Discussion in ' Stratocaster Discussion Forum ' started by teley , Jan 8, Fender Stratocaster Guitar Forum. Messages: Now I'm confused, because as far as I know, it's a very new amp, and it's surprising that Epiphone discontinued it so quickly.
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Hey Gooch, Just came across your post, and so glad I did. I have a "recipe" that I've been dying to share. These amps can easily be transformed into little boutique monsters that will urinate all over just about any other amps in the Watt range. T here is not really one single mod that will bring the amp to life, but a combination of upgrades and "tweaks". That being said, I am about to write a novel, so please be patient. I can assure you that it will be worth you time, and hopefully mine, too.
Be sure that when working on your amp, the power supply is unplugged, and the filter capacitors are fully drained. If you don't know how to drain the filter caps, you can Google it, or shoot me a PM.
I really have no idea what I'm doing, but what I'm doing seems to work. My opinions are based on my personal experience. If anyone has a different opinion, please do not be a "hater" as the kids like to say on the World Wide Web , but offer an alternative suggestion.
Tubes make a HUGE difference. I have found that the Mullard and Tung Sol reissues sound far superior to any other tubes. They just seem to "feel" better. Using a 12AT7 as a PI will compromise gain, but in return, your amp will have much more "touch sensitivity"' or "dynamic response".
And yes, a new 12AT7 will do just fine. I am running two 12AT7s, which draw considerably higher plate current than 12AX7s, but this has not been an issue for the power transformer s , and I've been running both of mine very hard, for some time now.
Simply by upgrading the tubes, I can assure you that you will notice a great improvement in tone, but there is so much more that can bee done,.
You should keep a copy of this. I will be referring to it often. Remove the chassis from the cabinet, and remove the board from the chassis. This will help greatly when putting everything back together.
First, you should bump up all of the filter caps. This will smooth the AC hum, and keep your amp whisper quiet, even when "dimed". Next, all of the poly caps should be upgraded. I like the M series caps, which are currently produced by Cornell Dubilier. Orange Drops are also very good. Funny, in a guitar, ODs are always my first choice, but in an amp, Ms are my first choice.
I've never tried it the other way. If I try something once, and it works, i stick with it. So, that being said, you should upgrade the following capacitors with the same values :. Not very expensive, or labor intensive, and wow, what a difference. Next, Let's address the reverb circuit. This seems to be everyone's big issue with this amp including mine.
The problem is that the tube is running too hot for the reverb tank. And as I stated earlier, change the reverb driver tube to a 12AT7. This will transform the reverb from "Out of control, Useless, Over the top" to just about the best tube driven reverb circuit you've ever heard. An other thing that can be improved upon is the tone stack.
Next on the agenda would be the pre-amp, and gain. Before I address the tube, I would like to look at resistor 3. The factory value is 68K Ohms. I think this is a little high. Most people use a 10K in that application, but I've found that to be just a little too hot and my intention was to build a really dirty amp. I am using a 33K in both of my Valve Srs. As I'm running them right now, I think I might like just a little bit more clean headroom, but I am running the preamp tube a little hot, and I can make a huge difference by simply rolling back my volume knob on my guitar L.
You can experiment with different values for that resistor, but i think 22K or 33K is where it's at. So, on to the tube. In case you didn't know, a 12AX7 is a twin triode, and the tube can be thought of as two separate valves.
The first triode is the first gain stage, and the second triode, the second I am currently using K Ohm resistors for the plate loads although I think K would be optimal. A value of 2. I am running 2. You will not be disappointed.
After all of these issues are addressed, you can, if you feel the need, tweak the "Voicing" of the amp. This is not nearly as difficult or expensive as you might think. This would simply involve changing a few capacitors. I like to use audio grade electrolytic caps when possible. C25 is a 22uF 50V electrolytic. Increasing the value will give you more bass response. Some people like to use as high as uf for the power amp C This can be very "boomy" sounding, but the factory Valve Sr.
I think I have a uf in C25 for the combo, but a uf or a uf will offer more bass response than the stock 22uf. For C8 the first cathode coupling cap , I'm using a uf, for more bass response.
I could talk about output trannies save your money, no audible difference and speakers shoot me a PM, I'll let you know what I use , but what I've laid out should really get you there. Let me know if this helps you, and if anyone else has anything to offer, I would be very interested myself. Thanks very much for your input. I have a Valve Sr combo way out of warranty that the head sounds like the opening 10 minutes of "Saving Pvt.
Ryan" when I turn it on, and I've been going to take it to my favorite luthier who also does amp repair for a going over. I'll also give him your list and ask for his opinion as well no offense intended. As for your warnings, I know two things about amps.
The first is that if you don't know what you're doing, they can kill you. You can post now and register later. If you have an account, sign in now to post with your account. Note: Your post will require moderator approval before it will be visible. Paste as plain text instead. Only 75 emoji are allowed. Display as a link instead. Clear editor. Upload or insert images from URL. Valve senior Mods. Reply to this topic Start new topic. Recommended Posts.
Report post. Posted September 12, Hi guys I'm new so I'm asking for help if anybody can point me in the direction of links to mods for the valve senior combo or any suggestions or advice for the amp. Any help will be greatly appreciated. Share this post Link to post Share on other sites.
Posted October 13, Posted November 16, So, on to the tube In case you didn't know, a 12AX7 is a twin triode, and the tube can be thought of as two separate valves. Posted December 14, Hi, Sorry for my late reply. Thank you for posting all of this.
I am finally going to start working on this amp soon. Posted December 17, Join the conversation You can post now and register later. Reply to this topic Go To Topic Listing. Sign In Sign Up.
valve senior discontinued
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Welcome To the Hoffman Amplifiers Forum
Hey Gooch, Just came across your post, and so glad I did. I have a "recipe" that I've been dying to share. These amps can easily be transformed into little boutique monsters that will urinate all over just about any other amps in the Watt range. T here is not really one single mod that will bring the amp to life, but a combination of upgrades and "tweaks". That being said, I am about to write a novel, so please be patient.