Monoprice 50w Hybrid Amp

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Comments

  • rooftop59
    rooftop59 Posts: 7,140
    The speakers look really cool from a distance, but zooming in I see why you’d want to finish them. I agree about mdf. If they were Baltic birch or something like that I would say poly and be done.

    Did you build the crossovers or does parts express have a kit?
    Living Room 2.1: Usher BE-718 "tiny dancers"; Dual DIY Dayton audio RSS210HF-4 Subs with Dayton SPA-250 amps; Musical Fidelity A308; NAD M51 DAC; Sony UBP-x1000es
    Game Room HT: Denon AVR-X4200w; Sony UBP-x700; Definitive Technology SM450; Definitive Technology LCR2000; Definitive Technology StudioMonitor350; Mirage Nanasats; Sub - HSU VTF-2 MK5
    Master Bedroom
    Cambridge Azur 551r; Definitive Technology promonitor 800; ACI Titan Subwoofer
  • zingo
    zingo Audiophile Posts: 11,255
    I did build the crossovers using modeling software with a few different version. The sound quality and frequency response I have now is amazing, except I think the absolute phase is slightly off which I need to trouble shoot.

    The tweeters are Vifa XT25TG30-04 and the waveguide profile was taken from Zaph Audio website. Enclosures were scaled similarly to PMC twenty series.

    607511d1490399146-fs-waveguide-tm-speakers-img_0119.jpg

    618413d1495898638-waveguide-transmission-line-monitors-img_6689-jpg

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  • mhardy6647
    mhardy6647 Posts: 27,258
    I hate busted links, so I borrowed the images ;)

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  • zingo
    zingo Audiophile Posts: 11,255
    edited July 2018
    I just ordered some NOS Russian 6P1P tubes to swap into the amp to test. I’m going to grab a pair of same area 6N1P tubes also, but I’ll be interested to test them separately for effect on the sound quality.

    There isn’t a ton of tube rolling that can happen with this amp, but I have historically liked NOS Russian military tubes, and it will also minimize my expenses.

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  • mhardy6647
    mhardy6647 Posts: 27,258
    edited July 2018
    Cool.

    I have been generally pleased with the military Russian/Soviet tubes as well (and FWIW, of course!)... still wondering whether 6922 and (???) even EL84 (as opposed to EL86/6CA5) might be close enough subs for the original tubes -- and I am still wondering what, if anything, those power pentodes are doin' in the circuit of these amps?!

    No, I haven't gone under the decks of the 25 watt morph here & tried to trace out the circuit -- yet. :|
  • verb
    verb Posts: 9,809
    Here we go again! :smile:
    s82emt3z44go.png
    Basement: Polk SDA SRS, Cary SLP-05 Pre with ultimate upgrade,Enlightened Audio Designs CD Transport, Northstar Designs Excelsio DAC, Cambridge 851N streamer, Marantz SA-14 SACD, McIntosh MC300 Amp, Silnote Morpheus Ref2 Digital Cables, Furman 15PFi Power Conditioner, Pangea Power Cables, Wireworld Oasis 8 RCA IC's, MIT Shotgun S3 IC's, MIT Shotgun S1 Bi-Wire speaker cables
    Office: PC, EAR Acute CD Player, EAR 834L Pre, Northstar Designs Intenso DAC, PASS ACA Monoblocks, Denon UDR-F10 Cassette, Acoustic Technologies Classic FR Speakers, SVS SB12 Plus sub, MIT AVt2 speaker cables, IFI Purifier2, AQ Cinnamon USB cable, Groneberg Quatro Reference IC's
    Spare Room: Antique Sound Labs Wave AV-8 Monoblocks, Tisbury Mini Passive Pre, Tjoeb 99 tube CD player (modified Marantz CD-38), Analysis Plus Oval 9's, Zu Jumpers, AudioEngine B1 Streamer, Klipsch RB-61 v2, SVS PB1000 sub, Blue Jeans RCA IC's, Shunyata Hydra 8 Power Conditioner
    Living Room: Peachtree Nova Integrated, Cambridge CXN v2 Streamer, Rotel RCD-1072 CD player, Furman 15PFi Power Conditioner, Polk RT265 In Wall Speakers, Polk DSW Pro 660wi sub
    Garage: Cambridge Audio 640A Integrated Amp, Project Box-E BT Streamer, Polk Tsi200 Bookies, Douglas Speaker Cables, Shunyata Power Conditioner
  • mhardy6647
    mhardy6647 Posts: 27,258
    @Zingo'll take out the PNW; I've got the NE.

