It's a Crack Jim, but not as we know it..
- Thread starter Shappers
- Start date
balancedtriode
New member
wow...
Industrial art, reminiscent of art deco with the mat black caps and transformer cover, the dark wood and chrome chassis plate ... beautiful!!!!!
Industrial art, reminiscent of art deco with the mat black caps and transformer cover, the dark wood and chrome chassis plate ... beautiful!!!!!
denti alligator
New member
This is amazing. Can you tell us more about the design?
Beautiful, that is some great handiwork Shappers! Is that a Bulgin switch you are using? Also looks like one of Keith's chassis, Neutrik locking plug, VT4C transformer covers and some fancy-pants silver wire, right? 
I actually haven't seen nice sturdy capacitor clamps that look like that, mind revealing your source?
I actually haven't seen nice sturdy capacitor clamps that look like that, mind revealing your source?
Well thanks again,
HF9, it was actually your diyaudioblog website which inspired me to start to make my own cables and now this amplifier, so thank you!
So the chassis is of course one of the late great Keith Kirby's boxes, he shipped it out just a month before he died. A terrible loss as he was a complete master at what he did. The wood is African padauk and I had originally intended for the wood to run along the sides but when I saw how beautiful the wood was I had to flip the box round and have the wood front dead center.
The transformer covers are hiding the PT-3 and one choke, there are two chokes, one up and one down. The covers looked a little lost once I turned the box, so I then had the idea of having the output caps sticking upwards. I finally found clamps big enough to hold them at banzaimusic.com. A nice company which actually have very nice prices for Mundorf caps (both being German).
I used a DACT Type 21 stepped attenuator which someone on here recommended, I like it a lot, it has a great feel. The knob came from HK after searching ebay for days to find "just the right one".
Signal wire is 1mm Mundorf Silver/Gold with teflon sleeving, Mundorf solder too.
The RCA chassis connectors are made by Amphenol, I actually danced when I found them as they exactly match the look of the locking Headset jack.
What else.. Two Belton octal sockets, the 12AU7 socket changed to a 6SN7. The ON/OFF switch is an Apem AV04.
I'm putting the speedball in presently and then I'm going to run it for a while before playing around with some bypass caps on the big output caps, I also have a nice collection of tubes to play around with.
Happy Days!
HF9, it was actually your diyaudioblog website which inspired me to start to make my own cables and now this amplifier, so thank you!
So the chassis is of course one of the late great Keith Kirby's boxes, he shipped it out just a month before he died. A terrible loss as he was a complete master at what he did. The wood is African padauk and I had originally intended for the wood to run along the sides but when I saw how beautiful the wood was I had to flip the box round and have the wood front dead center.
The transformer covers are hiding the PT-3 and one choke, there are two chokes, one up and one down. The covers looked a little lost once I turned the box, so I then had the idea of having the output caps sticking upwards. I finally found clamps big enough to hold them at banzaimusic.com. A nice company which actually have very nice prices for Mundorf caps (both being German).
I used a DACT Type 21 stepped attenuator which someone on here recommended, I like it a lot, it has a great feel. The knob came from HK after searching ebay for days to find "just the right one".
Signal wire is 1mm Mundorf Silver/Gold with teflon sleeving, Mundorf solder too.
The RCA chassis connectors are made by Amphenol, I actually danced when I found them as they exactly match the look of the locking Headset jack.
What else.. Two Belton octal sockets, the 12AU7 socket changed to a 6SN7. The ON/OFF switch is an Apem AV04.
I'm putting the speedball in presently and then I'm going to run it for a while before playing around with some bypass caps on the big output caps, I also have a nice collection of tubes to play around with.
Happy Days!
Great, thanks for all the useful information! Glad you found the blog. It was a great idea to flip the chassis sideways and the first time I've seen someone do that. It's a darn shame about Keith, perhaps someone will follow in his footsteps (I probably would if I had a garage).
Thanks for the link to Banzai Music, those nylon cap clamps look really nice.
Also, the recessed D-flange RCAs by Amphenol are a neat choice. I know that Neutrik makes them as well. They'll fit industry standard holes (like female XLRs, etc.).
