Bare Knuckle Pickups Forum
Forum Ringside => Guitars, Amps and Effects => Topic started by: EffigyForgotten on September 14, 2013, 07:48:03 AM
-
So right now my Bugera 6260 is loaded with JJ E34L's and i've been wondering what tubes you guys think are the "tightest" sounding, I also want to get more mid range "grind"
My favorite part about this amp is you can use practically any tube possible in any slot and the amp works, and does everything for you, just pop em in and play. I was thinking of getting 6550's or KT88's.
-
So right now my Bugera 6260 is loaded with JJ E34L's and i've been wondering what tubes you guys think are the "tightest" sounding, I also want to get more mid range "grind"
My favorite part about this amp is you can use practically any tube possible in any slot and the amp works, and does everything for you, just pop em in and play. I was thinking of getting 6550's or KT88's.
My experience with JJ's is that they sound quite round. The EH's I had, were more agressive in the midrange. If you want to stick to EL34's I would consider Svetlana's too.
No experience with 6550's and KT88's. Can't comment on that.
-
if you want midrange mullard are unbeatable, I think JJ valves are quite big sounding in the midrange compared to most.
-
I think, and don't quote me on this, KT88's are midrange monsters, believe they're what goes into Kerry Kings Marshalls and what he's been using forever, but they do have a lot of headroom. then again he cranks all hell out of his amps.
http://www.youtube.com/watch?v=w6xk8T87tSE (http://www.youtube.com/watch?v=w6xk8T87tSE)
Sounds grindy to me ;)
He also has a very tight sound I've always thought.
6550 is another Classic associated with Marshall tube apparently, but supposedly have a less prominent midrange.
Edit: Just came across this
http://proguitarshop.com/andyscorner/tone-tips-the-mighty-kt88 (http://proguitarshop.com/andyscorner/tone-tips-the-mighty-kt88)
-
Yeah I think that link has made me decide on getting 2 KT88's to go with my E34L's!
Do KT88's have more headroom and tighter low end than 6L6's?
Right now my amp is all JJ's except one Tung Sol 12ax7 in V1, almost the same effect as a tubescreamer in front of the amp, although more subtle. I like JJ's thicker/darker tone, but sometimes I can't find a sweet spot for the high not to sound to dull or to harsh.
-
Are you sure you can mix anything in there? I went and had a look at the specs and it says they're convertible from 6L6 to EL34. Now i know the tubes you're talking about are in the same respective families, but is there a section in you manual that says "anything from either"?
Tubes aren't just tubes, especially power amp tubes, a lot of them have different electrical specs (which fair enough, I'm not up on). Just advising a bit of checking first?
-
That was a sweet clip! Besides the great sound, it reminds me that Venom wrote some of the coolest metal songs of all time.
-
That was a sweet clip! Besides the great sound, it reminds me that Venom wrote some of the coolest metal songs of all time.
oh they were light years ahead at the time
https://www.youtube.com/watch?v=7GEbziEDL0s#ws (https://www.youtube.com/watch?v=7GEbziEDL0s#ws)
thread jack over, please go about your business ;)
-
Are you sure you can mix anything in there? I went and had a look at the specs and it says they're convertible from 6L6 to EL34. Now i know the tubes you're talking about are in the same respective families, but is there a section in you manual that says "anything from either"?
Tubes aren't just tubes, especially power amp tubes, a lot of them have different electrical specs (which fair enough, I'm not up on). Just advising a bit of checking first?
Yeah, you cant run more than 2 though, and they have to be on the outer sockets.
-
Are you sure you can mix anything in there? I went and had a look at the specs and it says they're convertible from 6L6 to EL34. Now i know the tubes you're talking about are in the same respective families, but is there a section in you manual that says "anything from either"?
Tubes aren't just tubes, especially power amp tubes, a lot of them have different electrical specs (which fair enough, I'm not up on). Just advising a bit of checking first?
Yeah, you cant run more than 2 though, and they have to be on the outer sockets.
Do you have a link specifying this? I have a friend who blew his PT running correctly biased EL34s even though it was specified in the manual that the PT could handle the current but it turns out it actually couldnt.
-
Are you sure you can mix anything in there? I went and had a look at the specs and it says they're convertible from 6L6 to EL34. Now i know the tubes you're talking about are in the same respective families, but is there a section in you manual that says "anything from either"?
Tubes aren't just tubes, especially power amp tubes, a lot of them have different electrical specs (which fair enough, I'm not up on). Just advising a bit of checking first?
Yeah, you cant run more than 2 though, and they have to be on the outer sockets.
