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BiasPro Feedback 1
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BiasPro Feedback 3

Hi Ken - Your Bias Pro products arrived very quickly and were easy to use. Instructions were clear, and I was able to bias my amps very quickly and interactively so as to get the sound I wanted out of them within the recommended safe bias ranges. With three amps to keep tuned up the Bias Pro should pay for itself very quickly.  No more trips to the tech with a few weeks wait when its time for new power tubes. I am completely satisfied.  Best wishes, josh
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With the limited space for feedback, I can't begin to express the value and pleasure of using the Bias Probe. I had recently acquired a 60 watt Crate Blue Voodoo. I knew from past experience that there are a lot of people writing bad reviews about equipment when they have no idea what they are talking about. Anyone criticizing a Blue VooDoo certainly is among those folks. In the condition this amp was in, it was easy to understand why someone would criticize it, but it was not the amps fault. With a little research and the acquisition of your tester I was able to easily and quickly determine that some Marty Friedman wanna-be had cranked the tubes up WAY to hot and the amp sounded like poop. With the voltage down to an acceptable range (as it was intended to be) this amp is second to none I've ever played (I'm 56 years old and have been playing about 45 years). It was a BLAST tweeking the amp myself and saved me a fortune. THANKS for a GREAT, affordable tool.  - dan62jb
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Hi Ken. Ordered the BiasPro recently for delivery to Australia. I must say the quality of your product is outstanding, a very robust looking meter. I had the opportunity to use it today on a re-tube of a Fender Hot Rod Deville. Works as advertised, easy to setup and use. I have mentioned the meter in a music forum here in Australia, so hopefully you gain more business from here in Australia. Best of luck, Ray.
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Hi Ken, I am very happy with the purchase of your BiasPro product. It came with very detailed instruction and useful information. The information is very easy to understand for 1st time user like myself. Keep up the good work!  Andro
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"I have been playing guitar seriously for a long time and have always used tube amps.
Being one of those guys that likes to experiment with different tubes, I was
attracted to products that would allow me to Bias my amps safely and quickly on my own.
I tried several similar products from other manufacturers but
was not pleased until The BiasPro. It is not only a well build unit in comparison, but
it was simple to use and provided the consistent accuracy I was trying to obtain.
If your searching the net for a Bias  Measuring Tool, look no further...This is the one!"  Tony Profera - Guitarist
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Hi Ken,  I received the BiasPro Tester Tool today - an excellent piece of kit, and it's been a pleasure dealing with you.  Within 5 minutes I found the probable cause for my 3 month old DRRI blowing power tubes after return from a manufacturer warranty repair (6V6s biased at 49ma) -10 minutes later I had the replacement tubes correctly biased and DRRI sounding as sweet as it should.  Many thanks for producing a quality tool and for being a straight-dealing guy (instantly refunding my over-paid shipping).  All the best,  Mark
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Got your package today,6/8.Thanks for the fast shipping.The tester is great!I had my Deluxe Reverb biased and ready within 10 minutes.I left positive feedback,thanks for doing the same.Thanks again for a great transaction.  Judy - judy8663
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Hi Ken,  The new quad stage bias pro is just great!  It’s such a good feeling to have a bit more control over what’s going on with my amps.  First thing I did was to find out the plate voltage on my old Fender Deluxe Reverb (AB763 circuit) and then figure out a bias range for a pair of NOS 6V6 tubes I’ve been wanting to try out.  I also found out the “matched” pair of Electro Harmonix that were in there were actually pretty far apart and were also running really hot...guess the bias must have drifted since I got it back from the tech almost two years ago.  Best of all is how simple and easy it was.  The whole process took only 10 minutes (and that included reading the instructions for the first time).  Wish I had done this a long ago, many thanks!  George
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Ken  Just wanted to let you know the Quad Bias worked great. I have a new Line6 DT 50 amp head that had cheap chinese tubes in it. I replaced with TungSol Russian EL34's.For reference the amp is spec"d for a 35mv bias. But you also need to have the head in Class A/B mode when biasing. Thanks again  Bart Puglise
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Howdy, Just letting you know I am AKA The Blues Bondsman on the Fender community page and I just promoted your item to my friends there also.  I posted your e-mail so they could find you.  Check out the forum and see modern amps section, my post about my twin reverb matched tubes
Later, Chris
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Received my Biaspro test probe today.  Excellent product !!!, super easy instructions and made my amp all it was suppose to be.  Thanks for a great, safe time saving hassle free way to check and adjust the bias of a tube amp.  Chris
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Ken,  I’ve had a chance to use your products and I couldn’t be happier. Quality at a great price, heads above what else is out there in this market. If I didn’t already own a Fluke 83-III, I would have bought your metered version. With the additional probes I’ve purchased I’m good to go. The Tube Dr. is ready for house calls! Thanks again and I hope to do business with you again. As I said, Top Notch gear and Top-Notch service right here in the good ole’ U.S.of A.!!! A breath of fresh air. I’ll pass the word along. Warm Harmonics,  David Kelly Duncan   *** A happy customer! 
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Ken, I received your product approximately 2 days after ordering it, LIGHTING fast shipping, packed securely with care.

