The tubes were already on route to my house before I talked to Kevin at Upscale. My only reason for contacting him was because I had received a partial refund for the order. I had ordered the tubes be cryoed and paid the 8.00 per tube. When I got a 32.00 refund, I then called Kevin. During the course of the conversation, I mentioned the Cronus Magnum and he said he wouldn't do it. When I pointed out that Nick at Rogue said it would be ok, he then said "go ahead and try it."
What Did I Do Wrong?
I have a Rogue Cronus Magnum integrated with the KT120 tubes. I wanted to try the EL34 sound in my system so I purchased 4 Shuguang EL34B tubes which were graded and matched from Upscale Audio. I checked with Rogue and was told to set the bias at 30ma. I received the tubes today, installed them and let them warm up for 30 minutes. The sound was a little ragged and distorted and try as I may, I couldn't get a reading on the bias meter.
Thinking I wrecked the amp, I reinstalled the KT120 tubes (thank God I marked which socket they came out of) fired the amp up and the sound is again full with no distortion. I checked the bias on the KT120's after 30 minutes and the bias on one tube was off a little.
Why did the EL34 tubes sound distorted and why couldn't I bias them? What did I do wrong? Do you think these tubes are all toast now?
Thinking I wrecked the amp, I reinstalled the KT120 tubes (thank God I marked which socket they came out of) fired the amp up and the sound is again full with no distortion. I checked the bias on the KT120's after 30 minutes and the bias on one tube was off a little.
Why did the EL34 tubes sound distorted and why couldn't I bias them? What did I do wrong? Do you think these tubes are all toast now?
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- 37 posts total
- 37 posts total