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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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9th Nov 2019, 8:21 pm | #61 |
Hexode
Join Date: Nov 2016
Location: Budapest, Hungary
Posts: 386
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Re: Vintage Radio and Phonograph cutter schematic
I believe that the hum is 50 cycle. Will re check again, might change the first 8A electrolytic cap too and will test this in another room further away from any other appliances.
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10th Nov 2019, 10:38 am | #62 | |
Hexode
Join Date: Nov 2016
Location: Budapest, Hungary
Posts: 386
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Re: Vintage Radio and Phonograph cutter schematic
Quote:
I think is 100Hz hum. Now I did change the 8A cap also. Now the filter and reservoir cap is the same. Made a small rail for that as It was easier to tie several leads to the rain instead of directly to the cap. Now, volume down no hum. Volume up massive 100Hz hum. I think these capacitors I have are not suitable for this. Shame I only have 275VDC and 350VDC rated one and not 450V. Would need to order a proper filter and reservoir cap.... |
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10th Nov 2019, 1:05 pm | #63 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Vintage Radio and Phonograph cutter schematic
No hum with the volume control turned down and massive hum with volume turned up suggests 50Hz hum, sometimes caused by a screened lead that has lost it's ground connection or a control grid that's floating, ie: no or extremely high resistance to ground, other causes could be heater/cathode leakage in a valve.
Hum problems can be difficult to diagnose via the internet.....Is the hum level the same on Radio and Pickup? Lawrence. |
10th Nov 2019, 2:11 pm | #64 | |
Hexode
Join Date: Nov 2016
Location: Budapest, Hungary
Posts: 386
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Re: Vintage Radio and Phonograph cutter schematic
Quote:
Until that will arrive can not do anything further sadly. I thank you so much for your help Lawrence. I am learning so much from you here seriously, I owe you one. Have a great weekend and will post here again when the cap's are her. Ordering from hificollective UK proper filter cap's. and forgot to answer your question, hum level is the same except the external speaker position on the switch. Last edited by Levente; 10th Nov 2019 at 2:18 pm. |
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