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MF X-Can V2 tweaks - Page 5

post #61 of 71
Thread Starter 
Quote:
Originally Posted by Fing
Unfortunately something went wrong and when I plugged it in, smoke came out of the amp.
How are you getting on with it Wai?

All the best.

Mike.
post #62 of 71
Unfortunately I chucked the original 470uF caps - so I might have to order some more from RS Components.

I ordered a pack of the Nikai non-polarized 470uF's to replace the output caps on the lower board, but I haven't used them, since I thought a straight replacement with 220uF Blackgates might sound nicer.

Will the Nikai non-polar be okay to use in the PSU board?

I forgot to mention that the blown tantalum was a 22uF coupling cap for one of the 1800uF Panasonic's I'd used to replace one of the 470uF's on the PSU.

The coupling caps I used were all much larger than I thought and as such, the tantalum cap might have been touching one of the other caps. I thought these things were shielded. Are touching cap's a big no-no?

I'm also trying to figure out the type of diode I should be using as a replacement. Are these a standard type/value?

I think my version of the X-Can V2 is different than the one in the pictures - probably an older design as I bought it just after the V1 was discontinued.
post #63 of 71

Tried the 6h23 Rocket Logos

Quote:
Originally Posted by weinstro
FWIW, I received some "rocket logo" Russian 6h23, yesterday. I'll install these on Saturday and see how they sound.
And they sound quite nice. I sourced these from Upscale Audio, purchasing the "gold" quality level. Fuller bass, treble is not quite as bright, which is desirable for my phones, Etymotic ER-4S.

In comparing (visually) the two tubes (6h23 vs. JAN Philips 6922), I would say that the Philips tube looks to have better build construction. On the bottom, the wiring on the 6h23 appears to be heavier. However, the 6h23's have completely eliminated the microphonics issue I was having.

All in all, I'm pleased.

Now, back to power supply work...

Regards,

Rob
post #64 of 71
Thread Starter 
Quote:
Originally Posted by Fing
Unfortunately I chucked the original 470uF caps - so I might have to order some more from RS Components.

I ordered a pack of the Nikai non-polarized 470uF's to replace the output caps on the lower board, but I haven't used them, since I thought a straight replacement with 220uF Blackgates might sound nicer.

Will the Nikai non-polar be okay to use in the PSU board?
The non-polars will be perfectly ok to use in their place.

Quote:
Originally Posted by Fing
I forgot to mention that the blown tantalum was a 22uF coupling cap for one of the 1800uF Panasonic's I'd used to replace one of the 470uF's on the PSU.
Did you observe correct polarity?

Quote:
Originally Posted by Fing
The coupling caps I used were all much larger than I thought and as such, the tantalum cap might have been touching one of the other caps. I thought these things were shielded. Are touching cap's a big no-no?
Capacitors should be shielded and they shouldn't explode if they touch together..... as long as the legs weren't touching?

Quote:
Originally Posted by Fing
I'm also trying to figure out the type of diode I should be using as a replacement. Are these a standard type/value?
I desoldered one and it's an IN4007

Quote:
Originally Posted by Fing
I think my version of the X-Can V2 is different than the one in the pictures - probably an older design as I bought it just after the V1 was discontinued.
Any photos?
post #65 of 71
Quote:
Originally Posted by Fing
I forgot to mention that the blown tantalum was a 22uF coupling cap for one of the 1800uF Panasonic's I'd used to replace one of the 470uF's on the PSU
At >4 times the original size, you should look at the size of the inrush current into the diodes. You may need to use diodes with a larger forward current rating. An alternative approach is to select current limiting resistors, but this will cause a voltage drop, unless you also select a transformer for the wallwart power supply with a higher secondary voltage rating.

Finally, why are you using a tantalum capacitor? Those are allegedly very bad sounding. They do have use, however, if you need a higher ESR, such as described in the Nat Semi application note for LDO regulators.

Regards,

Rob
post #66 of 71
I finally got around to substituting the 470uF non-polars as well as the diode and everything works fine!

I guess it was over-zealousness on my part in carrying out the mods.

I'd post pictures but I'm frankly embarrassed by the extra-ordinary untidyness of my soldering and positioning of my by-pass caps - they are far too large for the case.

Nonetheless very happy with the sound - a definite improvement.

Thank you for all your help Mike.

Rob: Using tantalums to by-pass the large value PSU caps is okay isn't it? The tantalums themselves are by-passed with polypropylenes.
post #67 of 71
Thread Starter 
Quote:
Originally Posted by Fing
I finally got around to substituting the 470uF non-polars as well as the diode and everything works fine!
Excellent! Glad you got her up and running again without too much bother

Quote:
Originally Posted by Fing
I guess it was over-zealousness on my part in carrying out the mods.
Not at all you were just unfortunate to have a bit of bad luck, these things happen to all of us and are part and parcel of the learning curve / sods law. Fortunately you got the amp up and running without too much bother so no harm done.

Quote:
Originally Posted by Fing
I'd post pictures but I'm frankly embarrassed by the extra-ordinary untidyness of my soldering and positioning of my by-pass caps - they are far too large for the case.
Don't be shy! as long as the components are soldered together and the amp is working then you've done a good job.... come on show us the ****

Quote:
Originally Posted by Fing
Nonetheless very happy with the sound - a definite improvement.
Give the caps a few weeks, it gets even better
post #68 of 71
Thread Starter 
A few more V2 tweaks uploaded. More to follow shortly......
post #69 of 71

I hope to start putting in cap and diode replacements I got from Mike next week.
Hope all goes well; More or less a solder newbie. have a bunch of old stuff to practice soldering and desoldering on again.

Austin

post #70 of 71

It was posted a long while ago in this thread but compenents for the upgrade were alongside the RS part numbers, namely:

 

 

10 x Panasonic FM 35V 1200uF (RS part number: 526-1777)
4x Pansonic FM 50V 120uF (RS part number: 526-1610)
2 x Nitai 35V 470uF non polar capacitors (RS part number: 768-598)
2 x SamWha 50V 10uF non polar capacitors (Nitai will do fine)
1 x 9mm 10K dual log ALPS potentiometer (RS part number 249-9159)

 

Now, as I'm in the UK I don't seem to be able to source these parts through the UK RS website as those part numbers don't exist. Can anyone tell me where I can source these bits and pieces from along with their part numbers please. I daresay I can get those values but if they don't physically fit in the can then they're a none-starter. Are there alternatives I could use?

 

Also the valve that PF recommends I can't find either. Anybody have any recommendations improving on the stock tubes that the V2 comes with?

 

TIA 

post #71 of 71

Oh and another thing. When he says he bypasses capacitors does that mean leaving the existing capacitor on the board and soldering another one to the same solder points (so effectively having both in parallel).

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