Monoprice 15 watt amp upgrades

Discussion in 'Amp Tech Center' started by Stewtech, Aug 22, 2019.

  1. Stewtech

    Stewtech TDPRI Member

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    Are those American tubes RCAs?
     
  2. Keefsdad

    Keefsdad Tele-Holic

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    Can't remember, possibly.
     
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  3. boredguy6060

    boredguy6060 Friend of Leo's

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    The speaker will cause the most dramatic change in sound over any other components.
    More than tubes or caps or cabinets. If you want to drastically change the sound of your amp, change the speaker.
     
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  4. Stewtech

    Stewtech TDPRI Member

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    Absolutely, now I just have to figure out which speaker will release the sound I want. I was thinking between Eminence, Weber or Jensen? Do you have any suggestions for a full American sound? Going to be playing anywhere from bluesy, chicken pickin, to Jazzy.
     
  5. Pontiaddict

    Pontiaddict TDPRI Member

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    Quick question, is V1 closest to the power tubes? Or farthest away?

    After reading page after informative page of mods for the Monoprice SR amp; some say the V1 is closest to the EL84s, however the YouTube video by D. Braun says V1 is farthest away from the power tubes.

    I’m confused and hoping to find more clean head room.
    Mods to date, replaced all tubes: JJ’s 5751, 12AX7, 12AX7, JJ EL84 match set.

    TYIA
     
    Last edited: Sep 10, 2019
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  6. VintageSG

    VintageSG Friend of Leo's Ad Free Member

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    Furthest from the power valves/closest to the input socket. Think of the valves in the order the signal goes through the amplifier.
     
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  7. Pontiaddict

    Pontiaddict TDPRI Member

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    Thank you.
     
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  8. Stewtech

    Stewtech TDPRI Member

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    I always thought V1 is furthest away from the power tubes?
     
  9. Pontiaddict

    Pontiaddict TDPRI Member

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    You are correct.

    That’s what VintageSG replied above, farthest from the power tubes.

    In my amp I installed a 5751 in lieu of the 12AX7 hoping for more clean headroom... the amp still breaks up before gain reaches 2, which leaves me still trying to coax a bit more clean headroom.
    Listening in on your thread thinking I might try a speaker swap to tame the break-up for my style. GA SC64, Creamback, Cannabis Rex or? It’s a tough decision, making something good, better.
     
    Last edited: Sep 11, 2019
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  10. Pontiaddict

    Pontiaddict TDPRI Member

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    Although I too have the itch for a new speaker/voice, two things I read today that, for me, are worth trying before a speaker swap. YOMV

    1.) 12at7 in V1.
    Reading the at7 is 60%<12ax7, the 5751 is 30%<12ax7 my guess is the lower pre amp power might help with the early break-up. Some say the difference is negligible, others thought it was notable.

    2.) Another forum suggested simply using the controls differently:
     
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  11. Stewtech

    Stewtech TDPRI Member

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    I was looking at the Creamback and the Rex but they seemed like overkill with wattage, so I was thinking Jensen C12Q since it’s 35 watts. I looked on a couple old speaker threads of fender players and a few said this option was there choice. Although another fellow said that the Eminence Maverick with the built in attenuation was ok. Do you know if the Monoprice amp is 15 watts if adding a speaker that is 50+ watts would give you more headroom or what exactly that would do to the sound?
     
  12. Stewtech

    Stewtech TDPRI Member

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    I think both the tube and the volume trick are definitely going to be on my list to try. Are you re-biasing your amp with ever tube swap?
     
  13. Pontiaddict

    Pontiaddict TDPRI Member

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    No, not on the pre-amp side, it’s not necessary.

    I did replace the EL84s with a matched pair, but the pre-amp tubs afaik can be swapped with no effect.

    Edit:
    Remember, the stock speaker is rated at 70 watts
     
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  14. Skydog1010

    Skydog1010 Tele-Holic Ad Free Member

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    What am I missing? I just got mine today and truly could not be happier! Just the way it is... I'm absolutely positively Goofy over this amp. Break up is perfect. Mine is clean as a slate roof pointed south in southernmost UK, with gain dropped off and tone cranked up.

    I really don't understand why someone would want to mess with it?

    What am I missing?
     
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  15. Stewtech

    Stewtech TDPRI Member

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    That is a plus, I think I am going to try a few different combos with the pre, I read that you should be able to exchange them with 12au7 and they might have the lowest gain... Definitely gonna get the JJ’s.

    Actually I always thought the seventy 80 was 80watts... I would think that a speaker more relative to the amp wattage would give a more focused, smoother tone? I do know that the fender blues junior has a 50 watt speaker and some decent headroom. I have been emailing Weber and it sounds like their Ceramic Blue Dog with light to medium doping and a wattage option. The 50 and 75 watt speaker sound clips sound sweet in a fender. https://www.tedweber.com/blue12f
     
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  16. Pontiaddict

    Pontiaddict TDPRI Member

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    Personally it’s just a matter of tailoring tone, it is great as-is agreed... however those I’ve heard with simple modifications were noticeably better.

    My quest is for a fatter tone, with smoother highs, reminiscent of my favorite amp from years ago. With the low entry price point of the Stage Right amp I can experiment within a reasonable budget and hopefully attain that goal.

    Not intending to diminish the product in any way, just personalize it.
     
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  17. Stewtech

    Stewtech TDPRI Member

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    I am glad to hear you are happy, I also thinks it’s a great amp! I just love to upgrade whenever possible and tweak to get different sounds for different situations. I am using this amp for daily use but also for experimenting.
     
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  18. schmee

    schmee Poster Extraordinaire

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    Well crap, My mono 15 has been sitting a month. Tried it yesterday and nothing but a garbled very low volume sound! Was fine when last played!
     
  19. Stewtech

    Stewtech TDPRI Member

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    Sorry to hear that. Can you return it?
     
  20. schmee

    schmee Poster Extraordinaire

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    Nah, it's the older model. I'll have to get it open and check it out, but I've been considering just modding it into a new small amp. I just dont trust it to gig with it and could use a ~15 watt amp in the arsenal. If I keep the transformers it should be fairly low wattage. Some possibilities:
    -Stick with EL84's; Carmen Ghia clone
    -Go to 6V6's; Princeton Reverb clone.
    -18w Marshall clone? AC15 CLone?

    I dont really need another 6V6 amp though, although that's my tone preference usually. Maybe a lower wattage Princeton would be good... hmmm
     
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