"The feedback pole R6 is also a 24.3K resistor."
I can't read the resistor designator for the lower-arm feedback resistor, it's 1K and the cap (C2) is 47µF, the pole is thus 3.4hz
6th Street Bridge: August 2010
I can't read the resistor designator for the lower-arm feedback resistor, it's 1K and the cap (C2) is 47µF, the pole is thus 3.4hz
6th Street Bridge: August 2010
Finally finished my B&K ST-140 rebuild last weekend
I was able to complete the rebuild (and correct some earlier mistakes) this weekend. Let it burn in for 72 hours at low volume and gave it a good listen after the burn in time. In short, I am VERY VERY pleased with the results. I was so pleased that I decided (in addition) to add an IEC socket and make up a custom power cord. Using a case nibbler in the B&K is, well, not fun. I'm looking for suggestions on how to do it better/easier/faster (for adding IEC sockets).
I could use some tips on wire management to help organize all the leads. In the future I'll list out all of the mods but let's suffice it to say that I threw out the PCB board that was on top of the PSU caps and I went old school and used solid core PTFE wire.
By the way - I used a polarized Nichicon KZ cap 22uf 50 in the C1 position (bypassed) and a Nichicon non-polar ES series 47uf 50v in the C2 position (bypassed as well). These two were giving me some headaches. All resistors have been replaced with metal film, and where I was able to attain, I used Dale or other military-grade resistors.
All the PSU caps have been bypassed using Aerovox 3.3uf 400v caps including 2 massive (grey plastic case) 35uf polypropylene caps in the lower right and left hand sections of the picture above.
More info to come.
Cheers.
I was able to complete the rebuild (and correct some earlier mistakes) this weekend. Let it burn in for 72 hours at low volume and gave it a good listen after the burn in time. In short, I am VERY VERY pleased with the results. I was so pleased that I decided (in addition) to add an IEC socket and make up a custom power cord. Using a case nibbler in the B&K is, well, not fun. I'm looking for suggestions on how to do it better/easier/faster (for adding IEC sockets).
I could use some tips on wire management to help organize all the leads. In the future I'll list out all of the mods but let's suffice it to say that I threw out the PCB board that was on top of the PSU caps and I went old school and used solid core PTFE wire.
By the way - I used a polarized Nichicon KZ cap 22uf 50 in the C1 position (bypassed) and a Nichicon non-polar ES series 47uf 50v in the C2 position (bypassed as well). These two were giving me some headaches. All resistors have been replaced with metal film, and where I was able to attain, I used Dale or other military-grade resistors.
All the PSU caps have been bypassed using Aerovox 3.3uf 400v caps including 2 massive (grey plastic case) 35uf polypropylene caps in the lower right and left hand sections of the picture above.
More info to come.
Cheers.
.... Greeks have many many old sayings ... most of them are really meaningful
there is one that says: someone with a small dick blamed the p$^&** hair ... farther explanation will be : whats the point of using exotic hardware in such a messy wiring and arrangement ?
i think you can do better than that
there is one that says: someone with a small dick blamed the p$^&** hair ... farther explanation will be : whats the point of using exotic hardware in such a messy wiring and arrangement ?
i think you can do better than that
Sakis - I understand your thoughts and thank you for your input. My goal is to improve my wiring skills as previously stated. That being said, the wiring in the picture is actually thought out - my initial goal was to minimize the length of runs. Also, I found that utilizing thick solid core wire is a bit unwieldy and is not nearly as flexible as others. It's a learning experience and I plan on making my next one even better! Cheers.
In the interim, I am absolutely loving the sound output and have another B&K ST-140 on the back burner waiting to be attacked!
BTW - I posted a couple of questions regarding wire management and requested input for modifying cases to add IEC connectors.... did you have any guidance that you wanted to share?
In the interim, I am absolutely loving the sound output and have another B&K ST-140 on the back burner waiting to be attacked!
BTW - I posted a couple of questions regarding wire management and requested input for modifying cases to add IEC connectors.... did you have any guidance that you wanted to share?
Last edited:
minimizing wiring should not be #1 priority ...important but not above order and thickness minimizing of distance is a tubish approach while transistors will be more happy with thickness and order .
Many people with tube background fall for this and think that a transistor amplifier will work better point to point made ...which to my understanding is a huge mistake
Kind regards
sakis
Many people with tube background fall for this and think that a transistor amplifier will work better point to point made ...which to my understanding is a huge mistake
Kind regards
sakis
What are some of the sources or tools that you utilize for making order out of wiring? I've been looking online and have not seen a good supplier.
Can you provide some additional insight as to why point to point wiring would result in a "huge mistake" for a transistor based amplifier? IMO, the original design which this particular revision B&K ST-140 came with, the PCB board connection between the PSU caps was a way to lower production costs and not make the amplifier perform better. Earlier revisions of the B&K ST-140 did indeed possess point to point wiring. I simply wanted to make the "pipe" nice and easy for the power to flow on through.
Can you provide some additional insight as to why point to point wiring would result in a "huge mistake" for a transistor based amplifier? IMO, the original design which this particular revision B&K ST-140 came with, the PCB board connection between the PSU caps was a way to lower production costs and not make the amplifier perform better. Earlier revisions of the B&K ST-140 did indeed possess point to point wiring. I simply wanted to make the "pipe" nice and easy for the power to flow on through.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.