Preamp Tube Experiments

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jdurso

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I just want to just share my adventure over the past few weeks with the Roadster and experimenting with NOS preamp tubes. I'm not going to go into detaiul on the tubes, but focus more on how the Roadster reacts to them, hence posting it here instead of the Tube section. Alrighty then, picture this if you will (cudos to those who get that one):

The whole point of me diving off the deep end was two fold... one i wanted to get more aggression out of the Roadster similar to what i used to get with my old 2 channel Triple Recto, and at the same time try and retain the sweet cleans of the Roadster. The second reason was to just learn more about my beloved amp, and hopefully understand in more detail what produces what. With the help of Shred (fellow BB forumite) I aquired a bunch of NOS tubes to start with (his "metal package" as well as a few others). Not only did he supplier some great tubes but also helped me out with understand each tubes characteristics and what each preamp position did in the gain structure of the preamp. After a few very very very long PMs I began to unravel the secrets of Randall's brilliant design. Now i'm not well versed in amp building or jargon so I use my ears and my jargon to explain things... so i apoligize if i'm not right on something or explain it in a weird way. By all means please correct me if something doesn't sound right as i consider myself to be still learning.

V1 & V2 - Most will say V1 is the most important slot of the preamp and they would be right... but not fully when in terms with the Roadster. In the Roadster i have found V1 and V2 really work together a lot more than other amps. I found V1 really sets up the whole preamp in terms of headroom, compression and the higher frequencies. I experimented with tubes that stayed very clean and some that broke up very early and what i found was the ones that stayed clean at high volumes offered the most headroom to the entire preamp no matter what i put in any other slot (with maybe the exception of V6 but we'll get to that in a bit). So with that logic if you throw a tube that has an earlier breakup point the entire amp will feel more compressed and will give you "heavier" or "crunchier" tones at lower levels which was great for channels 3 and 4 but limited channels 1 and 2 somewhat.

Ok so enough with V1 because its only half of what will completely define the amp in the end. V2 much to my suprise plays a much bigger part in the whole preamps structure than what i thought or read anywhere else. To me V2 is where you can add a lot of character by defining the mids and adding harmonic complexity. The way i came about this is if i put a very mid heavy tube in V2 the whole amp would ahve more mids. Putting in a tube with less would give the amo less and if you pick a tube that has the right amount of mids and that yield very rich harmonics, those characteristics will carry to the entire amp. What took a lot of time was trying every different combination in V1 and V2 to see what felt/sounded right and what i came to realize is that if you choose a preamp tube with the right headroom (breakup point) and the right characteristic in the highs, and then selected a tube with the right amount of highs and the right harmonic complexity, anything else i tried in the other slots had a minimal effect on the overall sound (with a slight exception for V6). So I ended up putting in a Sylvania in V1 due to it having a high breakup point and nice glassy highs and a Siemens in V2 as it seemed to have the richest harmonics and the perfect amount of mids. If any recto user has read this far here is why i love this combo in V1 and V2 so much:

1. More headroom which keeps the cleans super sweet and super clean with those glassy, sparkling fender highs
2. Overall the amp has more mids than with the stock tubes... why is this important? The leads are 10x better and creates a much full attack for rhythms
3. NO MORE FIZZ!!! Thats right the biggest downside to a recto in mot peoples eyes. Now the Roadster is probably the least fizziest Recto but my fizz is now non-existant unless i dime my presence. This solution is cheaper than running an eq in the loop and sounds better as its organically created.


V3 - I found through many nights or hair pulling and cursing that you need to select V3 very carefully and make sure its chosen in respect to whats in V1 and V2. V3 seems to control the overall amount of bass on tap. If V1 and V2 aren't strong enough in the high end and the tube in V3 has a very pronounced bottom end you end up with an amp that sounds very vintage and could be boarder line flubby even with most of the bass dialed out. It would also kill and sort of crunch you would expect out of channel 3 vintage mode. What i found to be the right balance was having tubes in V1 and V2 that were very strong in the highs and mids and then selecting a tube with the amount of bass you want. Warmer the tube in V3 the more vintage-y the amp would sound, and also the flubbier. I started and eventually ended up with a GE Long Plate in V3... when i started i didnt have the Sylvania and Siemens in V1 and V2, and having the long plate in V3 , i ended up with an amp that was waaaaayyyy too bassy. Then once i found the Sylvania and Siemens was the right tubes for me in V1 and V2, i tried every other tube i had in V3 and was trying to stay away from the long plate because of past experiments. I had a mullard in there until i tried the GE long plate ago and low and behold it had the right chemistry for me. The lows with the GE long plate are pronounced and strong without being flubby (the mullard i found super warm but also pretty flubby for v3).