Do you have a link specifying this? I have a friend who blew his PT running correctly biased EL34s even though it was specified in the manual that the PT could handle the current but it turns out it actually couldnt.
Nasty.. how'd that turn out? covered in the warranty?
-
Are you sure you can mix anything in there? I went and had a look at the specs and it says they're convertible from 6L6 to EL34. Now i know the tubes you're talking about are in the same respective families, but is there a section in you manual that says "anything from either"?
Tubes aren't just tubes, especially power amp tubes, a lot of them have different electrical specs (which fair enough, I'm not up on). Just advising a bit of checking first?
Yeah, you cant run more than 2 though, and they have to be on the outer sockets.
Do you have a link specifying this? I have a friend who blew his PT running correctly biased EL34s even though it was specified in the manual that the PT could handle the current but it turns out it actually couldnt.
Nasty.. how'd that turn out? covered in the warranty?
Unfortunately it was well out of warranty. It was the second amp he had from them. He got one of the very first models that had the fire and smoke mods which is why he ended up with a replacement after sending it back a couple of times.
In the end i ended up fixing it a few times. It works solidly now but most of the original amp has been replaced.
I do hear that the newer ones are a lot more reliable however.
-
Are you sure you can mix anything in there? I went and had a look at the specs and it says they're convertible from 6L6 to EL34. Now i know the tubes you're talking about are in the same respective families, but is there a section in you manual that says "anything from either"?
Tubes aren't just tubes, especially power amp tubes, a lot of them have different electrical specs (which fair enough, I'm not up on). Just advising a bit of checking first?
Yeah, you cant run more than 2 though, and they have to be on the outer sockets.
Do you have a link specifying this? I have a friend who blew his PT running correctly biased EL34s even though it was specified in the manual that the PT could handle the current but it turns out it actually couldnt.
Yeah, http://www.bugera-amps.com/EN/infinium.aspx (http://www.bugera-amps.com/EN/infinium.aspx)
Mine is a 6260 Infinium 2013. Haven't had a problem with it for about 5 months.
-
aahh, cool, bit like the orange DIVO system then
-
Before I bought the 6260 I was trying to decide between a used 5150 and it, and the fact I can use any power tubes I want, kinda sold me. Only thing I don't like about the amp is the lack of an resonance/depth control.
I'm going to install an 81/85 set I have laying around in one of my guitars this week to see what happens. Gonna set it up in B/Drop A \m/
-
I have a friend who blew his PT running correctly biased EL34s even though it was specified in the manual that the PT could handle the current but it turns out it actually couldnt.
You need to be careful as to how you measure bias, at least according to the following video with regard to test points on Peavey and Bugera amps.
http://www.youtube.com/watch?v=l2GGggxR6iA (http://www.youtube.com/watch?v=l2GGggxR6iA)
-
Anyone who thinks they can bias an amp by looking at the bias voltage alone shouldn't be biasing an amp. That is all that video proves. Anyone who knows what that test point is giving them will know it isn't a reliable way of biasing a valve at all.
That infinium thing might work (probably copied from this http://www.tubesync.co.uk/ (http://www.tubesync.co.uk/)) but that link is full of marketing garbage.
-
Anyone who thinks they can bias an amp by looking at the bias voltage alone shouldn't be biasing an amp. That is all that video proves. Anyone who knows what that test point is giving them will know it isn't a reliable way of biasing a valve at all.
That infinium thing might work (probably copied from this http://www.tubesync.co.uk/ (http://www.tubesync.co.uk/)) but that link is full of marketing garbage.
you sound a bit annoyed today ;)
-
Anyone who thinks they can bias an amp by looking at the bias voltage alone shouldn't be biasing an amp. That is all that video proves. Anyone who knows what that test point is giving them will know it isn't a reliable way of biasing a valve at all.
That infinium thing might work (probably copied from this http://www.tubesync.co.uk/ (http://www.tubesync.co.uk/)) but that link is full of marketing garbage.
you sound a bit annoyed today ;)
hahah! I do don't I. I think my 3 weeks of work with 2 days off, 10hr shifts, 50% of which have been over nights has finally caught up with me! I blame the london underground for getting me on a hype on the way into work earlier.
-
Anyone who thinks they can bias an amp by looking at the bias voltage alone shouldn't be biasing an amp. That is all that video proves. Anyone who knows what that test point is giving them will know it isn't a reliable way of biasing a valve at all.
That infinium thing might work (probably copied from this http://www.tubesync.co.uk/ (http://www.tubesync.co.uk/)) but that link is full of marketing garbage.
you sound a bit annoyed today ;)
hahah! I do don't I. I think my 3 weeks of work with 2 days off, 10hr shifts, 50% of which have been over nights has finally caught up with me! I blame the london underground for getting me on a hype on the way into work earlier.
right there with you on long shifts and time off, easy to get irritable. everyone gives me a wide birth for a couple days after i get back from work.
