Subject: Another plea for circuit help I do really hate asking JRB for help, as I realize that the Tube CAD Journal is devoted to what is possible, not what is broken. But I own such a poor sounding line stage amplifier that I am desperate. I now easily understand how the world switched from the vacuum-state to solid-state. It is an Antique Sound Labs AQ-2004 line stage. It looks cute, but sounds absolutely dead. My friends tell me to spend a few hundred dollars on part upgrades, which I just cannot afford right now. Two years ago I would thought that this was the only option. Today, after having spent the last year reading this journal, I know better: something is wrong with the topology and execution, not just the part quality. My guess is that the 12AU7 input tubes and the 12AX7 cathode follower are mis-biased and that the first stage should be drastically modified or removed. If you have the time and the wish to help me, I will be greatly thankful; if not, I understand, as you must get hundreds of requests per year. Thanks anyway for such a great FREE resource (much better than the late Glass Audio) for us tube lovers.
Paul Canada
|