I purchased the Quadstage MQ10 with octals. I have some previous biasing experience using a single adapter and a digital multimeter and decided it was time to purchase a tool that would make the job quicker and easier. I am not a professional repairman. I am a gigging musician who services his own amps and several of my friends.'

I wanted to find a unit that was quality made and I wanted it soon. I searched online and debated which product to buy from a certain auction site. There were several units made overseas and the delivery time was up to a month. I did some more searching and found your site.

I can honestly say your product and service is unparalled. I am was very glad to find a product that would do exactly what I needed for a reasonable price and is made in the USA. I am very glad to support the independent businessman.

The MQ10 is extremely easy to use and does the basic function it was designed - simply put it gives accurate readings between individual tubes or pairs or quads with the turn of a knob and an easy to read display.

For beginners, all the confusion has been eliminated and for experienced repairmen this tool will save you time and money in the long run.

Thank you again Ken. Glad a few minutes of internet searching led me to your product. I am EXTREMELY pleased.
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Ken, PV8CS adapter arrived on Saturday.  Worked like a charm!  I used it on my on my hand-wired Marshall 100 watt amp, Fender '57 Twin and '69 Deluxe Reverb.  Thanks again for all the correspondence, detailed instructions and super fast shipment.  Drew
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Hi Ken,  I purchased a QuadStage Q10 a few weeks ago and finally got around to use it to check the bias of the new tubes installed on my son Marshall JCM 800.  The unit itself is nicely built and serves its purpose well.  I'm neither a musician nor Amplifier tech, but like to tinker with stuff.  Your instructions were clear enough to be followed by an amateur like myself.  Thanks.
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BiasPro Amp Tester is an extremely finely constructed and accurate bias adjustment tool that should be in every tube enthusiast collection. It makes setting the tube bias extremely simple, even for the novice. Ken is without question the finest craftsman and seller here on Ebay. Buy with confidence from Ken
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Hi there, I have now received the Bias Probe. It is a great item and working really well.

I had a general tube question I was hoping you could help me with. I had suspected my amp was biased too high (being secondhand). I measure the "matched" pair of 6L6 I've had in the amp for 2 years - one measured 44 the other 36! These tubes are clearly not matched - could they have done any damage to my amp?

