A
apophis
Well-known member
Fryettes work best with sovtek or EH power tubes. As an alternative JJ 6550s sound KILLER in the deliverance so maybe use one of each type in each stereo pair and compare
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Devin
Well-known member
Idk if they even still exist but the ValveArt 6550's were my favorite power tubes for my Deliverance
Cheap, reliable and awesome
Cheap, reliable and awesome
boltzthrower
Active member
Hmm, I agree with “smooth” vs “aggressive” but my experience has been that KT88’s are tighter. That was with Sovteks. The EH 6550’s just sounded like KT88’s. But those are the only 2 brands of 6550’s I’ve tried so not a a big data set.
boltzthrower
Active member
OP, your description does sound like EH vs JJ, but also sounds like cold vs hot bias, so if you perhaps didn’t know where the bias was at it’s not a fair comparison.
Hiwatts-n-Gibsons
Well-known member
Same here. I only have those two experiences in two totally different amps. Hmmm, make that three because I remember the 6550 amp originally came with Sovtek 6550's. I liked the Tungsols better. They sounded bigger, bolder, and a little more lively, but the Sovteks had been in there a long time before I bought it.
midnightlaundry
Well-known member
I just watched the Fryette episode on Power Amps. He said JJ 6550's are really good right now..
R
Racerxrated
Well-known member
I'd reach out to them and ask....just to be safe.
stephen sawall
SEMI ERECT MEMBER
Anyone try KT120, KT150 or KT170 in anything ?
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Techdeth
RESIDENT ROCK PROFESSOR
I’m going to put electro harmonic kt88s inn my Larry
Hiwatts-n-Gibsons
Well-known member
It was just a thought. That's an expensive proposition at $300 for a quad of new production tubes, especially since I already have a quad of Gold Lion KT88's in it already. Those tubes should already outlive me.
japetus
Well-known member
Might wanna ask Larry about that
glpg80
Well-known member
They don’t like massive screen voltages, most amps wouldn’t work with them - those would need to be ran in ultra linear pentode which removes most modern guitar amplifiers as they triode strap or run much too high screen voltages. They also pull dumb heater current.
stephen sawall
SEMI ERECT MEMBER
Thanks Matt.
I think I might pick up some KT90. I believe they can be used where KT88 / 6550 are used.
Techdeth
RESIDENT ROCK PROFESSOR
I did and he told me how to bias it .Its safe . It can be el34 or kt88 which many people don’t know
Rocker68
Active member
What's in there now ?
glpg80
Well-known member
I’ve looked into KT90 and they’re a good tube. As long as the PT can handle the extra heater current the impedances are good enough for guitar amps. They should sound great.
Techdeth
RESIDENT ROCK PROFESSOR
EL34s . It’s pretty awesome . I just want to see what I like better
stephen sawall
SEMI ERECT MEMBER
I currently have 5 Fryette amps. I replaced and tested all tubes in all my amps in 2021. This is the information Fryette sent me in 2021.
We usually install EH KT88s when they come in to us for servicing.
That said, we recently evaluated EH, (new) Svetlana, GL Ruby and JJ KT88s along-side Tung-Sol and Sovtek 6550.
All were tested using the typical 2150/Two-Ninety-Two style power supply - 600V, 100W/pair.
EH and Svetlana performed identically despite that the factory says they have subtle differences (we couldn't see any mechanical differences, but that's not always a reliable indicator).
GL seem to have a bit higher transconductance, but not a significant difference in performance after biasing. Maybe a little snappier.
Ruby KT88s are tonally nice and balanced, but less power output and for the money, and a tendency to emit low frequency microphonics - typical of lesser build quality. The Ruby (any Chinese power tube really) bottles are always crooked and inconsistent in size (mostly too big). Factory says this is because they are "hand blown". Maybe they should sell them as art glass then.
JJ have the usual mid bump, which is fine if you like that sort of thing. Their quality seems to be improving, along with a significant price increase.
Tung-Sol 6550 - we've always like these but the sets we have for the test don't seem to stand out like they used to. Nice sound, but not quite the power output of the other Russian offerings or JJ.
The real surprise was the Sovtek 6550. On par with the EH and Svetlana KT88 in terms of output. The difference being that they seem more accurate/neutral than the usual sparkly KT88, so more in the vein of original GE6550. That's a good thing. Good output, solid build, reasonable cost and spot on performance. You can drop them on the floor and they won't break or short.
