Just don't touch anything unintentionally in there, especially if it's large and says 'sprague' on it.
If there's a tricky part, it's handling the chassis. The weight and balance are a bit awkward, and you want to position it such that you can either measure directly or install whatever adapter/tool on your power tube socket(s) and still be able to have everything connected...all with access to the trimpot. It's probably not a bad idea to pop out tubes (where you have the space to do so) prior to sliding/lifting the chassis out, if only to prevent minor catastrophes. Take your time!
As far as feeling more connected, it's totally true. And as far as learning, I really enjoyed collecting and reading books like Weber's and A.Pittman's. I googled a lot, too. I wanted to not only know how, but what and why. www.eurotubes.com/euro-i.htm#4 for instance.
Hey Prowler, I'd feel better if you took Myles up on his offer. Myles is the MAN - he helped me figure out what my target bias was for my SRZ and he's probably biased more amps than we all could shake a stick at. Although I know how to do it now I actually wish I'd had somebody walking me through it after I pulled the chassis. It's definitely nerve racking when your dealing w/ all that voltage. Once you get it down though it feels pretty darn cool - like your more connected to your amp..
Since you mentioned the SRZ I thought I'd say a few things here on this amp I have said a bit elsewhere in regard to the 6545 and SRZ-65.
The SRZ-65 has a strong tie in design wise with the Marshall JCM 800. The JCM 800 is considered one of the landmark rock amps of all time. This was not always the case for all. Mike Doyle (The Marshall Book) thought the JCM 800 was one of his least favorite Marshalls until one day by mistake he plugged a JCM 800 into an old Marshall cabinet. The 800 became one of his favorite amps at that point. He had discovered that the speakers used in the newer cab were not all that great and the JCM 800 really shined when the older Marshall cabs were used.
These amps look simple but because of their cathode tone follower front end (gets brighter the harder you hit the strings as an example) and the cascaded gain (Z does not use this design topology much in his other amps), these amps are very responsive to tube changes. I prefer V1 to be a slightly lower value compared to V2 which is going to amplify the signal from V1 even more than an amp without a cascaded front end. There are a lot of tricks you can do with tubes in V1 and V2 on these amps. I will be in the process over the next few weeks developing tube sets for these amps as Carl Verheyen is looking at SRZ-65s to replace his original Marshall amps that are becomming too valuable and fragile for tour use.
But .... the SRZ 65 is not a JCM 800 in all respects. Think of a tweeked JCM 800 such as those of Jeff Beck etc. These have been looked at a bit more closely than your run of the mill amp. The SRZ-65 has aspects missing in the JCM 800. The tube rectifier gives the amp player touch and swell (and a nicer sustain characteristic). The tone controls are more effective than any you will find on a JCM 800 for the most part. There are other changes too including nicer transformers and tone caps that are more transparent than the originals. I guess the bottom line on the SRZ-65 is that it is the best sounding Marshall JCM 800 that was ever built or something to that effect.
In any case, I will be happy to continue to help you whenever you'd like.
Anyone know which version of the Bias Rite I would need for my amp which has the GT EL34LS tubes in it?
You can use any bias rite, bias tool, bias probe, etc.
I prefer the bias tool that does not have an attached meter as it fits in my tool box easier, I already have a lot of meters, and do not want the complications of a tool with an integral attached meter but that is all personal preference.
yep, that's it. Don't touch those caps! You'll barely move it in either direction to set it. I use a little electrician's screwdriver (i.e. Radio Shack set) to adjust. You won't need that wrench for this ;D
Here is a photo of my SRZ chassis. Is this the bias adjustment point?
I replied to your email ... yes, as others have said ... that is the bias pot.
You can use many different bias tools that are on the market. I prefer the GT tool as I have used them for over a decade and they are less pricy as they do not have an integral meter. That means they have less to go wrong and fit in my toolbox more easily. You can use them with any $9.95 "Radio Shack" meter and one needs a meter in any toolbox anyway.
premiumplus (Dave): Due or do? Which or witch? Knob or nob? Their or there? Bass or base? Too much time on my hands...
May 24, 2020 6:31:30 GMT -7
roscoenyc: Ah, the incessant tire kickers. oh jeez.
May 25, 2020 6:57:46 GMT -7
GuitarZ: Needed some noise to fill a break in a tune I'm recording. It was too quiet. Just happened to have some High Quality Dr Z Ghia noise to fill the void. "Heal Your Sound with Dr Z! It's not just a guitar tone prescription!"
Jun 13, 2020 8:29:27 GMT -7
GuitarZ: Must be great to be a skunk. Eating bird food about 10' from our sun room. I'm clapping and yelling. At best, it might have given me one "yea what?" look while continuing to dine. At one point, there were two skunks and two racoons.
Jun 14, 2020 18:49:33 GMT -7
captainron (Ron): Hueter Toledo, just another business of today that doesn't care about tomorrow!
Jun 25, 2020 12:51:43 GMT -7
KeithA: Hueter Toledo....that business is gone to the dogs
Jun 26, 2020 8:22:26 GMT -7
easyed: Guitar Z, I encountered to ultimate garbage raiding combo once. We'd been having problems with the garbage cans being raided by raccoons for weeks. Late in the evening I heard rattling at the cans. I went out and found that he'd allied with a skunk. "OK"
Jun 30, 2020 11:40:27 GMT -7
GuitarZ: EasyEd - Someone at work topped us both. The inside of their car had been somewhat ransacked. They were blaming their son. They checked the video. It was a Bear! I'll stick with the racoons, skunks, foxes, and squirrels.
Jul 1, 2020 16:47:50 GMT -7
bigboki: In this age and time when everybody are struggling and especially S&Ms I am amazed to see that kind of ignorance. I am really sorry for your experience dear Dr Z but it is for the better. You don't want to do business with those kind of people anyway.
Jul 4, 2020 8:17:40 GMT -7
GuitarZ: Didn't want to restart the plumbing thread, so I figured I'd ShoutBox this. How the heck does cleaning the aerator on a faucet cause a leak to start under the faucet? Huh? Arggggh!!!!
Jul 10, 2020 7:40:17 GMT -7
The Bad Poodle Experience: well, Mike, it shouldn't have been the cause of a leak. double-check your work.
Jul 10, 2020 12:56:49 GMT -7
GuitarZ: I updated in the Plumbing thread that the Moen website says that a faulty aerator can cause a handle/base leak. Eiyy! I really don't understand how plumbing works. I was ready to double check all connections. But, the leaking stopped with cleaned Aerator.
Jul 11, 2020 18:13:56 GMT -7
jhen86 (jordan): Just got an email from Sweetwater rep that Z Wreck Jr's are back in stock. Just wanted to give everyone a heads up.
Jul 28, 2020 10:57:28 GMT -7
Lefty: Say a prayer for me fellas, I'm going to replace a bathroom faucet this weekend.
Jul 30, 2020 8:26:34 GMT -7
GuitarZ: Make sure you use your plumbers tape.
Jul 30, 2020 12:21:50 GMT -7
doctorice: Just replaced a kitchen faucet. Hardest part was getting the old one out -- had a weird flange on it. Good luck, Matt!
Jul 31, 2020 8:02:26 GMT -7
steiner: Just payed the plumer to replace a faucet and drains. Finally have non-leaking, speedy draining sinks!!!
Aug 4, 2020 8:08:03 GMT -7
GuitarZ: After finally training myself after 4 days to not bother trying to turn on the guest bathroom light because of the power outage, I just found myself bracing for the sound of the generator as I opened the garage door and it's now quiet. Power Back!
Aug 7, 2020 16:51:10 GMT -7