bluefoxicy Posted January 31, 2008 Share Posted January 31, 2008 Well the $40 pocket amp and the $30 pocket amp both suck so I'm thinking about throwing $150 or so at a real amp. I've been recommended the Roland Cube 15X, nice featureful solid state amp with lots of shiny knobs and a good sound to it, $100. I'm thinking about going with tube amps, however, so I'm peeking around for a cheap one... and there only seems to be one brand under $1000. So I'm thinking, Roland Cube 15X versus Epiphone Valve Junior. I hear the Junior sounds good and you can drop in some higher quality tubes (which cost what, $20?) to get an even better sound out. It's tube pre-amp and tube power-amp, only 5W but I don't need to wake the neighbors with back yard concerts (I'm still LEARNING to play... and progressing I might add). There's no effects knobs, but ... it's tubes ... they don't exactly respond gracefully to increasing input signal. You want overdrive? Crank the volume. Any thoughts? (mind you there's a solid state Fender in the next room, and a tube amp in the next house; I've heard both, but the tube amp isn't readily accessible) Link to comment Share on other sites More sharing options...
cGil Posted January 31, 2008 Share Posted January 31, 2008 Get a VJr. Or get a BlackHeart "Killer Ant" if you don't want to wake the neighbors. And you know you wanna cuz you know only tubes have THAT tone; and the less knobs and switches that are in the way, the better the tone is! So go for it! Gil... Link to comment Share on other sites More sharing options...
bluefoxicy Posted January 31, 2008 Author Share Posted January 31, 2008 Someone else is telling me the Roland has more controls (duh) and I can only control tone via the tone knob on my guitar with the Valve; and of course, the Roland doesn't have a bad sound.... Roland's got gain and effects, I can do without those. It has a 3-band EQ, I can do without that too right now BUT ... do you happen to know the proper capacitor values for lower filter bound on Bass, Mid, and Treble; and the proper RC circuits to short the Bass and Mid hot leads with to upper bound Bass against Mid, and Mid against Treble? I figure I can use 500k DiMarzio push-pull pots for each of these (I believe these are linear...), and have input go to common. Pushed in, output goes to the pot's hot in; pulled out, output goes to hot out (bypass the pot), which goes to common on the next pot switch. Pull all 3 knobs and you have bypassed the entire 3-band EQ stack. The push-pull I think is a nice touch; like you said, running a signal through a potentiometer turned all the way to 0 will still cause signal attenuation at certain frequencies, or get rid of quiet parts of the signal. Now if only I could build it.. later on, not now ;) Link to comment Share on other sites More sharing options...
jman99 Posted January 31, 2008 Share Posted January 31, 2008 Well although a tube amp sounds cool (and is cool) you mentioned that you are still learning to play. I am not sure what that means but if you are fairly new to guitar you may want an amp that is more versatile than a little tube amp. What kind of music do you like or who are you trying to sound like. A modern solid state amp will be able to emmulate a variety of sounds while the Epi jr will sound good for certain tones but not be that versatile. The roland also has effects. Not only are they usefull, they make playing FUN. If it is fun you keep playing. If you don't want them, turn them off. I'm quite sure you would like a little reverb now and then, if not some other stuff. My main amp is a PV classic 30. No effects other than reverb. But I have been hacking away for 30+ years so I know the sound I like and need. But guess what I am in the market for, you guessed it, a small solid state amp with some cool built in effects. Little solid state amps are alot of fun around the house. Loud crunchy tubes amps are great cranked up and at gigs. And then you may want at least 20 watt tube amps. If it were me I would get the Roland, or save a few bucks and get a VOX patherfinder 15R and a Bad Monkey pedal to stick in front of it. The Vox also has a decent speaker and reverb and tremolo. Nothing wrong with a jr, I wish I had one, but if it is going to be your only amp you may want to get something that will cover a bit more territory. good luck Link to comment Share on other sites More sharing options...
