Upgrading resistors and powersupply from the start.

[Tom-s]

Because i'd like to make the journey worth it from the start.

1.      What resistors in S.E.X. 3.0 would benefit from an upgrade?
Based on the info here: http://www.aikenamps.com/index.php/resistor-types-does-it-matter
Remove link if not allowed.

Input resistors -> Volume pot is worth an upgrade.
Grid stoppers -> Probably small influence -> Tantalum 180 Ohm 0.5w
What is the most sound influencing plate resistor?
CCS R1 -> Tantalum 500 Ohm 0.5w

Other suggestions concerning resistors?

2.    Where would the powersupply benefit from any upgrades?
Rectifier upgrades to Schottky diodes?

Edit: yes, read this thread: https://bottlehead.com/smf/index.php?topic=1126.0
Another interesting topic: https://bottlehead.com/smf/index.php?topic=36.0

 

[Paul Birkeland]

The 150K plate loading resistor benefits from being replaced by the C4S upgrade.

There are Schotttky diodes in the power supply where they will matter the most and ultra fast switching diodes where diode switching noise is less important. 

Switching out the volume pot is a popular mod, but be sure that it fits!

 

[Tom-s]

Thank you for the fast reply.
Yes, i figured the plate loading R by CCS would be the biggest upgrade in that area but i meant the CCS resistors.

The uf4007 rectifier diodes were the ones i figured could be upgraded (i have Schottky CSD01060A)?
Edit: Reviewed the manual. No go.

Concerning the volume pot; i was most intrigued by the Mainline volume pot (which i also ordered)(Sweetest whispers?).
https://bottlehead.com/smf/index.php?topic=10985.0
Is there any downside from duplicating this in my SEX (if i can make it fit?)?
I'm not planning, and most afraid off, introducing any noise into the circuit.
The 14.7K resister is the most important in that one. I will replace that one with Talantum and leave the rest as is Vishay/Dale RN60's.

Probably will do the same resistor change in Mainline, but that's for another thread.

 

[Paul Birkeland]

The Mainline level controls are not particularly similar to the Sweetest Whispers, but they are both stepped controls.  There isn't enough room in the SEX for two controls (we did discuss this when developing the S3X).  I think some stepped attenuators will fit, while others will hit the wood base.

 

[fullheadofnothing]

p. 11.

 

[Tom-s]

I will put the plan on hold for now. And see when the kit arrives.
I've found some selector switches that are so small i could make it all fit.

Edit: https://www.elma.com/en/products/rotary-switches/rotary-switching-products/product-pages/type-01-detail/
Type: 01- 1263

I'm aware of the strict selection of parts by the Bottlehead team and recommendation to start with the supplied part and change parts later on, but i'm afraid it will be hard to take it all apart again, change out resistors and make new holes in the top plate for the switches etc etc.

 

[Doc B]

Start with changing the pot after you build it stock first. The rest of that resistor and diode stuff will yield pretty small improvements for the effort.

 

[Paul Birkeland]

Edit: https://www.elma.com/en/products/rotary-switches/rotary-switching-products/product-pages/type-01-detail/
Type: 01- 1263

Just about every rotary switch manufacturer will list switches that would work great for an attenuator as a possible part number.  When you go to their distributors, however, shorting switches with solder lugs become extremely rare.  The same thing happens when looking for non-inductive high power resistors.  Often time the datasheet will specify a suffix to the generic part number for a non-inductive option, but nobody stock these parts.

For our current stepped attenuator, the switch manufacturer makes a run of custom switches for us every time we order, as the switch we use goes in and out of stock constantly and no vendor ever has more than a few in stock at any given time.

 

[tsingle999]

From my experience with multiple Bottlehead kits I would agree with Doc that the resistors make subtle difference. I would build the stock kit first and then switch out the coupling and parafeed caps whick make bigger differences. I have tried a few different stepped attenuators but I am in love with more inexpensive Carbon PEC pots that drop in pretty easily. Just my 2 cents... 

 

[Tom-s]

Thanks everybody for the feedback.
I'll start with the standard build first.