Kora Cosmos Mono Amps

Teslamade, I use to own the cosmos and the Red LED lights are linked to each of the 5ar4 tubes, when I owned them I had the same problem with one of the LED and it was due to a bad tube, swapped it out and all was good. Another thing to check is the bias.

Oops I meant 6as7 not 5ar4..........

Hi,
So when I change the tubes I can`t see the red lights ? Another thing ;check the bias ? What does it mean ?
Thank you Jsawhitlock !

Teslamade,

The red light (LED) is an indication there is a problem in that tube or that part of the cicuit. When I had my issue with the LED coming on it was because of a blown tube not only did I need to replace the tube I also needed to replace the fuse and rebias the amp. There is a fuse for each of the eight 6as7. Most likely you have multiple tubes that may be going bad and or a bias problem. The fuses protect the tubes from taking out the rest of the circuit. The bias has to do with voltage and tubes, there are adjustments inside the amp and this is be done with a few basic tools and volt meter. Some amps are easy to bias and some are more difficult, the Koras fall into the more difficult catagory as there are more steps involved. Be aware the voltages inside the amp are deadly and you may want to seek out a tech for this job. One note on the 6as7 tubes you want to use the Russian type 6as7 as it's been reported that other types of 6as7 tubes have a high failure rate in this amp.

Hi,
Yes I understand ! Thank you so much Jsaw ! Another thing ! What`s the different between Kora and the MCintosh Amps ?What is your opinion ? And do you like the MCD-301 SACD Player ? I`m very interested a new cd player I have a Conrad Johnson DF-2 cd player and I`m happy , this is a very musical cd player the highs are smooth as liquid the midrange natural and coherent , but the deep is not so deep I`m not really feel`it

Teslamade, I really enjoyed my time spent with the Koras, there short fall in my system was the ability to control the bottom end I really didn't have the right speaker for the amps, no fault of the Koras there fine amps but not with my speakers and that's what lead me to the Mcitosh gear. Yes I'm really enjoying the 301 it's a great player. Before changing cd player you may want to try another amp with your speakers as this was the case with my system, it made the biggest impact on the over all sound and swapping sources made less of a difference. Don't get me wrong every change makes a difference but the amp/speakers did more for my system. Happy Listening!

Jsawhitlock , I fix the problem ! I change the fuse and now I can`t see the red lights ! Thank you very much again I appreciate !

Glad it was only a fuse issue, Happy Listening!