stereomour parts upgrades sticky thx

[ee]

Paul and Grainger- thanks for the upgrade info and making it a sticky. I almost stuck this post on there but at the end didn't want to mess up the sticky. Answered my questions perfectly that I've been tossing around for a day or so regarding upgrades and which cap is where in the layout. I have studied the manual some and read manyof the postings for upgrades. You guys defined it perfectly so I can picture it in my head for the layout of the caps regarding their purpose in the stereomour.
Mine will be mating up with Fostex fe206en in the Vulcan BLH design that I just completed. It sounds good even on my SS integrated. But, as one of my friends said the other day "you are about to be on another planet".
I would like to know if a different parallel feed cap value would be suggested in this Fostex setup, something different from the 3.3uf might be more advisable. I have read postings here regarding the effects of higher and lower values. Just trying to clear it up in my mind to relate it to the speakers. Maybe just a try and see as you've said before.
Best of all I'm excited to be getting the Stereomour!
Eric

 

[Paul Birkeland]

Hello Eric,

Snap up a 1.5uF and a 6.8uF 630V Solen, then do the comparison for yourself.  (It will be educational, and very inexpensive)

-PB

 

[Grainger49]

Paul Joppa chose the 3.3uF value as the middle of a range, which I don't know.  But he encourages builders to experiment.

Increasing the value is costly for an experiment to a cheapskate like myself.  So I would spend the extra cash on a better sounding cap.  There are many!  The stock cap is a Solen.  A perennial favorite is the AuriCap.  I like Obbligato for inexpensive caps (relatively inexpensive) and Mundorf Silver/Oil or Silver/Gold/Oil.  If you want to go crazy, I did once, buy V-Cap Teflon caps.

But first always build it stock.  That way you know what changes your hard earned cash brings.

 

[Paul Birkeland]

Increasing the value is costly for an experiment to a cheapskate like myself. 

This is $20 experiment (including shipping).

 

[Grainger49]

In general an increase in the value of the Parafeed cap without changing the capacitor manufacturer will reveal a few notes in the bass and no change in sound character because you haven't changed the makeup of the cap.

You get this bass if and only if your speakers and room can produce those notes.

 

[Paul Joppa]

In the Stereomour, the "design center" value is 2.5uF for 2A3 and 5uF for the 45. (This is because the 45 uses a different tap on the plate choke, with different inductance.)

The range of good values is broad, nominally from 1/2 to 2 times the design center. For that reason we ship with the 3.3uF which splits the difference and always works no matter which way you build it.

In the past I have provided theoretical guesses about the audible effect of different cap values, but I have come to the conclusion that the effect of different speakers is larger than that of caps, so it's best to experiment with your own speakers (in your own room) in order to find a meaningful optimum value. I use the stock values at home in my SEX and Paramount amps, but I have invested in Auricaps. YMMV.

 

[ee]

Please tell me if I am on the right path for putting in bypass caps on power supply and cathode resistors to power supply board. I am refering to pg 67 of stereomour manual as my pic.
I could place a power supply bypass cap soldered at HV+ (coming from 100uf cap) going to ground  like a value of 0.1uf.
Secondly could place cathode resistor bypass cap soldered at K (the + of 220uf cap location) to ground like a value of 0.2 uf.
I will clip in the caps first to test them for values and effects first.
I am starting to wonder how crazy I'm gonna get building this but I've seen some good builds here for sure and being mentored to crazy is looking easy. Beautiful pieces of art being created.
Thanks
Eric

 

[Paul Joppa]

You will have noticed that one of the HV+ holes on the PC board is unused. It is there for exactly that reason - in case someone wanted to replace or bypass the last PSU capacitors. I figured when designing the layout that one could bypass the cathode caps with a cap from 6 to 16, and another from 10 to 20.

Be careful about the heat from the cathode resistors - heat will damage caps quickly, so maintain as much space between caps and those resistors as you can.