Gary, yes Jon is interested, but the estimate was much more than I want to pay for that amp now, since I also want to build several of the Pass amps.
At least 2 off Digital Multimeters to start with and then think about a dual channel oscilloscope after that.
What are the dimensions of the large can PSU caps in your 400A? - also the value and voltage rating thanks?
Yep, the ACA is the beginner Pass amp.
What are the dimensions of the large can PSU caps in your 400A? - also the value and voltage rating thanks?
Yep, the ACA is the beginner Pass amp.
I already own a MicSig STO1004 scope. I purchased it for automotive diagnostics. I'm trying to learn how to flip cars.
Here is a link to a manual for it. https://manualsfile.com/product/k4nwq5wwohu.html
I also own 3 DVMs, also purchased for car repairs.
Here is a link to a manual for it. https://manualsfile.com/product/k4nwq5wwohu.html
I also own 3 DVMs, also purchased for car repairs.
Regarding the specs on the Threshold 400A PSU caps; can I just get the model numbers, or would you prefer the actual specs?
All good on the instruments it seems.
Regarding the PSU electrolytic caps, just give me the following:
Capacitance in uF
DC voltage rating
They will both be written on the plastic sleeve on the caps.
Then the physical diameter of the caps and the height from the base to the top of the can (not including the terminal height). Measure the dimensions with a ruler will be fine - in mm will be very handy, but if you only have an inch ruler that is Ok as well.
Regarding the PSU electrolytic caps, just give me the following:
Capacitance in uF
DC voltage rating
They will both be written on the plastic sleeve on the caps.
Then the physical diameter of the caps and the height from the base to the top of the can (not including the terminal height). Measure the dimensions with a ruler will be fine - in mm will be very handy, but if you only have an inch ruler that is Ok as well.
Ok. I will get the info later tonight. Thank you, Gary
Paul You don't need the info on the other caps on the "FE" boards?
BTW, what is an "FE board?"
Paul You don't need the info on the other caps on the "FE" boards?
BTW, what is an "FE board?"
Yeh, no hurry on that.
FE - simply stands for "Front End"
The other caps on the FE will be easy to source and replace. Info on those will be handy at some point.
FE - simply stands for "Front End"
The other caps on the FE will be easy to source and replace. Info on those will be handy at some point.
Gary S, here are the specs you requested for the Threshold 400A PSU capacitors (2ea):
Manufacturer: Mallory
Type: CGS
Capacitance in uF (found on cap label) 15000mfd
DC voltage rating (found on cap label) 80vdc
Dia of caps (in mm) 63 cm
Height of caps, fm bottom of can to top of can (in mm) 125 cm
Thanks so much for your help!
Paul
Manufacturer: Mallory
Type: CGS
Capacitance in uF (found on cap label) 15000mfd
DC voltage rating (found on cap label) 80vdc
Dia of caps (in mm) 63 cm
Height of caps, fm bottom of can to top of can (in mm) 125 cm
Thanks so much for your help!
Paul
Hi Paul, thanks for the details. You wont find those original caps anymore - but a direct replacement is the Nichicon LNT 22,000uF 80VDC rated type. It is 63mm diameter and only 100mm high - so you gain some height and will fit existing clamps. You will also note it is a higher capacitance value, which is good for this type of amp. It is also rated at 105 deg C - so higher than the original cap as well.
Jon Soderberg uses this newer type value and it is the same one I have used on other Stasis rebuilds as well with other members.
Cheapest source is Mouser in the US at $43.64 USD each and they are in stock at the moment. The Mouser part number is: 647-LNT1K223MSE
Cheers,
Gary.
Jon Soderberg uses this newer type value and it is the same one I have used on other Stasis rebuilds as well with other members.
Cheapest source is Mouser in the US at $43.64 USD each and they are in stock at the moment. The Mouser part number is: 647-LNT1K223MSE
Cheers,
Gary.
Gary, thanks for doing the research for me. I noticed that that part number has a 2000 hour lifespan. Ive seen some others that have as much as 5000 hour lifespan. Should I be concerned about that? Is there possibly an alternative cap with a 5000 hour lifespan?
I have also done just a bit of research on PSU caps. One site opined that the larger caps don't go bad as quickly as the smaller ones. Have you heard that? I am not against spending $44 for a cap, I am just wondering if there is a way to determine if they are bad. Will a capacitance meter be able to determine if they are good, or if they need to be replaced.