V4 & V5 - With the help of the Mesa RK manual and Shred I learned V4 is for your reverb and V5 is for the fx loop. Going on his advice i went with a warmer tube for the reverb and as very clear/quiet tube for the fx loop. After much experimenting i found that Shred's formula was on point. I have a Mullard 12at7 in V4 as it gives me a warmer reverb than all the other tubes. In V5 i have a GE12at7wc as it is the clearest in tone and really sent the best signal to my Axe-fx. What i did find is putting the Mullard in V5 added a bit of warmth to my effects which can be great for warming up digital delays and reverbs. For my taste i found the GE a better tube as I kind of dig the little bits of digital characteristics the axe-fx adds (different than other digital fx i've used). Since the axe-fx has very complex reverbs, the mullard ended up warming them up into mush so that was the biggest reason for keeping the GE in V5. Now in the future I'm going to experiment with a some different tubes (other than the ones i have) in V4 to see if i can improve on the reverb anymore.

V6 - With Shred wealth of knowledge i found the phase inverter V6 to control the overall presence of the amp. V1 and V2 still have the most control over the highs and mids but V6 can determine how glassy or mellow they are. Put a tube thats very strong in the highs and your highs can be somewhat ear piercing and it can also add a little bit of fizz (not much but if you tend to run the presence high then yeah its there). I exerimented with 2 basic tubes here... one being Matsushita 12ax7 and a Mullard 12ax7. The Mullard has very smooth highs so i found putting it in V6 gave me a slightly mellower presence which if i were a lead player i might opt for it. The Matsushita has amazing highs and mids hat can border on brash. I ended up with the Matsushita mainly because it gave me a much wider presence sweep and giving me more control over the presence knob. The only caveat can be since it has very strong highs and mids that can breakup quite easily its important to note where you run your presence at. If i dime the presence some of the fizz comes back and the hgihs can be slightly piercing... but suprisingly the the sweep of the presence is so wide with this tube in V6 that as long as i keep the presence between off and 2 oclock i'm golden. For Channel 4 modern i keep my presence at 9 oclock since i use it mainly for leads and single note type stuff (*** well as a rhythm that sits further back in the mix when need be). In channels 1 and 3 i keep the presence around 1 oclock... this gives me the glassy like highs in channel 1 clean tweed (running gain very low) and gives me a nice crunchy metallica rhythm in channel 3. Actually i find my channel 3 vintage right now bordering mark IV territory which is awesome.


OK so in conclusion what i've taken away from this adventure is these few rules of thumb:
1. V1 controls the overall headroom and treble characteristics of the preamp, V2 contols the overall harmonic structure and mids of the preamp, V3 controls the overall bass of the preamp and works dependant of whats in V1 and V2, V4 controls the characteristics of the reverb, V5 controls the characteristics of the fx loop, and V6 contols the overall presence of the preamp
2. V1 and V2 have the most influence the overall preamp as far as reacting to different tubes
3. Putting a tube with earlier breakup in V1 will reduce the amount of headroom of the amp and can be beneficial to those want to get breakup at lower volumes (almost like using an attenuator)
4. V2 unlike most amps plays a bigger role in the whole scheme of things
5. Dont put a tube with a very strong bass in V3 if V1 and V2 dont have the highs and mids to balance it out
6. You can cure the fizz with the right tube
7. The right tubes in the preamp can eliminate the need for an OD infront or an EQ in the loop


Again i'm just using my ears and my own words to make these conclusions and descriptions. I maybe totally off on whats actaully is happening but all i have to go by is my ears. Keep in mind also i have not experimented with every tube out there so using the tubes i've used may bias my results. In all my tests i used my PRS loaded with Aldrich pups, two cabs (mesa roadster 2x12 and a basson 2x12), my axe-fx for testing the fx loop and planet wave cables throughout. One thing i want to point out is that because of the tubes i chose in V1 and V2, i lack a little saturation so I still use my OCD when i want that chug that "gives" a little. I think because the Aldrich pups, while hot, are very clear and even sounding, they take away from the chug at times so thats why the OD is still needed. I'm planning on experimenting with some different bridge pups to see if i can get away from using the OD for rhtyhms. With my Eclipse that has EMGs there is no need for the OD but there are certain things the EMGs lack that the Aldrich's give me so i'm kind of stuck at the moment. The only reason i'm bringing this up is so it doesn't turn anyone off thats into super heavy tones... because trust em this combination of tubes slays all the other combinations even if it slightly lacks a little saturation (basically sounds more VHT than what you'd think of when you think Mesa high gain).