bluefoxicy Posted January 31, 2008 Author Share Posted January 31, 2008 What kind of music do you like or who are you trying to sound like. A modern solid state amp will be able to emulate a variety of sounds while the Epi jr will sound good for certain tones but not be that versatile. I've got Troy Stetina books on like everything heavy metal, gonna work through Fretboard Mastery and such, do some speed drills and familiarize myself with all the theory and cross that against songs I can try to play. I've been using Paranoid and Rock You Like a Hurricane to get familiar with the guitar (chords, fingering, rhythm), and also pulled out some Nobou Uematsu and Koji Kondo stuff (some made for heavy metal, some definitely not) to play with lead. I got my Epi LP Special 2 (after new pickups etc) to sound like Eric Johnson's guitar through a cheap amp, albeit I think his has better sustain and a bit more brightness. End goal is to be able to play Dragonforce: Through The Fire and Flames by next year. While singing. Though you might have noticed I dip into much lighter stuff (Koji Kondo?) already, on purpose. There's a number of songs I pretty much picked off Guitar Hero 3 for playing on plain old guitar.... Link to comment Share on other sites More sharing options...
tunghaichuan Posted January 31, 2008 Share Posted January 31, 2008 As much as I like the little VJ and Blackheart amps, they really are one or two trick ponies. They do a nice low volume clean sound and a nice cranked sound. They won't do heavy metal without a pedal or extensive mods. You can spend time modding it to get other types of sounds, but only one at a time. If you want to change your sound, then you have to mod your amp again. Those tube 5W amps are loud to, and you need some kind of power attenuator to get them to give up the goods at low volumes. Also being tube amps, the tone changes as you crank them up as most of the distortion comes out of the power amp. Those Roland Cube amps are pretty versatile. For the kind of music you want to play, I'd recommend the Cube. They do a credible Dual Rectifer/SLO lead tone. They also do a nice crystal clean tone. They're not so great at bluesy breakup, though. SS modelers like the Cube series don't change the tone as you turn them up. In fact you don't want power amp distortion out of an SS amp as a general rule. Another nice feature is that they have an aux in for connecting a CD/MP3 player so you can play along. My $.02 tung Link to comment Share on other sites More sharing options...
bluefoxicy Posted January 31, 2008 Author Share Posted January 31, 2008 Whoa. This thing is awesome. My tone knob actually does something now (higher == massive distortion), the pick I use has a slight influence on the sound, the way I pick controls the sound, the pickups I use (via switch) have massive effect ... I like this. The 5W tubes ARE extremely loud, damn. I'll have to mod a good EQ into the head of the amp later on, probably build the circuit and solder it in in one piece (drill some holes for knobs, etc). I'm starting to understand how that'd make a difference in the tone produced .... The Cube is definitely on my list; but I like having a tube amp around along with the solid states that are all over the place here. There's a more advanced Valve Jr out there that costs $250 but I don't want to buy that right now! :) But yeah, one knob, not many options there. Link to comment Share on other sites More sharing options...
cGil Posted January 31, 2008 Share Posted January 31, 2008 I'm sorry to say that the Valve Special and Valve Standard simply have too many problems. The circuit boards are unstable like v1 and v2 VJr's, yet they have far more going on that can go wrong. A lot of folks wind up bypassing the DSP and all the wiz bang extras they bought those amps for in the first place, just to get some decent tone out of the things. The only bright side is that the TMB tone stack benefits from having an extra preamp tube, which the VJr and BlackHeart Little Giant both lack. Gil... Link to comment Share on other sites More sharing options...
