Feel free to ask Myles

[jlh]

Myles,

I've finally decided to repair/upgrade my old Gibson GA35RVT Lancer amp. I think I know enough to do it without breaking it or frying myself, but could sure use some advice. It appears that the push/pull phase inverter is a transformer so no issue there, but it is full of unusual tubes and some advice on replacing or substituting would be handy. I always loved the tremelo and reverb sounds that it has and it breaks up nicely at reasonable volumes, but the tone has always been kind of "honky". That is way too much midrange with no boom or shimmer. I've been told that it is just a crappy design and I'm stuck with that, but I'm hoping you can offer some advice. There is a schematic posted here:

Gibson Amp Schematics

The output tubes are 7591s. I know they can be had, but are they really the best choice? I noticed that THD has a yellow jacket to use EL84s in place of the 7591s. Is this a good choice or would it be a better idea to get some real 7591s from Torres or someone?

 

Also the preamp front ends are 6EU7s hard to get too. Same story anything better?

 

Finally should I look at changing some of the R/C values in the coupling and filter stages to let more bass and treble through if the tube changes don't do the job? This would no doubt be a LOT more effort and maybe more study than I want to do.

 

Sorry this is so long, but the topic has been percolating in my brain ever since the old filter caps went out and I shelved the amp. Thanks for being such a great and generous source of information Myles(stroke stroke).

Sincerely,

Jamie

[myles_rose]

Originally posted by jlh:

Myles,

I've finally decided to repair/upgrade my old Gibson GA35RVT Lancer amp. I think I know enough to do it without breaking it or frying myself, but could sure use some advice. It appears that the push/pull phase inverter is a transformer so no issue there, but it is full of unusual tubes and some advice on replacing or substituting would be handy. I always loved the tremelo and reverb sounds that it has and it breaks up nicely at reasonable volumes, but the tone has always been kind of "honky". That is way too much midrange with no boom or shimmer. I've been told that it is just a crappy design and I'm stuck with that, but I'm hoping you can offer some advice. There is a schematic posted here:

Gibson Amp Schematics

The output tubes are 7591s. I know they can be had, but are they really the best choice? I noticed that THD has a yellow jacket to use EL84s in place of the 7591s. Is this a good choice or would it be a better idea to get some real 7591s from Torres or someone?

 

Also the preamp front ends are 6EU7s hard to get too. Same story anything better?

 

Finally should I look at changing some of the R/C values in the coupling and filter stages to let more bass and treble through if the tube changes don't do the job? This would no doubt be a LOT more effort and maybe more study than I want to do.

 

Sorry this is so long, but the topic has been percolating in my brain ever since the old filter caps went out and I shelved the amp. Thanks for being such a great and generous source of information Myles(stroke stroke).

Sincerely,

Jamie

Jamie....

 

The Gibsons are great amps, and better according to a lot of my clients, than many others. They have less front end gain, so their frequency response is much wider, and they are not as bright.

 

Just about any of the tubes in there ... actually, all of the tubes in there, are still pretty easy to get from the right places.

 

The 6EU7's you can probably get from KCA NOS tubes or Vacuum Tube Valley. There are links to each of them on my personal website (the link is below in my signature).

 

I like to stay with the stock tube compliment in these amps.

 

For the 12AU7's these are a current GT item at:

http://www.groovetubes.com/product.cfm?Product_ID=1592

 

The 7591's are also a current item at:

http://www.groovetubes.com/product.cfm?Product_ID=1702 and are available in duets and quartets.

 

The THD Yellow Jackets are great in this amp, or frankly, any amp.

 

Don't change anything as far as resistor or cap values until you hear this amp with good fresh tubes. You may be happy at that point. If you are not, its usually easier to get a different amp that meets your tastes, rather than trying to mod one to get closer to your taste.