    :#
  • Conradicles
    Conradicles Posts: 5,984
    zingo wrote: »
    Cons-
    -Bass shy (I don't know if that a design issue, or the limited power)

    I just got mine hooked up and my initial impressions are exactly what you stated here. Going to give it a couple weeks in the office rig and decide if it is a keeper.

  • Conradicles
    Conradicles Posts: 5,984
    Seems like the mids and highs totally overpower the bass. Still, for $127 this was a bargain.
  • mhardy6647
    mhardy6647 Posts: 27,258
    Seems like the mids and highs totally overpower the bass. Still, for $127 this was a bargain.

    Hmm...

    How bad would it have to sound to be a bargain at, say, $79.95?

  • txcoastal1
    txcoastal1 Posts: 11,544
    Seems like the mids and highs totally overpower the bass. Still, for $127 this was a bargain.

    Are you running it crossed with a sub like Zingo?
    2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
    Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
    Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
    Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC

    erat interfectorem cesar et **** dictatorem dicere a
  • zingo
    zingo Audiophile Posts: 11,255
    It’s true that 18” and 2000w of Christie Digital does round out the bottom frequencies when testing ANY amplifier. :)
  • delkal
    delkal Posts: 755
    edited July 2018
    Seems like the mids and highs totally overpower the bass. Still, for $127 this was a bargain.

    The picture shows this amp has base and treble controls (if they work). I know true audiophiles are not supposed to use them but did you try any adjusting?
  • zingo
    zingo Audiophile Posts: 11,255
    Pushing the bass a little via tone controls does seem to fill out the bottom (when not using a subwoofer) without changing the sound quality much.
  • mark090852
    mark090852 Posts: 984
    delkal wrote: »
    Seems like the mids and highs totally overpower the bass. Still, for $127 this was a bargain.

    The picture shows this amp has base and treble controls (if they work). I know true audiophiles are not supposed to use them but did you try any adjusting?

    I was listening to mine last night, and adjusted the tone controls slightly. I raised the treble just a little bit, and raised the bass just slightly less. Improved the SQ enough that we can enjoy it in a little living room set up. Well worth the cost to me if it continues to work. Time will tell. Plus, my wife surprised me and stated she likes the looks of it A LOT! That right there is worth the price of admission!

    r51pimmmumg8.jpg
    McIntosh MA252 Integrated Amp, LUMIN D2 Network Music Player, Yamaha Aventage RX-A840 receiver, Emotiva XPA Gen3 2 channel amp, Polk LSiM 703 speakers. Oppo UDP-203 Blu-Ray player, Polk LSiM 705 speakers. Polk Signature S20 speakers.
  • rooftop59
    rooftop59 Posts: 7,140
    Does it sound like a tube amp?
    Living Room 2.1: Usher BE-718 "tiny dancers"; Dual DIY Dayton audio RSS210HF-4 Subs with Dayton SPA-250 amps; Musical Fidelity A308; NAD M51 DAC; Sony UBP-x1000es
    Game Room HT: Denon AVR-X4200w; Sony UBP-x700; Definitive Technology SM450; Definitive Technology LCR2000; Definitive Technology StudioMonitor350; Mirage Nanasats; Sub - HSU VTF-2 MK5
    Master Bedroom
    Cambridge Azur 551r; Definitive Technology promonitor 800; ACI Titan Subwoofer
  • mark090852
    mark090852 Posts: 984
    edited July 2018
    rooftop59 wrote: »
    Does it sound like a tube amp?

    Well, I'm sure it doesn't sound like a "good" tube amp. I haven't listened to a tube amp before, so I wouldn't be able to tell you if it has any kind of a "tube" sound to it at all.
    McIntosh MA252 Integrated Amp, LUMIN D2 Network Music Player, Yamaha Aventage RX-A840 receiver, Emotiva XPA Gen3 2 channel amp, Polk LSiM 703 speakers. Oppo UDP-203 Blu-Ray player, Polk LSiM 705 speakers. Polk Signature S20 speakers.
  • zingo
    zingo Audiophile Posts: 11,255
    It does not sound like a tube amp. I've been told the power comes from an LM chip (which I'll open it up to find out), which if implemented properly can sound good in class A/B. Aside from the cheap Chinese tubes, it does have a good build quality and sound quality if you are looking for a good chip amp. I'm probably going to swap some parts in it to see where I can get the sound quality, but you are not buying a tube amp; or have the maintenance of a tube amp.
  • Conradicles
    Conradicles Posts: 5,984
    txcoastal1 wrote: »
    Are you running it crossed with a sub like Zingo?

