Ampeg SVT 2 PRO retube

[BrutalPigeon]

Hello everyone,

I haven't retubed my SVT2 PRO in years. What tubes would you guys recommend? At the moment there are JJ inside and they worked out fine and they seem to be very cheap compared to EHX, Tungsol and so on.

I was thinking of getting matched sextet of JJ 6550 and JJ 12ax7 and 12au7 plus tungsol 12ax7 for V1?

Thanks.

 

[JimmyM]

Why are you retubing? Because it seems like the right thing to do after a period of years? Depending on your usage of them, tubes can sometimes last decades. My thought on the issue is "If it ain't broke, don't fix it." So unless the sound is degraded, I see no reason to replace any tubes. And when I do replace tubes, I only replace the one(s) that are broken, with the exception of power tubes, which I replace in triplet sets (each triangle is a triplet set, not each row). If, however, you insist, I'd probably go with JJ's again. Good solid tubes that won't break the bank. I would, however, pay a little extra for a 24 hour burn in just to make sure you're not going to pop in a tube that immediately fails.

Now if you want to have a little fun and experiment around with tone, V1 preamp is definitely the one to do it, since I hear little or no difference with any others. I have a Tung Sol 12ax7 that I bought on a lark just to see what happens, and it made my Heritage SVT-CL much brighter. Too bright for my tastes, actually. I ended up putting the stock JJ right back in. And when I need new tubes, I'll probably stick with JJ since they've been good and reliable for 6 years running and make my SVT sound like I think it should. But for those looking for a brighter and tighter sound would probably be well served by putting a Tung Sol in there. I'm just not one of them.

 

[BrutalPigeon]

Here is closure on this topic;

After thinking and researching for quite some time, I decided to take Electro-Harmonix 12AX7 and 12AU7 and with balanced tube for V1. For power tubes I took sextet of classic Sovtek 6550WE from. All tubes were ordered from TAD Germany.
I have also cleaned the tube sockets with dental brush. The process was really straight forward and after first setup of bias everything went smooth.

Sound has changed for sure. Now it sounds a bit more scooped sound with more upper mids and has more "low end/low midrange push" than before with JJ. Which I like, because I use a ton of midrange grit from B7K Ultra so slight scooped sound works great for me. Also amp got more punch and push which it was lacking before. Old tubes were circa 10 years old and were used every second weekend for a rehersals.

Cheers

 

[Wasnex]

Hello everyone,

I haven't retubed my SVT2 PRO in years. What tubes would you guys recommend? At the moment there are JJ inside and they worked out fine and they seem to be very cheap compared to EHX, Tungsol and so on.

I was thinking of getting matched sextet of JJ 6550 and JJ 12ax7 and 12au7 plus tungsol 12ax7 for V1?

Thanks.

I am with @JimmyM , if the output tubes are holding bias and the amp sounds decent, leave it alone. Tubes don't typically go bad unless they are being used. I have a 87 skunk SVT and it's still running all the original tubes. I had to replace the capacitors in the power supply because the original owner apparently never used the amp, but all the tubes are fine.

I also agree that if you do need to get new tubes, it's a good idea to pay the small premium for burn-in service on the output tubes. Modern output tubes have a pretty high infant mortality rate. The burn in gives an opportunity for bad tubes to self-destruct and also allows the getters to clear the vacuum of residual gases that are left over from manufacturing. The operating characteristics of tubes that have not been burned-in are more likely to drift. So it's best to do the burn-in before the tubes are matched. Basically the burn in makes the tubes more stable so they remain matched longer. Usually burn in service costs about $2 extra per tube.

Most of the small signal tubes can be replaced without concern, but I would urge a bit of caution if you decide to replace the two 12AU7s in the power amp. These tubes are drivers and control the bias of the output tubes. Here's my recommendations:
1. Replace the driver tubes in pairs.
2. Consider buying a matched pair of driver tubes. This is because one 12AU7 controls the bias for three of the output tubes, and the other 12AU7 controls the bias for the other three output tubes. You don't necessarily need matched triodes, which means the two sections (a & b) of one tube are matched. Instead you need matched sections between the two tubes; I.E. triode 1a is equal to triode 2a and triode 1b is equal to triode 2b.
3. Before pulling the old 12AU7 driver tubes, adjust the bias for minimum output tube current, and then let the amp cool enough so you can pull the old tubes. Install the new 12AU7s and follow the bias procedure in the manual. Here's why: when you install new driver tubes, it's likely they will be stronger. Stronger drivers pull the bias down, so the output tubes conduct harder. In extreme cases you can damage the output tubes or other circuitry. So preset the bias for minimal current in the output tubes.