 

As far as this being so long ... I guess you have not read many of my posts

[Zeptember]

OK. First off, i love the testing you've done on all these tubes, it saves us players a lot of hastle.Second, HELP!!! I have a Mesa/Boogie

Nomad 55 2*12 combo amp with 5 12ax7's. I orderd some 6l6's and 12ax7's(matched phase for v5) from bob at eurotubes. Love the 6L6's, but in the

pre, the 12ax7's arent working for me in the first slot. I switched them all out, thinking i would get a better sound, well, i did, somewhat. I loved the sound of all the channels(3), but i use a Perscription Electronics Experience through Channel 1 in a fasshon that they (the

jj's) don't like at all. Before i changed them, there were the usuall Soveteks in there, but with one JJ appearing in V2 (1st and 2nd stage channel 1). With that, the Prescription Electronics Experience sounded fantastic, it sounded like my amp was about to have a nuclear melt down!! So much distortion, and cut, that when i went over to channel 3's gain,it sounded that my trebble was all the way off. I love this fuzz pedal,but i am noticing when i use it in my clean channel (the only place i use it), it starts to clip at some point, the kinda distortion you hear like after the regular fuzz distortion with the JJ's in there, but the clean channel sounded better, and so did the rest of the amp with it in, but it didnt sound good at all with the JJ's, i lost all my lovely cut with that pedal, it sounds all muffled now, and its clipping like crazy! I did have some of this problem with the Soveteks in there, but just turned the trebble down on my amp to compensate for it and it worked with the Soveteks, but not at all with the JJ's. Concequently i had to put a

Sovetek back in V1 to fix the clipping problem, but now i want the rest of that good sound back when i had the JJ's. I need to know what you recomend for me as to finding another pre tube for v1 to cure this clipping problem, but still give me better tone than those pesky Soveteks. Maybe a Military Spec Jan. Phillips? Dunno? PLEASE HEPL! Oh and i need to know where i can get this tube too! Maybe on EBAY?

[myles_rose]

Originally posted by Zeptember:

OK. First off, i love the testing you've done on all these tubes, it saves us players a lot of hastle.Second, HELP!!! I have a Mesa/Boogie

Nomad 55 2*12 combo amp with 5 12ax7's. I orderd some 6l6's and 12ax7's(matched phase for v5) from bob at eurotubes. Love the 6L6's, but in the

pre, the 12ax7's arent working for me in the first slot. I switched them all out, thinking i would get a better sound, well, i did, somewhat. I loved the sound of all the channels(3), but i use a Perscription Electronics Experience through Channel 1 in a fasshon that they (the

jj's) don't like at all. Before i changed them, there were the usuall Soveteks in there, but with one JJ appearing in V2 (1st and 2nd stage channel 1). With that, the Prescription Electronics Experience sounded fantastic, it sounded like my amp was about to have a nuclear melt down!! So much distortion, and cut, that when i went over to channel 3's gain,it sounded that my trebble was all the way off. I love this fuzz pedal,but i am noticing when i use it in my clean channel (the only place i use it), it starts to clip at some point, the kinda distortion you hear like after the regular fuzz distortion with the JJ's in there, but the clean channel sounded better, and so did the rest of the amp with it in, but it didnt sound good at all with the JJ's, i lost all my lovely cut with that pedal, it sounds all muffled now, and its clipping like crazy! I did have some of this problem with the Soveteks in there, but just turned the trebble down on my amp to compensate for it and it worked with the Soveteks, but not at all with the JJ's. Concequently i had to put a

Sovetek back in V1 to fix the clipping problem, but now i want the rest of that good sound back when i had the JJ's. I need to know what you recomend for me as to finding another pre tube for v1 to cure this clipping problem, but still give me better tone than those pesky Soveteks. Maybe a Military Spec Jan. Phillips? Dunno? PLEASE HEPL! Oh and i need to know where i can get this tube too! Maybe on EBAY?

Zeptember ....

 

First off .... if you make posts this long, you will get a reputation of being as long winded as I have Like some folks say ... "ask Mylez what time it is, and he will try to tell you how to build a watch".

 

Second off ... You are more than welcome for the testing. It is starting to pay off in more consistant tubes for everybody. The Chinese folks sent a factory rep over here that I meet with a few times a month. The make changes every time we meet, and the consistancy is really improving. On the power tubes, they used to fail easily at high plate voltages, and had 20% less power than the Russian tubes of the same type. Now they handle higher plate voltages, and are 15% above the Russian tubes.

 

Your Nomad is a pretty cool amp. It falls in sound between the Mark Series of amps and the Rectifier series, which to a lot of folks, give it a lot of versitility.

 

Bob at Eurotube has great stuff, but only carries the JJ tubes. The JJ 12AX7 / ECC83, have their own tonal character. Some find these too agressive and midrange strong. They are also generally higher output than most 12AX7's, and with higher output comes less frequency response and more background noise. Its the normal tradeoff that cannot be avoided.

