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New Toy!!!

Got this today.... I would have got it to IOWA if it would have arrived last week... but now I am rethinking how I would have lifted it in the car. I am tired and need to take a break just unboxing it.

Anyways as the saying goes, those who can't built, buy.... here are some pictures in the box... 

anybody know what to do or any tips before i fire her up? Doesn't seem to have a manual or anything either physical or online....


  • Very cool! That will keep you warm when the snow starts flying up there. I've never seen that particular amp. Does it have any bias adjustments?
  • edited October 2019
    it says "Auto biasing design that eliminates manual bias adjustment"

    so i suppose there is no bias adjustment. It has knobs for power, volume and input selection, a switch for integrated or main and voltage selector, no other apparent adjustment mechanism on the exterior.

    the amp is musical paradise MP-501, single ended parallel mode using KT-120, whatever that means. It is not push pull but does have 4 KT-120
  • Oh, in case you don't know - never run a tube amp without a load (speaker or dummy) on the output terminals. It can drastically change the ratio of the output transformers causing high current draw. That can burn up your output tubes and possibly transformers too.
  • it does say that in a warning, but need to keep that in mind as we are used to just pull out and switching speakers with SS
  • edited October 2019
    Get that thing fired up, I want a pic of the tubes in action.

    ... and not to be nosy, but about how much did that set you back?   
  • I didn't see any bias adjustment looking on their website. Probably cathode biased outputs, so pop those tubes in and give it a whirl!
  • Here's the link for the amp:

    I opted for the 6SJ7 tubes which were extra and the KT-120, so all in below 1500$ drop ship from china
  • I'll have to see if I have any 6sj7 tubes for you. I know Craig needs some 6DJ8s, so I'll have the tube tester out anyway...
  • Holy Carp - those sj7 tubes have shot up in price since I last looked - $80/pair for metal JAN matched pairs!

  • Let me check my tube stock for 6SJ7's.

    Yes, you definitely MUST have speakers connected before you power up.  I would suggest connecting some cheap speakers, not your best high dollar pair for the first few test runs.  If something was miswired or came loose in shipping you don't want to destroy a great driver.  With enough B+ voltage and good output transformers a single ended KT150 tube can do about 20 -25 Watts.  So with two in parallel probably 40 - 50 Watts @ ~1% THD (mostly 2nd order).
  • Let there be light.... And some music would be good too...
    4x rca 6sj7 and 4x tungsol kt120

  • edited October 2019
    Bloody sweet.  Give it a rundown and let us know how it sounds.

    While on the subject, what tubes are those with the blue glow when under power?  Dad has a couple old whiteface Johnson CBs' and when modulating there are a couple tubes that glow blue with the sound of your voice.  
  • Sorry Ani, I checked my tube stock and no 6SJ7 tubes.  I have a bunch of other RCA and Sylvania metal case tubes like the 6SH7, 6SK7, etc.  
  • That will keep you warm this winter. 

  • PWRRYD said:
    Sorry Ani, I checked my tube stock and no 6SJ7 tubes.  I have a bunch of other RCA and Sylvania metal case tubes like the 6SH7, 6SK7, etc.  

    Thanks Craig for checking. The amp takes the following tubes: 

     V1 and V2 accept 6J8P, 6SJ7, 5693, 6*8, 717A, 713A and 6SH7 pre-amp tubes. V3 and V4 accept 6J8P, 6SJ7, 5693, 6*8 pre-amp tubes.

    I am planning to get a few other of the pre-amp tubes... if oyu have any and would like to part with, send me a PM.

    Power Tubes it takes KT120 or KT150. I have a quad of the KT120. KT150 doesn't make a difference in the power rating it seems, it is fixed at 55watts but supposedly is a bit more dynamic and lasts a lot longer than KT120, but that's for later...!


  • Sending PM to you
  • Craig - you beat me to it! We just back from a quick trip to Texas and I was going to pull out the tube caddy. I'll stil see if I have any of the other types. They're doing me no good sitting in storage.
  • PWRRYD said:

    Sending PM to you
    Hi Craig, I'll take them. Sent you a PM
  • Ani - I checked my stash and I don't have a matched quad of anything you could run. I do have some pairs if you're interested. 

  • Ani, did the tubes I mailed show up yesterday?
  • PWRRYD said:
    Ani, did the tubes I mailed show up yesterday?
    Hi Craig. Yes, I got the tubes. Checked my mail today and they were there! They look pretty good... Thanks!
  • Tom_S said:
    Ani - I checked my stash and I don't have a matched quad of anything you could run. I do have some pairs if you're interested. 

    Hi Tom, I can run most in pairs. Only the power tubes are required in quads. I'll take whatever pairs you have. I'll send you an message.
  • So.......   How does it sound?  Do you like it?
  • edited November 2019
    @PWRRYD sounds good. Had a quick listen and it sounds pretty good. Wouldn't say there is a huge difference between the tubes, but maybe it will dawn on me sometime... Still have to give it some more listen and go through a bunch of music, but so far it's good....

    By the time it cools down then change tubes to it warms up, to cool down to change tube and warm up.... will take some getting used to
  • Just use your mittens - I know it'll be standard attire up there soon. But seriously, gloves and a safe spot to place the warm tubes really helps when you are tube rolling.
  • edited November 2019
    fyi, my experience is that tube amps aren't generally happy being cycled on and off, I blew a recitfier tube and a fuse (kinda cool to see once, but could have been worse).  
  • Ani's amp doesn't look like it has a tube rectifier.
  • You are right - not good for tube rectifiers! 

    I wonder if there's an issue with something like this in direct coupled designs? What happens when you drop in a cold tube that's setting a bias point for another tube that's still nice and warm?
  • edited November 2019
    There's a lot of old wife's tales regarding tube amps... Also read that you should switch on and off and on, etc... Due to inrush current or something. So not really sure. Though this amp doesn't have any bias setting or power/standby switches, just one switch. 
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