The amplifier has been in storage for about 20 years, and in the last year it has seen very little use.
I have also done just a bit of research on PSU caps. One site opined that the larger caps don't go bad as quickly as the smaller ones. Have you heard that? I am not against spending $44 for a cap, I am just wondering if there is a way to determine if they are bad. Will a capacitance meter be able to determine if they are good, or if they need to be replaced.
The amplifier has been in storage for about 20 years, and in the last year it has seen very little use.
I found this one. It looks like it is also a good quality. https://www.mouser.com/ProductDetail/KEMET/ALS80A223DF063?qs=AQlKX63v8RtuKVNgRabIDA== What do you think?
The one weakness in the above cap, is its voltage rating: 63 vdc. That proabably disqualifies it, doesn't it?
Yes it does, as the power supply voltage will be around 72VDC or so on your amp. Also that cap is only 36mm diameter.
There is not much choice these days in the big can caps - not like the good old days. 2000 hours is fine, I don't think you will find one in the case size you need. The caps will last for way longer than 2000 hours by the way. Over 20 years or more some PSU caps could have been energised for more than 20,000 hours when you work it out.
Most people would say that if a cap is over say 20 years old then replace it. Capacitor technology is way better today than when those caps in your amp were made - nearly 50 years ago now!
The Nichicon LNT, I mentioned is the only one I found in stock anywhere at a reasonable price with the same diameter - so you don't have to muck around with the clamps.
There is not much choice these days in the big can caps - not like the good old days. 2000 hours is fine, I don't think you will find one in the case size you need. The caps will last for way longer than 2000 hours by the way. Over 20 years or more some PSU caps could have been energised for more than 20,000 hours when you work it out.
Most people would say that if a cap is over say 20 years old then replace it. Capacitor technology is way better today than when those caps in your amp were made - nearly 50 years ago now!
The Nichicon LNT, I mentioned is the only one I found in stock anywhere at a reasonable price with the same diameter - so you don't have to muck around with the clamps.
Is it your recommendation that I purchase two of them now? If so, should I install them right away?
Should I purchase anything else (parts or tools) from Mouser that could be used in upgrading the 400A?
Here are a couple of pieces of test equipment that might be helpful. What do you think of them?
https://www.amazon.com/gp/product/B0DDBPWYP8/ref=ox_sc_act_title_1?smid=A33KEXAIEXH1NV&psc=1
https://www.amazon.com/gp/product/B0DC54SK23/ref=ox_sc_act_title_2?smid=AY4CC4AFFA8HP&psc=1
https://www.amazon.com/gp/product/B0DDBPWYP8/ref=ox_sc_act_title_1?smid=A33KEXAIEXH1NV&psc=1
https://www.amazon.com/gp/product/B0DC54SK23/ref=ox_sc_act_title_2?smid=AY4CC4AFFA8HP&psc=1
OK, to answer the questions in order.
I am not quite sure of your intentions, if you are going to rebuild the amp, then buy the caps then. If the amp is working now, it won't hurt to put new PSU caps in. You mention 2 off caps - are there only 2 in your chassis? Normally in the Threshold amps of that rating there are 4 caps.
I would replace the diode bridge(s) that feeds the PSU caps at the same time. Any 35 amp rated at 600 or more VDC rating will be fine - even a 50 amp rated unit is not overkill. I usually use 1000VDC rated bridges.
As I mentioned previously, I would be replacing the output transistors with On Semi TO3 devices and new 3 watt emitter resistors.
Those two pieces of test equipment would come in handy over time if you are going to do more amps.
I am not quite sure of your intentions, if you are going to rebuild the amp, then buy the caps then. If the amp is working now, it won't hurt to put new PSU caps in. You mention 2 off caps - are there only 2 in your chassis? Normally in the Threshold amps of that rating there are 4 caps.
I would replace the diode bridge(s) that feeds the PSU caps at the same time. Any 35 amp rated at 600 or more VDC rating will be fine - even a 50 amp rated unit is not overkill. I usually use 1000VDC rated bridges.
As I mentioned previously, I would be replacing the output transistors with On Semi TO3 devices and new 3 watt emitter resistors.
Those two pieces of test equipment would come in handy over time if you are going to do more amps.
Here's a photo of the inside of my Threshold 400A S/N serial A78121065. As you can see there are 2 power supply capacitors, not 4.
