# Tube + bias question (marketing or truth?)



## Budda (May 29, 2007)

Taken from a eurotubes thingymabob:

_"You can actually get the bias up where it should be with warmer grade's of tubes"_

found here: Very Interesting Read for EL34 Recto owners

Is this true? It sounds like marketing to me, but I'm not very technologically inclined.


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## Rugburn (Jan 14, 2009)

Only mis-matched output tubes could affect the bias. I can't see how a well matched pair of tubes could "actually get the bias up where it should be". Consider that for instance, where the bias "should be" is a point of contention in itself. Tubes can either handle more current than specified or they can't, rather than dictate the amount of current they see. 

Shawn.


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## Wild Bill (May 3, 2006)

Budda said:


> Taken from a eurotubes thingymabob:
> 
> _"You can actually get the bias up where it should be with warmer grade's of tubes"_
> 
> ...


Actually, they're telling the truth! Just not the WHOLE truth!

When they match tubes, what they actually do is put the tube in a tester where there is a specific bias voltage and then measure the idling plate current. This will give a number for the tube, like "35", meaning that in that tester with that bias voltage the tube was idling at 35 milliamps of current. This number is only true for that store's brand of tester. Another store using a different tester might give a different number. It doesn't really matter. The same number will ensure that tubes are matched to each other, so that one will not try to hog all the work while the other one loafs in the circuit. The overall idle current will be set by a tech doing some measuring and adjusting.

Once they start matching up tubes by the same number they can sell matched pairs or quads. Tubes with higher numbers are said to be "hotter", in that they run at a higher idle current for the same bias voltage. To most amps, the actual number doesn't matter. When the tubes are installed in the amp a tech is going to measure the idle current and adjust the bias control voltage in the amp to set the idle current to the "sweet spot". He knows the sweet spot by measuring the actual plate voltage and then calculating a simple formula for that type of output tube.

Mesas are different. There is no adjustable bias voltage. The Mesa designer fixed the voltage so that the tubes would always be running a very safe, low idle current. To protect against someone putting a much hotter pair of tubes in the amp that might run at an idle current too high for good tube life (like maybe minutes!) Mesa tells you to ALWAYS buy your tubes from Mesa, implying that they are better quality. That may or may not be true but it doesn't really matter. It's just Mesa's way of getting your replacement tube money and making sure you are always running cold tubes that aren't likely to burn out quickly.

This means that many players are unhappy. They would rather run their own tubes in the "sweet spot" for better tone. When you bias tubes "cold" like with Mesas you can get a thin, tinny sound with less output power. In any other amp it wouldn't be a problem. The tech would be adjusting the bias control voltage but as I said, with Mesas you can't.

So you have two choices. One is to get a tech to make the Mesa amp's bias voltage adjustable. Then you can use any tubes you want and have them biased for best tone. Or, if you tell your tube store you're buying for a Mesa, they can sell you tubes a bit hotter but still safe.

At least, tube stores that know what they're doing can do this! There are some that aren't that swift. All I can say is that I personally know that thetubestore.com Audio and vacuum tubes for your amplifier. knows what they are doing with this problem. I trust them completely and have no problems recommending them.

Me, I'm a tech. I like the idea of always having adjustable bias best. That way its not a case of "it SHOULD be OK!" but rather " I MEASURED things and I KNOW they're ok!"

That's my story and I'm sticking to it!


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## nonreverb (Sep 19, 2006)

Wild Bill said:


> Actually, they're telling the truth! Just not the WHOLE truth!
> 
> When they match tubes, what they actually do is put the tube in a tester where there is a specific bias voltage and then measure the idling plate current. This will give a number for the tube, like "35", meaning that in that tester with that bias voltage the tube was idling at 35 milliamps of current. This number is only true for that store's brand of tester. Another store using a different tester might give a different number. It doesn't really matter. The same number will ensure that tubes are matched to each other, so that one will not try to hog all the work while the other one loafs in the circuit. The overall idle current will be set by a tech doing some measuring and adjusting.
> 
> ...


Well, SOMEONE around here happens to be the Mesa Warranty service centre for my region and this SOMEONE knows that the power tubes they're using are Chinese. Since in a warranty situation you can't use anything but their tubes, you're basically obliged to use 'em. However once the warranty's expired, you can easily mod their amps to adjustable bias....