bluefoxicy Posted January 31, 2008 Author Share Posted January 31, 2008 I'm sorry to say that the Valve Special and Valve Standard simply have too many problems. A lot of folks wind up bypassing the DSP and all the wiz bang extras they bought those amps for in the first place' date=' just to get some decent tone out of the things.[/quote'] Okay then, but the basic Valve Jr. is pretty simple and basic and workable. Well, I can build an EQ onto it later. Dad's saying stuff about blowing out the tubes if I don't understand the circuit and its limits but I think he missed exactly what I'm modifying here... it's just a couple more pots (and caps and tanks) to change the signal attenuation, not a bunch of extra tubes and pre-amplifiers and jack. I get vastly different tone depending on how I breath (or what pickups I use, tone knobs, even the thickness of the pick and how hard I use it has a minor yet audible effect); an EQ is really going to have an effect on this machine. I like it! Link to comment Share on other sites More sharing options...
tunghaichuan Posted January 31, 2008 Share Posted January 31, 2008 Another thing to consider is that you might be able to use the line/recording out of the Cube 15x to drive a Valve Junior. You may have to bypass the first stage of the 12AX7 and use the VJ as a power amp. tung Link to comment Share on other sites More sharing options...
cGil Posted January 31, 2008 Share Posted January 31, 2008 That would indeed sound awesome. Electrons in SPACE space space space... coming to an amp modeler near you! Gil... Link to comment Share on other sites More sharing options...
bluefoxicy Posted January 31, 2008 Author Share Posted January 31, 2008 Another thing to consider is that you might be able to use the line/recording out of the Cube 15x to drive a Valve Junior. You may have to bypass the first stage of the 12AX7 and use the VJ as a power amp. Hmm. Preamp bypass switch. Interesting idea. Running to guitar center for info. Trying to see if I can replace the 12AX7 and the EL84 with other tubes for a "better" sound, and if an in-line equalizer (guitar -> EQ -> amp) will do the same as rigging an EQ circuit up inside the amp (comes AFTER the vol pot). Just an information run, no buy. Link to comment Share on other sites More sharing options...
m-theory Posted January 31, 2008 Share Posted January 31, 2008 Running to guitar center for info. I believe that's the first time I've ever heard this phrase! Trying to see if I can replace the 12AX7 and the EL84 with other tubes for a "better" sound JJ makes the best new production el84, imo. They also have "decent" 12AX7 and a low-gain version of that tube as well, though you need to buy from someone who knows how to test them, and is willing to stand behind them for at least a reasonable amount of time. Like all new production preamp tubes, the JJ's are all over the place, gain-wise, and can be prone to microphonics, particularly the long-plate 803S (low-gain AX7). 5751 is another good choice for the preamp tube. Imo, the valve junior has stupid amounts of gain and can benefit from a lower gain preamp tube, but then, I'm sort of partial to plexi Marshall tones, so I really don't care much for excessive front end gain, which is what some tend to favor. Personal preference. and if an in-line equalizer (guitar -> EQ -> amp) will do the same as rigging an EQ circuit up inside the amp (comes AFTER the vol pot). Can't say that I've ever heard of putting an EQ in after the volume pot...don't know if that would work or not, although I can picture odd oscillations. EQ before amp, of course that will work. My personal view on EQ though, is that, if you need to use EQ, something's not right with the amp or guitar. The greatest guitar tones, imo tend to involve nothing more than a good guitar, a good amp, and some sort of boost for lead work. I'd recommend moving very slowly into the realm of add-on boxes or permanent modifications. You can waste a lot of money, time, and leave lasting holes in your amp that you might regret later. If you just got the amp, I'd say play it long enough to at least break in that speaker, get a feel for it at various volume levels, learn how your guitar volume changes the tone of the amp, try it through different speakers, if you can, etc. Take your time, get to know your gear. Then, you'll not only have a better idea as to what you really want to change about it, but you'll be better equipped to hear the difference and decide if whatever change you implement actually works, almost works, or doesn't work at all. 2c worth, from someone who's spent a whole helluva lot of money chasing the tone Gods over the past 30 years. Most times, simpler really is better. Link to comment Share on other sites More sharing options...