If you like jangly, go with EH KT88. For power, headroom and tighter performance, Sovtek 6550.
We buy tested matched tubes from our supplier. Their testing and matching is very reliable and consistently accurate. How do we know this? We test them again during production to verify it.
Then why pay extra to have them do it in the first place? Simple. They weed out the chaff and perform the burn-in process so we don't have to. It saves us a lot of time and effort.
Even so, we do find bad ones from time to time and those are returned for credit. And after all that, occasionally one goes bad in the field, which is not surprising given the beating they take in transit.
Online tube dealers often buy bulk with minimal or no testing and test/match their own. That's how they make their money. But their test regimen may differ from what the manufacturer can provide, so it's generally less reliable (I should say accurate) given that there is no industry norm these days for them to follow.
We set a broad range of rating numbers we will accept from our supplier. We do this because above and below a certain range the tubes are technically considered off-spec based on the published specs. And when a supplier provides their spec sheet to us, we expect the tubes to conform, and we'll reject those that don't. Our suppliers know we're on top of this, which helps insure we get what we asked for.
After we verify their ratings, we apply our own sticker to indicate we've done the additional verification. When a customer needs a replacement from us, we ask them what they have because then we'll be able to provide something that will keep the unit in the same approximate operating range the customer is used to. It's not really necessary to do this, but it is convenient for the end user.
About that bias range, the final bit of "Snake Oil": Depending on how the output transformer is made and the plate voltage of the amp. the bias range of the tube will either be narrow or broad. Fender output transformers are typically narrow because the impedance ratio is on the low side of the scale given the plate voltage they run (this is pretty common knowledge and explains why clones operate the same way), so the bias setting will make a more dramatic difference from one set of tubes to another. The Power Station PS-2 and PS-100 output transformer load line and plate voltage result in a more linear range of the tubes operation, which makes the bias setting, and by extension the tubes rating, less critical, as long as they stay within the published operating range.
Incidentally, all of that is the result of designing the PS amps to be more neutral sounding as we say, meaning they color the sound less, or to put in another way, more like a hi-fi amp than a guitar power amp. It's still a tube amp and exhibits familiar tube amp behavior, but tends to be less spiky and with lower distortion than a typical guitar power amp.
We usually install EH KT88s when they come in to us for servicing.
That said, we recently evaluated EH, (new) Svetlana, GL Ruby and JJ KT88s along-side Tung-Sol and Sovtek 6550.
All were tested using the typical 2150/Two-Ninety-Two style power supply - 600V, 100W/pair.
EH and Svetlana performed identically despite that the factory says they have subtle differences (we couldn't see any mechanical differences, but that's not always a reliable indicator).
GL seem to have a bit higher transconductance, but not a significant difference in performance after biasing. Maybe a little snappier.
Ruby KT88s are tonally nice and balanced, but less power output and for the money, and a tendency to emit low frequency microphonics - typical of lesser build quality. The Ruby (any Chinese power tube really) bottles are always crooked and inconsistent in size (mostly too big). Factory says this is because they are "hand blown". Maybe they should sell them as art glass then.
JJ have the usual mid bump, which is fine if you like that sort of thing. Their quality seems to be improving, along with a significant price increase.
Tung-Sol 6550 - we've always like these but the sets we have for the test don't seem to stand out like they used to. Nice sound, but not quite the power output of the other Russian offerings or JJ.
The real surprise was the Sovtek 6550. On par with the EH and Svetlana KT88 in terms of output. The difference being that they seem more accurate/neutral than the usual sparkly KT88, so more in the vein of original GE6550. That's a good thing. Good output, solid build, reasonable cost and spot on performance. You can drop them on the floor and they won't break or short.
If you like jangly, go with EH KT88. For power, headroom and tighter performance, Sovtek 6550.
We buy tested matched tubes from our supplier. Their testing and matching is very reliable and consistently accurate. How do we know this? We test them again during production to verify it.
Then why pay extra to have them do it in the first place? Simple. They weed out the chaff and perform the burn-in process so we don't have to. It saves us a lot of time and effort.
Even so, we do find bad ones from time to time and those are returned for credit. And after all that, occasionally one goes bad in the field, which is not surprising given the beating they take in transit.
