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Post by terryg on Feb 8, 2006 6:35:40 GMT -7
Definitely! 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.
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Post by myles on Feb 8, 2006 12:06:38 GMT -7
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.. Johnny, 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.
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Post by prowler on Feb 21, 2006 11:21:16 GMT -7
Anyone know which version of the Bias Rite I would need for my amp which has the GT EL34LS tubes in it?
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Post by terryg on Feb 21, 2006 12:57:38 GMT -7
I use the BR-AH (octal) with VI option for this, plugging the banana plugs into my cheapish Radio Shack DMM. The VI switch is nice & convenient, which is perfect for someone as lazy as I am
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Post by myles on Feb 21, 2006 13:01:24 GMT -7
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.
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Post by prowler on Feb 27, 2006 18:13:44 GMT -7
Here is a photo of my SRZ chassis. Is this the bias adjustment point?
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Post by johnnyl on Feb 28, 2006 8:17:24 GMT -7
looks like you found it. Right Myles? Be carefull of them big 'ol caps Prowler!
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Post by terryg on Feb 28, 2006 9:30:11 GMT -7
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
Oh yeah, don't forget your speaker load!
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Post by terryg on Feb 28, 2006 9:30:59 GMT -7
Looking at that picture makes me want one......
Hey johnnyl - Tim S. was just in a Rt. 66 recently (blowing fuses == toasted rectifier). He said he really liked it.
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Post by myles on Feb 28, 2006 9:47:29 GMT -7
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. The ones from GT are at www.groovetubes.com/product.cfm?Product_ID=1191There are also great ones out the from Weber and other folks.
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