bluefoxicy Posted January 31, 2008 Author Share Posted January 31, 2008 I've heard JJ a lot, really I'm looking at Groove Tube and Tung Sol at the moment; I'm seeing these in a lot of "GROOVE TUBE ROX MY SOX TUNG SOL SUX AND KILLS HIGH MIDS" versus "TUNG SOL ROX0RZ EVERYTHING AND I REPLACED ALL THE GROOVE TUBE CRAP I HAD" debates, and I can't tell who's right and who's wrong. I'm thinking these are both excellent and there's a personal taste issue going on here. Now, a real problem of course is the Groove Tube EL84 power amps! At a glance, Guitar Center has two major types, each with like 6 options for Duet/Quartet (???) and whatever the heck a "GT rating" is. http://www.guitarcenter.com/Groove-Tube-Gold-Series-GT-EL84-S-Matched-Power-Tubes-219169-i1125772.gc http://www.guitarcenter.com/Groove-Tube-Gold-Series-GT-EL84-R-Matched-Power-Tubes-219168-i1125766.gc $20-$70?! Then there's this $8 Fender: http://www.guitarcenter.com/Fender-EL84-Single-Amp-Tube-211208-i1125556.gc Okay what am I looking at here? A lot of price + marketing and I'm sure Groove Tube is brand name fanfaring on their really expensive models. But ... what's with all the specs? As for the EQ mod, I'm thinking on how an EQ works and what would control it. I related it to the tone pot, figured out how that works, and basically the EQ after the Vol pot theory comes from ... well, dig around inside a guitar one time and look at the wiring. Signal starts at the pickups, hits vol, then tone. Tone pot basically attenuates highs (from what I understand), so... yeah. Unless I'm totally off on this; this is mostly reverse engineering, not study. As for EQ affecting tone, touching my tone pot affects what comes out of my tube amp massively (unlike the solid state ones). I want to do that to different frequencies in a bit more fine-grained manner Someone told me he's never reproduced Knopfler's tone (he was trying to play Money for Nothing, using all kinds of modeling solid state amp settings and pick-up phase switching); I'm certainly not going to be able to do that either with an amp that has just a vol knob. A few more controls, phase switch and series/parallel push-pulls on my guitars, etc, and I can probably produce a lot of interesting sounds, certainly more than what I'll get out of it right now. Most of this is all research for things I'll build in the future. I'm not ready to swap tubes and drill holes in this thing yet. Link to comment Share on other sites More sharing options...
jman99 Posted February 1, 2008 Share Posted February 1, 2008 Quote: Running to guitar center for info. I believe that's the first time I've ever heard this phrase! Now that is just funny!!! Link to comment Share on other sites More sharing options...
tunghaichuan Posted February 1, 2008 Share Posted February 1, 2008 Now' date=' a real problem of course is the Groove Tube EL84 power amps! At a glance, Guitar Center has two major types, each with like 6 options for Duet/Quartet (???) and whatever the heck a "GT rating" is. http://www.guitarcenter.com/Groove-Tube-Gold-Series-GT-EL84-S-Matched-Power-Tubes-219169-i1125772.gc http://www.guitarcenter.com/Groove-Tube-Gold-Series-GT-EL84-R-Matched-Power-Tubes-219168-i1125766.gc $20-$70?! Then there's this $8 Fender: http://www.guitarcenter.com/Fender-EL84-Single-Amp-Tube-211208-i1125556.gc Okay what am I looking at here? A lot of price + marketing and I'm sure Groove Tube is brand name fanfaring on their really expensive models. But ... what's with all the specs? [/quote'] I believe the S in GTEL84S stands for Slovak, and is probably made by JJ. The GTEL84R is Russian and is probably a Sovtek EL84 or EL84M. GT charges a premium for testing their tubes, but in reality they sell the same tubes that everyone else does, with one or two exceptions. You can buy JJ EL84 tubes from Bob at www.eurotubes.com for $10.00 each or $19.00 for a matched pair plus shipping. A much better deal than the Groove Tubes. If you decide to go the Eurotubes route, email or call Bob and tell him you're going to use the tube in a Valve Junior. He can set you up with a tube or tubes that will sound good in the VJ. The Fender tube is probably Chinese, but I can't tell for sure. tung Link to comment Share on other sites More sharing options...