 

The stock Sovteks are 12AX7WA's, and a nice linear and sturdy tube (the choice of Fender in all their new amps, but in V1 and V2 of their Pro Reverb, Pro Concert, and Pro Twin, they use what they call a 12AX7A, which is a Chinese 12AX7C, which is warmer, more linear, and more expensive. That is why it is only in the critical V1 and V2 spots in these amps.

 

Two stages of JJ's in high front end gain amps is a problem. It gets buzzy, and indistinct. The volume/gain/master at anything above "3" is sort of useless.

 

Typically, you also have to watch the gain here, as V1 feeds the rest of the signal chain. Most of my clients with the Nomads (even the 45 and the big one), use a 12AX7C in V1 that was SAG selected at a rating of LESS than 100/108. In V2 we go for either a 12AX7R3 (Electro Harmonix) or a 12AX7C (Chinese), with their respective ratings under 100/100 ... and if I can find something in the 90's, we go with those. Less noise, and more usable range on the controls. More articulation too.

 

GT (Groove Tubes) let me start my own group (SAG - Special Applications Group), as I had a lot of clients that were using specifically selected tubes. Over time, the SAG scale was aligned to the Watford Valves scale, and now Bob Pletka at Eurotubes, and Charlie Kittleson at Vacuum Tube Valley, are all on the same page of music.

 

Info on SAG is at:

http://www.groovetubes.com/product.cfm?Product_ID=1773

 

VTV and Eurotubes can now also give you a "90" as an example, as well as Matched Phase Inverters.

 

The lack of clipping with the Sovteks was because the 12AX7WA is way down on output and gain from the other 12AX7's. V1 or V2 may be good in one case and bad in the other, so being they are both unknown, it is hard to know what is going on in your amp. The first thing I do when blueprinting an amp, is measure everything that is in there, so I have a known baseline.

 

NOS tubes are always more consistant and better sounding in older amps. In modern amps with a high front end gain structure, they still make a nice improvement, but the higher gain stages will mask a bit of the improvement. In a lower gain amp like a Fender tweed, they really make all the difference in the world.

 

On your amp, NOS JAN Philips are great tubes, make a nice difference in Mesa front ends, and are not expensive ... yet.

 

As far as where to get these .... www.vacuumtube.com has them, http://www.kcanostubes.com/, and one fellow I like a lot, but he is sort of a secret, is a fellow in NY named Doug Preston ( djp@optonline.net ) and one more secret is Phil at a place called the Tube Station ( DO NOT confuse this with The Tube Store!!!) ( tubestation3@rogers.com ). These are the guys I use and trust.

 

Hope this was of some help.

[Zeptember]

Thanks for the help. before you posted this reply, i replaced the sovetek tube with a mesa 12ax7 that has that rubber tube dampenier around it, which i was told to be a select chinese valve that has better dynamics that reads SPAX7-A on the dampener, and it works fine, but kept the JJ's in the rest of the slots. I hqave to disagree with you on the JJ's being usless at higher master levels, I noticed a HUGE improvment in my tone from those pesky Soveteks. But, my question still is, what tube wolnt break up in the fassion im hearing with my Prescription Electronics Experience pedal? And what am I hearing, what is it called?

[vintagevibe]

Myles, in your opinion what would be the best tubes to use in my ART Dual MP mic preamp? I use it to record acoustic guitar and vocals.

 

Thanks

[myles_rose]

Originally posted by Zeptember:

Thanks for the help. before you posted this reply, i replaced the sovetek tube with a mesa 12ax7 that has that rubber tube dampenier around it, which i was told to be a select chinese valve that has better dynamics that reads SPAX7-A on the dampener, and it works fine, but kept the JJ's in the rest of the slots. I hqave to disagree with you on the JJ's being usless at higher master levels, I noticed a HUGE improvment in my tone from those pesky Soveteks. But, my question still is, what tube wolnt break up in the fassion im hearing with my Prescription Electronics Experience pedal? And what am I hearing, what is it called?

Zeptember ....

 

There will be an improvement using most any tube over the Sovtek 12AX7WA. The JJ you have may be of a "rational" spec. Most of them are hot, and this is where the problem comes into play.

 

The SPAX-7A from Mesa was in the past an Electro Harmonix 12AX7EH. Maybe they are Chinese now, I don't know, but if you have a scan of the tube and can send a .jpg, I can tell you for sure.

