Solid state amp emulators Vs. tube preamps

Discussion in 'Effects, Pedals, Strings & Things' started by The Revolution, May 15, 2015.

  1. The Revolution

    The Revolution Member

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    I just hear more fizz than the froth of a tube pre, I hear it in the Marshall Valvestate amps and in these AMT V1, F1, M1 etc. Tech21 Blondes...it's in the rounding of the top end where the difference is. I suppose when you try to replace the tube section of a marshall with a refined fuzzbox there is going to be compromise. I use the Joyo American Sound (Tech21 Blonde clone)...I take a peavey and a marshall to gigs and sometimes need a Fender tone, it sorta gets the job done...but I can't help thinking that analog amp modelling isn't going to get much better, digital modelling or compact tube preamp pedals are the way to go...a Butler Tube driver etc.
     
  2. The Revolution

    The Revolution Member

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    Anyone else think tube pres like this Fender emulator from Effectrode just makes the Tech21 blonde and AMT stuff sound like fizzy toys?

     
  3. The Revolution

    The Revolution Member

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    its a high gain soldano type sounding unit, I thought it was a "Blackface" preamp in a pedal......sorry, still dreaming of someone building one of those I suppose...would have been good marketing Blackbird = Blackface....Effectrode missed that opportunity I guess.

    * They do say the clean tone is a blackface clone circuit....but the 2 dirty channels are something completely different.
     
  4. porticoguitar1

    porticoguitar1 Member

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    The clean of the Blackbird is a very nice Blackface sound. While I'm the foremost authority on that Fender amp, I have played one and my Blackbird is right on. No fizz. The drive channel (blue) is smooth and very D-style. The red is still too much for me. I'm keeping it for now - unless you make me an offer I can't refuse.
     
  5. The Revolution

    The Revolution Member

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    We need more Tube Preamp pedals that copy actual tube preamps...it would be great to stomp on your Vox Tube Preamp, then stomp on a Fender Tube Pre for that sound, and another for a Marshall.

    I just don't think these Tech21 and AMT solid state preamps are ever going to get the sound of tubes. Digital technology maybe one day..
     
  6. The Revolution

    The Revolution Member

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    I am sure the Kingsley and other company's tube pres are great in themselves, but i just get the feeling they would sell a bunch more units if they said "this tube preamp is an emulation of a 78 Marshall plexi" etc. "This is a Fender Deluxe clone in a pedal"..and make a lot of people happy at the same time
     
  7. whackystrings

    whackystrings Member

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  8. DaveKS

    DaveKS Member

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  9. 71strat

    71strat Member

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    Heres what you want.



    [​IMG] [​IMG][​IMG] [​IMG] [​IMG] The F-2B contains two independant preamp/tone control sections. The amplification is entirely vacuum tube powered. It is normally used as a stereo preamp to interface stereo instruments to power amplifiers. Jacks are provided on the rear for outputs from each channel. In addition a Mono output jack is provided which combines both channels when the F-2B is used with a Mono power amplifier
    [​IMG] [​IMG] Circuit detail

