Crack power supply upgrade

[ccoolliinn]

After building a standard Crack + Speedball I have only upgraded the output caps.

I'm very pleased with the results over the last couple of years but would like to investigate to possible improvements of power supply upgrades and recommendations of replacement caps.

Are the improvements in sound worth the time and effort.

 

[kgoss]

I would think the most cost effective upgrade would be the Crackatwoa with it’s shunt regulated power supply. 

 

[ALL212]

You have very limited room to do much in there so if you're not comfortable with close in work - it's good as is.  I've upgraded mine and I believe it increased the sound quality.  If you go back through the Crack threads you should be able to find some pictures of what's been done.  I believe primarily replacing one of the resistors with a choke and putting in better diodes in the form of a diode board.

As far as replacing the PS caps - probably not necessary but others may chime in here and have an alternative opinion on that.

Think carefully through this - you have a great build!

 

[Leland Hankins]

Regardles of what you do to your Crack it will never be as good as the stock Crack a-two-a.

 

[JamieMcC]

The choke mod is well worth doing imho its got a number of  things going for it

Its inexpensive  the Triad C-7x choke required is around £10
Its simple remove one resistor and reconnect the chokes leads to the same terminals.
Its an easily audiable improvment.

https://www.mouser.co.uk/productdetail/triad-magnetics/c-7x?qs=%2fPiZ59IM4y3T0O8Zu9aP3g==

 

[Bacci]

The choke mod is a no brainer. I recommend the Cree mod (https://bottlehead.com/smf/index.php?topic=7720.0) too, clearly positive difference to my ears. These are cheap upgrades.
Some people, including me, still prefer the Crack over Crack-a-two-a because of its looks and especially its smaller size.

 

[shrapnel]

How does the choke mod improve the sound? Can someone please quantify? Thanks!

 

[ccoolliinn]

Thank you for all the replies and sorry for the delay in returning a post. I decided to keep the Crack as it was in the photo, it sounds great and has never played up. When or should i say if i have problems that maybe the time to revisit this.

One slight problem but not the fault of the Crack is the fast volume increase with my Bayer Dynamic T90 headphones  8). I love their upfront nature but they seem almost too sensitive.

 

[Tom-s]

Try FAQ #3 to solve your volume control issues.

Life's too short. Especially if your waiting for Crack to fail on you. Turn it on/of 100x a day for 10 years and let us know how the thing is doing. Quiet possibly you'll have to replace the output tube by than. But good chance the power supply caps are still going strong.

As Paul Joppa would say: "I never met a power supply improvement that was not also a sonic improvement."

 

[Paul Birkeland]

I had a local customer bring by an Eros on Sunday that was from about 2011.  He asked me what parts inside needed to be replaced, and I told him he was at least 10 years early, and possibly 20+.

 

[ccoolliinn]

Try FAQ #3 to solve your volume control issues.

Life's too short. Especially if your waiting for Crack to fail on you. Turn it on/of 100x a day for 10 years and let us know how the thing is doing. Quiet possibly you'll have to replace the output tube by than. But good chance the power supply caps are still going strong.

As Paul Joppa would say: "I never met a power supply improvement that was not also a sonic improvement."

Thanks for the reply, seems to be a thing with T90 headphones some 880s were not as sensitive.  As for power supply upgrades  I am just happy with the performance in its current state.

Just out of interest has anybody removed the power supply side to a separate box, power isolation made big improvements to Naim amps i owned some years back. Being a valve amp where high voltage is present maybe this has no merit.

 

[Paul Birkeland]

External power supplies are a rabbit hole I won't go down again.  I have also owned Naim gear and I admire the marketing, but if you have a power transformer and unregulated DC supply in a box sitting right next to your preamp that's also in a metal box, why not put them both in the same box and add a wall down the middle?

 

[ccoolliinn]

Yes Naim is a system that sucks you into their way of thinking, great sounding gear all the same. Moved on to different pastures now, would consider building a valve amp but my PMC Twenty 23 speakers  8) would not be a good match.

 

[Paul Birkeland]

I'm sure 50W would do the trick.

 

[ccoolliinn]

Yep, 50amp would run them but I've found amps are not equal even with the same power and some drive or control some speakers better than others. My amp of choice after testing others for the PMC is a Rega Elicit. No more powerful than others but better control IMHO. Also it has a output link where I connect my Crack so I'm able to listen to all my souses.

 

[jufelling]

As shown in the picture of the initial post of this thread different output caps are used.
It looks like they're soldered to a different solder lug than in the manual.

In the manual it is 6U + 7U for one cap and 9U + 10U for the other cap.
Also the wirewound resistors are connected to 6L and 9L.

I assume the additional lugs in the picture above are added because of the size factor of the caps.
It seems like only the output caps + the wires that would normally be soldered to the original lugs are moved here.
The wirewound resistors seem to be soldered to the original lugs - this does not make a difference?

I'm asking since I also plan to upgrade my Crack with quite huge caps and therefore consider to use additional lugs.

 

[2wo]

The OP added turret post (single terminals) to mount those big caps to, then they would be connected to the terminals called out in the manual. No need to move the resistors..John

 

[jufelling]

Ah I see.
Thank you