 

Anything will break up fast with your pedal. Your amp is not exacly "pedal friendly". A guitar pickup is a high impedance low output device. A pedal is a low impedance high output device, that drives your front end into mush.

 

Try you pedal in front of a Fender black or silver face era amp. You will see it sounds much nicer and more articulate. Then try it in front of a Fender tweed era amp ... even nicer still.

 

The old four input Marshalls were better too, than today's higher gain front ends. Try it in front of a model 1962, 1987, or 1959. That is how Hendrix got a lot of his live sounds.

 

The GT S-45 is an amp specifically designed for pedal use also.

[myles_rose]

Originally posted by dino321:

Myles, in your opinion what would be the best tubes to use in my ART Dual MP mic preamp? I use it to record acoustic guitar and vocals.

 

Thanks

Dino,

 

Folks use 12AX7's and 12AT7's in those, depending on taste.

 

The best I have found is either the 12AX7C (but make sure it is the latest tooling version, the 12AX7R2 (Sovtek 12AX7LPS), or the 12AX7R3 (Electro Harmonix 12AX7EH) for 12AX7's.

 

For 12AT7's you need a selected tube, such as the GT SAG-AT7-MPI which is very low noise and highly matched for equal waveforms on the A and B sides, and used in a lot of high end tube mics, preamps, and compressors.

[vintagevibe]

Thanks myles. Your input is immensely helpful and appreciated.

[TieDyedDevil]

Myles --

 

I'm digging the small-bottle sound, lately. I have a Mesa/Boogie Blue Angel and a Maverick.

 

What would you recommend for these amps, should I decide to retube?

 

Also, can you explain power tube selection for cathode-biased amps? Is it different from fixed-biase amps? What are the effects of selecting tubes in a different bias range for a cathode-biased amp?

 

Finally, can you offer some insight into the interactions between the 6V6s and the EL-84s in the Blue Angel? What would be the effect of running the 6V6s hotter and the EL-84s cooler, or vice versa?

 

Thanks in advance for your suggestions and insights.

[paranoid]

Hi,

I just bought a Laney VH100R 100 watt head. I really didn't need 100 w of power but it was a cheap 2nd hand well sounding amp and so...

I'm now thinking about what speakers to combine with it.

My idea is to buy a 2x12 cabinet loaded with celestion speakers.

What COMBO of speakers do you think work fine with that cab?

 

Take in mind my power\wattage related problems.... so

 

-Should I install a 100w\50w switcher to reduce power amp wattage increasing the speakers effectiveness (consider also the beautiful power amp early overdrive and the saving in power tubes)

 

or

 

-Should I simply load the cabinet with speakers that guarantee me the right wattage? (It is true that for rock music you need a cab with much more watts than your power amp output?)

 

I thank you in advance if you want spend 2 minuts to clear some novice's doubts.

[ManInTheBox]

Hey Myles,

 

I am wanting to delve into Amp mods and Hot rodding, but know very little about amplifiers. I am pretty adept with electronics though. I was wondering if you could point me in the direction of some good resources to help me understand amp designs. Mainly guitar amps of course. How do you voice an amps eq ect...., How do you alter the tone of an amp, that kinda thing. Any help would be appreciated, and I apologize if the question has been asked before.

[myles_rose]

Originally posted by dino321:

Thanks myles. Your input is immensely helpful and appreciated.

Dino,

 

You are more than welcome.

[myles_rose]

Originally posted by TieDyedDevil:

Myles --

 

I'm digging the small-bottle sound, lately. I have a Mesa/Boogie Blue Angel and a Maverick.

 

What would you recommend for these amps, should I decide to retube?

 

Also, can you explain power tube selection for cathode-biased amps? Is it different from fixed-biase amps? What are the effects of selecting tubes in a different bias range for a cathode-biased amp?

 

Finally, can you offer some insight into the interactions between the 6V6s and the EL-84s in the Blue Angel? What would be the effect of running the 6V6s hotter and the EL-84s cooler, or vice versa?

 

Thanks in advance for your suggestions and insights.

TieDyedDevil ....

 

I am also something of a blue angel fan, as you can see on my website in the area of my personal equipment.

 

For both of these EL-84 based amps, there is only one tube to use, and that is the EL-84S, also known as the JJ EL-84. The Russian Sovteks are dark and not at all articulate. Those are what Mesa uses as stock.

 

Use a rating of #5-6 and they work great.