Also is it possible for a tube to "lose" current reading (from 44 to 36) over that period? Or does it mean I've just had the equivalent matched pair of 40ma all this time as I do love the sound I'm getting from them.  Many thanks for your help,  Scott
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Hi Ken:  Received the BiasPro today, Thanks. It looks great and I will put it through its paces. I have used a friends before and was pleased with its performance, thus my purchase. I do a lot of amp repairs and this just makes things a little easier. I have thought many times about making one but you know it goes, I just never seem to be able to work on my projects. Thanks for doing it for me!  Greg B, The Radio Guy
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Hey Ken, This is one Awesome product.Very user friendly with a great set of Instructions.Very cool design,very durable.With the MQ10 I was able to Bias my own Tube amps.The Best thing about the MQ10 is that I was also able to Match my own tube with the turn of a knob.The MQ10 will save me Money and Time.So no more Tech visits for simple issues such as Biasing and Tubes.Which in the long run will save me 3 times what I paid for the MQ10.Your responce to my questions and order were Fast and Professional.I received the MQ10 in a very secure and well protected package.I would have No Problem ordering from you in the Future.Thanx Ken and I wish you the Best.  Ron Smith
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Hey Ken, Thanks again for shipping the Biaspro to me so fast. It is very refreshing to do business with someone who communicates with their customer so well. I will definately look forward in doing more business with you as well as refering other!  Thanks again, Sean
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Hi Ken, Just a quick note to let you know that I used the 9 pin bias probe and it worked perfectly!  Very nice job assembling the probe.
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Hi Ken thank you so much for the bias probe it sure made my experience so much easier. I never thought that the bias probe would make much of a difference ,but it did. I was biasing a b- 52 amp and tried b- 52s tech support method which is a very dangerous one for the amp and the person doing the work and set the bias to their specs and after hooking up the bias probe I got a reading that was about 10ma off. I do know one thing for a fact after biasing this amp which was 34ma it has never sounded so good ever.Thanks for such a great product and I will use it every time the need arises. Thanks again   Mike
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Hi!I used the bius tool first time today. Having not done this type of thing before,I read/followed the directions carfully.I had no problems whatever!The proceedure went fast and smooth,with excellent results.  Thank you. Ken Peterson
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Hey Ken,  I just got a chance to use my BiasPro today.  It works great.  I was able to use it to help debug why my recently-acquired amplifier's tubes were red-plating (The previous owner nicked a wire on the bias pot and didn't repair it- the last few strands must have broken when I was transporting it.).  After that I re-set the bias using the easy-to-understand instructions you provided.  I'm very happy with the quality of the build on the BiasPro and I'm sure I'll end up using it for a long time to come.  Thanks, Jeff
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Hi Ken, Many thanks for the fantastic service and after sales service. I understand valves but not electronics and I wanted to set the bias on my amps to get the very best sound out of them. I cannot believe how easy this process is with the Bias probe tool that Ken produces.The difference in sound when the bias is set correctly is amazing. A fantastic product that every valve enthusiast should own.  Best, John Fuller
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Hey Ken,  Just wanted to let you know that i recieved your Bias Meter QuadStage BiasPro!  This is a very nice Bias Meter!  I have been looking for a Bias Meter for sometime now, but the prices just were out of my spending limit, untill i accidently stumbled across your meter on Ebay. I have been biasing my amps using the shunt method, and if anyone knows using this method takes a great bit of time & patience. Not to mention its a a bit dangerous unless you know what you are doing.
 
I took the meter out of the box, great packing by the way and super fast shipping. Right out of the box i connected the probes to the amp then the tubes to the probes, powered my Super Reverb Reissue up and sure enough the Bias was a little too hot as i expected. So i set the Bias from 40ma down to 33ma. Everyone that owns a tube amp needs one of these little babies as it saves time, and money, and most of all its Safe & very easy!!  Now i will check the bias in my 71 Deluxe Reverb, my 66 Twin Reverb as well.
 
The directions that came with this meter is very helpful, especailly for those who want to do this their self. Also a great little tube bias chart you added in your directions!  This looks to last a very long time, as it is very sturdy for a bias meter at this great price!  I would recommend Your meter to anyone who needs a great meter to bias their own amp with & save a lot of money in the long run. This is a great product period!!!  Easy as 1 2 3!    Thanks so much, ~ James
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Hello Ken, I am so glad I purchased the QuadStage BiasPro MQ10 from you, it is a perfect biasing unit for those with little to no experience biasing an amp. As soon as I recieved the QuadStage BiasPro I was already biasing my 63 Fender Deluxe Amp, I find that my two nos Tung Sol 6v6gta power tubes are about 4.0 ma off from each other so I put in a pair of nos RCA 6v6gta and find they are less than 1.0ma apart. I am also able to set the bias a bit higher at 27.0ma, the previous setting seemed a bit low at 22.0, what a great biasing unit you have here, it has already paid for itself, later I will be biasing my Soldano Hot Rod 50 amp and my friends two Fender amps, I highly recommend that anyone interested in biasing their tube amp, definitely check out the QuadStage BiasPro MQ10, thanks again,  Mike.
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Ken, Hey there, I just wanted to share my experience with your BiasPro tool.
 
I've never biased a tube amp before today.  Before taking on this little job I did a lot of research and reading, as well as taking all necessary precautions, so I felt confident to go ahead with it on my own.  I looked at all the test probes I could find, and your BiasPro tool seemed to be the best combination of functionality, workmanship, and price.
 
