Crack power supply and output caps

[hasafraker]

I ordered a set, after I get some hours on them I'll let you know what I think.

 

[Yoder]

I am new at this, and am curious how much one can deviate from the actual values. For example, with the 100 uv 160 volt capacitors how high or low could I go with either value? Thanks.

 

[JC]

With regard to the Voltage ratings of capacitors, it is almost never a good idea to use one with a lower rating.  This is because it is usually safe to assume that the designer chose the Voltage rating specifically to perform at the Voltage in the circuit, less whatever margin of safety the designer feels comfortable with, then chose the capacitor with a Voltage rating nearest to that which was commercially available, without going under his design's lower limit.  Practically speaking, you can usually choose a cap with a higher Voltage rating, although you may not find the increase in size convenient.

As far as the capacitance rating is concerned, what you can get away with will depend on how the capacitor is being used in the circuit.  If it is an output cap, for instance, the capacitance value may very well determine the lower limit of frequency it will pass.  If it is a power supply filter, the capacitance rating can effect other things.

Perhaps the designer will stop by and answer you specific questions.

 

[Grainger49]

I am new at this, and am curious how much one can deviate from the actual values. For example, with the 100 uv 160 volt capacitors how high or low could I go with either value? Thanks.

For the Crack output capacitor you might get away with a smaller value if it is a better sounding capacitor, non-polarized, Black Gate or film.  But as you make the value smaller the bass begins to erode.  It might be only a couple of notes if you only change by 10% or an octave if you cut the capacitor value in half.

So better at the same value or even a little smaller with a better sounding cap.  Larger values if you are sticking with electrolytic caps.

 

[mingles]

There's an excellent chart that shows the low frequency cutoff using different output cap values and different headphone impedances. It's definitely worth consulting:

http://www.bottlehead.com/smf/index.php/topic,526.msg6045.html#msg6045

 

[hasafraker]

Ok! The Erse caps showed up today and sweet christmas they're huge! I was worried at first that I might not have room for them, my speedball should be here sooner or later and I almost waited but yeah... no such luck so I made sure I left room for the SB. I put some pictures on my flicker account so anybody interested in these caps will know how big they are.

http://www.flickr.com/photos/28861421@N02/

 

[ztsen]

i always read good thing about black gate caps, can we mod the Crack using this?  any recommendation?

 

[ToolGuyFred]

i always read good thing about black gate caps, can we mod the Crack using this?  any recommendation?

I am running my crack with 33uF Black Gates which work fine with my 300 ohm Sennheisers. They sounded a bit bass light initially but improved as they ran in. (Got my son to confirm this impression in case I'd just got used to them.)

There are two problems with Black Gates:

• They tend to be quite costly.
• They are no longer made, so if you can't find the type, value and voltage you want then you never will.

I fell victim to the second problem last year when I upgraded my Lowthers to a more efficient model of driver. My ParaSEX amps were fitted with film caps, 10uF before the PSU choke and 15uF after. The higher efficiency speakers showed up too much hum, so I searched for 47uF 500V Black Gates to replace the 15uF film caps (47uF film caps just wouldn't fit in the case). I searched for weeks and eventually had to settle for Mundorfs which I hated until I strapped 2.2uF film caps across them (then everything snapped back into focus).

 

[jrebman]

I may eventually use some black gates in my Crack.  I have a tightly matched pair of 150 uF 350v NHs, and another pair of the same, but not as tightly matched.  I may use the matched pair as the output coupling caps, and the other pair in the power-e configuration as the last power supply cap.

Then again, I may not feel that it's necessary, and I'll save the caps for another project, another day.

-- Jim

 

[eeyore]

Anyone tried Mundorf Mcap 400V? It is available at 100uF and 150uF.