 

The GT version of this tube is at:

 

http://www.groovetubes.com/product.cfm?Product_ID=1687

 

You can also get these tubes at www.eurotubes.com where they are a bit less expensive, but not dynamically matched. In any case, I use both GT and Eurotubes versions, with great results in each case.

 

For preamp tubes, I prefer the 12AX7R3 in V1

and V2 of these amps. This tube is also known as the 12AX7EH from Electro Harmonix, or the 12AX7C, but only the latest tooling variant:

http://www.groovetubes.com/product.cfm?

Product_ID=1158

 

On the issue of class A vs. class A/B, that would require a lot of writing here that has already been done a lot in the past. There are other posts in this area that might point to that, and various articles on the net. There are also links that go into this in great detail in the area of tube operation, on my website.

[myles_rose]

Originally posted by paranoid:

Hi,

I just bought a Laney VH100R 100 watt head. I really didn't need 100 w of power but it was a cheap 2nd hand well sounding amp and so...

I'm now thinking about what speakers to combine with it.

My idea is to buy a 2x12 cabinet loaded with celestion speakers.

What COMBO of speakers do you think work fine with that cab?

 

Take in mind my power\wattage related problems.... so

 

-Should I install a 100w\50w switcher to reduce power amp wattage increasing the speakers effectiveness (consider also the beautiful power amp early overdrive and the saving in power tubes)

 

or

 

-Should I simply load the cabinet with speakers that guarantee me the right wattage? (It is true that for rock music you need a cab with much more watts than your power amp output?)

 

I thank you in advance if you want spend 2 minuts to clear some novice's doubts.

paranoid ....

 

First, always use the proper ohm load with the amp set to match the speaker load.

 

All amps sound more magical when pushed, and a 50 watter is easier to push than a 100 watter.

 

Pulling two tubes from a 100 watter to make it a 50 watter works in some ways, but the power supply was designed for 100 watts, so will not sag or work like a 50 watt supply in a 50 watt amp.

 

Your best bet is to use a THD Hot Plate.

[myles_rose]

Originally posted by tundrkys:

Hey Myles,

 

I am wanting to delve into Amp mods and Hot rodding, but know very little about amplifiers. I am pretty adept with electronics though. I was wondering if you could point me in the direction of some good resources to help me understand amp designs. Mainly guitar amps of course. How do you voice an amps eq ect...., How do you alter the tone of an amp, that kinda thing. Any help would be appreciated, and I apologize if the question has been asked before.

tundrkys

 

Your first step should be to get a copy of:

 

http://www.groovetubes.com/product.cfm?Product_ID=1188

 

Then you will be on your way with some basic tech info and basic mods.

 

Myles

[TieDyedDevil]

Originally posted by myles111:

Originally posted by TieDyedDevil:

Myles --

 

I'm digging the small-bottle sound, lately. I have a Mesa/Boogie Blue Angel and a Maverick.

 

What would you recommend for these amps, should I decide to retube?

 

Also, can you explain power tube selection for cathode-biased amps? Is it different from fixed-biase amps? What are the effects of selecting tubes in a different bias range for a cathode-biased amp?

 

Finally, can you offer some insight into the interactions between the 6V6s and the EL-84s in the Blue Angel? What would be the effect of running the 6V6s hotter and the EL-84s cooler, or vice versa?

 

Thanks in advance for your suggestions and insights.

TieDyedDevil ....

 

I am also something of a blue angel fan, as you can see on my website in the area of my personal equipment.

 

For both of these EL-84 based amps, there is only one tube to use, and that is the EL-84S, also known as the JJ EL-84. The Russian Sovteks are dark and not at all articulate. Those are what Mesa uses as stock.

 

Use a rating of #5-6 and they work great.

 

The GT version of this tube is at:

 

http://www.groovetubes.com/product.cfm?Product_ID=1687

 

You can also get these tubes at www.eurotubes.com where they are a bit less expensive, but not dynamically matched. In any case, I use both GT and Eurotubes versions, with great results in each case.

 

For preamp tubes, I prefer the 12AX7R3 in V1

and V2 of these amps. This tube is also known as the 12AX7EH from Electro Harmonix, or the 12AX7C, but only the latest tooling variant:

http://www.groovetubes.com/product.cfm?Product_ID=1158

 

Thanks, Myles --

 

I have noticed your Blue Angel. I've recently discovered the joys of having amps that are small enough so I can get some useable power tube distortion, and I'm loving the Blue Angel the most of all of them.