m-theory Posted February 1, 2008 Share Posted February 1, 2008 I think the "S" groove tube is a JJ, and the "R" is a Sovtek (crap, imo). I'm sure that the Fender tube is also Sovtek. There's a huge amount of marketing BS surrounding new production tubes, very little of which means anything substantive. There are only 3 or 4 factories in the entire world that are making tubes these days. Brand name and hype aside, they all come from one of these 3 or 4 places. None of them make "outstanding" tubes, in comparison to the giants of yesteryear, but some of them make SOME tubes to a "decent" level of quality. None of them make ALL tubes to that level. The characteristics that they all seem to share is a horrendous lack of consistency in gain structure, and an astonishing tendancy to be prone to microphonics (noise). It's critically important, whether buying NOS or new production tubes, to buy from someone that fully tests each and every tube for gain, conductance, balance (triodes) and microphonics. Otherwise, you're wasting your money. Today's tubes are just too inconsistent to rely upon mass market gimmicks, imo. I've had very good luck with Eurotubes, for JJ tubes. If I were you, I'd give them a holler, tell them what you've got and what you want to hear from the amp, and take that advice. They're cheap enough that you're not going to be out a tremendous load even if you end up hating them, but from my experiences, you'll like what you hear. You might want to yank the tubes in yours first, to see what's actually in there, because some of the new Vjr's apparently ship with JJ's. When you're feeling up to it, you should start reading up on setting the bias on the amp. From what I've read, they still tend to run that EL84 extremely hot, and that leads to mushy, ugly distortion and shortened tube life. Don't open up the chassis without being fully aware of the dangers posed to your very life within, however. It's not difficult to dial in the bias, but it's also not difficult to cause yourself serious, perhaps fatal harm, by dinking around inside a tube amp without knowing what you're doing. Link to comment Share on other sites More sharing options...
bluefoxicy Posted February 1, 2008 Author Share Posted February 1, 2008 I think the "S" groove tube is a JJ' date=' and the "R" is a Sovtek (crap, imo).[/quote'] It's critically important' date=' whether buying NOS or new production tubes, to buy from someone that fully tests each and every tube for gain, conductance, balance (triodes) and microphonics. Otherwise, you're wasting your money. Today's tubes are just too inconsistent to rely upon mass market gimmicks, imo.[/quote'] GT charges a premium for testing their tubes' date=' but in reality they sell the same tubes that everyone else does, with one or two exceptions.[/quote'] Buying GT is effectively a quick-and-dirty way to get this testing at a premium? Or do they just test for horrendous sounding crud and blown tubes, not for actual good audiophonics? I'm guessing these quartet/duet matched tubes mean packs of 2-4, so at $34 for a "duet" that's ... $17 each. I'd be willing to pay that for properly tested tubes, but yeah cheaper is better for my wallet. (Their 12AX7 preamp tube is $18) When you're feeling up to it' date=' you should start reading up on setting the bias on the amp. From what I've read, they still tend to run that EL84 extremely hot, and that leads to mushy, ugly distortion and shortened tube life. [/quote'] Not sure how I'd want to adjust that. "Cooling it off a little" is going to have an effect, I don't know what the right level is. Is the reading material out there going to tell me how to dial it up, or is it going to tell me how to identify a hot tube and figure out how much to cool it off? Groove Tubes seem to rate how fast they distort... I suppose whether I'm using a low, mid, or high rated tube is going to affect how I should bias the amp. Though I don't see this kind of rating on like Fender tubes or Ruby tubes or such. ?_? Don't open up the chassis without being fully aware of the dangers posed to your very life within' date=' however. It's not difficult to dial in the bias, but it's also not difficult to cause yourself serious, perhaps fatal harm, by dinking around inside a tube amp without knowing what you're doing.[/quote'] Monitors get a discharge before getting opened because the capacitors in the transformer hold a fatal dose of electricity (riiight.. understatement there). The question is, though, can I kill that off by shorting the hot/cold pins across each other on the power plug? (On monitors the advice I've heard is unplug it and throw a screwdriver across the prongs for a minute to bleed the caps) Link to comment Share on other sites More sharing options...
