David_NC
Super Member
I recently picked up a near mint KA-7500. This one has had all caps replaced, opamp replaced with a modern socketed version, 25/75uS switch bypass, and rerouting AC off the main board, among other mods and updates. I'm really impressed with the sound; I don't recall FM sounding this good! I do have some questions about it:
Here's it is with my KA-9100. I need to get a wood case for the tuner or leave it off the amp for a consistent look. I'll also try to get the lighting brightness and colors to match a bit better. I will say that after using this amp in a secondary system for a few weeks with a pair of ADS L780/2's and with this tuner for a couple weeks, it's becoming one of my favorite vintage systems. The 9100 is all original at this point and still sounds very nice. It'll be serviced at some point, which I hope will improve it even more. As it is, it's fully functional, but I'll need to clean a couple controls again. That task is definitely more involved on this amp than on other pieces of equipment I have!
- Noise - some stations have pretty high levels of noise (hiss) despite being properly tuned with very good signal strength. Engaging the mpx filter helps some, setting the IF to narrow helps a bit (but changes the sound in other ways), and mono all but eliminates it. This is really only noticeable on a couple stations.
- Alignment - To get the best sound quality, the needle in the tuning meter is right at the line separating center-tune and the right of that line. This give the best sound, lowest noise, and highest signal strength. Also, the tuning indicator is about .3 higher than the stations' actual frequency when properly tuned. I can physically change the move the indicator, I'm sure, but I wonder if this would also be resolved when correcting the off-center center tune issue.
- Antenna - I'm in north-central Orange County, and it seems that most of the stations I listen to are in LA, which is pretty much northwest and 35-40 miles or so from me. Most antennas I see now are omnidirectional, which I don't think would really help as much with those LA stations. I can get a mast about 15-20' up at most, and I won't be using a rotator. Most antennas I see seem to be for HD stations, and I'm not sure if these are the same, as they look smaller than regular antennas. One that seems to be fairly common online is Stellar Labs 30-2460. Would one like this be a good one to try?
Here's it is with my KA-9100. I need to get a wood case for the tuner or leave it off the amp for a consistent look. I'll also try to get the lighting brightness and colors to match a bit better. I will say that after using this amp in a secondary system for a few weeks with a pair of ADS L780/2's and with this tuner for a couple weeks, it's becoming one of my favorite vintage systems. The 9100 is all original at this point and still sounds very nice. It'll be serviced at some point, which I hope will improve it even more. As it is, it's fully functional, but I'll need to clean a couple controls again. That task is definitely more involved on this amp than on other pieces of equipment I have!
I'm not sure if it's been aligned recently. The guy I bought it from mentioned all the work that had been done on it but didn't mention alignment, which makes think it hasn't recently. I'll see if I can find out, though.