You can replace any of the 12AX7s or 12AU7 in the preamp without in concern. You can also replace the 12AX7 in the power amp without concern. I wouldn't be a bad idea to have at least one spare 12AX7 and one 12AU7 to trouble shoot these tube positions. If the amp is acting up (turns on and holds bias, but noisy or won't pass signal), simply roll a new tube of the appropriate type through the amp to see if you can eliminate the problem.

 

[Wasnex]

Here is closure on this topic;

After thinking and researching for quite some time, I decided to take Electro-Harmonix 12AX7 and 12AU7 and with balanced tube for V1. For power tubes I took sextet of classic Sovtek 6550WE from. All tubes were ordered from TAD Germany.
I have also cleaned the tube sockets with dental brush. The process was really straight forward and after first setup of bias everything went smooth.

Sound has changed for sure. Now it sounds a bit more scooped sound with more upper mids and has more "low end/low midrange push" than before with JJ. Which I like, because I use a ton of midrange grit from B7K Ultra so slight scooped sound works great for me. Also amp got more punch and push which it was lacking before. Old tubes were circa 10 years old and were used every second weekend for a rehersals.

Cheers

Congrats. From what I have read the 6550WE is a good tube for SVTs. Also I have had good luck with TAD, although they do tend to be expensive . If the old tubes are beat, fresh tubes typically sound way better. I have rolled the EH12AX7 in couple of amps and didn't care for it. It was bright fizzy on top, and very lean on the bottom, but none of the amps were SVTs. I have seen several people who like them in SVTs, so .

 

[BrutalPigeon]

Hey Wasnex,

Thank you for your extensive reply, you seem to be very knowledble on this tubes topic. I did many of things you suggested your self.
I did find out that 12au7 in power amp are very important for stable bias, maybe I made mistake by not geting paired match... As far as I know, 12au7 in the preamp is just for drive knob? So it is not that important at all.
But I did take balanced v1, because I have heard it is very important since V1 makes most impact on sound. Also, I did take spare tube of each 12ax7 and 12au7 just in case of troubleshooting. Because I did bought tubes last year for my SVT3 PRO and one 12ax7 died after just few hours of use.

Also about the sound of EHX 12ax7, they definetely have less mids than JJ. EHX has more bite in the upper mids and treble and more low end than JJ. JJ sounds has more like a SAD face EQ, EHX is more like a HAPPY face EQ if that makes sense And since I am playing metal 99% most of time with heavy distorsion, I think that EHX suits me better. It makes the amp punchier.

 

[Inconnu]

Is there any ressources that list the typical sound of preamp tubes, like : ehx as more highs and lows, jj are more mid oriented, that brand is brighter the the other, etc.?

I’d be curious, because I really want to explore that without buying tons of tubes!

 

[BrutalPigeon]

Yes, this one is quite solid.
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[Wasnex]

Hey Wasnex,

Thank you for your extensive reply, you seem to be very knowledble on this tubes topic. I did many of things you suggested your self.
I did find out that 12au7 in power amp are very important for stable bias, maybe I made mistake by not geting paired match... As far as I know, 12au7 in the preamp is just for drive knob? So it is not that important at all.
But I did take balanced v1, because I have heard it is very important since V1 makes most impact on sound. Also, I did take spare tube of each 12ax7 and 12au7 just in case of troubleshooting. Because I did bought tubes last year for my SVT3 PRO and one 12ax7 died after just few hours of use.

Also about the sound of EHX 12ax7, they definetely have less mids than JJ. EHX has more bite in the upper mids and treble and more low end than JJ. JJ sounds has more like a SAD face EQ, EHX is more like a HAPPY face EQ if that makes sense And since I am playing metal 99% most of time with heavy distorsion, I think that EHX suits me better. It makes the amp punchier.

IMHO the JJ ECC83S doesn't seem to have any highs or lows, so I agree with EQ shape.

 

[BrutalPigeon]

I find JJ ECC83s to be better suited for an guitar amps which is too dark by default or if you want that extra midrange attack. They do work very good in Engl's and Marshalls from my expirience.

 

[JimmyM]

IMHO the JJ ECC83S doesn't seem to have any highs or lows, so I agree with EQ shape.

