Lonestar bias mod

[splatter]

I just did the bias mod on my out-of-warranty LSC and after an easy installation measured my plate voltage with a bias rite at 466 Volts. The OEM bias setting had been set to 36 mA giving me a plate dissipation of only 16 watts. I had to turn the bias adjustment several times to get the bias up to 43 mA. As Splatter reported, the difference was striking, it was like a new , better sounding amp in both channels, and I just couldn't believe the improvement in tone. I haven't really put it through it's paces but the overall feel and tone of the amp are just amazing.

Thanks, Splatter!

No need to thank me I'm just a hack that stumbled across a good idea the guys at mansell guitars had . ( no I don't work there ) .
The difference is amazing though isn't it . Glad you like it Pine
Oh btw I went backand looked at what I had written down for my plate voltage and I belive it was 467

 

[djw]

Yep, I think I'm going to have to get me one of these... believe it or not, I've been debating the warranty question since I've still got a couple of years left on mine. So maybe I'll just order the trimpot and hang onto it until the warranty expires or I succumb to mod madness.

 

[Charles Reeder]

This is great!

I fully intend to install one (or 2) of these as soon as I can take the time. As Ive mentioned in my postings...I really am technically ignorant...but I do know how to read and set the bias on amps...and I can certainly do the required work for the 'bias-kit' installation.

However: I must state that I don't totally discount Mesa's decision to take their fixed bias stance...(there really is some logic and merit to it besides just making a profit selling tubes). For those who are new to tube amplifiers and fooling around with them...it is best to follow Mesa'a advise until such time as you fully comprehend what we're all talking about here. Play it safe for the time being. Read and ask questions.

But for those of us who wish more control over our amp's performance parameters...and have taken the steps to educate ourselves on this matter...it's the most obvious and logical next step.

I will now (upon installation of the kit) feel empowered to try out some of the more expensive tubes that I avoided before. I avoided them...knowing that if they didn't happen to fall within the range of Mesa's fixed-bias settings...I would be stuck with some really nice and really useless tubes! Now, I know I can at least try them out...even if I end up not being 'blown-away' by them.

All that said...it is still useful to keep a 'log' of the various ratings and 'color codes' of the various tube suppliers (including Mesa). Once you get the bias on your amp set for tubes with a particular letter, number or color coding...try and buy only tubes with that rating (whenever reasonably possible). That way if you need to make an emergency tube swap at a gig...the spares you bring with you will be quick and easy 'drop-in' replacements.

So, let's go for it! Viva Lonestar! Charles

 

[lostcause]

Just a bump to see if anyone else has done this bias mod yet and if so what were your opinions. Thanks

 

[shawnpurcell]

Hey There,

I just ordered the bias mod!

I have 2 questions:

1. How did you mount the little mod board on the outside of the chassis?

2. If I want to get 6L6 ma draw up from 18ma to about 38ma, for groove tubes power tubes for instance, would I want a higher or lower numbered tube?

Thanks so much!

Shawn
http://www.myspace.com/shawnpurcell

 

[pine]

Hey There,

I just ordered the bias mod!

I have 2 questions:

1. How did you mount the little mod board on the outside of the chassis?

2. If I want to get 6L6 ma draw up from 18ma to about 38ma, for groove tubes power tubes for instance, would I want a higher or lower numbered tube?

Thanks so much!

Shawn
http://www.myspace.com/shawnpurcell

I actually drilled a hole in the chassis floor and (after deburring the hole and triple wrapping the wires with heat shrink and electrical tape where they went through the hole) used the double sided mounting square the little mod board comes with to stick it on the bottom of the chassis. I'm not sure about the answer to your second question, I just adjusted the bias pot through several turns to get it up to around 42 ma, which was right for my plate voltage.

 

[splatter]

Hey There,

I just ordered the bias mod!

I have 2 questions:

1. How did you mount the little mod board on the outside of the chassis?

2. If I want to get 6L6 ma draw up from 18ma to about 38ma, for groove tubes power tubes for instance, would I want a higher or lower numbered tube?

Thanks so much!

Shawn
http://www.myspace.com/shawnpurcell

the board had double stick tape on it so thats no problem.
as far as groove tubes go the # on them has nothing to do with how you bias them . The # rating GT gives them is suppose to represent how soon the tube breaks up . The lower the # the quicker it breaks up .