 

I'll give your tube recommendations a try when I return from Boston next month.

[ManInTheBox]

Hey Myles, Thanks for the quick response. I feel I should apologize for not really believing you, or your expertese. i originally posted months ago, concerning my BlueVoodoo. The highs were extremely bright in the clean channel, and you suggested a few tube swaps. Me, believing a tube is a tube, I held back on the tube swapping, well, I swapped around the tubes I had in there, but realized no effect, so the amp has sat here for the most part with both switches in the off position. I am preparing to send the amp back to the manufacturer, to see if they can fix it, and I decided to go ahead a buy a few more tubes, and see what happens. Amoung the tubes I bought, I opted for one 12AT7. The place I go to hands out MesaEngineering tubes at the same price as sovteks, even though they are probably the same.

I installed the 12AT7 into the V1 position, and voila, I am pretty close to where I wanted the amp to be. crystaline highs, and blooming lows. I still think it sounded better when I first got it. Of course I am going to write the manufacturer, and find out exactly what came stock with the amp, and probably retube again.

The tubes I pulled out were Sovtek 12AX7WB. the ones I put in are 12AX7-A, is there a big difference between these tubes, and can I ask for them by name? Also, the tubes I bought today, are marked russian 2, whereas the ones I installed six months ago are marked Russian one, is this a significant difference.

[ManInTheBox]

Oh yeah, now I have this pinging type of noise whever I play a D or B on any of the high 5 strings, or a G major chord. Sounds funny I know, but that is what is going on.

I am thinking maybe the voice coil of the speaker. I swapped all the tubes one at a time with one that had never been in the amp before, including power tubes, so I knowe it ain't the tubes.

[myles_rose]

Originally posted by TieDyedDevil:

 

[/qb]

Thanks, Myles --

 

I have noticed your Blue Angel. I've recently discovered the joys of having amps that are small enough so I can get some useable power tube distortion, and I'm loving the Blue Angel the most of all of them.

 

I'll give your tube recommendations a try when I return from Boston next month.[/QB]

 

TieDyedDevil ....

 

The Blue Angel is a sleeper. I frankly, don't know how Mesa sells it for their price when you look inside and see what is going on in there !

 

I mostly use the 6V6 section, but for the AC-30 / Matchless sort of sound, will go to the EL84 section on occasion.

[myles_rose]

Originally posted by tundrkys:

Hey Myles, Thanks for the quick response. I feel I should apologize for not really believing you, or your expertese. i originally posted months ago, concerning my BlueVoodoo. The highs were extremely bright in the clean channel, and you suggested a few tube swaps. Me, believing a tube is a tube, I held back on the tube swapping, well, I swapped around the tubes I had in there, but realized no effect, so the amp has sat here for the most part with both switches in the off position. I am preparing to send the amp back to the manufacturer, to see if they can fix it, and I decided to go ahead a buy a few more tubes, and see what happens. Amoung the tubes I bought, I opted for one 12AT7. The place I go to hands out MesaEngineering tubes at the same price as sovteks, even though they are probably the same.

I installed the 12AT7 into the V1 position, and voila, I am pretty close to where I wanted the amp to be. crystaline highs, and blooming lows. I still think it sounded better when I first got it. Of course I am going to write the manufacturer, and find out exactly what came stock with the amp, and probably retube again.

The tubes I pulled out were Sovtek 12AX7WB. the ones I put in are 12AX7-A, is there a big difference between these tubes, and can I ask for them by name? Also, the tubes I bought today, are marked russian 2, whereas the ones I installed six months ago are marked Russian one, is this a significant difference.

tundrkys...

 

No need to apologize for anything for a start.

 

A lot of folks belive tubes are tubes, and for the most part, this is actually a good assumption. All tubes are made in the same few factories, but all tubes have wide ranges of tolerances. They are still hand made, and even a few 10,000ths of an inch, changes characteristics.

 

Where the differences come into play, is testing and grading. There are a number of great vendors out there, and a number of bad ones. The more intensive the testing, the better the end result. Testing takes time, and that means money. One reason Groove Tubes stuff is thought of many times as expensive, is that their testing is very extensive, and they test for many additional factors that translate into longer tube life, a better match over the entire frequency range, and higher reliability.