Pffft! That's an exaggeration. Funny, but still an exaggeration.

 

[Wasnex]

Is there any ressources that list the typical sound of preamp tubes, like : ehx as more highs and lows, jj are more mid oriented, that brand is brighter the the other, etc.?

I’d be curious, because I really want to explore that without buying tons of tubes!

Tubes and More = Antique Electronic Supply

I believe the second link is a duplicate of the info at Amplified Parts from the link in post #8. I am not sure if these two companies are the same, or if the just share a distributor and pricing.

12AX7 / 7025 Tube Reviews - www.thetubestore.com

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Analog In

Keep in mind that the circuit has a significant impact on how tubes behave. There is no guarantee that a tube will sound and behave exactly the same in two circuits. In some circuits you barely hear any different when you try different models of tubes. In other circuits, the tone changes noticeably.

Both Antique Electronics Supply and RF Parts have a couple of 12AX7 sampler packs that appear to be a pretty good deal. I think there is some duplication in the 10 tube sampler under different labels, but it also includes three of my favorite 12AX7s. Mullard 12AX7 (ECC83), JJ ECC803S, Sino 12AX7B.

The 5 tube sampler doesn't include any of my favorites. Actually I would probably have no use for the EHX 12AX7, JJ 12AX7 (ECC83S), and Sovtek 12AX7WA in either pack, but YMMV. It's relatively cheap and you could have some fun and learn a bit. The Tung Sol and Ruby are good sounding tubes.

 

[BrutalPigeon]

But to my ears, EHX does not such that much different than Tung-Sol. Very similar style of voicing. Also very similar structure of tube, even tho they are different replicas(Tung-sol vs. philips)... Tungsol has more gain, that is for sure. With slight twist of EQ knobS you can make identical I'm sure. Both great tubes in my book.

 

[Wasnex]

But to my ears, EHX does not such that much different than Tung-Sol. Very similar style of voicing. Also very similar structure of tube, even tho they are different replicas(Tung-sol vs. philips)... Tungsol has more gain, that is for sure. With slight twist of EQ knobS you can make identical I'm sure. Both great tubes in my book.

In my tube rolling experiments, the EHX was drastically different from a Tung Sol. The Tung Sol had big highs and lows and was very hard and punchy. The EHX was bright but had lean lows.

I rolled these tubes in the OD channel of my Trace Elliot V8; here are the notes:

Genalex ECC83 (Sino) The V8’s distortion channel (V2) tends to emphasize highs and rolls of the bass. The Genalex transitions smoothly from clean to distortion and has the most even tone/distortion of all tubes auditioned for this position. The timbre with the Genalex in the circuit was most similar to the bypassed (clean) tone and remained relatively tight with lots of fundamental all the way down to open B. This tube produced the least fizzy/buzzy distortion of tubes auditioned.

Second choice: The generic Sino 12AX7B was by far the highest gain of the tubes auditioned in this position. Distortion comes on almost as smoothly as the Genalex but the tone is a bit thinner and the low end washes out earlier. The distortion is a bit brighter.

Third choice: The Tung Sol 12AX7 distortion and timbre were very similar to the Sino 12AX7B, but it had about the same amount of gain as other tubes I tried. The Tung Sol’s transition from clean to distortion is a bit less linear than the Sino.​

Fourth choice: The Electro Harmonix 12AX7 had the leanest/brightest timbre and produced the most uneven fizzy/buzzy distortion. The EH also had the least linear transition from clean to distortion and the break over into distortion varies with frequency. Low notes require a stronger signal to distort than higher notes.

All of these tubes can excel with different timbres of high-gain distortion. The Genalex stands out with the best touch sensitivity at low gain settings, and with clearer tone and lows that hold together longer with higher gain settings.​

 

[BrutalPigeon]

Well you have really made your trial and error testing. Now when I'm reading your posts, I'm thinking of getting different V1's to check which one suits me the most. Even though, at the moment the amp combined with 8x10 fridge is kicking maximum ass

 

[Wasnex]

Well you have really made your trial and error testing. Now when I'm reading your posts, I'm thinking of getting different V1's to check which one suits me the most. Even though, at the moment the amp combined with 8x10 fridge is kicking maximum ass

Nothing wrong with buying a few more tubes and having a bit of fun, but IMHO the most important thing is to trust your ears and be happy .

