Check your messages. You have a nice care package that I'll ship out tomorrow.
In the mean time you could try rectifiers without snubber boards if you have spare rectifiers. Unsoldering those boards would be a massive pain.
In the mean time you could try rectifiers without snubber boards if you have spare rectifiers. Unsoldering those boards would be a massive pain.
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Nice! I am glad I reached out about the Thermistors (?)! It might have been a more protracted saga otherwise. Seem like we might be closer to the solution. I'll await your updated boards and do it right. I am in no rush I have my ACA and B1/Korg test setup in place... Thanks to ALL T
Hi folks,
Finally had a chance to install my Aleph Jzm in my system. I was super impressed with the initial sounds, couldn't be happier. I wanted to share some gear shots. Enjoy!
Jim.
Finally had a chance to install my Aleph Jzm in my system. I was super impressed with the initial sounds, couldn't be happier. I wanted to share some gear shots. Enjoy!
Jim.
Hey gang I was admiring @hamelka 's setup and noticed it also shows the Aleph JZM in a confined space like I use(d). While I was having problems I pulled it out thinking I had an overheating problem. What are the thoughts of the group about confined spaces and overheating and the use of fans and fan controllers so that we can use confined spaces...
one thing is decreased size of heatsinks and forced cooling, another thing is whatever size of heatsinks and confined space.... and how much of assisted/forced cooling you need
use common logic, and measurements..... say that 50C at top of heatsinks is sweet (max) spot
everything else must be adjusted to your particular case
all roads are leading to Rome
use common logic, and measurements..... say that 50C at top of heatsinks is sweet (max) spot
everything else must be adjusted to your particular case
all roads are leading to Rome
On this scale I'm running my Aleph Jzm at about 55C. It's my opinion that these IRFxxx based amps sound best run hot.
Aww. @tgrier said "admiring. Thanks for that. I got curious about the confined space and let the amp warm up for a while and took some temps around the heatsinks and found a max of about 114 degrees Fahrenheit (46 degrees C - somewhere between blimey hot and crikey hot - savage hot maybe? dunno). I do kind of have a hidden secret - due to the depth of the enclosure, I did have to cut the back out of my cabinet to let the a$$ end of the amp hang out a bit. Maybe that helps? So far (knock on wood) I haven't had any apparent issues, but I guess time will tell.
Also, I didn't know you couldn't write a$$ on here. Odd.
Anyways, Jim.
Also, I didn't know you couldn't write a$$ on here. Odd.
Anyways, Jim.
Ok, after assembling the amp boards and rthatcher’s PSU (thanks RT for answering a few ?s), i am ready to test the PSU and then the amp boards. Thanks to modushop for the chassis.
A couple of questions from a relative novice.
I plan to follow the wiring strategy used in the build guide (copying is flattery, right?).
I have 30mm standoffs for the PSU and planned to run those wires under the board, probably with wire insulation laying on the chassis silver plate (not chassis bottom plate). There was discussion earlier in this thread about sending wiring under the silver plate and strictly avoiding wire contact with that plate.
I assume, based on build guide, that the insulated wriring on the silver plate is OK as long as no bare wire hits the plate.
Correct?
Next question. Thermal paste for rectifiers? A detailed youtube vid from an English gentleman building an Aleph J suggested using the paste. I bought a small tube, should i use it?
One more. Since (unfortunately) the store was out of kerathrem, i bought some online for my ZM Iron Pre build (which is so lovely), but found out for the Aleph Jzm that the k pads just cover the footprint of the mosfets with no overhang for pads.
With careful placement i see no k pads sticking out from under the mosfets and there is a small border between the metal underbelly and the edge of mosfets.
The tests for mosfet / heatsink placement/grounding are all good.
I assume all is good. Safe assumption or should i get bigger k pads?
Thanks,
Chuck
A couple of questions from a relative novice.
I plan to follow the wiring strategy used in the build guide (copying is flattery, right?).
I have 30mm standoffs for the PSU and planned to run those wires under the board, probably with wire insulation laying on the chassis silver plate (not chassis bottom plate). There was discussion earlier in this thread about sending wiring under the silver plate and strictly avoiding wire contact with that plate.
I assume, based on build guide, that the insulated wriring on the silver plate is OK as long as no bare wire hits the plate.
Correct?
Next question. Thermal paste for rectifiers? A detailed youtube vid from an English gentleman building an Aleph J suggested using the paste. I bought a small tube, should i use it?
One more. Since (unfortunately) the store was out of kerathrem, i bought some online for my ZM Iron Pre build (which is so lovely), but found out for the Aleph Jzm that the k pads just cover the footprint of the mosfets with no overhang for pads.
With careful placement i see no k pads sticking out from under the mosfets and there is a small border between the metal underbelly and the edge of mosfets.
The tests for mosfet / heatsink placement/grounding are all good.
I assume all is good. Safe assumption or should i get bigger k pads?
Thanks,
Chuck
You want to avoid running the wiring through the holes or near any of the sharp edges without some sort of protection. If the edge cuts the insulation of some of the wires over time... bad things can happen.
Yes. Correct.
If you have it, use it, but it's not strictly necessary.
If it passed the tests, you are in good shape. Carry on.
Update: Got the amp back up and running and I have it baking right now and getting bias and offset setup. I want to thank everyone for feedback, advise and troubleshooting ideas. We will see but it looks like it was a short on one of the rectifier boards and/or bad crimps that caused the buzzing.
?: Should I set the bias to a different value when using a 20v trans than the 18V trans outlined in the Build Guide? What are you guys using?
Thanks, Tony
?: Should I set the bias to a different value when using a 20v trans than the 18V trans outlined in the Build Guide? What are you guys using?
Thanks, Tony
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Personally, I would bias just the same for 20VAC or 18VAC secondaries. The key is making sure the heat sinks are adequate and not hotter than say 55°C at the most in a warm room. You have big heat sinks so that should not be an issue. I have my Aleph Jzm(s) cranked up to 55°C heat sink temp and they both sound amazing.
Good work Tony!!!
Good work Tony!!!