    No, no subwoofer.

  • Conradicles
    Conradicles Posts: 5,984
    delkal wrote: »
    Seems like the mids and highs totally overpower the bass. Still, for $127 this was a bargain.

    The picture shows this amp has base and treble controls (if they work). I know true audiophiles are not supposed to use them but did you try any adjusting?

    Yes, did not like the results.
  • Conradicles
    Conradicles Posts: 5,984
    @zingo , mine is very noisy. Like when you turn it on, after about 5 or 6 seconds, I get some pretty audible distortion coming thru the speakers. Yours do that?
  • zingo
    zingo Audiophile Posts: 11,255
    tpvvpxdh1gt6.jpeg

    I just grabbed a pair of these NOS Russian 6N1P-EV tubes and I’ll test these separately from the other pair once they are delivered.
  • zingo
    zingo Audiophile Posts: 11,255
    @zingo , mine is very noisy. Like when you turn it on, after about 5 or 6 seconds, I get some pretty audible distortion coming thru the speakers. Yours do that?

    No but I have heard that complaint with the 25w version. I always have the volume off when I turn on any system, but I paired my phone to the Bluetooth, turned the pot all the way up without anything playing, and only heard faint electrical noise; which I would expect in that situation.

    I even tried having the system on and keying my HAM radio, and the amp didn’t seem to pick up any noise there.
  • zingo
    zingo Audiophile Posts: 11,255
    I received both sets of tubes so I will put a little time on them and test them verses the Chinese tubes.

    I also just picked up a local minty pair of Monoprice K-BAS speakers which I think are very interesting; a hybrid transmission line cabinet design for improved bass response. I'm also going to test these with the hybrid amp and listen to a Monoprice system.

    5.25" Polypropylene + Mica Cone Woofer
    1" Liquid-Cooled Titanium Dome Tweeter
    39Hz-20kHz ±2.2db Frequency Response
    8 Ohms Impedance
    87dB Sensitivity

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  • mhardy6647
    mhardy6647 Posts: 27,258
    For the record (so to speak) and FWIW, I am listening to the fairly new, remastered and "completist" release of Pete Townshend's first solo album/project, Who Came First on redbook CD, via the "25 watt" Monoprice hybrid amp morph on the Frankenaltecs.

    I finally kinda got the hang of the wonky tone controls and got them to some semblance of flat (i.e., relative to the SE 2A3 ampliifer's sound) response... and things are not sounding too bad.

    Gonna play with the tubes in this one, too, soon -- even though I am not at all convinced that they're actually doing anything but boiling electrons off of their cathodes and dissipating some power as heat from their plates. :|
  • mlistens03
    mlistens03 Posts: 2,751
    edited July 2018
    mhardy6647 wrote: »
    on the Frankenaltecs.

    Seems like a lot of risk involved there... ya know, with the bomb Monoprice.
  • zingo
    zingo Audiophile Posts: 11,255
    Initial impressions of the Russian tubes over the Chinese tubes is a more full sounds and a bit more bass. Next step will be to take apart the amp and see the inner gutty works.
  • mhardy6647
    mhardy6647 Posts: 27,258
    zingo wrote: »
    Initial impressions of the Russian tubes over the Chinese tubes is a more full sounds and a bit more bass. Next step will be to take apart the amp and see the inner gutty works.

    Cool. Consider yourself affirmed :)

    FWIW:
    I contacted the local Soviet/Russian tubes maven asked if he has a couple of the 6p15/EL86/6W5 pentodes that occupy two slots in the "25 watt" amp (for whatever reason). 6N1P I've got, since there's a Decware SE-84B "Zen" amp here to this day.

    Yeah, I need to pop the top, too. I've been loath to, mostly because I am preternaturally lazy (of course), but also because the finish on the darned thing is pretty nice looking, and I don't want to mess it up :|

    That's my story & I am sticking to it.
  • zingo
    zingo Audiophile Posts: 11,255
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