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Solid State Amplifiers => Tubes and Hybrids => Topic started by: rodriki1 on May 28, 2010, 01:12:21 AM

Title: sorry for another question about tube vs transistor
Post by: rodriki1 on May 28, 2010, 01:12:21 AM
to make a story short,

sorry for bothering with this subject again.

but i must say i liked so much this article below:

http://milbert.com/articles/tubes_vs_transistors_in_electric_guitar_amps

and i do not understand why things like this are not well accepted.

but this not the point.

i would like to ask... the transistor amp might be the carvin SX series????
if it is true that it is a carvin, why the man behind the idea (john murphy) did not
used or suggested an equalization after the preamp (as he did in his article
about duty cycle modulation).

thanks


Title: Re: sorry for another question about tube vs transistor
Post by: Jack1962 on May 28, 2010, 12:21:51 PM
Well I have no idea bro , but I will say this , a properly engineered amp weather it be tube or solid state will sound good and  be reliable. Which one sounds best is a personal choice I have heard both types that sound great and I have heard both that sounded bad. I use both tube and soild state amps myself , I personally prefer my tube amps.

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Title: Re: sorry for another question about tube vs transistor
Post by: rodriki1 on May 28, 2010, 09:42:06 PM
well Thanks for your answer.

that is the point. WHY there is this preference for the tube amp.

SAG?? COMPRESSION??? LOW FI SOUND??? DIRTY in the sound??

but my question is that amp they used in the test sounds to be carvin sx.

thanks.
Title: Re: sorry for another question about tube vs transistor
Post by: teemuk on May 29, 2010, 02:44:58 AM
Quote
but my question is that amp they used in the test sounds to be carvin sx.

Actually, I think it might have been a Fender. This study is after all made by some members of the Rivera-lead design crew that practically redesigned all Fender amplifiers in the 1980's and lifted the reputation of the company (as an amp maker) out of the swamp it had sunk in.
Title: Re: sorry for another question about tube vs transistor
Post by: Enzo on May 29, 2010, 04:04:45 AM
Didn't the article state that the preamp was custom made for the testing?  As opposed to using a commercial preamp.


Interesting paper, I'd note the preamp testing was limited to "linear" settings, meaning I guess that it was only tested running "clean."  Thus no attempt to compare overdriven preamps.
Title: Re: sorry for another question about tube vs transistor
Post by: bry melvin on May 29, 2010, 04:43:37 AM
Actually I don't think ther was a Carvin SX that used 4558s then. Ithink the first SXs were around 87 and MOSFET.

The current SX isn't all op amps ...couple of Jfets.

That said there isn't really an eq IN an SX... tone stack but not really an EQ. I always DO use an eq on the Carvins here. And after the preamp. It's in the effects loop  along with a effects processor AND a tube Preamp actually.

Not sure why someone would think that they used Carvin for that paper.

To me that paper doesn't mean a whole lot. The amps weren't used in the test in a manner that a musician would use them.

Actually there are "fanboys" that will debate this (tube vs ss) till you can't buy tubes anymore! Musicians use whatever works 'till they get an endorsement, then they get THAT equipment reworked until it does what they want.

Very few recordings are done with what is used onstage. And today onstage EVERYTHING ends up getting miked and put through a PA.

I use Marshalls Peaveys Vintage 60s Guilds Sunn Fender and Ampeg amps depending what I am playing/recording.

In the Studio it is VERY difficult to use high powered tube amps. Often what SOUNDS like a big tube stack is not. Even Hendrix and Clapton have recorded with little Champs and Princetons etc. on occcasion.

FWIW My preference for a Blues overdriven "tube" amp in the studio is a Carvin SX coupled with a JCM 800 on the low input (feeding to both) and outputting both by DI through ART processors for effects. I get four channels to tweak afterwards in the mix.  Everything is not always what you think it is on a record.

