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Beginning to enjoy the DIY side of this hobby, but still a novice as far as circuits are concerned.

 

Have some Russian Teflon and PIO caps that recently arrived to upgrade the input caps in this PH16 valve phono stage.

 

Plan is to use double sided tape for mounting these rather large capacitors. Although may have to ask advice / work some magic to fit the large FT-3 in between the board and chassis!! (Pic 1)
 

I only ordered two pairs, but there are 6 positions that are recommended upgrade in the manual. (Pic 2)
 

With the aid of additional circuit maybe if needed (would have to check with designer I imagine), which positions should I replace first? (Pic 3)

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45 minutes ago, crtexcnndrm99 said:

Beginning to enjoy the DIY side of this hobby, but still a novice as far as circuits are concerned.

 

Have some Russian Teflon and PIO caps that recently arrived to upgrade the input caps in this PH16 valve phono stage.

 

I think you mean output (coupling) caps?

 

(There would not be series caps at the input of a phono stage ... but there is, typically, a series cap on each channel's output - to stop DC offset from passing into the next component.

 

Quote

 

With the aid of additional circuit maybe if needed (would have to check with designer I imagine), which positions should I replace first? (Pic 3)
 

 

I noticed that the voltage on the big black cap is 400v.  Are you sure your Russian Teflon and PIO caps are 400v (or more)?

 

Andy

 

Edited by andyr
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1 hour ago, andyr said:

 

I think you mean output (coupling) caps?

 

 

You'd be right there. Well that's a concerning start.. (!)

 

 

1 hour ago, andyr said:

I noticed that the voltage on the big black cap is 400v.  Are you sure your Russian Teflon and PIO caps are 400v (or more)?

 

Andy

 

Both 600v or more ones thankfully. 

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Wondering, Andy, whether to go for the first or second pair of WIMA caps for replacing with the Teflons 🤔

 

Also, was surprised to see the black encircled MKP caps are 1uF (given that this is a stock unit) when the diagram says they should be 0.33uF (which is what I bought in the PIO).

Edited by crtexcnndrm99
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You will benefit most replacing the output caps compared to the input? or inter-stage ones.

Do you have a schematic for this phono stage?

 

Edit: i see the out is near those black SCR caps? need to identify what caps are doing what.

 

Edited by muon*
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3 hours ago, crtexcnndrm99 said:

Wondering, Andy, whether to go for the first or second pair of WIMA caps for replacing with the Teflons 🤔

 

Sorry, have no idea.  :(  But if they're both in series ... then both of them!  xD

 

3 hours ago, crtexcnndrm99 said:

 

Also, was surprised to see the black encircled MKP caps are 1uF (given that this is a stock unit) when the diagram says they should be 0.33uF (which is what I bought in the PIO).

 

 

You do not want to replace 1uF with 0.33uF - as that will cut off bass response.  But by all means replace 1uF with 2.2uF.  :)

 

Perhaps you can use the 0.33uF ones you bought in the 'interstage' positions - obviously only if these are currently <= 330nF.

 

Andy

 

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Things are looking clearer now, thanks to all. 

 

Have installed the K40Y-9 in the 'output cap' position. Turned on and no smoke or other such alarming signs :D 

 

In relation to the 1uF -> 0.33uF, I will check with the designer, Roy Mottram, and see also what size the Mundorf upgrade option that he recommends for all 3 locations above are. 

 

The FT-3's are going to be more of a challenge due to their size!

 

 

Now I need to go buy some heat shrink....

 

 

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Update on progress - 

 

K40Y-9’s were successfully installed in the output caps position last week. We’re installed with leftover short lengths of Duelund 16GA tinned copper in oil cable. Enjoyed a few hrs of listening before the TT was all disconnected in anticipation of the new one (however due to multiple hiccups and parts needing to be sourced, said turntable is going to be finished until early next week).

 

Have just ordered some Elna SILMIC II caps for the power supply. 
 

Next step will be considering which position to install the single 22uF obliggato film cap in the power supply, while waiting for the Elna’s to arrive. Would also like to replace some of the wiring with the Duelund scraps if there is enough left. 

 

Also, have some 4mm stainless to install in the middle of the chassis to effectively separate the psu from main PCB (and grommets for for hole to route cables through). 

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56 minutes ago, crtexcnndrm99 said:

 

Also, have some 4mm stainless to install in the middle of the chassis to effectively separate the psu from main PCB (and grommets for for hole to route cables through). 

 

 

4mm ss - wow!! ... an overkill, I would've thought?

 

Me - I use 1.5mm mild steel dividers to separate transformers from PCBs.

 

Andy

 

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39 minutes ago, andyr said:

 

4mm ss - wow!! ... an overkill, I would've thought?

 

Me - I use 1.5mm mild steel dividers to separate transformers from PCBs.

 

Andy

 

Naturally, I didn’t measure beforehand and it was thicker than expected! However it was a very small cheap square piece off eBay so I didn’t mind some overkill :D 

 

id heard of the mild steel and mu metal though... even considered on of those transformer covers, but this seemed like an easier install at the time.

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