Stereo Amp has 2 twenty watt power amps

Discussion in 'Amp Central Station' started by Bluego1, Sep 9, 2019.

  1. Bluego1

    Bluego1 Tele-Holic

    Age:
    56
    Posts:
    654
    Joined:
    Aug 3, 2018
    Location:
    Spokane, Washington
    For a total of 40 watts:cool:. So two 10-inch speakers. So please humor an idiot. I assume:eek: that if I run a stereo effect pedal through it, it will deliver that stereo sound, utilizing both speakers and both twenty-watt power amps. However, my guitar will only deliver a mono signal (right?) and does that mean it will only activate one speaker, and thus only twenty watts of power? Or does the signal come out both speakers in mono? What is the effect on the guitar signal if it runs into a stereo effect pedal before the amp? What if the pedal is in the effects loop instead?
    Does anything I asked make sense?;)
    Really in love with reviews and demos of the Roland JC 40 but am I wasting utility if I don’t record? I didn’t see a mono model. TIA.
     
  2. Wally

    Wally Telefied Ad Free Member

    Posts:
    32,487
    Joined:
    Mar 17, 2003
    Location:
    Lubbock, TX
  3. corliss1

    corliss1 Friend of Leo's Platinum Supporter

    Posts:
    3,215
    Joined:
    Sep 13, 2008
    Location:
    Lansing, MI
    It would also be good to know what amp you're talking about :D
     
  4. Mexitele Blues

    Mexitele Blues Tele-Meister

    Age:
    41
    Posts:
    394
    Joined:
    Mar 7, 2018
    Location:
    Westminster, CO
    If you plug into the mono input on the jc40, the same signal will hit both power amps, until you engage the chorus.
     
    Bluego1 and radiocaster like this.
  5. W.L.Weller

    W.L.Weller Tele-Holic

    Posts:
    519
    Joined:
    May 20, 2014
    Location:
    Queens
    Reading is fundamental.
     
    KG7IL likes this.
  6. corliss1

    corliss1 Friend of Leo's Platinum Supporter

    Posts:
    3,215
    Joined:
    Sep 13, 2008
    Location:
    Lansing, MI
    He says he's in love with the jc40, but the wording wasn't clear to me if that's the amp he's also talking about as he seems to have some experience with it.
     
    Last edited: Sep 9, 2019
  7. W.L.Weller

    W.L.Weller Tele-Holic

    Posts:
    519
    Joined:
    May 20, 2014
    Location:
    Queens
    I'm not trying to be unpleasant, but I see exactly one amp being referenced, either by name or specifications.
     
  8. dconeill

    dconeill Tele-Afflicted

    Posts:
    1,139
    Joined:
    Jun 1, 2004
    Location:
    arlington, virginia, usa
    The owner's manual is your friend. Get it and read it. The owner's manual is available at
    http://cdn.roland.com/assets/media/pdf/JC-40_e02_W.pdf


    Item 1 in the owner's manual says (lightly edited and reformatted):
    1 INPUT jacks. Connect your electric guitar or effect unit [to the input jacks].
    • If you’re connecting a guitar directly, or a monaural effect unit, connect it to the L/MONO jack.
    • If you connect a stereo-output effect unit to [both input] jacks, you’ll obtain a stereo effect with the left and right speakers of the JC-40.*
    • If you connect your guitar to the R jack, the sound is heard only from the right speaker.

    So: if you plug just your mono guitar into the L/MONO jack, the amp will take care of routing the signal to both channels.
    If you plug just your mono guitar into the R jack, the amp will only use one power amp and speaker (i.e., 20 watts).
    If you plug your mono guitar into a stereo effects box and run two cables (one per side) to the L and R inputs, the stereo signal coming from the effects pedal will be amplified as a stereo signal.

    Item 12 in the owner's manual describes how to use the effects loop - broadly similar to using the inputs with respect to stereo effects. From the manual, it looks like the effects loop "send" is mono, while the effects loop "returns" can be stereo if two cables are used.
     
    Bluego1 likes this.
  9. Wally

    Wally Telefied Ad Free Member

    Posts:
    32,487
    Joined:
    Mar 17, 2003
    Location:
    Lubbock, TX
    If you have a stereo guitar and plug into both channels, then you have a stereo rig. The stereo effects is a synthetic stereo derived from a mono signal...but it is interesting. This song has a great intro for hearing movement as well as placement across a stereo soundstage...as the fellow in that link talks about.


    I have a Morley stereo wah/pan pedal that can pan my ES-345’s stereo signal across the soundstage in that manner....the wider the placement of the speakers the better the stereo effect. A stereo combo amp is limited. I once owned a GA78 ‘Bell’ amp..same as the Gibson GA78 or Maestro GA78...with the angled front that threw each side of the stereo away from the center. I did not like it nearly enough to keep it. Maybe if it had been a GA79RVT with Reverb I would have kept it?? I like two identical combos set far apart....or stereo amps with separate speakers spread far apart.
     
    muscmp and Bluego1 like this.
  10. teleplayr

    teleplayr Tele-Holic

    Posts:
    854
    Joined:
    Feb 7, 2012
    Location:
    Nicoma Park, Oklahoma
    An amp that has two 20 watt power amps is twenty watts, not 40.