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## parkhead (Aug 14, 2009)

although I disagree with Mesa on almost everything else they do ... cough 

I actually agree with their pre set fixed bias and pre matched tubes concept 

since the end user can get repeatable results on the road without having to find a service tech 

Further 


1 -Any competant tech can bias the Mesa amp and set it up for an indvidual player by adjusting the bias 
or installing an adjuster 

2 -Any incompetant tech or non-tech cannot adjust the bias and mess up the amp 

Unfortuantely as little as 10 years ago most amp techs would bias an amp cold automatically to prevent warantee tube failures ...
Or bias the amp very cold using the scope and signal method commonly practiced in the 70's 

Over the years I've purchased plenty of bad sounding vintage amps cheap, found the bias set to the lowest current setting with a semi new set of tubes installed ... rebiased the amp to hotter current specs 
kept the same tubes and had a great sounding amp 

I'm not pointing fingers ... just pointing out that I often got amazing deals on very Bad sounding vintage amps that
consistently were cured by properly adjusting the bias after someone else had Improperly adjusted it
15 years ago there were very few amature, internet educated techs if any 

this issue was particularly bad with old Marshall amps which seem to have suffered the worst of the amature MOD, 
holes drilled anywhere, biased cold or bought and never ever serviced properly for years scenarios 

P


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## nonreverb (Sep 19, 2006)

parkhead said:


> although I disagree with Mesa on almost everything else they do ... cough
> 
> I actually agree with their pre set fixed bias and pre matched tubes concept
> 
> ...


Well, say what you like but poor quality tubes are...well... bad tubes. Once upon a time, Mesa offered a GE tube type in years past. They were excellent tubes. The problem is that their latest offering the STR430 is a Chinese tube which IMO is not a particularly reliable tube...regardless of who's doing the bias. Yes there are a few bad techs out there but I would think most who have been doing bias long enough know better than that!


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## parkhead (Aug 14, 2009)

with all due respect to the hardworking techs who post on this board ...

I stand by my post 

Exhibit A: please refer to the thread "please help me find a tech in edmonton...." 

I don't agree with most of Boogie marketing practices and cheap tube rebranding practices at all

I simply pointed out that "exhibit A" is far more common than those of us lucky enough to have located 

a competant tech might realize. 

I am not a tech but after several experiences just like the ones described in the edmonton thread decided to learn 

some stuff ... 20 years later I get calls from techs asking me questions about obscure vintage amps


to sum up: 

Given that finding a good tech in some areas is far more difficult in some regions than in others 

Given that Randall Smith may have a specific current setting he feels works best with his amps (right or worng) 

Given the odds that 1/2 of the competant techs out there might have a different biasing methodology than Randalls prefered method

Given that the marketing and tech support people taking the phone calls would prefer to answer 
"ok you are in yellowknife ... just order STRXYZ plug them in and play " 

I can see exactly why Randall Smith would make boogie bias fixed and non adjustable 

So to sum up 

Boogie had good resons for doing this 
Boogie used to sell awesome matched american tubes 
Boogie now sells chinese matched tubes 
Boogie can take your 1-800- call and tell you the amp is just plug and play 
Boogie gets a tube sale after the amp sale & thats considered good business 

I suspect that in the amp Buisness like the Motorcycle business the money is in the T-Shirt sales
not the amps & Motorcycles?

would you like fries with that sir ? 

How bout a matched set of manufacturers special tubes? 



P


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## Wild Bill (May 3, 2006)

parkhead said:


> with all due respect to the hardworking techs who post on this board ...
> 
> Exhibit A: please refer to the thread "please help me find a tech in edmonton...."
> 
> ...


Sadly, I have to agree with you whole heartedly, Pat!

I went full time professional with repairs and builds about 5 years ago. Immediately I was bowled over by how many "hatchet jobs" from other so-called techs were coming my way! I think some of them were actually done by the customer himself, he just didn't want to admit it. Others were coming from music stores!

The music stores I could understand. I researched that scene before I went pro. Most gave me the same story. They had to provide warranty service or they couldn't get the franchise to sell that particular brand. There's a factory warranty system in place and they simply put the repairs into it. However, once the warranty had expired, they just couldn't care less! As far as they were concerned, the customer was on his own! They preferred that he bought a new amp and who cares what he did with the old one. They were just not interested in working with someone like me on mods or after-warranty repairs.

