I hate hackery. Here's another Dr Z I de-hacked and tweaked a while back: • Dr Z JAZ 20/40 Needed ... For more info, Subscribe to this channel, join us at PsionicAudio, or email us at info@psionicaudio.com.
I owned a beautiful Maz-38 for years and had to feed it new tubes regularly. The biggest issue was a noisy reverb, it actually whistled. When I investigated, the Doc had used gray, unshielded cables ( think Radio Shack ) to and from the reverb tank. I bought some shielded Monster cables and put them in, voila.
They are a bunch of jackasses. You do get the full boutique experience with them. Excessively expensive. Not particularly well made. Rude and condescending jerks answer the phone. They won't give out any technical information out at all and insist you ship the amp back to them. I have had much better conversations with an irritated Alex Dumble. He said, "Do you know how an Ampeg STV PI and the drivers are wired up to the power tubes? Work on it from there!" or "It's kinda like a Dynaco only with a Hi Watt tone stack & cathode follower. Figure it out from there." Two or three sentences, but those sentences all gave me information that I could use to fix the amps.
@@Satchmoeddie - I was traveling to the east coast and dropped it off for a servicing at their back door. They let me in the shop back room while we did the paperwork for shipment to me after. They were pretty cool but I definitely felt like an outsider. It played very well except for the reverb thing I fixed and blown mains fuse when the tubes were like 9-10 months old. I never moved it as it was a heavy beast. It sat in church on a isolation stand with a padded Tuki cover.
@@JohnDoe-xr5is True, but the build quality does show a lack of good QC. My mother did tube era electronic assembly work for a burglar alarm company, so I kind of get the reasons why things are assembled the way they are from her experiences. At various points every company has some growing pains. Adding new employees and or a second production line, and something has gotta to give. Taylor went through this a couple of times.
@@TheStimpy60 I need to order a good Tuki type cover for my 1968 Ampeg Gemini II. I went to an estate sale to buy a rare Walther P7 pistol, but some fool paid about 170% the going price for a P7 and then I noticed a new looking Ampeg with lots of treasures from the 1960s in the back of the amp. I ask the auctioneer,. "Does that stuff in the back come with the amp?" Yes! A new Maestro Fuzztone with the box, a 1960s Electro Harmonix wah labeled for Guild Guitar, a Honey (pre Shin Ei) Wah also labeled for Guild Guitar. A Maestro 3 speed phase shifter. Someone had put a threaded plate on the phase shifter so it could mount on a mic gooseneck for keyboards or maybe a mixing desk. It was the only one that looked used, and it was pretty beat up. I spent maybe $800 or $850 for the whole lot. The speaker sounded torn, but when I looked the owner's manuals for all the stuff in the amp and little slip case for the Meastro Fuzz were stuck inside the speaker frame. Good thing it was a 15 inch!
I bought a new 18Jr. (late '90s), same issues, reverb whistling, etc. I sent it to him and they updated it to whatever was current at the time, I only paying for a set of new tubes from them. I went thru a couple z's thinking? they would give me an AC15 vibe, but never worked for me, they aren't that. Chords didn't work for me. Great lead guitar amps for cutting through a mix though, preferred them with Humbucker style guitars, SG, Les Paul, etc, rather than Fenders. Thanks for posting.
I really love your channel, I am a amp collector and I have just about every amp you fix, 6l6,6v6,el34,el84 dr Z, Morgan, vox , marshal, fenders and egnator, I am a vox lover. Thanks for your videos I am learning a lot.
Oh dang, those preamp tubes were Mullard military surplus. I wonder if that was a desperate attempt to solve problems that were actually coming from inside the amp.
As a rule I'm not a fan of soldering the bus bar across all the pots like that, but soldering it to the back of Alpha pots as well? Jeez, that's trouble waiting to happen.
OMG, this is EXACTLY what the PRS MT15 does, it's got that strong 60/120hz (I think) hum. Everyone on the PRS boards and really just everywhere is trying to figure out what the problem is. It's too bad you haven't got one of those in the shop. A common thought is that the heater wiring/FX in/out internal wiring are picking up noise from the transformer eddy currents, because of the size of them amp, BUT, there are similar sized amps out there that don't hum, so that doesn't fly for me.