bluefoxicy Posted February 1, 2008 Author Share Posted February 1, 2008 Monitors get a discharge before getting opened because the capacitors in the transformer hold a fatal dose of electricity (riiight.. understatement there). The question is' date=' though, can I kill that off by shorting the hot/cold pins across each other on the power plug? (On monitors the advice I've heard is unplug it and throw a screwdriver across the prongs for a minute to bleed the caps)[/quote'] Okay reading this, I see that you actually have to test the darn thing by running it hot and feeling up the EL84's power pins! (oooh, not fun). Working with live circuits is a bit different... the main thing there is to make sure you don't create a ground path (especially crossing near your heart!) so if you do get shocked you (hopefully) just hurt your hand. Yek. Now I just gotta figure out if the bias is controlled by a resistor or a pot. If it's a resistor urgh, have to solder something else in. I wonder if I could put a linear pot INSIDE the case in series with a base resistor (pot goes to 0, I don't want 0 ohms resistance here obviously) and mark it up for like 100k, 600k, 1100k... Eh. Have to look inside and see if there's a pot in there already, and figure out if it'll care if I use a pot. Link to comment Share on other sites More sharing options...
m-theory Posted February 1, 2008 Share Posted February 1, 2008 Buying GT is effectively a quick-and-dirty way to get this testing at a premium? The only testing that I'm aware of that GT does is a rough gain match, that allows them to lump tubes into convenient bins and call them "matched." I highly doubt they're matching and grading accurately, and am fairly certainly that they're not doing anything else. I'm guessing these quartet/duet matched tubes mean packs of 2-4, so at $34 for a "duet" that's ... $17 each. I'd be willing to pay that for properly tested tubes, but yeah cheaper is better for my wallet. (Their 12AX7 preamp tube is $18) Too much. Especially for tubes that aren't even fully tested. I gladly pay my tech an extra 8-10 per tube for the testing that he does, but that's only because I know that he's actually testing them completely. Not sure how I'd want to adjust that. Read the big thread on mods. You've got a lot of reading to do before you start this. The term "hot" in this context doesn't just refer to temperature. It refers to the amount of current being drawn across the tube. Too much current causes the amp to sound blatty, mushy, inarticulate, and is significantly reduces tube life. Too little current doesn't sound good, either. The goal in biasing a single ended amp is to adjust the plate current to as close as possible to the maximum dissipation of the tube, without going over, bearing in mind that voltage flucuations at your given outlet will have an affect on this. Groove Tubes seem to rate how fast they distort Marketing BS. Their ratings are based on gain characteristics. I wish they'd never have unleashed that pointless, stupid gimmick, because it only makes people think that they never have to adjust the bias on their amps. All they have to do, to go from dirty to clean, is swap tubes. Absurd. Now I just gotta figure out if the bias is controlled by a resistor or a pot. Pots are resistors, but SE amps don't have any way to balance bias, as class A/B amps do, because there aren't multiple output tubes to balance the bias on. Bias and voltages are adjusted by swapping resistors. I wonder if I could put a linear pot INSIDE the case in series with a base resistor Where are you going to find a 5 watt pot that's going to fit inside the chassis? You're way overthinking this. It's a simple resistor swap. There are mountains of references in the mod thread that will guide you, step by step through the process. If you're unsure of yourself, as it sounds you are, you need to either spend some serious time reading up on this until you fully understand it, or pay somebody a few dollars to set the bias for you. Btw, once you get the bias set for a particular tube that you KNOW has been very carefully tested and graded for gain, you shouldn't need to re-visit this again, as long as you buy the same tube from the same dealer, and it's graded the same. Link to comment Share on other sites More sharing options...
