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Mesa Strategy and Prodigy discontinued. Also PH cabs.

#482
Lance Bunyon said:
So the JJ mod I had done to the 400+ is valid now with new Mesa tubes?
Click to expand...

Depends...what did the mod entail?

Mesa tubes are graded to work at a certain bias voltage in your amp. It doesn't matter which company made the tubes, only how the tubes are graded. As a result, the bias in the 400+ was originally set to a certain voltage and was not adjustable.

Often when techs install tubes from another vendor in a Mesa amp, it's not possible to get tubes that are graded exactly the same way Mesa does. One solution is to install a variable potentiometer so the bias becomes adjustable. Another solution is to change the bias scaling resistor to another fixed value that produces a bias voltage that works with the new tubes.

Usually vendors match tubes on two parameters, plate current and transconductance. Unfortunately ratings don't translate from one vendor to the next because test equipment and practices are not standardized. The claim is as long as you use tubes from the same vendor, with the same plate current and transconductance ratings, then you don't need to reset the bias.

The problem is each amp design uses different operating voltages and (in my experience) many tubes don't maintain good matching over a wide range of operating voltages. For best results you would want the tubes matched at the exact operating voltages that are used in your amp. I believe TC Tubes offers this in their matching service, but many tube vendors do not use test equipment capable of reproducing the high voltages used in most high power bass amps.

You may note that Mesa tubes are quite expensive. Perhaps part of the reason is their extensive testing and matching process involves selecting those relatively few tubes that do maintain tight matching over a wide range of operating voltages...but that is just a guess on my part.

My personal opinion is it is always best to check the quiescent current passing through the tubes and adjust the bias as necessary when you install a new set of tubes. YMMV.
 
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#483
Wasnex said:
Depends...what did the mod entail?

Mesa tubes are graded to work at a certain bias voltage in your amp. It doesn't matter which company made the tubes, only how the tubes are graded. As a result, the bias in the 400+ was originally set to a certain voltage and was not adjustable.

Often when techs install tubes from another vendor in a Mesa amp, it's not possible to get tubes that are graded exactly the same way Mesa does. One solution is to install a variable potentiometer so the bias becomes adjustable. Another solution is to change the bias scaling resistor to another fixed value that produces a bias voltage that works with the new tubes.

Usually vendors match tubes on two parameters, plate current and transconductance. Unfortunately ratings don't translate from one vendor to the next because test equipment and practices are not standardized. The claim is as long as you use tubes from the same vendor, with the same plate current and transconductance ratings, then you don't need to reset the bias.

The problem is each amp design uses different operating voltages and (in my experience) many tubes don't maintain good matching over a wide range of operating voltages. For best results you would want the tubes matched at the exact operating voltages that are used in your amp. I believe TC Tubes offers this in their matching service, but many tube vendors do need use test equipment capable of reproducing the high voltages used in most high power bass amps.

You may note that Mesa tubes are quite expensive. Perhaps part of the reason is their extensive testing and matching process involves selecting those relatively few tubes that do maintain tight matching over a wide range of operating voltages...but that is just a guess on my part.

My personal opinion is it is always best to check the quiescent current passing through the tubes and adjust the bias as necessary when you install a new set of tubes. YMMV.
Click to expand...
Tech did the resistor hack. Wish I never had it done!
 
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#486
I say again and again that often leaving well enough alone is the best track to take. I see the results of well intentioned mods regularly and rarely do they end up being beneficial. More often they cause problems that weren't there before.
 
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#487
strategy owner w 8x10 traditional here ... love it ... as far as the kt88s go is there a danger of these tubes going out of production??? (I'm new to the tube world) if so should I stock up? another random ? any idea how many strategy were produced
 
#488
Played another casino combo Fri & Sat nights this past weekend. Strategy and one 212 was sounding especially sweet, the guitarist and the FOH guy couldn't stop complimenting.