Title: Re: sorry for another question about tube vs transistor
Post by: J M Fahey on May 29, 2010, 09:23:17 PM
The test is very interesting , specially because it shows no significant perceived differences.
It clearly implies that a Twin type amplifier was used as the tubed one, a low-damping/current-feedback SS one .
In each and every test, only 1 (one) listener found a difference, and it was almost always ripple modulation in the tube amp.
The SS one, being a huge Op Amp, showed great immunity to ripple, which only appeared when overdriven.
The "Tube=even harmonics/SS = odd harmonics" fallacy is repeated mindlessly even as their own spectrum analyzers show that is not the case.
It can clearly be seen that the tube amplifier produces both  strong odd and even harmonics, they should be at least 15 to 20 dB below what's shown, not the puny 1 db shown, which can rather be attributed to output tube mismatching, Phase Inverter mismatching and non-correction of that because of the low NFB available.
And there was absolutely no difference between clean Tube and SS preamps.
The test was incomplete, because there are differences between Tube and SS amps when played loud, at stage levels, not trying to overdrive them but when inevitably some signal peaks clip because of guitar signal dynamics.
A VS100/212 (or a VS8240) and a Twin, when played "clean" on 5 or 6, sound quite different, the tubed one having more apparent headroom, "bite" and "natural sustain", the SS one starting to sound broken, although both have good preamps, same power output and comparable quality speakers.
There is where a difference still exists, that gray area between clean and distorted.
The only "famous" SS amps I found comfortably happy in that no man´s land were LabSeries ones, which allow for a careful and independent tweaking of  distortion and compression and the excellent Pritchard amps, whose real schematics nobody knows. Of course the many patents can be read, but what's actually used is anybody's guess.
Another *very* good but mysterious amp is the Bluetone.
Most other SS amps can be excellent either side of the barrier, but not on both.
Best cleans: Roland JC and those powerful Peavey steel amps.
Best distorted: Randalls and Ampeg VH140/150
Title: Re: sorry for another question about tube vs transistor
Post by: bry melvin on May 29, 2010, 10:20:22 PM
I agree with the inconclusive Greatly.

It is interesting but as a musician doesn't create a Eureka moment for me. I use both SS and tube simultaneously to make sure I can get the sound I need. I usually need it just at the edge of that no man's land of clean but distorted.

I have reservations concerning the tests equipment. It is very likely that the Fender twin was a silverface or Post cbs blackface. I USED to play with pre CBS Fenders ( in the 60s).  Back then no one wanted the CBS versions as the sound changed drastically and they were REALLY prone to self destruction. If so the whole thing is moot as I wouldn't touch one with a ten foot pole.(although today a lot of people love them) A lot of us moved to Marshalls and Sunns etc. back then.
I really liked the mid 60s Guilds,and still hold on to them.

The solid state amp used in the test is unidentifed and nebulous in description. So it's kind of meaningless as there is nothing for the Musician to say...THAT is the SS amp I need.

Lately I buy mostly solid state: they are reliable and much better sounding at low SPL. I AM partial to Carvin's SX series, but use others on occasion. One of the "favorites" I have stayed away from is the Roland Jazz chorus. There were some good ones, but the innards of those have changed multiple times.Recent ones haven't been that popular. A lot of them are sold through past reputation and found wanting. ( I know several musicians with one stuffed in the closet) .I own a couple of big Road Cases of rack gear that let me duplicate just about any sound I need but I still like to play with four 2x12 setups half tube and half solidstate.( usually old Marshalls and Recent Carvins).
 
I haven't bought a Fender amp since CBS actually. I depend on  Pre CBS and copies (MoJo Weber Torres) for that.

Fortunately for most of my tube amps I have accumulated classics and keep them maintained. My stage tube amps run from early 60s to an 82 Marshall being the newest.