The BiasPro lived up to all my expectations – using it made my bias job a piece of cake!  The BiasPro is very well made and I'm sure it will serve me for many years to come.  I would absolutely recommend the BiasPro to any pro or hobbyist.  It is a must-have for anyone servicing tube amplifiers.   Thanks again, and best of luck to you!  Nate
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Hi Ken, I have left feedback and will send a more detailed report as and when I gain a bit more use. I repair amps as a hobby for a local Music shop so it will not be long.  Up until now I have been using my DVM but your Bias Tool will be a lot quicker.!  I might need another set of leads in the future to speed up the 'set up' on four valve output amps!  Best regards  Bob Smith.
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I recently received 2 BiasPro tube amp bias probe tester tools, one 8 pin and one 9 pin. After using these tools to measure the bias on several amps (EL84 and 6V6) that I own, I can say that I am completely satisfied with my purchase. The bias probe tools are hands down the easiest and safest way to measure the bias setting on power tubes. The BiasPro tools are well made and with a little care they should be good for many years of use. If you know where to shop, you can save a few dollars by buying the parts and make your own bias probe tool, but the price charged for the BiasPro tools is fair, considering the cost of parts, assembly time, and convenience. I give the BiasPro tools 2 thumbs up, and would not hesitate to recommend them to a friend.  - sleeveless
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Got my bias pro the other day and biased up a marshall and fender amp to test it.Worked like a charm.Very well constructed.Will obviously last for years and priced reasonably as well.Thanks a lot for making my life easier and my amps sound better..  Brett,Port Charlotte,Fl...
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Hi Ken, The tester works great. I think I need a second set of octal leads. I'm such a cheapskate only getting 2..I just end up having to switch sockets back and forth! If you could please send me an invoice for a pair of the octal leads I'd appreciate it. I'll certainly leave some positive feedback for your website though I don't know what more to say besides simple and works great...which I guess is pretty good! Thanks again.   Best Regards, Bill
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Greetings Ken, Just wanted to let you know how pleased I am with the BiasPro Q10 Quad I recently purchased from you.  The unit is very compact and lightweight, and works flawlessly when connected to my Fluke 87 DMM.  The slim profile of the tube sockets actually allowed me to measure the bias current without having to remove my Soldano SLO chasis from its headshell.  This saves me a tremendous amount of time, as I've always had to pull the SLO chasis when using a Weber Bias-Rite in the past.  I've actually decided to sell my Bias-Rite after purchasing the BiasPro Q10 Quad!  Thanks for making such a great product, and for the extremely fast delivery.  Matt Gentry  Katy, TX
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Hi Ken, I used the tester with my Fluke for the 7591's last week and it was excellent, very nice! I was able to test all my USA 7591's to achieve a quad that were all between 33 and 35 milli-volts in my vintage Fisher 500c. Now the receiver works beautifully.

After my restoration and tube matching, it really sounds better than ever. I listened to my music all weekend!  Thank you so much for your assistance and help; a great tester. I'm very happy and impressed. Thanks a million,  Chris
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Hi Ken,   Just letting you know that I finally got a chance to try out your Meter-ed Dual Config Quadstage Amp Tube Bias Probe Tool today. I love it! What an awesome product! Very User friendly, especially for someone like me who is not an electrician and who is very timid around hi voltage electrical equipment such as my amp. The Bias Probe  tool also helped me to find two tubes that tested excellent in my tube checker but Your Bias Probe tool found problems with bad current fluxuations.  Id like to thankyou as well for taking your time to answer all of my questions. Very sorry about the ordering mixup iam very new to EBay and PayPal.  Thanks again,   Chris
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Hi, I bought the Very Awsome QuadStage Bias Probe tool for Biasing Tube Amps. It is a great piece of gear Its constructed very well and seems to be a great tool.  I almost bought a bias tool that cost $145.00 and I'm happy to say I didnt.
 
I must say this is my first Ebay So I was very scared that I would not get the meter or it would not work or it would be junk, but the meter is just great. It has already saved me from the super high bias I had on my amp that would have blew the new tubes I had just put in.
 