    The F-2B was inspired by the Fender Dual Showman amplifier. In the late '60's, we routinely added preamp output jacks to Dual Showman amplifiers and substituted an external power amplifier for the built-in quad 6L6's, most usually a MacIntosh 75.
    [​IMG]The F-2B came about to provide the same preamp functionality in a rack-mounting package, as the Dual Showman was considerably wider than the standard 19 inch rack.
    [​IMG]We took the opportunity to make a small improvement in the input jack circuit, while providing identical functionality. Plugging into Jack 1 alone gives full sensitivity, while Jack 2 alone is attenuated 6 dB. If signals are plugged into both jacks simultaneously, mixing resistors combine the signals and give isolation to the two input sources. In the original circuit, the mixing resistors are always in series with the grid of the first stage, and contribute a small amount of Johnson (thermal) noise. Our jacks have additional contacts which completely switch out the mixing resistors when using Jack 1 and the ultimate quietness of the tube is preserved.
    [​IMG]As in its predecessor, the instrument signal is amplified by the first stage before any volume control. Without the wide dynamic range provided by the 300 volt supply, the first stage could be easily overloaded by large transients which are characteristic of electric instruments.
    [​IMG]The tone control section follows, with a circuit attributed to Tom Walker, wherein the Bass and Treble controls contribute mostly boost and the Mid control provides cut only. While there is no absolutely flat position, the response is reasonably flat with the controls set at 2 - 10 - 2, with the bright switch off. The circuit can be described as interacting, such that the frequencies affected by each control is changed somewhat by the settings of the other controls. Additionally, when all 3 tone controls are turned to 0 then no signal is passed at all. These effects, while not suitable for a music reproduction system, have nonetheless proved highly pleasing for electrical instruments and have been adopted by a wide group of manufacturers.
    [​IMG]The Volume control immediately follows the tone control section. The Bright Switch connects a capacitor around the volume control, the value of the capacitor being selected to bypass only the high frequencies. The effect of the Bright Switch is also interactive with the Volume Control, and there is no effect if the Volume control is turned up to 10, and the magnitude of the effect changes, depending on the setting of the control.
    [​IMG]The signal loss of the passive tone controls and the volume control is made up by the second stage, also a common-cathode vacuum tube stage. The second stage plate circuit feeds the output jack. Since the output impedance of the tube circuit is fairly high, the power amplifier(s) should be located adjacent to the F-2B so that short connecting cords can be used. While the output circuitry of the F-2B can satisfactorily interface with the vast majority of power amplifiers, the F-2B does not work well if the power amplifier input impedance is lower than 10 K Ohms or if the power amplifier has very low sensitivity.
    [​IMG]The mono output on the rear of the F-2B provides a facility to use a stereo instrument with a mono power amplifier. The mixing resistors associated with the mono jack are only connected together when a plug is inserted, thus preserving maximum stereo isolation when using the separate Channel A and Channel B outputs. Another application is to connect the two channels in cascade, by a cable from the Channel A output jack on the rear to the Channel B input jack on the front. The power amplifier is connected to Channel B's output. The signal from Channel A is high enough to drive the first stage of Channel B into distortion. The tone controls of Channel A are used to emphasize those frequencies which will be most distorted, while the controls of Channel B shape the color of the resulting distortion. Channel A's volume control sets the amount of distortion, while the Volume Control of Channel B sets the output level (Master Volume). [​IMG]The power transformer has taps so that the F-2B can be operated from 100, 120 or 240 volt lines (Mains). It is necessary to open the cabinet and solder the correct tap to the power switch to make the voltage change, however. The Line (Mains) input connector is the IEC (computer type) so the power cord is detachable. The layout of the circuitry and the lead dress to the front-panel components are carefully planned to reject external hum fields. In addition, an internal hum-balance control rejects hum from the AC heater supply. The package is a single unit standard EIA rack mount steel enclosure designed to survive on the road.
    [​IMG]
     
  10. ballynally

    ballynally Member

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    God, that's a very impressive and extensive way to NOT have an amp.
    Frankly, i do not get the focus on the pre amp valve section alone, as just about everything in an amp's circuit is interactive (eq/grid/voltage etc.). Then there is the phase inverter/ transformer section and valve setup which is most of your amps' sound (never mind speakers).
    But.. it is nice to have control over the sound independent of output section. I remember Ry Cooder talking about his setup in which he had the perfect sound independent of output volume ie, he had broken the link between the two sections. There is certainly an argument for that.
    I just find it easier to have different amps for different gigs. I can bring a small valve amp to a gig to create my sound then loop it to a bigger, possibly solid state, amp if i need more volume. Or mic it..
     
  11. The Revolution

    The Revolution Member

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    Well, yes, but it isn't a pedal now.. And I don't have space for a whole rack preamp. This unit a bit part of Dave Gilmours sound that doesn't get mentioned much.
     