Well congrats on your build. With the Speedball and some bypass caps that baby will really sing! You just have to decide which ones... Mundorf Silver Oils, AmpOhm PIOs, Jensen Copper... maybe even some Duelunds if you have a nice tax refund
Thanks for the link to Banzai Music, those nylon cap clamps look really nice.
Also, the recessed D-flange RCAs by Amphenol are a neat choice. I know that Neutrik makes them as well. They'll fit industry standard holes (like female XLRs, etc.).
Well congrats on your build. With the Speedball and some bypass caps that baby will really sing! You just have to decide which ones... Mundorf Silver Oils, AmpOhm PIOs, Jensen Copper... maybe even some Duelunds if you have a nice tax refund
One last picture..
I installed the Speedball today and tried a couple of bypass caps on the big output caps.
They seemed to open up the sound, but are they too big for bypass caps? I wanted to bypass with Russian Teflons but all I found in my box were 0.47uF ones. Perhaps 0.1uF would be more suitable?
Can't wait until tomorrow to take this into work with me so I can hook it up my proper DAC and HD650 headphones. I've only heard it with my old '70s headphones and I always thought they sounded terrible, this Crack though really made them sing like I never knew they could 8)
I installed the Speedball today and tried a couple of bypass caps on the big output caps.
They seemed to open up the sound, but are they too big for bypass caps? I wanted to bypass with Russian Teflons but all I found in my box were 0.47uF ones. Perhaps 0.1uF would be more suitable?
Can't wait until tomorrow to take this into work with me so I can hook it up my proper DAC and HD650 headphones. I've only heard it with my old '70s headphones and I always thought they sounded terrible, this Crack though really made them sing like I never knew they could 8)
There's tons of information regarding how to calculate a bypass cap in high speed devices (http://download.micron.com/pdf/technotes/TN0006.pdf) but with audio there are far too many different opinions to really have a set precedent. I've seen people using anything from 10% to .1% as well as cascading with multiple bypass caps, and there are a number of people that feel that bypassing is not worthwhile. I feel that commonly many DIYers will use a value of 1%. I'll sometimes step it up in a to a higher value in a power circuit for the purpose of ripple reduction.
The Russian Teflons take quite a bit of time to burn in. I think Grainger here has a method that he uses to burn them in before use. I've also read about people "nuding" the Russian Teflons (removing the metal shells) with a positive effect. http://www.enjoythemusic.com/diy/0411/capacitor1.htm
Might be a fun little experiment if you're bored
The Russian Teflons take quite a bit of time to burn in. I think Grainger here has a method that he uses to burn them in before use. I've also read about people "nuding" the Russian Teflons (removing the metal shells) with a positive effect. http://www.enjoythemusic.com/diy/0411/capacitor1.htm
Might be a fun little experiment if you're bored
Grainger49
New member
Here is a link to the less painless than listening break in post:
Fast Break In Post
Fast Break In Post
4
4krow
Guest
"It's a Crack Jim(captain), but not as we know it." LOL!!! I just got it! HA
BTW, that is really quite fine workmanship, be proud.
BTW, that is really quite fine workmanship, be proud.
Thank you for the cap advice. I was tempted to break-in my caps a-la-Grainger but now I'm hooked on the music and don't feel like delving inside for a while.
My ears are hearing some sublime music even though it is all new and the 4 big caps need a long time to break in, so I will just run it as it is and know that it is only going to get better
Just out of interest I've been trying some different tubes and so far the winners are: Sylvania 6SN7WGT paired with a Tung Sol 7236. Just layers-upon-layers of sweet clear musical music.
I'm an ex-Avionics engineer who is now desk-bound in a boring technical writing job, so when I get a chance to use my hands and get all my tools out I jump on it and do things the best job I can!
Steve
My ears are hearing some sublime music even though it is all new and the 4 big caps need a long time to break in, so I will just run it as it is and know that it is only going to get better
Just out of interest I've been trying some different tubes and so far the winners are: Sylvania 6SN7WGT paired with a Tung Sol 7236. Just layers-upon-layers of sweet clear musical music.
I'm an ex-Avionics engineer who is now desk-bound in a boring technical writing job, so when I get a chance to use my hands and get all my tools out I jump on it and do things the best job I can!
Steve
Grainger49
New member
Shappers said:
I have the same trouble with my Eros. I did get in the Mundorf Silver/Oil output caps but there is a list of other things waiting.
It is hard to give up the music!