I hope i didnt bore anyone and i apoligize for such a lengthy post. At the end of the day it was well worth the experiment because at this point i have no need for an EQ in the loop and almost no need for an OD in front (at least for rhythms). I hope someone finds this helpful at some point as i think picking up the right few tubes can be cheaper than buying all these external units to try and conjure the sound you have in your ehad out of the amp. Yes it does take more time and can be more frustrating than just using an EQ or OD but the fruits of your labor will be repaid tenfold once you get the right combination. Plus i can't say that i've ever played so much guitar than i ahve in the last few weeks.... ended up writing about 3 songs and 2 other strong song ideas in the process. I havent been that productive with writing ina few years so i'm a very happy camper right now... and will be mroe so when my mills acoustics cab gets here at the end of the week :twisted:
 
this is a great read... I'm still getting my head around it. Do you think this applies to other Mesa amps like the rectifier series?
 
Awesome post, Jon! I'm curious as to what you found works the best as I'm considering getting a Mark V because I'm just not finding 'my' tone with the Roadster now and am unable to dial out the fizz. :)
 
mixtery said:
this is a great read... I'm still getting my head around it. Do you think this applies to other Mesa amps like the rectifier series?

Well i think the principles will be similar but i can say it should almost definitely work with the RK as the Roadster has the same preamp design. Shred and I talked about this, and he has way more knowledge and experience with other Rectos especially the 2 channel designs.

It would be interesting to try this on say a 3 channel DR and see if V1, V2 and V3 work in the same manner. I would assume they would be similar but not the same because if you play one of them stock side by side with a stock roadster there are differences right off the bat. So the principle of it may be the same but i have a feeling V1 would play an even bigger role in a standard DR/TR like they do with the 2 channel DR and TRs.

Maybe one of the tube guru's can chime in as I a definite newb with exerimenting with the preamp and knowing more about the design.
 
Kaz said:
Awesome post, Jon! I'm curious as to what you found works the best as I'm considering getting a Mark V because I'm just not finding 'my' tone with the Roadster now and am unable to dial out the fizz. :)


I felt like i was in the same boat a few weeks ago before and while i was experimenting (especially once the Mark V was announced). I will say I never really thought my roadster was that fizzy but i always run my presence pretty low (chan 2 - off, chan 3 -10, chan 4 - 9) other than on channel 1. But i did find with a Sylvania in V1 and a Siemens in V2 that the fizz was non-existant, especially with a Mullard in V6. I kept the Matsushita in V6 because i wanted a wider sweep of presence and so right now if i dime the presence i get a slight fizz but since i never run it close to that high i'm all good.

Here is what I have in the preamp.... not sure what exact model the Sylvania and Siemens are since some of the logos are kind of scratched out.... i'll check tonight though since Shred labeled all the boxes:


V1- Sylvania 12ax7 short-plate
V2- Siemens ecc83 long-plate
V3- GE 12ax7a Long plate
V4- Mullard 12at7
V5- GE 12at7wc 6201
V6- Matsushita 12ax7a

The Mullard i was swapping in and out of V6 was a Mullard 12ax7a/7025a... when i put that tube in V6 it made the whole amp smoother. I'm not here to make recommendations though... if i was better versed in this stuff maybe, but i'm just going off of what i hear and what i like in tone which could be different from everyone else. Also because the Sylvania and Siemens are very clean sounding you do loose slightly in the saturation deptartment. But you can get around that with a good OD or the right pickups... that much I'm convinced of because with an OD infront i'm in chugging heaven and with my ESP same deal, but certain things become a little sterile.
 
Rosetta Stoned!

Great post, bro. I used to make similar long posts about my Studio Preamp on the Rack Pieces forum but got sick of all the assholes saying "you're wrong" and "that is not a fair comparison". We shouldn't have to apologize in our post that we "might not be 100% correct" but that's just how it is in these times of techno-douchebaggery.

Reading this post really makes me regret selling my Roadster, and would have saved me about $3000 on all the amps I bought and sold between the Roadster and my current rig. I sold it because I just couldn't get a fizz-free high-gain lead tone out of it. I had great luck with the Roadster when it came to low-gain "in-between" type of tones, but I found the fizz on mine was unavoidable once any gain knob passed a certain point; and that point wasn't very high up on the dial.

I really want to try another Rectifier head but they are just so overpriced. My entire rack setup now is barely worth the same as one used Single Rectifier head.