 

[BogeyBass]

id say if there is a big jump in tone or gain its usually a turd cheap tube.
usually the small plate guitar type tubes.
not sure of the whole line the Electro Harmonics but they were usually fizzy and nasty
usally died or krickle crakled sooner then others.

maybe circumstance but every tube head i got with a tube going bad was either those EH tubes or some generic groove tube.

anyhoo as always mention the Sovtec LPS which is a darn good sounding tube and consistent

nothing wrong with tube rolling. just seems the more turdy tubes usually have big tone changes bright this or mid that etc etc. early breakup late breakup etc etc just points to turds ....sometimes

alot guys report good luck with this or that and its cool. sometimes even a new turd tube sounds better than a ancient tube that needs to be pulled or is just plain stale sounding.

so its a grain of salt. some guys say...ohh i dont like that tube. you mean the 10 year old stale one you pulled out is the comparison lol
or guys like me saying i have more dead EH tubes than all the others. maybe circumstance or its " the cheap one" so you probably run into them more often.

at one point a salesman pointed out that there is a suffix on the groove tubes for Russian or Chinese and of course the " Russian" one is better.
i bought both. The Chinese tube sounded better actually.

think the mean and fizzy and high gain tubes some guys like.
anyways blah blah. i just go for the Sovtec LPS most the time and it does everthing well.
sometimes it just dont matter. even a so called " turd" tube will at least wake up a amp and sound much much better than a really old tube.
or likewise if you got a pinger or krackle tube. its gotta come out and anything at that point sounds better

 

[Arthur U. Poon]

Not to derail or piggyback on another person's thread, but I've got a couple of questions regarding 12AX7 tube choices for V1:

I wish I would've known about tube rolling back when I owned an SLM-era SVT-CL and an SVT-2Pro. Both had too much raspy distortion once I cranked them up to gig levels with the ultra-loud bandmates I had in those days.

I talked with Dino about this ages ago on Alembic's forum, and he suggested diming the master and using the gain to control my overall volume. This worked to a degree, but I still wanted less preamp breakup when I was gigging. BTW, I was using an SLM-ERA 810E that was most likely manufactured in the mid to late 90's.

So, @Wasnex and @JimmyM :
Which 12AX7 in V1 would you recommend if you were looking for slightly less breakup from an SVT-CL's preamp? And if 12AU7 tubes work in conjunction with getting less preamp distortion at stupid volume levels, I'd be interested in your suggestions on those as well.

I'm slowly getting my wife to come around on letting me buy another SVT setup (or a Fender Super Bassman or a Traynor YBA300). Our daughter has just started College and our youngest is only 2 years away from enrolling in College too, so I have to get the most "Bang for my bucks" when I buy an all tube head. I'm leaning towards a clean used SVT-CL and a clean used 810E to make the "sticker shock" lower, to increase my odds of getting my wife's OK. I know what to expect from an SVT-CL/810E setup, so it's my first choice.

Thanks, Fellas!

 

[JimmyM]

Not to derail or piggyback on another person's thread, but I've got a couple of questions regarding 12AX7 tube choices for V1:

I wish I would've known about tube rolling back when I owned an SLM-era SVT-CL and an SVT-2Pro. Both had too much raspy distortion once I cranked them up to gig levels with the ultra-loud bandmates I had in those days.

I talked with Dino about this ages ago on Alembic's forum, and he suggested diming the master and using the gain to control my overall volume. This worked to a degree, but I still wanted less preamp breakup when I was gigging. BTW, I was using an SLM-ERA 810E that was most likely manufactured in the mid to late 90's.

So, @Wasnex and @JimmyM :
Which 12AX7 in V1 would you recommend if you were looking for slightly less breakup from an SVT-CL's preamp? And if 12AU7 tubes work in conjunction with getting less preamp distortion at stupid volume levels, I'd be interested in your suggestions on those as well.

I wouldn't really know that one, Arthur. Since the Tung Sols are a lot brighter, maybe you could try one of them and see if the brightness makes it feel like it's going a little cleaner louder. A 12au7 will merely move the distortion point to a higher spot on the knob, much like hitting the active switch. But it's my experience that the SVT is what it is, and maybe you can eke out a tiny bit more one way or the other with different tubes but don't be looking for miracles.

 

[BrutalPigeon]

He is right. SVT sounds like a SVT and different tubes will not make it sound that much diffetemt. Considering tubes are new or in good condition.

Discussion here is pretty much about small details in sound between different tubes. To an untrained ear, they are probably not noticable at all. But in sound, devil is in the details