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Post by gtrplr on Sept 18, 2021 11:33:31 GMT -7
Hello everyone,
I am new to the forum, and I just purchased a 2003 Maz 18 2x10 with verb. In incredibly good shape and I believe to be all original. I have quite a bit of knowledge with Fender amp circuits, and have built many kits as well as repairs (mainly Fender) over the years. The problem is with the V5 (phase inverter?) tube socket. I have pulled the preamp tubes one at a time from V1 to V5 with the issue still there with everything pulled except for V5. Then I pull V5 and the issue is 99% resolved. So then I put V5 back in, and it reappears. When I gently move around the tube it makes a lot of shorting type sounds, if that makes since. I have cleaned the control pots and tube sockets with deoxit. I have installed a brand new set of tubes without any change. Any help with diagnosis would be appreciated. I am also thinking about sending the chassis in for the MKII update, what do you think?
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Post by "Z" Steve on Sept 18, 2021 12:03:48 GMT -7
Welcome to the forum! It appears you've done most of the things possible without replacing the socket, but if you are already looking into the update I would have the team go through the entire chassis and check for issues. Who knows what may have come loose or starting to fail since 2003. This way you are starting with a clean bill of health and all you should have to be concerned with are failing tubes!
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Post by dcarver on Sept 18, 2021 12:13:27 GMT -7
You are correct, V5 is the phase inverter. Tube info is on the Dr. Z website. (Support Tab > Tube and Bias Info) There's a link to the site (Dr Z Amps.com) up there in the header. Here's what it says:
Maz 18 (reverb)
V1: JJ ECC83S, V2: JJ ECC83S, V3: JJ ECC81, V4: 12AX7/ECC83, V5: Sovtek 12AX7LPS, V6/7: NOS 6N14N (EL84 – matched pair), V8: Sovtek 5AR4
Recommended Bias Point: Cathode Biased (no re-biasing necessary)
Fuse Value: 1.5A 250V SLO 1.25″ x .25″
From your description, it sounds like something is making intermittent contact. Remove the chassis and look for a bad or broken connection at or near the V5 socket.
If it were me, I'd send it to the mother ship. At 18 years old, I'd say it's due for a checkup. Pretty much everybody who has posted about the MkII updates says it takes a great amp and makes it even better. Let us know how it works out for you. Cheers DC
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Post by gtrplr on Sept 18, 2021 12:44:01 GMT -7
Thanks for the replies. I will go ahead and double check the socket connections on the socket. It sounds like even if I do get if fixed it would be a good idea to send it for an update. Before I actually even received the amp I had filled out the request form for an update. I have not heard back as of yet. Is there another way to contact the shop, or is that the best way? Has anyone sent theirs in lately for service? I am wondering about the turnaround time. I will post back after I check out the socket.
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Post by dcarver on Sept 18, 2021 13:00:31 GMT -7
I've never sent an amp back to the factory, but plenty of forum members have, and posted about it. From reading posts, usually it seems to be about a 3 to 4 week turnaround time once you get an RA and get it to the factory.
repairs@drzamps.com is the contact as far as I know.
There's a phone # on the Z website (Support tab > Warranty and Repairs) you might try.
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Post by gtrplr on Sept 18, 2021 15:13:00 GMT -7
Thanks for the info,
I replaced the tube socket, and it 100% fixed the shorting out issue. It did not however fix the idle hum issue. I am just going to wait until I do get a response from my request form and send it in. I do believe that would be better than trying to track it down, especially with my unfamiliarity with these amps and the upgrade is in order at this time anyway. Thanks again for the replies and suggestions.
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