I had an awful lot of hope for that Roadster. I nearly cried when I saw the guy I sold it to posting videos of himself making god-awful music through it. It sounded... well just horrible.
 
good post J , better you then me testing this **** though ! I might have to mess with mine a little, I still dont get the fizz thing mine has none of that??? just sounds badass even for the heavy **** Im only at 1 oclock with the gain so mabye people are cranking it alot, I dont know why though?, although I cant imagine getting rid of the eq it just works too well.
 
DMTransmutation said:
Rosetta Stoned!

Great post, bro. I used to make similar long posts about my Studio Preamp on the Rack Pieces forum but got sick of all the assholes saying "you're wrong" and "that is not a fair comparison". We shouldn't have to apologize in our post that we "might not be 100% correct" but that's just how it is in these times of techno-douchebaggery.

Reading this post really makes me regret selling my Roadster, and would have saved me about $3000 on all the amps I bought and sold between the Roadster and my current rig. I sold it because I just couldn't get a fizz-free high-gain lead tone out of it. I had great luck with the Roadster when it came to low-gain "in-between" type of tones, but I found the fizz on mine was unavoidable once any gain knob passed a certain point; and that point wasn't very high up on the dial.

I really want to try another Rectifier head but they are just so overpriced. My entire rack setup now is barely worth the same as one used Single Rectifier head.

I had an awful lot of hope for that Roadster. I nearly cried when I saw the guy I sold it to posting videos of himself making god-awful music through it. It sounded... well just horrible.

Well if you're happy now then I wouldnt worry about it (even though getting that 3000 back would be nice huh?). I don't know if the Rectos are for everyone. I think a lot of people get them and expect to get a tone out of them that just isn't there (or atleast not there without some help from ODs and EQs). So if your happy with your tone right now I would regret any of it... but i do apolagize if i cause you some GAS as the guys talking about the Mark Vs are giving me.


here's my thing with the fizz.... i think every recto has it... no matter if we're talking a 2 channel, pre-500, tremoverb, rectoverb, DR, TR, Roadster, Road King, etc. I think that fizz (or as i call it sizzle) is just part of the sound, but the difference to me is whether its musical or not. I find in the 2 Channel rectos have the sizzle but its a good sizzle as it blends in nicely. Thats the type of sound I've been able to achieve with this tube combination. Now take a 3 channel DR or even some of the roadsters out there and the sizzle is definitely too present in the sound of the amp and is a turn off to most people. Mine from the start really didnt have that fizziness but it definitely lacked some of that musical sizzle... these tubes have basically reduced the sizzle and what was left made it more musical, which is why i opted for the matsushita in V6 rather than the Mullard. The Mullard completely took it out which some would probably love... to me it didnt have that recto sound which i love so i opted for the matsushita which gives me the sizzle if i want it and when i turn the presence off its more mullard like.

Also a big part of suppressing the fizz is what you have in V1 and V2. I orginally started with a RCF ecc83 in V1and it had a very early breakup. i also had a Mullard in V2 which was super warm. That combination gave me a slightly darker, super smooth and creamy high gain which was amazing for leads but for me lacked the right presence for rhythm work. No matter what i put in V6, as long as those tubes were in v1 and V2 the Roadster was as smooth as a babies bottom. The gainw as very rich as well, and you could actually get pretty awesome bedroom level tones.

again, i hate to apolagize, but if anyone thinks i'm a little off base with my assessment please point it out.
 
155 said:
good post J , better you then me testing this sh!t though ! I might have to mess with mine a little, I still dont get the fizz thing mine has none of that??? just sounds badass even for the heavy sh!t Im only at 1 oclock with the gain so mabye people are cranking it alot, I dont know why though?, although I cant imagine getting rid of the eq it just works too well.

I think everyone hear's "fizz" differently. Like i said in the post above, all Rectos have the fizz... the difference to me is if that fizz is more of a musical sizzle which adds character and is THE recto tone, or it could be a very annoying fizzy layer in the higher spectrum of the amp which is very un-musical. I find the 3 channel rectos and some of the Roadster's I've played have that fizz (much less in the roadster though). Something happened in the preamp design when they moved over to the 3 channel models... maybe to make the cleans better there has to be a greater overall presence in the amp? Or maybe to make the cleans better V2 has to play a more integral part in the tone stack like i found with the roadster? I dont know, thats all speculation but it is pretty evident somehting happened when they added the 3rd channel to create such an annoying fizz.