    The only way you'll get more than 20 watts is if the amp is made to bridge the power amps, and that's something that's normally only used on a self contained power amps.
     
  11. Asmith

    Asmith Friend of Leo's

    Posts:
    3,117
    Joined:
    Nov 27, 2014
    Location:
    East Yorkshire, England
    Surely if you plug into 2 20 watt amps then you get 40 watts of power. Each speaker is fed 20 watts. Like a conventional 40 watt amp driving a 2 speaker cab.

    Also JC40
     
    Bluego1 and Wally like this.
  12. Thin white duke

    Thin white duke Tele-Afflicted

    Age:
    45
    Posts:
    1,008
    Joined:
    Oct 1, 2017
    Location:
    italy
    Yes, if you use the two returns for example you can also play with a wet-dry set up, two separeted power amps....
     
    Bluego1 likes this.
  13. Mexitele Blues

    Mexitele Blues Tele-Meister

    Age:
    41
    Posts:
    394
    Joined:
    Mar 7, 2018
    Location:
    Westminster, CO
    If you're talking about hifi stereo system nomenclature you'd be right. A stereo amplifier rated at 100w is likely to be 100w/channel, for 200w total. Guitar amps are not subject to this inanity.
     
  14. Wally

    Wally Telefied Ad Free Member

    Posts:
    32,487
    Joined:
    Mar 17, 2003
    Location:
    Lubbock, TX
    Well, a stereo guitar amp has the same type of approach as does a musical reproduction system....two independent preamps, two independent power amps, two independent speaker systems. It is not insanity, ime, but rather versatility. Ommv....
     
    muscmp and Mexitele Blues like this.
  15. beninma

    beninma Friend of Leo's Silver Supporter

    Age:
    42
    Posts:
    2,268
    Joined:
    Mar 17, 2017
    Location:
    Massachusetts
    If you just plug the guitar in the onboard chorus is stereo AFAICT.

    I have a Cube Street and it does this too, it sounds really nice.

    It would be cool if this amp did a thing where it phase shifted one of the speakers if you just have a mono signal with no effects like the Orange Rocker 32... I haven't got to try that but it supposedly sounds really nice.
     
    Bluego1 likes this.
  16. Mexitele Blues

    Mexitele Blues Tele-Meister

    Age:
    41
    Posts:
    394
    Joined:
    Mar 7, 2018
    Location:
    Westminster, CO
    No S in inanity, lol. Just referring to how we talk about wattage between hifis vs. guitar amps. If the JC40 were a hifi, it would be called a 20w amp.
     
    Bluego1 likes this.
  17. Wally

    Wally Telefied Ad Free Member

    Posts:
    32,487
    Joined:
    Mar 17, 2003
    Location:
    Lubbock, TX
    Yes, I did misread that one. Inane...insane...definitely a difference...sometimes coinciding????

    Stereo amps are usually described as power per channel, as you say. I have a quad system that is described by power X channel...4 of them. Have no lengthy experience with Roland Jazz chorus type of amps. I took a JC-120 in a trade in such a way that I could get rid of it quickly. I sold it to a fiddler in less than a week for $125...was glad to see it go. I have no use for one. Roland describes this JC40 as a 40 watt amp. They say there are two identical signal paths there....so each path has a 20 watt output. It is not a twenty watt amp. It is two 20 watt amps sitting in one package. Imho, it is not inane to understand this....it is simplicity.
    Gibson described their true stereo guitar amps’ power per channel, iirc. When I hook up my Es-345 to two identical Super Champs, there is 36 watts there...18 watts per amp/pickup. There is no other way to understand it from where I stand.
     
    Bluego1 likes this.
  18. Tomm Williams

    Tomm Williams Tele-Afflicted

    Posts:
    1,052
    Joined:
    Jun 11, 2016
    Location:
    USA
    Since we’re talking stereo amps I just had to post my ‘59 Stereo King image.jpg
     
    Wally, Bluego1, BB and 2 others like this.
  19. Paul in Colorado

    Paul in Colorado Telefied Ad Free Member

    Posts:
    23,351
    Joined:
    Mar 17, 2003
    Location:
    Fort Collins, CO
    My stereo amp is a Rivera S120-210. It has two 60 watt power amps each feeding a single ten inch speaker. There is an effects loop on the back coming off the preamp feeding each power amp. I usually plug a TC G-Major 2 into the loop and see what weird sounds I can create. It also has an onboard chorus.
     
    Bluego1 likes this.
  20. Bluego1

    Bluego1 Tele-Holic

    Age:
    56
    Posts:
    654
    Joined:
    Aug 3, 2018
    Location:
    Spokane, Washington
    Thanks peeps, didn’t mean to run and hide. You’ve been helpful!
     
    Wally likes this.
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.


  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.