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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    All those options sound Wonderful! Me personally, Unless you can also put in a rectifier for the CGhia, I would go Marshall and run your existing 6V6 amp in stereo with it to get an Trainwreckish vibe. If you were to swap the speaker what would be your choices?
     
  2. schmee

    schmee Doctor of Teleocity Ad Free Member

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    I have lots of speaker choices, but the Mono15 seems to have issues of and on and I dont trust it. It's nice and lightweight and has that old school TV front look. I need a lighter amp for some things. Especially the duo. I've been trying SS for that but there just is no comparison. A BF Deluxe is not a real small amp really with a good speaker in it.
    But the rectifier is a problem for converting the Mono15. However, for the duo, I want a nice quiet amp, so I may try with a SS rectifier first and see how I like it.
     
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  3. Stewtech

    Stewtech TDPRI Member

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    Have you tried Quilter amps? I agree the deluxe is a little big but such a sweet sounding amp.
     
  4. schmee

    schmee Doctor of Teleocity Ad Free Member

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    So did a little testing today. Nothing makes sense on the Power Trans :
    Orange to Orange: 48 ACV Bias tap?
    Grey to Ground: 35 ACV
    Grey to Grey: 7.5 ACV Heater tap? pretty high...
    Red to Ground: 36 ACV
    Other Red to ground: 60 ACV
    Red to Red 530 VAC ! Uh oh!
     
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  5. Stewtech

    Stewtech TDPRI Member

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    That is all above my head, I hope someone knowledgeable reply’s soon for you!!
     
  6. reckless toboggan

    reckless toboggan Tele-Holic

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    [​IMG]
     
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  7. Stewtech

    Stewtech TDPRI Member

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    I have heard good things about this amp. What are your thoughts?
     
  8. reckless toboggan

    reckless toboggan Tele-Holic

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    It's inexpensive but it's not cheap. It sounds and feels like tubes because it is. All the dynamics, harmonics, and sweet punch and gritty dynamics with guitar pick attack, and volume and tone knobs. The TurboSound 8" speaker is one of the better stock sounding speakers I've heard, and we designed to match specifically to this amp. It's a bit stiff at first and takes a bit longer than normal to break in (give it a month or so), but gets ever sweeter as it does. There's only a slightly cocked wah sound to it,...maybe an 16th or an 8th of the travel on a wah for the a cocked wah sound. Whereas most 8" speakers I've heard are like a wah pedal at the half way setting (ie. wet blanket, dark, and flat). I'm thinking maybe someday I might put a nice 10" speaker in this, but the stock one suits it'd purpose as a practice amp, and you can run it through a nicer external speaker cabinet if you wanted a bigger, more open sound.

    I swapped an RFT NOS 12ax7 tube (gain rated at 105) into it and it sounds great, really opened it up and made it more articulate. Waiting on some power tubes to roll. I feel that the stock 12ax7 needs to be replaced (the new tungsol's also work very well), but the stock el84 doesn't need to be replaced as it sounds fine... I'm gonna roll the el84 anyway because why the **** not.

    The clean tones (crank the volume and control it with the gain) on 5 watt mode are really good. Something between Fender-ish and almost Vox-ish. Anything from jazzy to really, really punchy (the tone control is great here, wide open is super punchy and as you back it off it goes right down through to jazz tones. Running the tone wide open with the volume at max and the gain at about 2 or 3 and driving it all with a telecaster or a gretsch is a thing of beauty). The overdrive in 5 watt mode is a very slight breakup, great for vintage tweedy open blues tones, again, great with a hot Tele or Gretsch.

    On 1 watt mode, the amp becomes more balanced between the cleans and the overdrive. The cleans sound 90% the same as in 5 watt mode, but the gain knob gets gets a bit of extra overdrive that still sounds vintage but gets into middle rock sounds in the 50s and 60s vein. The cleans are a bit more coloured but still punchy with a bit of grit and saturation, or jazzy depending on where you set the tone knob.