Hands down this is a great tool and Ken does great work on these meters. You really cannot go wrong with this tool and I would tell anyone simply buy this Probe. Its a great piece of gear with a great price.  Thanks Ken, I will be buying more later.  Best Regards, LG
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Hi Ken,  I'm back home and have just used your tester to check and adjust the bias on my old Scott amp. I've got two pairs of closely matched tubes and the meter is confirming this which is nice as it allows you to confirm that they remain closely matched over time without needing to use a tube tester.   It seems to be working great and is a much better to check bias then using resistors and hoping you won't electrocute yourself! I'll be back in touch with you shortly to buy two more 9 pin cables.  Regards, Greg
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Hi Ken, The bias tester arrived today. Plugged it into the stereo amp as per the directions, warmed the amp up for 10 minutes and had the bias on the 4 tubes set in a minute flat. It was great! Nice stable reading instead of it jumping all over the place as you get your fingers singed trying to keep the multimeter probes in those crappy little contact holes behind the power tubes. I found that the bias on two tubes weren't  the same, which explained the hum I had on one channel and the bias on one channel was quite a bit different to the other channel?!? The unit worked perfectly and feels nice and solid. Thanks for a simple to use and very useful product.  Cheers, Vic (Melbourne, Australia)
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Just wanted you to know how grateful I am to you for making these up for me.  Using the (2) Bias Pros, I went through my collection of 6973s and successfully assembled two matched quads.  I then installed each quad and set the bias current to 18-20 Milli-amps as you suggested.  The results were great.  My (2) Knight KA-55 stereo amps never sounded better; much more power and much better fidelity.  I needed to increase the bias voltage to -27vdc;  -2 volts lower than the nominal -25 volts called for in the schematic.  I installed regulated, adjustable DC power supplies to replace the inadequate unregulated fixed bias supplies, which were only putting out -23 volts.  I suspect the tubes were biased much too high and were saturating at higher power levels.  Now I have far more CLEAN power out of these amps than I ever imagined was possible.  6973s sound great if they are biased correctly.  Sincerely, Mike Stamper Windsor, CT
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Hi Ken,   GREAT looking unit you have here, performs wonderfully!!  I have been using it daily!!   I have many amps, but the one I like to test tubes on is this little Bogen PH10 that is now converted to play a guitar thru...I need to run the guitar into a small transistor amp to up the line voltage but I get some great tones in this 6V6 amp.  I also play 5881's thru it, and watch the mA readings...having fun with all of this stuff.   I have been collecting tubes for the past three years just for my own amps, and for the ones that I want to build, and sell in the future.   The thing I like about this is that not only being accurate, I can leave it on and watch the voltage/milliamps swings during play, and that I have found that amps are not static, that a tube will show one thing, then after a while another, then lose a milliamp, gain a small percentage back, and since all of the components work in tandem, we need to realize that tube amps will fluctuate, and that is the same with tubes.    I will be using this for a long time.  Should I have any problems I will let you know but trust this is a very durable unit, as which are the leads.  Thanks for your prompt shipment.  good luck with your business..   john
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Hi Ken,   The Bias Pro arrived last week - sorry it took me until today to find time to test it. (I am a teacher, so it is an extremely busy time of year.)   Works great.  I left you very positive feedback, and 5 star answers to the questions.  Thanks for the positive feedback you left me.   Thank you for a very smooth, easy and pleasant transaction.  I appreciate those who make good-quality products, sell them at reasonable prices, and do so in a nice, considerate way.  It has been a pleasure doing business with you and I will be glad to recommend you and your bias probe to others.   All the best,   Don Denaburg
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Ken: I have to thank you for your products. They seem to be well thought out, nicely made and at a reasonable price. I have gone thru two different sets of your competitors bias probes. None of them last very long and one set even damaged several of my amplifiers before I figured out that it was shorted out internally. I wished I new about your products earlier, I certainly would have been a long time customer by now.  Next payday I will order two additional 8 pin probes.  Thanks again   Bill Page
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Greetings,   I wanted to let you know that I received the BiasPro today and I am VERY impressed. Positive feedback is on the way. Do you have a web site that would allow me to buy additional adapters for the 8 and 9 mini setups. Again thanks for the quick ship and the nice product. Now to chase down some info on the Twin Reverb RI  and the 6L6GE tubes.  Thanks again,   John    fendercats
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You got it! Thanks again - I used the Bias Pro today on 3 om my amps. Works great. Really revealing on just how "matched" some tubes sets are...  dougc
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Hi   Ken,   Just thought I'd let you know that the MQ10 Quad  worked wonderfully.   I read a few articles, and watched  -  and re-watched  -  a few 'YouTube' presentations of the Biasing procedures . .    Anyway,  your Metering System was simple to use ( once understood ! ), and, as I'd guessed'  a Twin Reverb that I'd purchased was, indeed,  all over the place in terms of the mA reading of the Power Tubes.  the MQ10 helped tremendously in making sure that the new replacements were operating within Fender specs  Again,  Thanks !  - Michael H.   /   Boulder CO
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 Just to let you know, I am a repeat customer. I bought the 8-Pin one from you earlier this year and it works great. - ceng
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I wanted to let you know how pleased I am with the BiasPro I just received.  I have a single octal tube amp (Fuchs Lucky 7) that I wanted to check the bias on but did not want to pay a tech to do the job.  This was my first time biasing and your instructions along with the BiasPro made it a breeze.  The BiasPro and my multimeter showed my amp was running hot at 62 mv instead of the factory recommended 50.  A few fine turns of the bias adjustment got it right in line.  The tool is solid and looks like it's going to hold up for many, many years of usage.   Thanks from a satisfied customer!  Steve Daily