Online tube dealers often buy bulk with minimal or no testing and test/match their own. That's how they make their money. But their test regimen may differ from what the manufacturer can provide, so it's generally less reliable (I should say accurate) given that there is no industry norm these days for them to follow.
We set a broad range of rating numbers we will accept from our supplier. We do this because above and below a certain range the tubes are technically considered off-spec based on the published specs. And when a supplier provides their spec sheet to us, we expect the tubes to conform, and we'll reject those that don't. Our suppliers know we're on top of this, which helps insure we get what we asked for.
After we verify their ratings, we apply our own sticker to indicate we've done the additional verification. When a customer needs a replacement from us, we ask them what they have because then we'll be able to provide something that will keep the unit in the same approximate operating range the customer is used to. It's not really necessary to do this, but it is convenient for the end user.
About that bias range, the final bit of "Snake Oil": Depending on how the output transformer is made and the plate voltage of the amp. the bias range of the tube will either be narrow or broad. Fender output transformers are typically narrow because the impedance ratio is on the low side of the scale given the plate voltage they run (this is pretty common knowledge and explains why clones operate the same way), so the bias setting will make a more dramatic difference from one set of tubes to another. The Power Station PS-2 and PS-100 output transformer load line and plate voltage result in a more linear range of the tubes operation, which makes the bias setting, and by extension the tubes rating, less critical, as long as they stay within the published operating range.
Incidentally, all of that is the result of designing the PS amps to be more neutral sounding as we say, meaning they color the sound less, or to put in another way, more like a hi-fi amp than a guitar power amp. It's still a tube amp and exhibits familiar tube amp behavior, but tends to be less spiky and with lower distortion than a typical guitar power amp.
stephen sawall
SEMI ERECT MEMBER
This is from a post by support years ago of tubes that are usable in Fryette amps in a 12AX7 spot.
"12AX7
This is the original version of this tube. The earliest ones were all made in the USA by the usual manufacturers like RCA, Sylvania, GE and Tung Sol. Very early ones have rather large size plates. The "plain" version without the "A" suffix can only be used in parallel filament circuits, not series, unless the filament circuit is DC powered.
12AX7A
This later version has improved noise specs, mostly due to the improved filament design and can be used in series or parallel AC or DC filament circuits. Many manufacturers produced plain 12AX7's well into the 60's and 70's, but many of those could be 12AX7A's marked 12AX7. Current production noisy or untested tubes are often labeled 12AX7 while tested and selected ones are usually designated 12AX7A.
7025
This is the "hi fi" low noise version of the 12AX7. All other specifications are the same as 12AX7. Tubes marked with 12AX7 and 7025 both should be low noise, too.
ECC83
This is the European equivalent to 12AX7
ECC803, ECC803S E83CC
This is the "premium" version of the European 12AX7. The "S" on the ECC803S means "select" version. These are usually found on Telefunken brand tubes.
5751
This is the "milspec" version of the 12AX7, but is also slightly different. The 5751 has the same plate resistance as the 12AX7, but the gain factor is only 70 compared to 100 for the 12AX7. The 12AT7 also has a gain factor of 70, but since its plate resistance is lower, it draws more plate current than the 5751 and 12AX7, making it less suitable for use in low current high gain stages. The older "real" 5751's have extra thick mica spacers and extra support rods to minimize microphonics.
6681
Mobile version of the standard 12AX7. These are usually standard 12AX7's which have been specially tested to assure they will perform well in circuits with +/- 20% variation in filament voltage. Amperex Holland 6681s are a great example of this tube, and very well suited for use in guitar amps."
Here's a quote from Steve on the topic..
"As far as tube selection, it has always been and will always remain the case that our designs are based on generally accepted published tube data and design parameters for any given type. The word “type” is bold because unlike some manufacturers, we never have and never will optimize our designs for a particular brand. This is an important distinction. A tube type is defined by its intended function and operational parameters, 12AX7, EL34, 5U4, etc. A tube brand, Sovtek, Shuguang, Mullard, etc, is defined by its adherence to, or deviation from, generally accepted published tube data. These days, deviation from generally accepted published tube data gives rise to certain types which exhibit noticeably different and sometimes undesirable traits in a particular brand. Thus you find certain Russian 12AX7s that are problematic in cathode follower circuits and EL34s that exhibit excessive idle current behavior or peaky response characteristics (mid emphasis, spiky top end, etc).