tunghaichuan Posted February 1, 2008 Share Posted February 1, 2008 bluefoxicy, Here is a quick and dirty guide to biasing the VJ that I wrote with some help from the SEwatt.com crew: http://www.diycustomamps.com/valvejunior.htm#vjbias Not hard to do, but inherently dangerous as the amp has to be on and powered up. Be very careful if you try this. I think the guide explains things pretty clearly, but post if you have any questions. tung Link to comment Share on other sites More sharing options...
bluefoxicy Posted February 1, 2008 Author Share Posted February 1, 2008 Marketing BS. Their ratings are based on gain characteristics. I wish they'd never have unleashed that pointless' date=' stupid gimmick, because it only makes people think that they never have to adjust the bias on their amps. All they have to do, to go from dirty to clean, is swap tubes. Absurd. [/quote'] Interesting. Pots are resistors' date=' but SE amps don't have any way to balance bias, as class A/B amps do, because there aren't multiple output tubes to balance the bias on. Bias and voltages are adjusted by swapping resistors. Where are you going to find a 5 watt pot that's going to fit inside the chassis? You're way overthinking this. It's a simple resistor swap. There are mountains of references in the mod thread that will guide you, step by step through the process. If you're unsure of yourself, as it sounds you are, you need to either spend some serious time reading up on this until you fully understand it, or pay somebody a few dollars to set the bias for you. [/quote'] I like to avoid soldering; do work exactly once. But point taken; I didn't realize that was 5 watts going INTO the power amp. Btw' date=' once you get the bias set for a particular tube that you KNOW has been very carefully tested and graded for gain, you shouldn't need to re-visit this again, as long as you buy the same tube from the same dealer, and it's graded the same.[/quote'] Interesting point. Guess this isn't a case of swapping things out to change things, this requires some fiddling and soldering to change the sound. Maybe I'll just order JJs or whatnot; or just go with the cheap Fender 12AX7 and EL84 tubes to avoid thinking about it. I decided to pull the back panel off to see what kinds of tubes are in there now, and ... it won't come out! Oh well. It's really hard to pull off I guess :s (undid all the screws around it). I should be able to pay a guitar technician to bias the amp for me right? (hmm, the place I usually go to says they don't know what rebiasing is and that I have to ask the tech when he gets in...) The only major concern here is gonna be I have to pick good tubes to keep using, and have the amp rebiased; I might as well change tubes right off if the thing runs the EL84 hot out of the box, since I should probably rebias it in that case. Link to comment Share on other sites More sharing options...
m-theory Posted February 1, 2008 Share Posted February 1, 2008 I like to avoid soldering; do work exactly once. But point taken; I didn't realize that was 5 watts going INTO the power amp. There's nothing wrong with pulling out the soldering iron once in a while to tweak an amp, pedal, guitar, or cord, if you know what you're doing with the tool. It's not 5 watts going into the amp. You need a MINIMUM 3 watt resistor at the plate. 5 watts is better. The wattage rating on a resistor has nothing to do with power. It's all about how much current it can handle before it melts or bursts into flames. Maybe I'll just order JJs or whatnot; or just go with the cheap Fender 12AX7 and EL84 tubes to avoid thinking about it. I'd really avoid buying any tubes off the shelf, frankly. You're far better off either buying them from an amp tech that has testing equipment, or one of the reputable tube dealers online, that all religiously scrutinize each tube that they sell. Opinions on tubes are a dime a dozen, but if you really want GOOD tubes, whether new production or NOS, you're best off talking to somebody that works with them every day, rather than just buying whatever happens to be lying on a shelf somewhere. I should be able to pay a guitar technician to bias the amp for me right? I'd suggest you visit an amp tech. There are at least a couple hanging around here that might be willing to dial your amp in for you, if you're willing to pay a few dollars for the service. It really isn't rocket science, but it does require at least some level of skill with an iron and basic knowledge of what you're doing. Btw, I have read that the new Vjr's back panel is very difficult to remove. That's another question for someone around here that's dealt with them. The good news is that version 3 included a decent output transformer, and could very well have a JJ el84 and either a JJ or EH AX7...dramatic improvements from the earlier Sovtek offerings, imo. The bad news is that they're apparently still sending them out with FAR too much current across that EL84. On the output tube and future biasing: If you buy brand xyz from someone that tests carefully and keeps records of his sales, it's simple to just go back to that place when you need fresh tubes. As long as the amp is biased properly for a given tube, and you buy that same tube from the same source, you're golden. Link to comment Share on other sites More sharing options...