Some of them had an employee who might have picked up a bit of knowledge and they'd let him do repairs. I haven't seen a good one of these yet! If he was any good, why would he keep working there at low wages? Usually it's a young fellow brimming with confidence and totally ignorant of what he DOESN'T know! That makes it extra hard for the customer. Most of us can smell a con job but when the guy talking to us BELIEVES his own BS it's harder to know the true story. The guy might be totally wrong but absolutely sincere.

The best example I can give is one from a couple of years back where a young fellow of maybe 15 years brought me a Marshall that he had taken to a music store for repair. "It still doesn't work!", he told me. "It's the same way as when I brought it to them!"

I opened up the amp and nearly barfed! It looked like whoever worked on it didn't even have a real soldering iron but had just heated up a nail on the stove! It was just a mess. I cleaned up the screwups, found the real problem and fixed it.

I had a soft spot for the kid. I still remember being his age, not having much money and dreaming of lots of things like my first real guitar amp! I had put a lot of time into the amp and a new set of output tubes but I scaled down the labour and charged him only $150.

When the lad showed up to pick up his amp the first thing I noticed was that his dad had driven him in a car worth at least $60k! He was very happy to get his amp back and told me "That's fabulous that you're only charging me $150. The store had charged me $300 and they never fixed it!

The first thought that went through my head was "You paid them?!" The second was " They got twice as much as me to screw it all up?! What's wrong with this picture?!"

If I'm backed up sometimes I'll give a referral but I'm really careful of who I give. If I send the customer to a turkey it will make BOTH of us look bad! There just aren't that many good techs around and most of them are in the bigger population centres. If you live in a small town it can indeed be hard to get some competent help.

Except of course when I DELIBERATELY send some PR of a rude customer to a local turkey! I've told that story before. I figure mean people deserve it! I've been blessed with almost 100% great customers who I treasure dearly. They've been good to me and I owe it to them to return the effort. Why should I be slowed down in servicing the good people by trying to make someone uncivilized and overly demanding happy?


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## Rugburn (Jan 14, 2009)

I have to say Bill, between your very helpful and cautious posts, to the great things so many folks I've talked to have to say about dealing with you and your work; you're kind of a rarity in my experience. If I had a dollar for everytime I heard a story where the tech/store had the amp *FOREVER* and it came back so-so or the same, I'd pack up my little Champ clone and all my Loonies and bring 'em to you.

Shawn.


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## parkhead (Aug 14, 2009)

I had a few similar horrid experiences with vintage amps in the early days of trying to find what I needed 
(back when they were just "used amps" I might add)
and I too have seen the "work" the best example being a marshall MOD "artist" who uses OLD Guitar strings as grounding buss wire in his mods 
(yes this is real ..... ) Oh and his marshalls never sound good go figure, but they do get extra holes and switches !!!

One of the key problems is that there is very little money in amp service, those who are good and don't move on to greener pastures are truly dedicated individuals ... who have taken their Music Industry Vow of poverty 

Over time I turned the frustration to my advantage 

first learing to fix simple stuff myself, next learning to use my eye at swap meets to score vintage parts 
from tv repairmen and such 

next I was willingly to buy problem amps from people (often at a great price) confident that I could fix it myself 

or find the right person to do the job ...

I strongly feel that a player wanting control over his or her signature sound owes it to themselves to establish a relationship with a great tech or learn basic technical service & maintenance themselves 


and about boogie tubes... I think we are all on the same page 

P


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## nonreverb (Sep 19, 2006)

parkhead said:


> I had a few similar horrid experiences with vintage amps in the early days of trying to find what I needed
> (back when they were just "used amps" I might add)
> and I too have seen the "work" the best example being a marshall MOD "artist" who uses OLD Guitar strings as grounding buss wire in his mods
> (yes this is real ..... ) Oh and his marshalls never sound good go figure, but they do get extra holes and switches !!!
> ...