Bottom line is that we encourage you guys to familiarize yourselves with various tube “personalities” and I want you to rest assured that any current manufacture or NOS type that adheres to generally accepted published tube data, is a candidate for use in our amplifiers. However, it is very important to be aware that some of the tube talk you see posted on various discussion forums can be flat out fabrication. Just because a 12AX7 can be swapped out in some amps where a particular circuit is somewhat forgiving of type-swapping, doesn’t necessarily mean that is true for any and all amp designs.
Our warranty is predicated on the assumption that the amp is built tested and guaranteed to perform as advertised using the correct types of tested, properly installed tubes. If you want to try different brands, you are certainly encouraged to do so, and I think you will find that while you make like the result at first, you may find that subtle changes in performance may affect your perception of overall performance down the road. So it’s a good idea to keep a stock set around in order to get reacquainted with stock performance. We often find our customers are very surprised to discover what they didn’t realize they were missing later on.
It is very time-consuming to explain repeatedly why swapping types is not a good idea and what the ramification might be since there are a myriad of possibilities there, so we just can’t spend the time rehashing that info. We have researched this stuff extensively, and I feel confident that whatever you may have read elsewhere, our expertise on the matter is probably pretty well founded, and we are not likely to concede our engineering decisions to the end user based on hearsay."
"12AX7
This is the original version of this tube. The earliest ones were all made in the USA by the usual manufacturers like RCA, Sylvania, GE and Tung Sol. Very early ones have rather large size plates. The "plain" version without the "A" suffix can only be used in parallel filament circuits, not series, unless the filament circuit is DC powered.
12AX7A
This later version has improved noise specs, mostly due to the improved filament design and can be used in series or parallel AC or DC filament circuits. Many manufacturers produced plain 12AX7's well into the 60's and 70's, but many of those could be 12AX7A's marked 12AX7. Current production noisy or untested tubes are often labeled 12AX7 while tested and selected ones are usually designated 12AX7A.
7025
This is the "hi fi" low noise version of the 12AX7. All other specifications are the same as 12AX7. Tubes marked with 12AX7 and 7025 both should be low noise, too.
ECC83
This is the European equivalent to 12AX7
ECC803, ECC803S E83CC
This is the "premium" version of the European 12AX7. The "S" on the ECC803S means "select" version. These are usually found on Telefunken brand tubes.
5751
This is the "milspec" version of the 12AX7, but is also slightly different. The 5751 has the same plate resistance as the 12AX7, but the gain factor is only 70 compared to 100 for the 12AX7. The 12AT7 also has a gain factor of 70, but since its plate resistance is lower, it draws more plate current than the 5751 and 12AX7, making it less suitable for use in low current high gain stages. The older "real" 5751's have extra thick mica spacers and extra support rods to minimize microphonics.
6681
Mobile version of the standard 12AX7. These are usually standard 12AX7's which have been specially tested to assure they will perform well in circuits with +/- 20% variation in filament voltage. Amperex Holland 6681s are a great example of this tube, and very well suited for use in guitar amps."
Here's a quote from Steve on the topic..
"As far as tube selection, it has always been and will always remain the case that our designs are based on generally accepted published tube data and design parameters for any given type. The word “type” is bold because unlike some manufacturers, we never have and never will optimize our designs for a particular brand. This is an important distinction. A tube type is defined by its intended function and operational parameters, 12AX7, EL34, 5U4, etc. A tube brand, Sovtek, Shuguang, Mullard, etc, is defined by its adherence to, or deviation from, generally accepted published tube data. These days, deviation from generally accepted published tube data gives rise to certain types which exhibit noticeably different and sometimes undesirable traits in a particular brand. Thus you find certain Russian 12AX7s that are problematic in cathode follower circuits and EL34s that exhibit excessive idle current behavior or peaky response characteristics (mid emphasis, spiky top end, etc).
Bottom line is that we encourage you guys to familiarize yourselves with various tube “personalities” and I want you to rest assured that any current manufacture or NOS type that adheres to generally accepted published tube data, is a candidate for use in our amplifiers. However, it is very important to be aware that some of the tube talk you see posted on various discussion forums can be flat out fabrication. Just because a 12AX7 can be swapped out in some amps where a particular circuit is somewhat forgiving of type-swapping, doesn’t necessarily mean that is true for any and all amp designs.
