^ditto. Really great build there.

I've found that there is a CL60 thermistor in Yun's BOM. But I'm not sure how to mount this part on the PCB or in the connection wires.

Is it functioned as a fuse? if so it is, could I put it between the transformer and the power switch?

Any advice will be appreciated.

Look up the Firstwatt F5 amp design to see how it should be used.  It's role is to limit the inrush current as the amp is switched on.  You need one for 230V and two for 117V. 

Emooze, great build!

Look up the Firstwatt F5 amp design to see how it should be used.  It's role is to limit the inrush current as the amp is switched on.  You need one for 230V and two for 117V. 

Thanks a lot.

I've found another problem with the fast recovery diode.

In the latest bom it shows as:　STTH512FB　but it used the type : 511-STTH1210D (mouser PN). I found another type as 511-STTH512FP (mouser PN) mentioned in the megatron thread. I'm not sure what is the difference between the two types. And which one should I choose?

can't check right now. but the difference is most likely whether it's insulated or not.

use the insulated one, especially if you are using the mini board.

Take the stth512fp which is the isolated version. do not use non-isolated diodes. the stth512fb is a spelling error and does not exist.

Thanks a lot.

I've found another problem with the fast recovery diode.

In the latest bom it shows as:　STTH512FB　but it used the type : 511-STTH1210D (mouser PN). I found another type as 511-STTH512FP (mouser PN) mentioned in the megatron thread. I'm not sure what is the difference between the two types. And which one should I choose?

Yup, do not use the uninsulated diodes.

Thanks for the kind words and sorry for the delay, finals week here. It's been a struggle but I'm just happy she's making music now. I would say I've got a new space heater but I haven't seen anything above 90F on the main heatsinks yet.

 

Definitely, altogether, a much better sounding amp over my last one. Now I think I need to start saving up for O2s.

Thanks for all of the comment.

But I've already  ordered some STTH1210D, so is it OK to add some TO-220A insulator rube to this diode like this?

http://www.ebay.com/itm/TO-220-Transistor-Silicone-Rubber-Cap-Insulator-x-10-/400244726109

 

ps: I'm building the large version of the PSU board.

Hi Leonjo,

 

You can use either if you're using the larger version of the PSU board. The insulated version is needed for the smaller board because the distance between the diodes are very close (it's like almost 2mm). If you use the 1210Ds on the newer smaller boards, you'd have to figure a way to insulate them. As to your insulator tubes for the transistor, there isn't any rating so it's hard for anyone to tell you if it'll work.

 

I hope that helps

Hi Leonjo,

 

You can use either if you're using the larger version of the PSU board. The insulated version is needed for the smaller board because the distance between the diodes are very close (it's like almost 2mm). If you use the 1210Ds on the newer smaller boards, you'd have to figure a way to insulate them. As to your insulator tubes for the transistor, there isn't any rating so it's hard for anyone to tell you if it'll work.

 

I hope that helps

Hi RistaR

 

I see. Thanks a lot for your kindly comment.

welp, heard a huge pop from my kgsshv, but not before some weird static buildup in the left channel. Can't tell if the headphones are damaged, but sound still comes out. All of the LED's on the amplifier board are still lit, so I'm not sure where the problem could be, power supply?

OK, more troubleshooting questions:

I was asked to look at my first build because it won't start:

After I replaced the burned fuse, it does start briefly, the led's turn on and then the relay clicks it off.

The replacement fuse is not burned.

I am thinking it could be the relay or the e24 not the toroid neither the PSU and maybe bypassing both to see if that is the case.

Edited December 22, 201312 yr by eggil

Bypass the e24 and try it with a switched extension cord instead.  This is the main reason why I use latching switches instead, I despise relays... 

 

welp, heard a huge pop from my kgsshv, but not before some weird static buildup in the left channel. Can't tell if the headphones are damaged, but sound still comes out. All of the LED's on the amplifier board are still lit, so I'm not sure where the problem could be, power supply?

 

Most likely the PSU.  A spec of dust can always cause a brief short to ground which could account for the pop. 

 

The amp should under no circumstance cause damage to the phones.  We made sure of that but there is always that one time...

Thanks Birgir, I suspect is something minor.

Well, it is the transformer. I removed it from the amp and every time it starts it blows a fuse.

Already emailed Primrose

Another one bites the dust. 

finally got off my butt and fixed the PSU. It's making music now, and I hope it will continue do so...

I'm now using the trafo Palchiu gave me... loaded, the voltage drops to 460VAC, so I guess it's fine.

That trafo weighes about 0.3lb heavier than the SumR one while with the same output current at 150mA.

 

eggil, that sucks... I'm sure RIchard will replace yours. He did replace mine, but took around 1 month.

I still have the SumR raplcement on hand, if you need it, I can send it to you now while you wait for your replacement. Just PM me.

 

That's at least the 4th one that KGSSHV has killed... maybe 150mA is not enough...

I think sumr has a bit of holiday lag in him at the moment, he's taking quite a while to manufacture and deliver my high-current KGSSHV transformer.

Thanks jwzhan. I take it is the 450 VAC for the 500 VDC rails? 150 mA?

150mA is overkill so the problem is just with SumR.  All the other ones I've had made had no issues. 

Is the 150 mA specified as AC RMS? What is the DC current draw of the amp?

If it is 80 mA DC then 150 mA RMS isn't overkill at all, it's a bare minmum.

Thanks jwzhan. I take it is the 450 VAC for the 500 VDC rails? 150 mA?

 

yup, it's 450V @ 150mA for 500V PSU