Why should amplifier manufacturers consider that they are the only ones that can get the correct tubes. I used replacement KT120’s that are only manufactured by Tung Sol anyway so why insist that you must purchase them from AR when they have to buy them from Tung Sol. If they couldn’t be used why have a bias control????
thazeldean,
I got the impression from reading your original posted message the amp was repaired under warranty in your country. Is that correct?
Did the repair center send you paperwork stating they did indeed install a new circuit board and replaced any other parts they found defective? The amp was indeed repaired?
If you lived in the US and sent the amp to ARC, here is what may have happened if you refused to let ARC install their tubes in the amp to complete the repairs of the amp.
Should replacement vacuum tubes be required to complete a repair or update, only Audio Research tubes will be installed in order to assure product performance and to validate the 90-Day Limited Service Warranty.http://www.audioresearch.com/en-us/company/service-and-policies
If a customer refuses the use of Audio Research parts and/or tubes needed to complete a repair or update; the product will be returned unrepaired at the owner’s expense.
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thazeldean said:
Why should amplifier manufacturers consider that they are the only ones that can get the correct tubes. I used replacement KT120’s that are only manufactured by Tung Sol anyway so why insist that you must purchase them from AR when they have to buy them from Tung Sol. If they couldn’t be used why have a bias control????ARC buys the power tubes from a vendor that agrees to test the tubes and select tubes that meet ARC’s minimum spec requirements. At ARC the power tubes are burned in for 48 hours before they are then retested again to make sure they meet ARC’s specs. The tubes are closely matched to tubes with the same tube characteristics for push pull circuit/applications. This extra testing process costs money.
What testing procedure/process did the Vendor use that you bought your power tubes from? Not all tube vendors are created equal.
Part 1
http://www.analogplanet.com/content/analogplanet-visits-audio-research-corporation#gZsaU2i7XlIuyD6b.97
Part 2
https://www.youtube.com/watch?v=nvL9FNuPwkE