So it could just be you got a great amp out of the batch or a good set of preamp tubes thats giving you a fizzfree sound. or it could be your so used to it because you dig the recto sound that it doesn't phase you as actually being there. I will say however that i like the fact i dont HAVE to use an EQ anymore or even an OD for that matter. I think there is a huge difference between wanting to use something and having to, and i have hated HAVING to use my EQ over the past few years in order to get the tone i needed. Its very freeing not having in the loop anymore because I find i'm tweaking less and playing a hell of a lot more.... its actually inspired a whole bunch of new songs which hasn't happened in quite some time.

So i would say if your interested in trying it, then go for it, just dont go over board on the the more expensive tubes if you dont have to. but if your happy with your amp then i would say dont touch anything and stick with what works. My motives were to elarn mroe and try and get more out of the amp... if i was prefectly happy i would never have done this.
 
Laskyman said:
Amazing read- so where do I get a Sylvania and a Seimans............


Laskyman


haha thats a **** good question isn't it. I bought them from Shred so i guess he would be the one to ask. I would look around eBay or maybe check with the guys that frequent the Tube forum on the BB.
 
Thanks for the detailed explaination JDurso. Does anyone know if this will have a similiar affect on a 3 channel DR. I have been wanting to experiment with different preamp tube, but nervous about spending money on NOS tubes. May be suggestions for cheaper preamp. Right now I use mesa el34 in poweramp and play rock and hard rock, once in a while some metal. Any help would be appreciated. Thanks
 
njsurf said:
Thanks for the detailed explaination JDurso. Does anyone know if this will have a similiar affect on a 3 channel DR. I have been wanting to experiment with different preamp tube, but nervous about spending money on NOS tubes. May be suggestions for cheaper preamp. Right now I use mesa el34 in poweramp and play rock and hard rock, once in a while some metal. Any help would be appreciated. Thanks

NOS arent necassarily expensive. You can find most of the tubes i have in my roadster for between $5-20 a pop, but we're not talking crazy expensive. From what I've read, i would think you would have an even easier time with a 3 channel Recto as I've heard V2 has less of a role and you dont have to worry about the tube for reverb.
 
Amazing reseach!!!!!!!!! thanks for sharing... this is been a great guideline in order to find a balance sound that suits my playing :D

thanks alot!!!!
 
Cool thread.
The most I experimented with preamp tubes was putting a low noise 12ax7 in V1 and V2 since I know both are very important positions. I managed to get a lot of the hiss out that ways.

What have you guys done by way of power tube experimentation??! I find that really affects tone as well.
 
I wonder what the result of putting a 12au7 in V1 are. I'm wondering will that get me a earlier breakup or the opposite?? Maybe I should try it.
 
orangine2002 said:
I wonder what the result of putting a 12au7 in V1 are. I'm wondering will that get me a earlier breakup or the opposite?? Maybe I should try it.


I have found the opposite true as far as breakup... most that i have tried (Sylvania, Philips) had lots of headroom but were almost too clear and i could never get used to the breakup (this is in V1). i did however find them pretty good in the PI and in your effects loop slot (V4 or V5 depending on if your amp has reverb or not). Since they're more of a hi-fi tube (or at least i'm told they are) it makes sense that they would have a lot of headroom and would be clear... also makes sense that if you want a clear effects loop you'll want to use a tube with those characteristics.
 
hey jdurso this is a great guide for us folks looking for a better tone... it's been a while since i posted in here and if I remember I was asking for advice on od pedals... I ended up buying a bb preamp
i have a boogie road king 2 head... and recto 2x12... i love the recto sound and the sparkly cleans so the roadking ii was the obvious choice for me... however, now that i have the amp for two years, i'm well beyond the honeymoon period and sometimes i want to improve certain things... in my case I run the amp with very little to no bass at all on channel 3 and 4 because the amp itself sounds kind of flubby and any bass I add makes things worse. My guitar is an ibanez rg2550 (basswood) with air norton (neck), fast track 1 (middle) and steve's special (bridge).
How are things going with your new tubes? I would like to try changing the tubes to have a tighter bottom end and less bass on tap without using pedals...
 
Pre-amp tube gain factors explained here;
http://thetubestore.com/gainfactor.html

Many people associate "headroom" with "low gain", but it's not exactly same thing.
Headroom really means, "How loud can I turn up the power section before it starts to distort?"
A 100 watt amp has more "headroom" than a 20 watter, regardless of the distortion supplied by the pre-amp tube(s).
Replacing a 12AX7 (gain factor = 100) with a 5751 (gain factor = 70) will give you 30% less pre-amp gain. This means that if you get a particular lead-type sound with the gain knob on "7", you now need to turn the knob up to "10" to get the same level of distortion.
However, your amp doesn't get louder.
 
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