  12. The Revolution

    The Revolution Member

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    There have been many marshall, engl, peavey and many other "brand" tube rack preamps for years....this thread is about pedal versions of them..Matchless Hotbox and Vox Over the Top Boost deserve a mention, though the videos on youtube sound pretty bad..
     
  13. thetangmang

    thetangmang Member

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    What you want is an ethos. I completely gave up all my tube amps for the ethos and I actually like it more than I ever did like my amps. No more worrying about the volume to tone purity ratio as I have perfect sound at any volume (I go direct to a QSC K8). Added bonus is that I sold off most of my drive pedals after I got the drive channel set up just right.
     
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  14. bgh

    bgh Supporting Member

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    I have an Effectrode Blackbird preamp pedal, and love it. It's been years since I played a BF Fender, so I cannot easily compare it to one. But, I can say that I really like the cleans produced by the pedal.

    The blue (Dumble) channel is very nice too. The red (Soldano) is a little too much for me.
     
    Last edited: May 20, 2015
  15. ProfG

    ProfG Member

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    Ditto on the Ethos. In the last year I took on a gig requiring me to go direct and use IEMs. The Ethos has been fantastic. It's very responsive to picking dynamics, volume knobs, pickups, etc., just like a tube amp. The proof is the live recordings--the Ethos sits in the mix perfectly.
     
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  16. SKJ

    SKJ Member

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    Actually several of our preamp pedals are emulations of, or are inspired by classic designs: Constable - plexi pre, Squire BF - blackface pre, Squire TB - top boost pre, Squire D - ODS clean channel, Page ODS - ODS overdrive channel....

    Simon Jarrett
    Kingsley Amplifiers
     
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  17. tech21nyc

    tech21nyc Member

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    I think something the OP is missing is that by virtue of running "any" preamp whether tube or solid state into the front end of a conventional guitar amp you are stacking two EQ sections. There is no way that any distortion,OD, fuzz or preamp cannot be changed by the sound of the preamp it's going into. This is why we encourage people if using our amp emulating products to use the efx return of an amp to bypass the preamp section.

    In modern channel switching amps they usually have discrete preamp sections that independently hit the PI and power section of a guitar amp.

    One workaround when using a preamp is to rig up an A/B box solution if your amp has a series efx loop. You split your guitars signal or the end of your pedal board to stereo and send one signal to the input of your amp and the other the the B channel of the A/B box. You then take the EFX send of your amp and route that to the A channel of the A/B box. Finally route the I/O port of the A/B box to your amp's EFX return jack. You now have a channel switching amp with two independent preamps. There are a number of other options as well like running different effect to each preamp etc.
     
  18. bgh

    bgh Supporting Member

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    My AMT pre-amp pedal is typically run straight into the effects return. It works best like that. The Effectrode works well that way, plus, if I cut the gain down on it, it sounds very nice going straight into the amp. In fact, on my Mark IV, I can actually get some very "chimey" tones doing just that.
     
  19. ryandfl

    ryandfl Supporting Member

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    Going to have to disagree. I had a Blonde for some DI stuff at the same time that I had my Fender Showman from '65. While they didn't sound identical, the pedal sounded pretty great. I felt no need to go through extra trouble micing, for my purposes. I enjoyed jamming with it.

    Probably going to get another Blonde, now that I have an OCTATRACK again!

    That said, those clean blackbird demos sound excellent.
     
  20. The Revolution

    The Revolution Member

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    I use the Blonde knockoff into the amp return, even though it sounds more tubey via the amps tube pre. I am going for a clean, authentic fender tone and if I put it into the front input of my peavey - it just ends up sounding nice but..Peavey-ish. There isn't enough eq on some of the Kingsley stuff, one tone knob instead of 3. Yes I think a vox tube preamp in a pedal and a fender tube pre in a pedal would do me just fine...the peavey classic 50 preamp is great too, trashy, gnarley....between fender and a vox maybe...
     

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