 

[Charles Reeder]

I just orderted one of the bias mod kits. Will let everyone know my impressions after I receive and install it.
Cheers: Charles

 

[pine]

I just orderted one of the bias mod kits. Will let everyone know my impressions after I receive and install it.
Cheers: Charles

I think you're gonna love it Charles

 

[Charles Reeder]

Greetings:

I received my Lonestar bias-mod-kit a few days ago...but have not had the opportunity to install it yet. I can comment that it is very proffesionally assembled and small enough to allow plenty of location options. I have ordered a kit for my Stiletto and will probably be ordering a 2nd Lonestar bias-mod-kit soon... assuming of course that everything lives up to expectations.

If you will check out the photos which Splatter included I will explain how I intend to mount my bias-kit. You can see a gap in the rows of circuit board between the thin boards at bottom of photo and the large circuit board. I will drill a hole (approx. 1/4" diameter) through the chassis underneath where the 'ribbon' wire spans the two boards. It easily unclips...so no problem moving it for the drilling. Drilling there will put a hole dead center between the two inner pair of output tubes and approx 1-1/2 inches behind them. I will mount the bias kit from the inside with the potentometer screw facing down into the hole I drilled. I will attach face of potentimeter with adhesive to the chassis. The small square of circuit board will just fit into the gap between the 2 rows of circuit boards...slightly under the larger board.

Bias adjustments can be made from the exterior without removing the chassis...but the bias circuit will be protected by its' location within the chassis. It should work out well. Will post when results are in.

Charles

 

[djw]

Greetings:

I received my Lonestar bias-mod-kit a few days ago...but have not had the opportunity to install it yet. I can comment that it is very proffesionally assembled and small enough to allow plenty of location options. I have ordered a kit for my Stiletto and will probably be ordering a 2nd Lonestar bias-mod-kit soon... assuming of course that everything lives up to expectations.

If you will check out the photos which Splatter included I will explain how I intend to mount my bias-kit. You can see a gap in the rows of circuit board between the thin boards at bottom of photo and the large circuit board. I will drill a hole (approx. 1/4" diameter) through the chassis underneath where the 'ribbon' wire spans the two boards. It easily unclips...so no problem moving it for the drilling. Drilling there will put a hole dead center between the two inner pair of output tubes and approx 1-1/2 inches behind them. I will mount the bias kit from the inside with the potentometer screw facing down into the hole I drilled. I will attach face of potentimeter with adhesive to the chassis. The small square of circuit board will just fit into the gap between the 2 rows of circuit boards...slightly under the larger board.

Bias adjustments can be made from the exterior without removing the chassis...but the bias circuit will be protected by its' location within the chassis. It should work out well. Will post when results are in.

Charles

Awesome. Looking forward to it, Charles!

 

[pine]

Greetings:

I received my Lonestar bias-mod-kit a few days ago...but have not had the opportunity to install it yet. I can comment that it is very proffesionally assembled and small enough to allow plenty of location options. I have ordered a kit for my Stiletto and will probably be ordering a 2nd Lonestar bias-mod-kit soon... assuming of course that everything lives up to expectations.

If you will check out the photos which Splatter included I will explain how I intend to mount my bias-kit. You can see a gap in the rows of circuit board between the thin boards at bottom of photo and the large circuit board. I will drill a hole (approx. 1/4" diameter) through the chassis underneath where the 'ribbon' wire spans the two boards. It easily unclips...so no problem moving it for the drilling. Drilling there will put a hole dead center between the two inner pair of output tubes and approx 1-1/2 inches behind them. I will mount the bias kit from the inside with the potentometer screw facing down into the hole I drilled. I will attach face of potentimeter with adhesive to the chassis. The small square of circuit board will just fit into the gap between the 2 rows of circuit boards...slightly under the larger board.

Bias adjustments can be made from the exterior without removing the chassis...but the bias circuit will be protected by its' location within the chassis. It should work out well. Will post when results are in.

Charles

Only problems I can see with that is that when you are pushing up with a screwdriver through the hole to adjust the bias, you might push the board off its adhesive mount and it will be loose inside the chassis, it'd be a pain to take it all apart to remount it.

 

[mansfieldguitars]

You could also use some silicone or hot glue to mount it. I use hot glue all the time with mods done on perf board with great results. Thanks to all for purchasing my bias mods and bias probes. I'm always here to help with any problems or questions. I have been real busy and have not had the time to post on here often so the best way to reach me would be by email. Thanks again!!!

John

 

[splatter]

just bought a lsc head over at tgp . Got it yesterday and my mod kit should be here Tuesday I hope .Now I will have one for church and one for the studio . I also need some c90 speakers to go with it .

 

[Charles Reeder]

Hey! About time huh!

Received both 1-LSC and 1-Stiletto kit. Can confirm I will be getting another LSC kit.