Well, the used amp market is definitely a mine field to the uninitiated and the old saying of caveat emptor definitely applies. I dunno, maybe I'm looking through rose coloured glasses. Apart from one guy, all the techs I know are pretty decent fellas here in Ottawa. Most of the abominations I see are due to home tinkerers who get out of control and screw up repairs, mods etc. or their friends who profess to be tech geniuses and get over their heads. It's funny, where Hammond organs are concerned, I've dubbed myself the hole at the bottom of the sink as I inevitably get the call or see every Hammond service job or problem in Ottawa. Parkhead, you made your case regarding do it yourself. I was an ex hi tech guy and somehow got into Hammonds. The only reason that I'm somekind of go-to guy now is that I spent years reasearching them and yes, trial and error. Fortunately the error was mostly on donor organs that I could make mistakes on.
I would hope that young guys with keen interest will be able to get into this field after my generation is done. Unfortunately, that will require a few to do horrendous jobs at first that guys like Bill and I and others here will have to contend with....but hey! Look on the bright side....at least it keeps us in biz. 
P.S I don't find Mesa that bad an amp although they're pricey...I get way more JCM 2000's on the bench.


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## parkhead (Aug 14, 2009)

Things are better now than they were, but the Guitar string thing is REAL 

There are quite a few good techs in the GTA now and a better circulation of knowledge 

Regarding Boogie, fine amplifiers, agressive marketing I have no real axe to grind. 

P


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## Wild Bill (May 3, 2006)

parkhead said:


> Things are better now than they were, but the Guitar string thing is REAL
> 
> There are quite a few good techs in the GTA now and a better circulation of knowledge
> 
> ...


I do! I have a problem with respect for Randall Smith! Mesa has been patenting circuits that have been around for decades as if they were new! The US patent office seems to think that it's easier to just grant the patent, expecting that the market will fight it out in court. This saves the government the money of doing searches, especially with older technology that not a lot of people understand any more.

So some boutique maker gets a letter from Mesa's lawyers saying "You're copying one of our patents! Cease and desist or we will sue your ass off!"

The poor little guy is perfectly within his rights. The circuit long ago became public domain. However, he doesn't have the money to compete with Mesa's lawyers in court! So even though he's in the right, he has no choice but to cave.

This is simply bullying! To make matters worse, ever compare the "crunch channel" from a SLO-100 Soldano with a Dual Rectifier? If Mike Soldano had have had more money, he could have sued THEIR ass off! This seems hypocritical, big time.

JMHO.


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## nonreverb (Sep 19, 2006)

Wild Bill said:


> I do! I have a problem with respect for Randall Smith! Mesa has been patenting circuits that have been around for decades as if they were new! The US patent office seems to think that it's easier to just grant the patent, expecting that the market will fight it out in court. This saves the government the money of doing searches, especially with older technology that not a lot of people understand any more.
> 
> So some boutique maker gets a letter from Mesa's lawyers saying "You're copying one of our patents! Cease and desist or we will sue your ass off!"
> 
> ...


A sneaky as it is, the real fault lies with the patent office not doing their due diligence. I'm sure there are many other examples of this with other products.


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## parkhead (Aug 14, 2009)

hah ahhaha hah hahh 

lets not worry about the patent office and the electronics guys 

If you want to talk about poor oversight, bordering on criminal negligence lets talk about the SEC 

by now none of you should be wondering how the SYSTEM works 



p


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## Wild Bill (May 3, 2006)

parkhead said:


> hah ahhaha hah hahh
> 
> lets not worry about the patent office and the electronics guys
> 
> ...


Hey, I respect the SEC about as much as I respect Randall Smith!

I accept it's an imperfect world but that doesn't mean I have to accept those I don't respect just because they have a lot of company. You do what you have to so you can get along but nobody's forcing us to accept a skunk at a picnic.


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## nonreverb (Sep 19, 2006)

money + human nature =.........


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## bluesician (Mar 14, 2007)

deleted


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## Wild Bill (May 3, 2006)

bluesician said:


> As a Boogie Mark 1 Reissue owner, I appreciate the convenience of buying a matched set of Mesa tubes without needing to adjust the bias.
> 
> As far as price is concerned, The Tube Store sells a pair of matched SED 6L6's for $60.00 American. The Guitar Shop (which sold me my Boogie) will sell a matched set of 6L6's for $40.00 Canadian.


Ah, but the Boogie tubes are NOT SEDs!

Boogie does not and never has made their own tubes. They buy the cheapest Russian or Chinese and then match and brand them themselves. They are not total junk, of course. If they get too many failures Boogie will turn to another manufacturer. Still, they are NOT SEDs and it makes no sense to compare prices of apples to oranges.


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## nonreverb (Sep 19, 2006)

An interesting fact Bill, Mesa does sell Mesa branded higher quality tubes.....too bad they're an upgrade and not standard


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## bluesician (Mar 14, 2007)

deleted


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