Anyways, on the amp biasing side of things, can it be done with just a multimeter, or is having one of those bias probe type things with sockets a good idea?
-
a bias probe to stick in the socket is probably the safest way to check bias yourself. sometimes it will still require you to take the chassis out of the shell though, which carries a risk.
the way they work usually is thus...
They take a voltage from the anode of the valve, say 480volts DC (the plate voltage)
They measure the voltage present across a 1ohm resistor between the valves cathode and ground. The 1ohm resistor makes the maths easy to convert the values so 1mV = 1mA. The resistor is usually part of the bias meter. So a reading of 26mV means the idle current draw of your valve would be 26mA. You measure each valve to check one isn't drawing too much more or little current than the others, but matched sets should be reasonably close.
So then you end up with 480volts DC on the plate and an Idle Current of 26mA. Once you know that you can use something like this... http://www.ax84.com/biascalc.html (http://www.ax84.com/biascalc.html). Put in the plate voltage and the tick the valve type and you'll get the desired Idle Current for 60%, 70%, 80% etc disapation (disaption being the maximum output of the valve).
So in this example, say we used El34's... we'd want an Idle Current of around 43.75mA per valve @ 480volts. So then you adjust the bias voltage itself (what the peavey test points tell you) which in turn will raise the idle current from 26mA up to 43.75mA (or 26mV / 43.75mV as displayed on the meter). This is all best rule of thumb. Some people use only their ear, some use an oscilloscope. As you can see from all that, knowing the negative bias voltage alone is only part of the story.
Anyway, that is an easy and reasonably safe way to go about it with the minimum of fuss and understanding. Sometimes the idle current includes the power drawn by the 'screen' of the power valve, which means you end up biasing a few mA colder than you think, this would depend on the design of the meter you use to test with.
I have a personal method for setting bias using only a meter, but I can only do that with one of my two meters (a more expensive true RMS fluke). It took me a while to get confident with that method since you need to poke around at some of the highest voltages in the amp, so it's not worth going into.
What Peavey probably do in the JSX (if its like how the 5150 is biased), is give a suggested voltage that actually biases the amp really cold. my old 6505 would idle at 14mA per valve, which is SUPER cold. I added a bias mod and adjusted it up to 36mA. It sounded louder and less fizzy. So much better. The advantage of a bias that cold is that you could pretty much put in any matched set and it would be accidently too hot whatever. Making maintainance a bit easier especially since on a stock amp like that you can't adjust the bias anyway.
-
Nice one D, will have to grab a set of bias probes then, my amp could prolly do with a revalving.
I heard the 5150 was cold biased, people complained about crossover distortion a lot
-
I'm sure I make it sound a lot harder than it is if you use a special meter.
Yeah 6505/5150's are notorious. 5150/6505+ has an adjustable bias but the range is pretty narrow on it. I fixed one recently that had died and the highest bias point it would reach was around the 60% mark. Some valves will naturally just be hotter. That's why you get matched sets and thats how eurotubes can supply valves to get you to a particular bias point in a non adjustable bias amp, by selling selected sets for a given circuit. It's probably what Mesa do too with their branded valves.
there is some argument that crossover distortion adds to the tone of the 5150... but I prefer it biased hotter. Oddly enough, you can bias an amp using a scope and looking at the knee in a sine wave created by crossover distortion. If you dial out the knee you end up around 70% dissipation when you check the votages and current draw, but if I recall it works with some valves and not others, like it works with 6L6's and not with EL34's. There is a video of Lee Jackson biasing with that method on youtube I think.
A lot of valve reliability issues come from some weird decision somewhere in the amp usually, I think. You have a Soldano so it's most likely nails anyway. Those Sovtek button base 5881's they send out with them are crazy rugged and handle stupid voltages.
-
was thinking of changing those out for 6L6GC's for a while. But then i thought, well Soldano power sections are designed to be "HiFi" anyways, so there was not really any point in changing them out for the sake of power tube overdrive characteristics.
Don't make it sound hard at all, especially for an electronics morons like me, I appreciate you taking the time to write it up.
Soldano are known for biasing slightly cold as well, although when i say slightly, i mean slightly, nowhere near as cold as the 5150. apparently thats a concious decision on Mikes part, not sure of the technicalities behind it.
There is a real argument for aspects of the Soldano sounds similarities to old Hiwatts with massive head room.
The new 25+ IS designed to have the power section break up, really interested in it.