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Do you bias your amps or take them to a tech

  • Hell No! I take it to a tech

    Votes: 2 11.1%

  • Absolutely. Techs are dumb

    Votes: 16 88.9%
  • Total voters
    18
About 15 or so years ago I started getting into the Randall RM's that have bias points on the back. Told myself that I should stick with amps that have bias points from that point on so that I could do it myself easily.

Did pretty well with that up until a few months ago when I picked up a Splawn. I am so used to checking the bias every so often that I am thinking about picking something up that will allow me to check the bias without removing the chasis. Weber Bias-rite? If it needs a tweak, I will be fairly annoyed.
 
Fordman65 said:
Long time Mesa Boogie user here so biasing was never an issue for me. If I did happen to own something not Mesa related that required new tubes, I would just take the amp to the tech for service. Not including tubes, about $75 each time.

Just bought some equipment and going to start doing this on my own. What's interesting to me, is there is so much talk on tone, what's good/what's bad etc. yet there is very little discussion on things like this.

I also find that topics like below are also rarely discussed. (Maybe there is nothing to discuss though)
speaker break-in
pickup height and pole settings
speakers out of phase (most common when running dual amps, or the cab is not wired correctly)
cable capacitance and how that interacts with true-bypass pedals etc.

I wonder how many more people would enjoy their sound if the above things were dialed in? Maybe modelers are so mainstream now that some of the above is no longer relevant to some.
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Purchasing some bias probes and learning how to bias your amps is a worthwhile endeavor for sure. A properly biased amp will sound better.
As to your other points:

Speaker break-in: yeah, most speakers will sound brighter / a bit harsh until they have some miles on them. Most people know this already.

Pickup height and pole piece height: There's a lot of room for adjustment and dialing in the pickup to the guitar. Yes pickup height matters. Not sure if it's never discussed because it's a well known thing, or because nobody worries about it. I think it definitely matters, and spend a lot of time time dialing in the pickup height on all my guitars.

Speakers out of phase: well.....if you can't tell when your speakers are out of phase, nothing you will read on a forum will help you....

Cable capacitance: I'm not aware of any specific interaction between true-bypass pedals and cable capacitance, but higher capacitance cable will roll off the high end of your guitar signal. It's why different cables sound ...well...different.
 
fek said:
About 15 or so years ago I started getting into the Randall RM's that have bias points on the back. Told myself that I should stick with amps that have bias points from that point on so that I could do it myself easily.

Did pretty well with that up until a few months ago when I picked up a Splawn. I am so used to checking the bias every so often that I am thinking about picking something up that will allow me to check the bias without removing the chasis. Weber Bias-rite? If it needs a tweak, I will be fairly annoyed.
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The bias adjust is usually inside the chassis.
Them main thing I always do is bias the tubes that are in the amp first to lower the bias just in case
the new tubes run hot from the get go. That way you wont red plate the new tubes.

And even once the tubes are "burned in" you wont drift only a few mA's at most
 
When I got my Splawn 10 years ago it forced me to learn how to not only just bias my amp but how to safely get in there and what to do and not do. To me, those safety tips was the important part. I have no EE type background and get anxiety just changing a light bulb. I did a ton of research and found lots of good info but felt a detailed tutorial of how to bias an amp SAFELY was needed - so I created one.

If you are interested - I can find it.

I generally like to work on my own stuff so testing tubes, changing tubes, biasing amps, general troubleshooting, messing with pedals, experimenting with pickups and pick up height, stings, set ups, etc etc is part of the hobby.

PS: I have a Weber probe, and several meters.

Just biased some new EL34 IIs not that long ago. Decided to go a little hot this time.

At2u1mY.jpg
 
I finally took the plunge about a year ago and learned how to bias my amps. Significant, noticeable improvement in tone and feel with closely matched and correctly biased glass.
 
I like doing my own. I don't want to have to depend on a tech when I want to try different tubes. Plus it's not a bad idea to check the bias after the tubes have had some playing time on them.

Is your tech using an oscilloscope to bias the amp? If not he's not doing anything that you probably can't do yourself. I think it's a good skill to have, and there's plenty of info online for most amps and how to bias them properly and safely.
 
I didn't like paying for it and decided to learn how and that started a whole amp modding/building hobby.

Regarding all those other things...your ears are your best test instrument/sensor for most of this stuff. For example, some people go to great lengths to negate/reduce any cable capacitance...but Jimi used 100' coiled cords (don't quote me on that, they were very long). Eddie allegedly used to boil new guitar strings because he hated the sound of new strings. It's whatever gets you the tone you're after.
 