(1.) Why do any of us really NEED a kit? Well, according to most amp manufacturers; they recommend a bias setting of at or about 35mv per 6L6 tube. If you'll read a Fender HRD manual they say go for 70mv (BUT) that's because the biasing measurement method they describe gives the combined reading of both tubes simultaneously. Therefore 70mv divided by 2 tubes equals 35mv. My Fender Pro-Serieies concert (50-watts and 2-6L6 tubes) also recommends 35mv per6L6.
All this said....keep in mind ALL manufacturers are going to advise CONSERVATIVE measurements.

So somewhat 'hotter' may reasonably be assumed to be not only safe but sonically more appeallimg! Splatter went for about 42mv per tube if I recall. Reasonable. I tried it and am using it.

(2.) Here's the problem. I tried Mesa 6L6's in several colors. Only the Yellows and Greys got me within the ballpark of being adequately warm. Various batches of Yellow in my 2 LSC amps got me anywhere from 33mv to 37mv. (The fairly normal manufacturer recommended range) Greys were 28mv to 32mv. Reds and greens in the low to mid 20mv range. COLD!

(3.) I like using hotter tubes in the outer pair position...so now I bias a pair of Yellows at 42-43mv in the outer slots and a pair of greys in the inner slots. They automatically fall below the Yellows but still in the warm range.

The mv's fall when you switch from 50-watts to 100-watts. The outer Yellows at 42mv will drop to about 40mv. Switching to Tweed power will drop it some too...but the setting is high enough now to retain warmth on the Tweed setting.

All through this article I've mentioned the various Mesa Color-Codes. You are NOT constrained to use those tubes or those codes. I merely used them to illustrate what results were obtainable with those particular tubes in both the fixed bias stock configuration and with the installed adjustable bias.

It all comes down to this. (1.) All tubes are now usable and can be brought into the correct range. (2.) A superb amp with some oddities and personal adjustment limitations has been made nearly perfect.
Highly recommended device.

Now about the device itself. It is very neatly crafted so as to be almost foolproof. It is small enough for ease of mountiong. Using Splatter's drawing the location is easily found.
Mansfield recommends using as little wire length as possible. I figured this was because of possibly introducing a 'line-loop' causing hum. I installed the device with all the wire still on it planning to experiment with location. I didn't get any hum; but oddly the amp sounded flat even after biasing to 42mv. I don't know the cause of this; but once I picked a location and cut the wires to just several inches; this problem disapeared. So keep the wires short.

The adjustment screw is very small and at first thought; I figured I'd like it bigger...but...after consideration; I believe small is better. How many times have I caught people turning anything they could find to turn on my amp? The small size will also prevent you inadverdantly knocking it out of adjustment by a casual brush of the hand while doing another task.

The LSC Bias-Kit makes a great amp better.
In the case of the Mesa Stiletto....I would go so far as to say it is an ABSOLUTE MUST HAVE for this amp! They don't listen much over there but I'm going to post them some results next week anyway. They can listen (or not)!

Thanks Splatter! Thanks Mansfield Guitars!!

 

[djw]

Ordered mine just now. Can't wait. Thanks for sharing your findings everyone!

 

[splatter]

Charles,can you post some clips of the stilettos dirty channel
after the mod ?I've always been curious as to what the stiletto
would sound like if it were biased hotter

 

[Charles Reeder]

Alas Splatter! Ican't post any clips of a bias kit in a Stiletto (or a Lonestar for that matter). I don't have the equipment or the know-how. I just started using a computer several years ago due to a very generous (and insistant) gift from my son.
I will say this about clips in general, though. I would NEVER make a buying decision based upon one. There are simply way too many variables at play for me to feel I've received a true and reliable impression from one.

About the Bias-Kit and the Stiletto. With the Lonestar I could get some tubes from Mesa that would take me up into the 33 to 37mv territory....not hot....but good and warm...so the potential of the Lonestar could be grasped theoretically...and if you didn't want it super hot....some very real honest classic tones were available. The bias-kit expanded upon that versatility and made the LSC into a real jewel of an amp. The LSC does not achieve all of t's potential without the bias-kit...BUT it is still very usable.