bluefoxicy Posted February 1, 2008 Author Share Posted February 1, 2008 There's nothing wrong with pulling out the soldering iron once in a while to tweak an amp' date=' pedal, guitar, or cord, if you know what you're doing with the tool.[/quote'] Every attempt leaves room for mistakes. Ever jump cars with a motorcycle? After the 100th time, is it safe to do it 100 more times? (Hell no) In general I treat everything like software engineering. If I have to rewrite major sections manually and create/acquire new parts and gut the existing stuff etc instead of just pulling one thing out and plugging something else in (or turning a knob), it sucks. Imagine having to solder to change tubes. :s I'd really avoid buying any tubes off the shelf' date=' frankly. You're far better off either buying them from an amp tech that has testing equipment, or one of the reputable tube dealers online, that all religiously scrutinize each tube that they sell.[/quote'] I have heard that the Tung Sol tubes were pretty hit-or-miss, with okay SNR but still a fair number of bad tubes coming out of the factories when the company first got bought by its current owners. I have also heard, however, that the SNR is dropping rapidly and they're mostly spitting out good quality tubes, and that the good tubes were always good tubes. Mind you (personal convo with someone who does tube testing): The Russian made tung sol is better sounding then your run of the mill sovtek but in my opinion it sounds a bit compressed when pushed and is a bit shallow in the low end. There have been a few bad batches of the faux tung sol’s in the past but I have heard that they are getting more consistent. The best to way to find out if you would actually like them is to try them. I think it's relatively safe QA wise to go with a Tung Sol pre-amp tube, though it'd be preferable to find one that's gone through a strict testing process. I'm pretty much thinking I'll eventually get the JJ EL84 tubes. I'll pick up a JJ 12AX7 matched and balanced gold pin, and a Tung Sol 12AX7. Whichever 12AX7 I like best I'll continue buying. Link to comment Share on other sites More sharing options...
m-theory Posted February 2, 2008 Share Posted February 2, 2008 Every attempt leaves room for mistakes. That's why you should know what you're doing before you start. Yeah, you can screw things up if you're unfamiliar with the basics. If you are familiar, however, you can not only avoid those screwups in the first place, you can easily fix them if/when they do occur. Just like anything else...the more familiar you are with whatever, the more success you have. I have heard that the Tung Sol tubes were pretty hit-or-miss All new production preamp tubes are hit-or-miss. My amp tech buys hundred lots of everthing that comes out, and tests every single tube in the lot. Very few have "great" characteristics all around. Most have very low gain and are microphonic. Only a handful per hundred-lot are "high gain" (a relative term with today's tubes), balanced, matched, and not displaying microphonic characteristics. It's the nature of the beast. They simply do not make tubes the way that they did yesteryear. Whichever 12AX7 I like best I'll continue buying. Assuming that what you buy has been tested properly, it's entirely likely that you're going to find whatever you buy to replace the stock preamp tube, far better than stock. Beyond that, it's a matter of micro-analyzing various brands, including NOS, to get a real feel for how each is different. Tone is a totally subjective thing, so it may well be that what YOU think is "best" is what someone else thinks is "horrible." Doesn't matter. What matters is that whatever you end up with inspires YOU. Link to comment Share on other sites More sharing options...
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