47396623_10218300210883458_3664840991757565952_n.jpg?_nc_cat=109&_nc_ht=scontent-sea1-1.jpg
 
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#489
agedhorse said:
I say again and again that often leaving well enough alone is the best track to take. I see the results of well intentioned mods regularly and rarely do they end up being beneficial. More often they cause problems that weren't there before.
Click to expand...
Like my motorcycle mechanic said about modding bikes: If you think you are better than the bunch of engineers at Honda (or whatever) Good luck boy!:smug:
 
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#491
I put today a 12AU7 in V1 and a 12AT7 in V2 to clean more and try to get more headroom in the pre. I found the amp saturating soon in 6/7 hours using the key in active (with passive bass).
The overall volume has gone down but it looks like I got more headroom
Has anyone used this setting or is there any problem with this?
 
#493
agedhorse said:
Just going to jump in here to say that both the Strategy and Prodigy are really hot rodded amps and it's becoming more and more difficult to get consistent quality production KT-88 tubes that can handle the high voltages and currents that are necessary under the wide variety of real world conditions that these amps see in the wild (and getting more and more difficult every day it seems) . They are an expensive tube (especially a set of 8), and when reliability suffers the costs of replacements can get pretty high awfully quickly. Since our warranty is both long and liberal (as many of you are aware of, and some of you have taken advantage of), it has just become impractical to continue with such a costly, almost custom build type amp. There are some still available throughout the dealer network, as well as showing up on the TB classifieds. The warranty is transferable, so if you want one just keep your eyes open.

As far as the Powerhouse cabinets, the days of players seeking out 100+ pound cabinets is coming to a close. Absolutely nothing wrong with the speaker, just that tastes have changed away from this to cabinets like the Subway and similar lighter weight more compact cabinets. There are plenty of new and used PH cabinets out there so there's certainly no shortage plus we continue to stock all the repair parts and warranty service should it be necessary.

Don't worry though, I am always working on new designs and listening closely to what Talkbass players are looking for, as you all seem to be ahead of the curve more than anywhere else. Now's your chance to speak up! ;)
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I was thinking of getting a Prodogy Four 88 but saw that they are discontinued, although some have popped up on Sweetwater new/used. A fellow tb'r just messaged me he has one in excellent condition when I'm ready to buy... Do you think that will go well with my two Hartke 1x12's. . I miss the tube amps from the 60's and since this one weighs 29 lbs, I think I can carry it. If I can get my wife's permission I'd like to get one. My current head is a Hartke LH500 solid state. Thanks for any input.
 
#494
dbase said:
I was thinking of getting a Prodogy Four 88 but saw that they are discontinued, although some have popped up on Sweetwater new/used. A fellow tb'r just messaged me he has one in excellent condition when I'm ready to buy... Do you think that will go well with my two Hartke 1x12's. . I miss the tube amps from the 60's and since this one weighs 29 lbs, I think I can carry it. If I can get my wife's permission I'd like to get one. My current head is a Hartke LH500 solid state. Thanks for any input.
Click to expand...


IMHO, it would be best if you can try before you buy. I believe you will find the Prodigy is unlike the tube amps of the 60s. So while I think a Prodigy would sound fabulous with your Hartkes, you might not like it.
 
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#495
Wasnex said:
IMHO, it would be best if you can try before you buy. I believe you will find the Prodigy is unlike the tube amps of the 60s. So while I think a Prodigy would sound fabulous with your Hartkes, you might not like it.
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I'm using a Prodigy with 2 Aguilar GS 112's. Agreed it is not like the old suff ( I have a 60's B-15) But it is pretty flexible sonically and I'm happy with the sounds. Good idea to try.
 
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#496
Wasnex said:
IMHO, it would be best if you can try before you buy. I believe you will find the Prodigy is unlike the tube amps of the 60s. So while I think a Prodigy would sound fabulous with your Hartkes, you might not like it.
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Very much agreed.
 
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