The Stiletto is just an entirely different (for the better!) amp with the bias-kit installed! It can now be made to sound like that OTHER-WORLD-CLASS tube amp that begins with a capital 'M'!
The hottest Mesa tubes I had come acrosss (hotter ones may be available and I just missed them) biased in the fixed bias Stiletto Deuce of mine at about 28mv. COLD. After installing the bias-kit and adjusting into the 36-37mv range; I got that solid 'thrumming' midrange these amps (Ma...... amps) are known for with a rich upper frequency haze of complex tube harmonics. The bass remained tight, the midrange sang and the highs wailed (without being brittle, harsh or delivered by ice-picks. The horrible out of balance highs and lack of bass I have read about with the Stiletto Ace, the DEUCES AND TRIDENTS (vesions 1 and 2) was not there. It sounded'like it 'orta' sound!
Tried amp with bias set all the way up to 42mv. Mids became too 'mushy' for me and the bass began losing definition....but the highs continued to blend in nicely. This setting is definitely NOT for me...but it is a viable and useful setting which some folks may find udeful for certain material. BTW, with the bias set to 42mv the amp can be set 'down' to 'tweed' and some useful sounds are available there as well.

This is the extent of the testing I've been able to do with the Stiletto as I just had 'Rotator-Cuff Surgery on my left shoulder. My concentration comes and goes (as does the pain) and my playing isn't succinct enough to draw any major, permanent conclusions at this time.

I would say that it's the VERY-RARE INDIVIDUAL who wouldn't benefit from having the bias-kit installed in their Lonestar Classic.

I would say that ANYONE who owns (or even occasionally borrows) any of the Stiletto Series of amps....MUST get this kit-installed....ASAP!

Cheers: Charles

 

[Charles Reeder]

Alas Splatter! Ican't post any clips of a bias kit in a Stiletto (or a Lonestar for that matter). I don't have the equipment or the know-how. I just started using a computer several years ago due to a very generous (and insistant) gift from my son.
I will say this about clips in general, though. I would NEVER make a buying decision based upon one. There are simply way too many variables at play for me to feel I've received a true and reliable impression from one.

About the Bias-Kit and the Stiletto. With the Lonestar I could get some tubes from Mesa that would take me up into the 33 to 37mv territory....not hot....but good and warm...so the potential of the Lonestar could be grasped theoretically...and if you didn't want it super hot....some very real honest classic tones were available. The bias-kit expanded upon that versatility and made the LSC into a real jewel of an amp. The LSC does not achieve all of t's potential without the bias-kit...BUT it is still very usable.

The Stiletto is just an entirely different (for the better!) amp with the bias-kit installed! It can now be made to sound like that OTHER-WORLD-CLASS tube amp that begins with a capital 'M'!
The hottest Mesa tubes I had come acrosss (hotter ones may be available and I just missed them) biased in the fixed bias Stiletto Deuce of mine at about 28mv. COLD. After installing the bias-kit and adjusting into the 36-37mv range; I got that solid 'thrumming' midrange these amps (Ma...... amps) are known for with a rich upper frequency haze of complex tube harmonics. The bass remained tight, the midrange sang and the highs wailed (without being brittle, harsh or delivered by ice-picks. The horrible out of balance highs and lack of bass I have read about with the Stiletto Ace, the DEUCES AND TRIDENTS (vesions 1 and 2) was not there. It sounded'like it 'orta' sound!
Tried amp with bias set all the way up to 42mv. Mids became too 'mushy' for me and the bass began losing definition....but the highs continued to blend in nicely. This setting is definitely NOT for me...but it is a viable and useful setting which some folks may find udeful for certain material. BTW, with the bias set to 42mv the amp can be set 'down' to 'tweed' and some useful sounds are available there as well.

This is the extent of the testing I've been able to do with the Stiletto as I just had 'Rotator-Cuff Surgery on my left shoulder. My concentration comes and goes (as does the pain) and my playing isn't succinct enough to draw any major, permanent conclusions at this time.

I would say that it's the VERY-RARE INDIVIDUAL who wouldn't benefit from having the bias-kit installed in their Lonestar Classic.

I would say that ANYONE who owns (or even occasionally borrows) any of the Stiletto Series of amps....MUST get this kit-installed....ASAP!

Cheers: Charles

 

[Trev57]

I have been somewhat (alright -- Completely) dissatisfied with the sound of my Stilleto Deuce since buying it over a year ago. I have owned it along side my Marshall, Roadster and Soldano amps. I recently had a sell off to reduce my inventory of music gear, and was again dissapointed because the Soldano and Roadster got snapped up, but nobody would touch the Stiletto. So when I read this post (and switched over to the Lonestar page to read that too) I wondered if this might be the answer for my beautifully engineered and built pile of useless sounding crap that litters my studio floor. I have contacted mansfield to see if they will post a kit to the UK, but I also wondered if similar results can be obtained by simply swapping tube colours? I have always played through tube amps, but am not even slightly knowledgeable when it comes to electronics. So all the technical talk about tubes generally goe straight over my head.