Posted by Walt N

October 12, 2024 - 11:24 am

It just seems that turning the volume knob a short distance (like the 3rd "dot") is pretty loud. I hadn't used it for a while and initially figured the RP100 playback was screwed up. I checked the rail voltage there and it was fine. So, I tried playing an LP and it also sounded loud. No, it sounds just fine. Just loud. I'm old and could be crazy as you already know!

Posted by Steve L.

October 11, 2024 - 12:34 pm

Hi Walt, The gains of the amplifying stages are pretty much set by the resistor values and shouldn't be grossly increased by reasonable changes in power supply voltage. Is the music distorted or trashy sounding? The next step would be to get an idea of how much of an effect it is. Will be happy to help further if needed.

Posted by Walt Northrup

October 11, 2024 - 09:18 am

PREFACE: I may be losing my marbles. It seems to me that all of a sudden, my Cortina is too loud, both channels. I originally thought it was the RP-100, but it's too loud from the phono input as well. Not sure what to check unless it's the rail voltage. As I said, maybe I'm just going over the edge, so to speak.

Posted by Steve L.

February 18, 2024 - 08:14 am

Hi John K, Thank you for your interesting post. That was resourceful, to keep spare power transistors and to do matching in the school lab. Yeah, before output current limiting circuits were universal, it was just a matter of time if the amp was moved around a good bit. I mentioned in the article that I didn't feel that I could use it as a test amp in the lab, due to the risk of a brief output short. But if it were left installed in a stereo system, it would be quite safe. My word--the Pioneer SX-1250 you mentioned was at the opposite end of the spectrum from the thrifty and compact Cortina. I see the Pioneer boasted 160W per channel and weighed-in at 64 pounds!

Posted by John K.

February 17, 2024 - 09:29 pm

I don't know how I tripped across this, but it brings back memories! I bought the cortina kit in 1968, when I was in 9th grade. I used that thing all through college until 1976 when I had a real job and bought a Pioneer Sx-1250... I always had a bunch of power transistors around for when someone would inevitably short wires in my dorm. I use the equipment in the school lab to match beta. Great little amp... nice sound.. lots of memories... thanks for the tour after all these years!

Posted by Steve L.

August 07, 2022 - 02:35 pm

Hi Walt, I agree, that narrowing the possible sources of the noise to either the Cortina or the computer equipment is a good move. While the Cortina is suspect because of its age, there is so much more complexity on the computer side, it incurs risk as well. I don't see anything "stupid" about digitizing the LPs. Makes them more accessible and portable. Back in the 1970s, I used to record each new LP at the very first playing. That preserved the (hopefully) pristine pressing and made play more convenient. With Dolby (B) and CrO2 tape, my Hitachi D800 could reproduce the new record almost perfectly.