HiFi Subjectivist ¦ Audio Forum ¦ NVA User Group

Sorted it the easy way, deleted the Musicbee app and all the bits, re-installed since I still had the download and everything's fine again.

Two days ago made my first attempt to bias my amplifier, first mistake was setting the multi-meter to mV, but looked at articles on-line again and found out the answer, should just be V, well it was the first time I've ever used one. After that everything went well, tried to set the bias to 370 (hoping that is correct for KT88's) and got with 2 of that figure, the tinniest twists on the screw adjuster could change the reading by 30 - 50, when I've watched others doing it on You Tube they seem to be more accurate but with my amp the adjuster was too sensitive at times. The only fly in the ointment was tube no. 3, where I could only get a reading of 250, does that mean the tube is on the way out, do I need to buy a complete set of four more tubes and am I alright still using as is?

At the moment my valve amp is sitting on the sidelines, so have my Topping PA3 in use, a different amplifier now driving the Cesti MBR's compared to the JBL Control 1's and it's quite listenable. Forgot to mention I purchased a 15.6" touchscreen monitor to replace the far too small 7" one I was using, at least I can touch the right part of the screen. Also a few days ago I won a Auralic Aries on ebay, no one else made any bids, to replace the mini pc and tc monitor, unfortunately the Lightning app only works with Apple so a 2nd hand i-pad mini 2 has been purchased as the remote. These will be sent to my uk address, so I will not be able to give them a listen, although my brother will a try them out, I'll report back to to give you his thoughts. Hoping this Auralic will be better sounding than my mini pc, I can then use that combined with the tc monitor and a separate keyboard/mouse to replace my aging laptop.

Well I purchased some 6550 tubes to replace the stock ones in my amplifier. When re-biasing, the multi meter probe slipped and I shorted a resistor, anyway I have now had it repaired and picked it up on Friday. I have to say I am delighted with the result of the valve change, the best way to describe the improvement, the sound just got 'bigger', bass has more grunt, and with the old tubes I always felt there was a little hardness at the top end, that has gone now. They have only had about 15 hrs of use so there may be a little improvement to come, even if there is not, I'm a happy bunny.

Good result Dave.

Multi meter probe slippage has seen the demise of many cdp's with unavailable integrated chips. Glad you got it sorted and luckily it was an easily repaired item.

Thank you Stu, when I went to collect the amplifier he biased it while I was there and used crocodile clips, so much easier, why didn't I think of that. I have a set of croc clips and can easily be attached to the probe so hopefully will make my life easier in the future. Still enjoying the amp by the way, working my way through some of my favourite recordings. Next up will be swopping pre amp tubes, looking forward to that little experiment.

It's all part of the fun Dave.

The diy audio world would be nowhere without crocodile clips. It is said that at Owston meets you are considered an amateur unless you have a few crocodile clips holding your amp together