For small Venues I use a Peavey Hybrid (Heritage VTX on the low Watts setting) with a tube preamp and an effects processor in the effects loop, and a 64 Guild Thunderbird (about 40 watts with built in inedependent reverb SE amp [6mb8 and 12ax7])

Back in the 60s I used to use Teneyck SS amps. Used to get a lot of What is that?  Found out about them when the music store that used to supply my rentals  (Usually Solarus, Colleseum, and Sentura amps weren't available for a last minute gig).
Title: Re: sorry for another question about tube vs transistor
Post by: rodriki1 on May 30, 2010, 02:13:38 AM
Actually I don't think ther was a Carvin SX that used 4558s then. Ithink the first SXs were around 87 and MOSFET.

you are right thanks.  the year john murphy designed sx was 1983... and the article
was 1981. thanks
Title: Re: sorry for another question about tube vs transistor
Post by: rodriki1 on May 30, 2010, 02:18:24 AM
The only "famous" SS amps I found comfortably happy in that no man´s land were LabSeries ones, which allow for a careful and independent tweaking of  distortion and compression and the excellent Pritchard amps, whose real schematics nobody knows. Of course the many patents can be read, but what's actually used is anybody's guess.
Another *very* good but mysterious amp is the Bluetone.
Most other SS amps can be excellent either side of the barrier, but not on both.

i can supose that you had your hands on a pritchard (expensive) amp???
those very complex circuits can really sound like a compressed pentode output????

thanks
Title: Re: sorry for another question about tube vs transistor
Post by: rodriki1 on May 30, 2010, 02:20:33 AM
another question.

can i believe that there is in this earth a reliable
model for pentodes that could be used in spice????  :duh ;D

i mean with grid compression and so on??
Title: Re: sorry for another question about tube vs transistor
Post by: J M Fahey on May 30, 2010, 06:10:21 AM
Quote
i can supose that you had your hands on a pritchard (expensive) amp???
those very complex circuits can really sound like a compressed pentode output?
I wish I had !!!
And yes, they do sound on the same league of a very good Twin or Super Reverb on 6, in the hands of a skilled Musician, which is a very difficult task.
I suggest you get into their site, download and listen carefully to the many examples, specially the "Sword of Satori".
A lot of guys listen to these clips and find them unimpressive, it being "old guys" type music, (very tasty), no chest-thumping distortion, palm-muting, whatever.
For me, having tried to achieve true overdriven pentode sound for about 38 years, I find them miraculous.
Those SX amps are very good too, although Pritchards got slightly closer to the goal.
The Bluetones are called by some "a one-trick-pony".
Being that their "one trick" is to reproduce perfectly whatever a 50 Watt Plexi does at any level, we must applaud them.
I think they missed the point commercially, being that their only product is a 30 watt Combo, and that with a nerdy cheesy computer geek designed front panel, with a lot of blinking leds that turn it into a Science Fair project lookalike.
If they had made a classic styled 100W head, driving stacks of 4x12", they would be in *many* stages.
Can't suggest any Spice models, since I never learnt to use simulations.
Yet I think the current Pentode models *should* provide the answers, it's just that we don't ask the correct questions yet.
Teemuk knows a lot about it, having even written his own models !!!!
Phatt and Mensur also use simulations and practical on-stage experiments, to achieve interesting results.
Look around, there's also this guy whose name I don't remember this very moment  :-[ , who modeled a pentode with a bunch of op-amps.
Follow this SS Forum, there's a lot of cool guys experimenting along these lines, and now you are also getting into it.  :tu:
Title: Re: sorry for another question about tube vs transistor
Post by: Jack1962 on May 30, 2010, 04:08:51 PM
another question.

can i believe that there is in this earth a reliable
model for pentodes that could be used in spice????  :duh ;D

i mean with grid compression and so on??
I personally don't use spice or any other computer sim programs , If I want to design a circuit I do it the old fashoned way I breadboard it lol lol lol.

well Thanks for your answer.

that is the point. WHY there is this preference for the tube amp.

SAG?? COMPRESSION??? LOW FI SOUND??? DIRTY in the sound??

but my question is that amp they used in the test sounds to be carvin sx.

thanks.

that's a very good question , yes I like the sag , however if it has a solid state rectifier it has very little sag lol lol lol . Low FI Sound , brother you really need to play thru a good tube amp, the sound quality is in my opinion 100% better that a solid state amp. Dirty , yea that overdriven tube sound is what every solid state  drive circuit has been trying to get for years lol lol lol Now with all that said what I really like is the warmth of the tube amp , the soild state amps have a fantastic clean , but the drive channels all go way past overdrive into distortion That's why I use a multiple amp setup lol lol lol  Finally , the amp they used wasn't a carvin SX brother.