    On the 0.1 watt setting cranking the clean volume has sweet grit saturated overdrive. When you crank the gain and the volume in the 0.1 watt setting you get vintage 60s to 70s mid-rock overdrive that reminds me of a good Traynor. At this point the amp is pretty quiet, but still mic's up well for recording. It sounds hudge in any watt setting when it's mic'd up. You're going to be running the tone knob between 7 and 10 most of the time to get that open sound. Tone wide open let's everything through, and backing it off only cuts tone. It doesn't add tone as you turn it up, only subtracts tone as you back it off from max.

    The reverb is digital and utilitarian, but neither outstanding nor offensive.

    The clean channel takes pedals really well as does the overdive channel, but if you use a high gain overdrive pedal cranking the pedal volume to slam the front end of the amp, you'll get ghost sounds from your favorite local radio stations. If you use gain pedals with the volume at until and then use the pedal's gain knob for overdrive/distortion, you'll get sweet breakup from the amp as a bed/foundation for whatever pedal shenanigans you like.

    Headphones out that mutes the speaker and acts as a DI out. Not amazing sounds, but utilitarian.

    As a bonus, it sounds great running it through an external cab. I think the tones oveall are very Traynor like. So, vintage Fendery cleans with vintage tweedy/baseman/early Marshally (JTM 45) type gains.

    Well worth the money...actually, worth a lot more than the price. It gives more expensive amps a run for their money. Does it keep up with a Marshall Class 5? Hell no.

    Buts it's such an amazingly good value. Very happy I have it. It's the inexpensive tube practice amp I've been hoping for with very pleasing tones and great feel.

    It's not that little, ****ty solid state practice amp that sounds terrible no matter how you set it, it's not that expensive egnater or boutique 5 watt amp that sounds good but is the same price as a nice 50 watt head, it's not that versatile solid state modeling practice amp that feels dead under your fingers.

    It's an inexpensive 5 watt tube amp, with that alive feeling under your fingers, with good foundational clean tones, and good mild to mid foundational overdrive tones, that gets the job done and punches way above its class and price.
     
    Last edited: Sep 22, 2019
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  9. Stewtech

    Stewtech TDPRI Member

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    Thanks for the detailed review! I have had this amp in the back of my mind for a while, I love small amps. Thanks for bringing this amp up!!
     
  10. hoglundtw

    hoglundtw TDPRI Member

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    How about an upgrade to the looks? I guess the stock model is trying to emulate the early '60s brown face Fender amps with that cream vinyl, but I think it looks like crap. So I bought some lacquered tweed fabric for $35 and a quart of water-based contact cement and went to town. I think it looks great! Monoprice 15w recovered in tweed.JPG

    Note the face looks black, but that's just reflection off the original silver. I also added brown chicken head knobs and a brown handle. Should I nail on a Fender logo?

    Goes well with my partscaster Tele, Strat and Jazzmaster in the background. You can also see the lap steel I built from scratch.

    Let me know if anyone wants tips on how to make it come out looking good.
     
  11. Stewtech

    Stewtech TDPRI Member

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    I will take...5 of those please! Looks Great, and so does your Tele! This thread would be greatly upgraded if you have the time to give instructions on how to pull that off!!
     
  12. hoglundtw

    hoglundtw TDPRI Member

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    Stewtech - Glad you liked it. Unfortunately, I didn't record the process or even take pictures along the way. But I've gotten so much from being a reader of this forum, that I decided to give something back and spent a good amount of my Saturday creating the attached PDF of how to recover the Monoprice 15W in tweed including some pics of details of the finished product and drawings I made on my tablet of key steps. Took me probably 8 hours in total for the project as I had to figure everything out on my own. Spent around $100, half of it was for some good water-based contact cement which you could probably source cheaper than I did.
     