 

Then again, there is a price trade off for all things in life. There are folks that do not have the resources to test for low vacuum, gas leakage, grid leakage, or distortion at given levels of output and frequencies. BUT .... in many cases, these are super tubes from great vendors. Bob Pletka at Eurotubes sells JJ tubes that at beautifully matched. I send many folks his way, even though he is a direct competitor. Why? He has great pricing, some things nobody else has (his integrated quads), but even more than that, he is a great guy that helps folks and sets them in the right direction. My personal bottom line life agenda in one area, is to help players sound better. If they only have $50, and my products are $100, I will send them elsewhere, to folks I trust. ... folks I also purchase from.

Charlie Kittleson at Vacuum Tube Valley is a great resource. KCA is a great resource. There is a fellow back east named Doug Preston that is a smaller tube supplier, that is fast becomming known by a few folks too.

 

Stock tubes that come with amps are chosen to be reliable. If sonic qualities want to be improved, then you have many options later. If you liked the amp enough to buy it with the stock tubes, then that is super ... you can only go up!

 

It is also harder these days from an economic standpoint. Amp makers are pushed hard from many directions to stay in business. It is easier and cheaper to stock one tube such a 12AX7, than two, adding a 12AT7. For decades, Fender used the 12AT7 as their drivers. In new amps, this was replaced with 12AX7's. The gain on a 12AX7 is supposed to be 100, and on a 12AT7 about 70. This still goes for NOS tubes. For new tubes, they can be +/- 50% of this. So, in many cases a 12AT7 will have more gain than the 12AX7, and also be able to deliver 7-10 times the current drive. AT7's are the ticket in the new Fender amps from my point of view.

 

The 12AX7WA and WB are much the same, other than the B is more closely selected, and has a price at the cost level of about $1.00 more.

 

The 12AX7-A today is usually a Chinese tube, and Fender uses these in the Pro series amps in V1 and V2 as they are more linear than the WA Sovtek and higher quality. In the rest of the preamp positions they use the WA.

 

12AX7A - can be NOS USA or 12AC7C Chinese

 

12AX7R2 - Sovtek 12AX7LPS (a good tube that at the amp maker cost level is over 2x the cost of a 12AX7WA.

 

12AX7R3 - Electro Harmonix side of the Reflector Factory - as expensive as the R2 LPS.

 

Hope this helped

[myles_rose]

Originally posted by tundrkys:

Oh yeah, now I have this pinging type of noise whever I play a D or B on any of the high 5 strings, or a G major chord. Sounds funny I know, but that is what is going on.

I am thinking maybe the voice coil of the speaker. I swapped all the tubes one at a time with one that had never been in the amp before, including power tubes, so I knowe it ain't the tubes.

tundrkys ....

 

For a start, try running your amp into a seperate speaker cab without using the internal speaker if a combo or a different cab than what you are using.

 

If it is not that, then false tones come from filter caps that are shot.

 

I don't remember your amp. What was it, and how old is it?

[ManInTheBox]

tundrkys ....

 

For a start, try running your amp into a seperate speaker cab without using the internal speaker if a combo or a different cab than what you are using.

 

If it is not that, then false tones come from filter caps that are shot.

 

I don't remember your amp. What was it, and how old is it?

It is a Crate BlueVoodoo 6212 combo. I would like to try what you suggest, however I don't have another cab, or any friends (or friends with cabinets). So I'll probably try some new speakers in the near future. Any suggestions. It is a 60 watt open back combo. It currently has Crate 30 watt speakers. I know your specialty is tubes, but would you know how different wattage speakers would change the sound? Would 70watt speakers give me a cleaner sound, could I push them harder? If I am going for TexasBlues overdriven sound, would I be better off going with lower wattage? Who would be the right guy to ask these questions?

[myles_rose]

Originally posted by tundrkys:

tundrkys ....

 

For a start, try running your amp into a seperate speaker cab without using the internal speaker if a combo or a different cab than what you are using.

 

If it is not that, then false tones come from filter caps that are shot.

 

I don't remember your amp. What was it, and how old is it?

It is a Crate BlueVoodoo 6212 combo. I would like to try what you suggest, however I don't have another cab, or any friends (or friends with cabinets). So I'll probably try some new speakers in the near future. Any suggestions. It is a 60 watt open back combo. It currently has Crate 30 watt speakers. I know your specialty is tubes, but would you know how different wattage speakers would change the sound? Would 70watt speakers give me a cleaner sound, could I push them harder? If I am going for TexasBlues overdriven sound, would I be better off going with lower wattage? Who would be the right guy to ask these questions?

tundrkys ....