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Title: Re: sorry for another question about tube vs transistor
Post by: rowdy_riemer on May 30, 2010, 11:26:24 PM
Don't knock the sim programs. I have no doubt that pentodes can be modeled as well as JFET's, MOSFET's, etc. The problem with simulated components is that real world components behave a little differently. While they are ultimately no replacement for testing using real components, simulations can be great for quickly running through different ideas. If it works in simulation, it MIGHT do well when you breadboard it. If it chokes in simulation, there's a good chance there's a problem with your design(but not always). Of course with digital applications, software simulation kicks lots of ass.
Title: Re: sorry for another question about tube vs transistor
Post by: Jack1962 on June 01, 2010, 02:35:44 PM
Oh I'm knocking really knocking them I guess I'm just not that good with the computer lol lol lol , I'm sure you can do a fairly good simulation of a circuit if you give the computer enough information to work with. I tried the sim programs , spice was one of them as a matter of fact and they work pretty well with solid state circuits , however with the nature of tubes , I personally think they are a waste of time. With all that said , if they work for you then more power to ya .


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Title: Re: sorry for another question about tube vs transistor
Post by: rodriki1 on June 01, 2010, 08:32:26 PM
thanks all for the attention given here.

J M Fahey suggested the listening of pritchard amp, so i did that.
i gave a closer "look" (hear) at sword of satori.
really amazing job. i passed the eye over all his patents but never stopped
to really enjoy the sound of it.
so we can think that he is close enough?? i found that in my humble
opinion he sound like better than many tube amps.
Like someone said one idealized tube amp.

What makes me impressed is that VOCAL CHARACTER OF SOUND
AND THE WIND NOISE "INDIDE" THE SOUND OF GUITAR.
I know there is some sort of filtering after and before like
i have discussed a lot with "phatt".
I can not understand yet, what makes the guitar "scream".
Besides the skill of the player...
Would be sag with bias shifting???
I will keep researching. As you said pritchard is still a
mistery too!

thanks


Title: Re: sorry for another question about tube vs transistor
Post by: Jack1962 on June 02, 2010, 07:09:38 AM
yea I listened to that pritchard amp sample as well , it does sound good the PRS don't hurt the tone either lol lol lol , along with the ability to play lol lol lol
Like I have said before I have heard good sound amps both tube and SS , however this amp does sound really good , I don't know maybe it's just me but it sounds alot like a Lab Series  amp to me.

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Title: Re: sorry for another question about tube vs transistor
Post by: J M Fahey on June 02, 2010, 09:11:26 AM
Well, me too. I think *the* reference in good "somewhat tubey" SS sounds is the Lab series.
Roland and Yamahas (and Polytones in a very narrow "niche") are excellent "clean-only" amps, and Randalls good "very-dirty-only" amps, but the in-between Twin/Super Reverb sounds are very difficult to get in a convincing way, specially because today few guitar players want them (almost everybody wants buzz-saw and/or chest thumping sounds, even from tube amps), and those who do, already have a Twin/Dumble/etc. amp.
Statistically most people are happy with their SS Peaveys, Fenders, Valvestates or Crates, because they do not know otherwise and, besides, you *can* play with them, even in the current state of development.
And buzzy/dry SS distortion is not that different from buzzy/dry Tube preamp distortion; not everybody can play his tube amp on "7" all day long.
And if you need to stick an SS distortion pedal  up front "to warm up the sound", we are all back on square one.
Title: Re: sorry for another question about tube vs transistor
Post by: Jack1962 on June 03, 2010, 09:06:47 AM
I agree JM , I went to a club last weekend , there was a band playing this new heavy metal, 1 was playing a Mesa Triple Recto the other was playing a Randall SS , to be honest with there setup I couldn't really tell much difference in there tone lol lol lol


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P.S. that's a terrible thing to do to a Triple Recto lol lol lol