    Attached Files:

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  13. Stewtech

    Stewtech TDPRI Member

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    This is Strong Work, Thank You from the bottom of my heart!! I never really thought I could upgrade the outside but will be studying your PDF thoroughly!! Your Hard work and Ingenuity are Very much Appreciated!!
     
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  14. reckless toboggan

    reckless toboggan Tele-Holic

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    Not to derail the thread, but I received the tubes I had ordered and rolled through a few different combinations.

    I ended up with a Mullard cv4004 12ax7 and a Genalex Gold Lion EL84.

    It went from a good practice amp, to a good amp, period. The cocked wah sound I referred to in my previous post has been minimized ever further, so as to not even really be noticeable.

    Like it's a time vampire and you don't want to stop playing it, good ... and you can't believe all that tone is coming from just this little inexpensive practice amp, good.
     
    Last edited: Oct 4, 2019
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  15. Stewtech

    Stewtech TDPRI Member

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    Your opinion is absolutely appreciated, since I read this I am deciding on if I really want a nice overdrive pedal or the Bugera and run it in parallel with the Monoprice? You know how it is... forever evolving, adapting and experimenting. I love it all especially when they are priced so kindly! Please contribute to this thread at Will my friend!!
     
  16. reckless toboggan

    reckless toboggan Tele-Holic

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    Well, obviously you should get both the overdrive pedal and the Bugera, just to be safe.
    [emoji6]
     
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  17. V52S

    V52S TDPRI Member

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    Hello,

    Did tube, speaker, and reverb upgrades over a 2 month period in my Monprice 15 watt amp.

    Harmonica sound wasn't quite right for me so I replace the stock tubes with a Matched set of Mullard EL84 output tubes, V1 to a Mullard long plate 12AT7, V2 to a JJ 5751, and V3 to a Mullard long plate 12AX7.

    That change helped tame it a little. I use a Bulletini volume controlled mic which has a loud low gritty output to it.

    Reverb was next - went with the 3 spring MOD 8EB2C1B and cleaned that area up. A touch more spacey and drippy.

    I chose an Eminence Legend GB128 50 watt speaker for it's low end capability.
    The highs are not as shrill now either.

    Last is the Negative Feedback circuit, R22 47K resistor, replaced with a 5K in series with 100k pot to dial in the clean or nasty sound.

    For me this a great combo for harping.

    :) -v-
     
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  18. Stewtech

    Stewtech TDPRI Member

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    Thanks for the Detailed response! What are differences between Mullards and JJ’s that made you choose them for tube placement? That reverb mod sounds brilliant, do you have a sound bite?
     
  19. V52S

    V52S TDPRI Member

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    I've been using Mullard tubes since dirt. Yes, I'm an oldie but goodie.

    Anyway, the JJ tubes give a bit of a darker flavor to the sound while the Mullards are a bit brighter in sound and the 5751 gives better response in the reverb circuit.
    If I wanted to darken the sound a bit more I'd get a matched and burned in set of JJ EL84 output tubes.
    The long plate tubes up front tend to clean the sound a bit but are more susceptible to tube noise and
    internal ringing. I'm using high heat silicone tube rings for that, 2 on each shortie with 3 on each output tube and Yes!, they made a difference in my particular amp.
    Keep in mind I have set my amp up for harmonica playing not guitar so my likes may not be what you're looking for in sound but it give you an idea of what different tubes can do.
    No sound bite, sorry, but the reverb only cost me $23 so it was worth the try and I liked it.

    -v-
     
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  20. Stewtech

    Stewtech TDPRI Member

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    Thanks again! I am very thankful for your response as I am not familiar with tubes brands. The mullards definitely sound like a good possibility cause I am going for a brighter sound but not spikey. I have also heard about the tube rings being shotty on the Monoprice so I will keep those silicone rings in the back of my brain! I also Love the Spring Reverb idea as buying a good Spring Reverb pedal will probably cost just as much. Thanks Again!!
     
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