I have a 330C, it was my first vintage reciever (we are about the same age so I guess that makes me vintage too). I found it a garage sale for 5 or 10 dollars. I knew nothing about vintage gear but at that price I took a gamble. I got home and found that it sounded so good that I now also have an HK 730 Twin, plus gear from Luxman and Sansui, I always keep some 'hidden' cash in my wallet for just such an occasion. Thanks for the informative video, I hope my multimeter is accurate enough to check bias, do I do that under a constant load such as playing pink or white noise?
Thanks for the sharing. Based on the service manual, do the bias adjustments with the load of 8 ohm 50W resistor connecting across the speaker terminals (see page 4 shown in Service manual).
Trying to figure out the little brother to this. the HK 230 The Idling adjustment you showed was excellent. The Bias is a different adjustment for the speakers out terminals to adjust as close to zero as possible. did you do that adjustment?
Sorry for the late response. I don't own HK230. But based on the service manual: www.hifiengine.com/manual_library/harman-kardon/230.shtml. On page 7, it shows how to make Pre-driver/Driver adjustments - by using VR501/VR601 to adjust DC balance. It requires hooking up a 8ohm (50W) dummy load resistor at speaker terminals and in parallel connects leads of the oscilloscope, and feeding with 1K HZ sign wave to AUX inputs from a signal generator (starts with minimum outputs). Then following the descriptions of the procedure.
@@VintageAudioFan Thanks for the reply. I don't have an osiliscope yet. okay digital ones on Amazon are probably good enouph. From the manual and other forums there is a .5 volt across the speaker terminals which is normal and that goes to zero with the speakers hooked up. Something to do with the 230 being a capacitor coupled design. I tried it on junk speakers and it works. I have it hooked up to a good set of speakers and it is very good.
"*Connect 8 ohm (50W) resistor across left and right speaker terminals."??? The one thing people need to see during your service and it is not shown. How did you perform this requirement Vintage Audio Fan? It seems that this is the step that there is never enough straight forward, concise instruction on. Some of us need like the "twenty seven eight-by-ten color glossy pictures with the circles and arrows and a paragraph on the back of each one explaining what each one was", type of thing. Just sayin. Besides from that thanks for everything.
Great Service Video
I have a 330C, it was my first vintage reciever (we are about the same age so I guess that makes me vintage too). I found it a garage sale for 5 or 10 dollars. I knew nothing about vintage gear but at that price I took a gamble. I got home and found that it sounded so good that I now also have an HK 730 Twin, plus gear from Luxman and Sansui, I always keep some 'hidden' cash in my wallet for just such an occasion.
Thanks for the informative video, I hope my multimeter is accurate enough to check bias, do I do that under a constant load such as playing pink or white noise?
Thanks for the sharing. Based on the service manual, do the bias adjustments with the load of 8 ohm 50W resistor connecting across the speaker terminals (see page 4 shown in Service manual).
@@VintageAudioFan Thanks for the info, I guess I need a resistor!
very informative
Trying to figure out the little brother to this. the HK 230
The Idling adjustment you showed was excellent. The Bias is a different adjustment for the speakers out terminals to adjust as close to zero as possible. did you do that adjustment?
Sorry for the late response. I don't own HK230. But based on the service manual: www.hifiengine.com/manual_library/harman-kardon/230.shtml.
On page 7, it shows how to make Pre-driver/Driver adjustments - by using VR501/VR601 to adjust DC balance. It requires hooking up a 8ohm (50W) dummy load resistor at speaker terminals and in parallel connects leads of the oscilloscope, and feeding with 1K HZ sign wave to AUX inputs from a signal generator (starts with minimum outputs). Then following the descriptions of the procedure.
@@VintageAudioFan Thanks for the reply. I don't have an osiliscope yet. okay digital ones on Amazon are probably good enouph. From the manual and other forums there is a .5 volt across the speaker terminals which is normal and that goes to zero with the speakers hooked up. Something to do with the 230 being a capacitor coupled design. I tried it on junk speakers and it works. I have it hooked up to a good set of speakers and it is very good.
"*Connect 8 ohm (50W) resistor across left and right speaker terminals."??? The one thing people need to see during your service and it is not shown. How did you perform this requirement Vintage Audio Fan? It seems that this is the step that there is never enough straight forward, concise instruction on. Some of us need like the "twenty seven eight-by-ten color glossy pictures with the circles and arrows and a paragraph on the back of each one explaining what each one was", type of thing. Just sayin. Besides from that thanks for everything.
I had to do all that on mine too
by the way fix the title from 300C to 330C