Our warranty is predicated on the assumption that the amp is built tested and guaranteed to perform as advertised using the correct types of tested, properly installed tubes. If you want to try different brands, you are certainly encouraged to do so, and I think you will find that while you make like the result at first, you may find that subtle changes in performance may affect your perception of overall performance down the road. So it’s a good idea to keep a stock set around in order to get reacquainted with stock performance. We often find our customers are very surprised to discover what they didn’t realize they were missing later on.
It is very time-consuming to explain repeatedly why swapping types is not a good idea and what the ramification might be since there are a myriad of possibilities there, so we just can’t spend the time rehashing that info. We have researched this stuff extensively, and I feel confident that whatever you may have read elsewhere, our expertise on the matter is probably pretty well founded, and we are not likely to concede our engineering decisions to the end user based on hearsay."
stephen sawall
SEMI ERECT MEMBER
Here is the Mesa information..
RED
"Headroom" available: Very High
Clipping: Low
YELLOW
"Headroom" available: High
Clipping: Low
GREEN
"Headroom" available: Medium High
Clipping: Medium
GREY
"Headroom" available: Medium High
Clipping: Medium
BLUE
"Headroom" available: Medium Low
Clipping: Medium High
Best Regards,
Marcus Daniel | Customer Service
Mesa/Boogie | MESA ENGINEERING
4 -Red
4.5 -Yellow
5 -Green
5.5 -Gray
6 -Blue
6.5 -White
With Groove Tubes basically, a #1 will distort sooner, and a #10 later.
THIS IS COMPLETELY OPPOSITE WHEN IT COMES TO MESA FIXED BIAS AMPS. In fact, GT distortion rating of 4 has MORE headroom than a 6 rating, not less. Again, this is only relevant for fixed bias amps, and has to do with the percentage of max plate dissipation a tube is pulling at idle.
This applies when the tubes are installed into a FIXED bias amp such as a Boogie. This means that the Groove Tubes will draw close to the same current at idle as the corresponding color codes of MESA tubes. The red color code idles cooler and is further from clip (breakup) , and the white color code idles hotter and is closer to clip (breakup). Reds = headroom , White = quicker distortion. 8) This is what Marcus was saying.
The early and late breakup that Groove Tubes is talking about is the tubes installed into an ADJUSTABLE bias amp with the tubes biased to the same current draw. That is, if you took a #5 tube and a #10 tube and biased them do both draw 70% mpd, that the #5 would distort sooner and the #10 would have more headroom.
"7 is about as high as you can go and even with a 7 in the output section I would check the bias." -Myles Rose
RED
"Headroom" available: Very High
Clipping: Low
YELLOW
"Headroom" available: High
Clipping: Low
GREEN
"Headroom" available: Medium High
Clipping: Medium
GREY
"Headroom" available: Medium High
Clipping: Medium
BLUE
"Headroom" available: Medium Low
Clipping: Medium High
Best Regards,
Marcus Daniel | Customer Service
Mesa/Boogie | MESA ENGINEERING
4 -Red
4.5 -Yellow
5 -Green
5.5 -Gray
6 -Blue
6.5 -White
With Groove Tubes basically, a #1 will distort sooner, and a #10 later.
THIS IS COMPLETELY OPPOSITE WHEN IT COMES TO MESA FIXED BIAS AMPS. In fact, GT distortion rating of 4 has MORE headroom than a 6 rating, not less. Again, this is only relevant for fixed bias amps, and has to do with the percentage of max plate dissipation a tube is pulling at idle.
This applies when the tubes are installed into a FIXED bias amp such as a Boogie. This means that the Groove Tubes will draw close to the same current at idle as the corresponding color codes of MESA tubes. The red color code idles cooler and is further from clip (breakup) , and the white color code idles hotter and is closer to clip (breakup). Reds = headroom , White = quicker distortion. 8) This is what Marcus was saying.
The early and late breakup that Groove Tubes is talking about is the tubes installed into an ADJUSTABLE bias amp with the tubes biased to the same current draw. That is, if you took a #5 tube and a #10 tube and biased them do both draw 70% mpd, that the #5 would distort sooner and the #10 would have more headroom.
"7 is about as high as you can go and even with a 7 in the output section I would check the bias." -Myles Rose