 

I do a bit on speakers and pickups too .....

 

Speaker wattage rating does not have too much to do with the character of the sound. There are many other factors.

 

AlNico magnets versus ceramic magnets alter the sound character. Speaker cone materials, suspension, and voice coil construction also have a large impact.

 

Celestion Vintage 30's have a differerent sound altogether than a Jensen P12R as an example.

 

This is a hard question, as it is much the same as, "what amp sounds better ... a Fender Twin reverb or a Marshall JCM 900". It all boils down to personal taste.

 

The best thing you can do, is take your head to a music store that has different cabinets, see what sort of sound you like, and then find out what speakers are in the cabinets.

 

The other factor is closed back versus open back. Again, very different. Originally, the reason (or one of them) for the closed back Marshall 4x12, was that speakers only had a 15-20 watt rating. When the voice coils got hot, you'd hit a strong chord, and the coil would slam into the end of the slot, and stick.

 

So .... with a closed tight back, speaker movement was constricted, and this happened less often. It had a tighter sound, that lots of folks came to love.

 

An open back 2x12 cab such as the THD, has more output than a 4x12 Marshall, and also has much wider sound dispersion. You also get a HUGE sound out of these, as program material comes from the front and back of the cabinet. This is also one of the reasons the open back Fender amps sound so big and loud ... the Twin reverb as an example.

[SpeedysComing]

Hi Myles and everybody. Long time since I posted, but been busy as a bee. Anyway, I seem to be mysteriously drawn to checking out a Mesa Mark1 Reissue. I know that at full power it is a very loud amp. But I know that it takes 6v6's in tweed mode. Do you think for a basement noodler I can get good tone (blues and rock with the effects loop jumpered) at lower levels with the 6v6's? Also would like to know if you have an opinion on the build quality of the new reissues. Thanks in advance.

[myles_rose]

Originally posted by Speedy'sComing:

Hi Myles and everybody. Long time since I posted, but been busy as a bee. Anyway, I seem to be mysteriously drawn to checking out a Mesa Mark1 Reissue. I know that at full power it is a very loud amp. But I know that it takes 6v6's in tweed mode. Do you think for a basement noodler I can get good tone (blues and rock with the effects loop jumpered) at lower levels with the 6v6's? Also would like to know if you have an opinion on the build quality of the new reissues. Thanks in advance.

Speedy'sComing ....

 

I have done a lot with the original Mk. I and the re-issues. (if you look on my website in one of the areas, I think I may have some pictures).

 

In any case, using 6V6's in the tweed power mode works well enough, but it is not at all like the sound, feel, or touch of say a Fender Deluxe. The voicing of the Mesa is different, and there are other factors.

 

What helps, is the tweed power mode and using only two of the four output tubes (stick the amp in 60 watt mode rather than 100 watt mode), and then also only use input 2, which is more of a Fender front end, then input 1 (which cascades with volume 1 and 2). This will not color the sound as much.

 

Both the original and re-issue are built very nicely, but there are a few things to keep an eye on, which is considered normal routine in these amps.

 

First, Mesa uses self tapping screws (at least in my amps) to fasten the power transformer, output transformer, and other parts to the chassis. They are not thru bolted. In these small combo high power amps, the vibration can make things come loose in a few months during hard use. Using loc-tite etc., does not seem to work all that well. My "routine" on my amps, and those I support that are on tour, is every three or four months, I pull the chassis and tighten down everything. After a few times of doing this, you will learn what stays tight and what does not. It is different in each amp.

 

These amps are very roadworthy. Even with the loosining issue, about all that happens is funny noises from within the amp. When recording at low levels, this can be a problem, but in live use, it is generally not an issue. The pots, wiring, and other internal parts are good quaility and the build quality is just fine. These amps last forever.

 

I think you will enjoy your amp for many years. There are a lot of cool features on these amps that are pointed out in the owner's manual, that are not common knowledge.

[SpeedysComing]

Thanks Myles, I 'll be checking out your website.

[myles_rose]

Originally posted by Speedy'sComing:

Thanks Myles, I 'll be checking out your website.

You are more than welcome

[SpeedysComing]

Hi Myles. Can you check this out is you have time and let us know if it's cool - thanks.

 

http://www.twilightpc.com/podxt.htm

 

http://www.instituteofnoise.com/for...=&TOPIC_ID=2453

[SpeedysComing]

I should have said at the AES Show.