I started biasing myself about 7 yrs ago. Mostly a Marshall guy and I prefer vintage (JCM 800 and older) so I picked up a ‘Bias Tool’ on eBay for 25 bucks; it plugs in to your multimeter and works great. You have to do each tube individually so it’s extra work compared to other Bias meters out there but I don’t mind.
Speaker phase issues? You’ll know immediately if there’s a problem. The net has many useful speaker wiring guides. One thing I’ve learned is to make sure the wood screws are tight. Almost every vintage cab I’ve bought has needed some tightened.
Pickup height/pole adjustment- this is just trial by experimenting. If it’s too compressed sounding then I lower the pickup but raise each pole piece...becomes a little clearer sounding. But less hairy. Not putting out what you think it should? Raise it up...if that doesn’t work your ground may have to be re soldered.
I should add that my experience with Marshall’s, once I got the bias within a normal range (30-40ma per tube depending on the PT voltage, and my ears) some amps went from anemic to amaze balls. My 83 2203 has GE 6550s and sounded thin when I got it...bias was between 15 and 21 ma per tube! Super low...now they are between 33-39 and it kills. Biasing can make all the difference in the world.
 
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311splawndude said:
When I got my Splawn 10 years ago it forced me to learn how to not only just bias my amp but how to safely get in there and what to do and not do. To me, those safety tips was the important part. I have no EE type background and get anxiety just changing a light bulb. I did a ton of research and found lots of good info but felt a detailed tutorial of how to bias an amp SAFELY was needed - so I created one.

If you are interested - I can find it.

I generally like to work on my own stuff so testing tubes, changing tubes, biasing amps, general troubleshooting, messing with pedals, experimenting with pickups and pick up height, stings, set ups, etc etc is part of the hobby.

PS: I have a Weber probe, and several meters.

Just biased some new EL34 IIs not that long ago. Decided to go a little hot this time.

At2u1mY.jpg
Click to expand...
yes sir...i'd be interested in seeing the tutorial. i need to learn this stuff...there are no amp techs around here within 50 miles or more and they good one(s) stays booked for weeks/months...
 
As a tech, I can say that I rarely see amps come in for just a rebias, in fact, I can't remember the last one. I am going to ignore the "techs are dumb" in the poll.

I think its good for players to learn how to bias their amps. I will say its important to understand your wall voltage. Is it stable or does it vary a lot? I always put the line voltage that I set the bias at, which at my place is pretty stable at 123VAC. I usually target in the low 60s as far a bias, so there is room either way if the wall voltage the person is using the amp at is higher or lower.
 
MrDowntown said:
yes sir...i'd be interested in seeing the tutorial. i need to learn this stuff...there are no amp techs around here within 50 miles or more and they good one(s) stays booked for weeks/months...
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Here you go. Don't laugh. I was a complete noob when I wrote this but wanted it to be as detailed as possible for the next noob :LOL:

https://splawnfans.proboards.com/thread/7786/amp-biasing-tutorial
tl/dr

1.) Buy matched power tubes
2.) unscrew chassis from amp (not rubber feet)
3.) DO NOT touch the insides of the amp (potential shock)
3.) rest chassis upside down on something safe, or against the wall. KEEP SPEAKER CAB plugged in.
4.) install bias probe, then multimeter, then turn on. Read milliAmps. Never detach probe or MM while amp is on.
5.) Turn tiny brass screw (not white plastic one) to the
left counter-clock wise is colder
right clock wise is hotter

use one hand, preferably with a rubber glove, stick your other hand in your pocket, where tennis shoes, use rubber/plastic handled screwdriver.

Granted that is for a Splawn so #5 will vary
 
Can be scary. I mean you can die so there is that.

But 311splawndude taught me how and biasing an amp is super easy.

On the flip side I've heard some techs claim all these bias probes are junk, especially the amps with the bias probes on the back (not sure the name) and that if you want a true reading you want an actual oscilloscope which most players won't have. Sooo idk, flip the coin.

I have only done a few amps myself but I think from personal experience, the items you listed below like cab phase, pickup height, etc. And just simply learning how to dialing an amp and having decent ears is a better thing to learn than biasing an amp.
 
Fordman65 said:
My intention of the post was to see how many folks self bias their amps, but also to point out the many "little" things that have an impact on tone. So many flippers of guitars and amps and I wonder how many people put time into the little things or do they just attribute bad tone to a particular amp or guitar.

I recently asked about new pickups and one of the responses was, "maybe your guitar is just dead." While that can certainly happen, with today's manufacturing techniques and very high attention to quality, especially in Uber high level guitars, that seems unlikely to me. The response just got me thinking about all this.
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One thing I learned over time was, if a guitar sounds ‘dead’ or doesn’t resonate well, before returning it you can try some cheap upgrades to help it. Different Trem Block, better pups, blocking the Trem etc. I had a great playing 88 Jackson but it just didn’t sound good. Put a Brass block in, better pups and it was much better.
 
I picked up a Rivera K-tre with power tubes that started to fail about 4 years ago. Not much selection for amp techs in my neck of the woods so I bought a weber bias rite tool and watched a few youtube vids and figured it out. So far so good. I will say do not fuck around and touch the insides of the amp like I did the first time I opened my Ktre... I was just cleaning some obvious dust and ZAP! After that I learned of the dangers of fucking around inside a tube amp lol.
 
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