Wow, yes. I have tried a bunch of stuff…but I think I got it now. I plugged in a footswitch to the back, noise gone. Also, have a short patch cable into the effects loop (never used)
Love watching your keen troubleshooting skills. Nicely done. Its a shame that people hoping to save a buck hand over their prized amps to unskilled techs.
The two orange dipped caps that are siliconed together, where those two caps' leads connect with the lead of a resistor. That looks kind of suspect. There is flux around it so... It still looks like, uhm, shall we say, less than professionally executed. The tech service at Dr. Z, well, quite frankly, it sucks. Factory special modification that had 12AX7 stamped over 12AT7 by DrZ and when I called to ask, I was told to ship them the amp. How about I just fix it as in, "I shall fix it", and they can sit 'n' spin. I have designed better amps in my sleep.
So I am thinking about buying a new 2022 Z plus or Maz 18 mkii with reverb. Are these amps that are not built that well either? What would you buy in the 2000-2800 range that is built well to last? I enjoy your videos and your advice and input would be appreciated a lot.
I don’t know the Z +. Only get the Maz Mk II with reverb in combo form. The reverb buzzes in the heads. In that price range you could get Carr, Top Hat, Suhr, a few others. All better built than the Dr Z. But at that point it gets subjective. If you like the Dr Z it’s far from awful. Just not as well built as the others.
The Z plus is a two version 15/8 watt 1x12 with reverb amp similar to a Z wreck like Brad Paisley uses. I had no idea the Z amps where not built that well as the inside construction I have seen always looked pretty good and clean and hand built with all due respect. You mentioned 3 amps that where built better but I have not heard of any of them other than Suhr but I thought they just made guitars? What are two or three others besides Carr, Top Hat, and Suhr? I would appreciate what others besides those 3 you mentioned. I mean I respect you work on these amps and know your stuff but at 68 years of age. I don’t want to buy but one more amp in combo size with reverb to hang onto and not have to worry about having to have it fixed after one or two years. Be playing mostly clean and some natural blues break up and overdrive. Thank you
He did, then deleted it. I don't know why. I got the impression he just skimmed the video though - he mostly just defended himself by saying what I said in the video - the worst stuff here was done by a hobbyist repair and he fixed the reverb/MV in later amps
@@PsionicAudio Nice to know he has checked out the video. He seems a really nice guy. I like to watch his videos. He is talking just like Joe Walsh...funny guy.
I know this is an old comment but there are 2 jacks, one is clearly visible, but the second jack is far right corner with a dark shadow over it. If you look closely you can see the guitar chord get plugged in.
Had a maz 18 jr. One of the capacitors discinerated. I have know idea how maybe a tube went bad. Replaced the capacitor and power tubes. Dr z was not helpful at all when asked what the number on the capacitor was. Because it blew up, it was difficult to identify. Of course schematic is impossible to find.
In a class A/B amp, tube rectifier can be a source of sag as well as soft starting the tubes if you bypass the standby switch. But yes as Lyle has pointed out in a previous Vox video, you can do a great job mimicking a rectifier tube, especially sag with silicon diode rectifier and cleverly placed resistors. It’s not part of the signal path, so it probably isn’t missed if you believe in tube tone.
@@georgejobin1744 The GZ34/5AR4 is a timed warm up tube, so it soft starts, for whatever that is worth. All rectifier tubes warm up kind of slowly. I have a soft start / over voltage cutout circuit I modified from someone else's design. Amperite used to make thermally timed delay tubes, which used to be inexpensive, but now they are pushing $25 or $30 each. Those are great for letting the tubes' heaters all warm up before putting the plate voltages to the tubes, and since it's a thermal delay it stays about as hot as the cathodes in the tubes. If you short cycle the on off on it comes right back on. If it's cold it takes close to however many seconds the delay is rated for. There are ways to strap a rectifier tube up with solid state diodes an still get some sag too.
