lot of discussion about fake sellers in our forum.Most of the ebay sellers you discussed here are fake sellers. The pricing is very attractive.But fakes.

last year I brought some components from Hongkong,not from Ebay but from a big distributer.About 2500USD purchase.most of them are fakes. They looks very similar to original.lot of money lost.They send samples before shipping they are originals. Lost my money.

I can not say all the ebay sellers are fake sellers. I know some reliable chinese and hong kong based ebay sellers,but avoid unknown ebay sellers from these areas.

If you are looking for matched pairs,you can contact this seller from israel ,a member of our foum.
4 x IRFP240 IRFP9240 Matched Quad | eBay

or
items in store on eBay!

from Hongkong

Best Regards
Joshvi

 

[Luke]

I have bought semis from these guys:
Search results for: 'irfp250'

They are a reputable business and the irfp250 is only $1.50 and shipping is cheap.

Nice looking amp BTW

 

[kees52]

Hi Kees 52,

Lot of discussion about fake sellers in our forum.Most of the ebay sellers you discussed here are fake sellers. The pricing is very attractive.But fakes.

last year I brought some components from Hongkong,not from Ebay but from a big distributer.About 2500USD purchase.most of them are fakes. They looks very similar to original.lot of money lost.They send samples before shipping they are originals. Lost my money.

I can not say all the ebay sellers are fake sellers. I know some reliable chinese and hong kong based ebay sellers,but avoid unknown ebay sellers from these areas.

If you are looking for matched pairs,you can contact this seller from israel ,a member of our foum.
4 x IRFP240 IRFP9240 Matched Quad | eBay

or
items in store on eBay!

from Hongkong

Best Regards
Joshvi

Thank you for the info, I do have igbt,s ordered a year ago for a 3.5 Kw smps, these blow and peaces have to dig out of the wooden wall, I find there has needed more protection for the sellers, because this fakes can be a real danger.

It is a nice idea to have trustable sellers put on these forum, because finding electronic stores get less, and bigger ones do alone sell mass for cheap. World change in a wrong way unfortanely.

But Tayda is a nice store thanks.

kees

 

[kees52]

I have while I did respons in previous post get a message from a seller who did complete refund, I have the expericence she do refund easely, I have sometimes also feelling the chinese also get chinesed.

This means do she now what she are doing.?

regards

kees

 

[xrk971]

Luckily, I have been fortunate to get good IRFP240/9240's from vendors on Aliexpress. My one experience with fakes is with 2SC5200/2SA1943. I used a vise to crack one open to confirm, and sure enough - the fakes consistently have a tiny die that is covered with white RTV silicone and the die is crooked and not aligned on the thermal tab. The real one is much larger, no silicone and aligned squarely on tab. Externally, the pins and tab have a rougher solder-covered appearance with rounded corners on the genuine. The fakes are shiny and angular like freshly stamped with metal shears/stampers.

Aliexpress is good about refunds for problems if you can verify - they refunded me. My 98% of other transistors have been good though. Especially KSA1381 and KSC3503's all good - look like real Fairchild parts.

 

[kees52]

Ebay refund also without a problem.

I have also paypal protection.

regards

 

[kees52]

I have redone the pcb because I did get stuck, eagle is very difficult with some things, a real german wisdom I think.

This looks better and now I can do the preamp more easely however needed double sided to get it small.

Eagle has very nice graphics but sometimes ticking a trece for moving or special the polygon I can't tick it for move, or only one side. Special polygon sufaces when on both sides I can not edit the top because it do not select.

But it give nice outcomes dispite his shortcomings.

regards

 

[xrk971]

That looks really nice Kees. Great progress - thanks for all your efforts on this amp!

Btw, I just confirmed that a set of 2SK1058/2SJ162 lateral MOSFETs from Aliexpress are real and work as advertised. Tested in JK's thru-hole VSSA. Units appear to be old stock Hitachi's.

http://www.diyaudio.com/forums/soli...hrough-hole-version-jason-83.html#post4778046

Similar transistor mounting scheme as you are using here...

 

[kees52]

Well I almost there, it is quite difficult to get a circlotron on pcb, because of the cross system. The second one will do more easy I think because it is balanced the same direction.

regards

 

[kees52]

I do not now why eagle do make such trouble, now it refuses the polygon update and it do not report non connected traces when do drc and it loose connections..

and as such I can not connect ground pins.

I go over to a other pcb program, like cadstar or diptrace.

regards

 

[xrk971]

Sorry to hear of your troubles. That's such a disappointing waste of your time. May I suggest Sprint? Many folks here seem to use it to make beautiful layouts.

 

[kees52]

Sorry to hear of your troubles. That's such a disappointing waste of your time. May I suggest Sprint? Many folks here seem to use it to make beautiful layouts.

I have sprint but make mistakes is very easy because it is as drawn with a pen, it has no feedback to schematics, it indeed do work nicely.

The eagle do also miss traces, when I was amost done suddenly traces are gone and such things, not very trustable software.

Pictures are diptrace tryout version.

 

[xrk971]

Sprint needs manual checking - but that's ok. The circuit is simple enough that if you post schematic side by side folks here can look at it. You get about 100 pairs of eyes to look it over basically.

 

[kees52]

Sprint needs manual checking - but that's ok. The circuit is simple enough that if you post schematic side by side folks here can look at it. You get about 100 pairs of eyes to look it over basically.

I prefer a program who check also, because it is compact, when you miss a trrace after let making the board you also do not like that.

regards

 

[kees52]

Well After search for the eagle trouble I get find the solution and so did go on, it is just the adjustment of eagle who is tricky sometimes.

just take a look at the pcb, I haver a clearance of 0.8 mm for polygon who is on both sides and connected to the gnd.

the power lines have to be tinned because of current flowing to it, I have made a very compact board 83 x 100.3 mm with regular through holes components except the gate diodes for the power fets who are smt.

The next board I go try with diptrace who looks promissing, I have the demo now.

regards

 

[xrk971]

Very nice work Kees!

Thanks for your persistence on this.

One small request: if not too much trouble, can you make the inputs Q1 and Q3 2SK170's flat-to-flat to allow thermal bonding and wrapped with shrink tube so they track each other temperature wise? Also, maybe same for Q3 and Q4?

Thanks,
X

 

[xrk971]

Hi Kees,
It would be useful for you to post the schematic that goes with this board side by side so we can check for errors if any. Does Eagle have ability to display in a more eye friendly format like the layouts shown by folks who use Sprint?

I have a hard time with black background and green and red traces.

White background with blue or black traces like how Sonal or Prasi make it in Apex thread is very easy to verify.

Thanks,
X

For sample, here is great layout by Sonal that is easy on the eyes. This is the F11/12 that is excellent sounding.

 

[kees52]

Very nice work Kees!

Thanks for your persistence on this.

Thanks,
X

X

When I am not persistence on this then why i bother electronics right? we need to have this to make the hobby succesfull.

I see the pcb with the easy eyes however it is not a circlotron and have n and p fets and source resistors, that make things much more easy, I have a circlotron who is balanced and have double feedback lines who are crossed, and it needs small, but it is a nice pcb indeed, saw mje340 do work well in audio also mje15030 and mje 15031 aree very good drivers.

I look at the request puting the input mosfets such it can be temp connected, I think then I need switch to top some traces.

I put schematic here, but now eagle do check, so making things errous is ruled pretty out.

But future I do use as I say diptrace.

 

[xrk971]

No worries, I realize your topology is much more complex. It looks very symmetric. Nice.
Thanks. So looking forward to holding the PCB in my hand