I just bought an awesome little 6V6 SE amp from a Canadian company called Musical Paradise, its called an MP301 and it only costs $200!! Dead quiet and ballsy, I was shocked! Point being, this amp is their bottom-of-the-range, and their $800 top model uses these GuiGuang 300B's. They sell them separately...for $100 a matched pair, brand new! Maybe someone bought them from there, didn't like them, and flipped them on e-Pay to you? If Musical Paradise sells them, then I assume that they are bottom-feeder grade bottles just like the rest of what they use to keep their amazing prices so...well, amazing! Years ago I auditioned several types of 300B as a driver stage in the top-of-the-range $20k Cary 845 PP amps, and the Shuguang's were just horrible, even worse sounding than the JJ's or Sovteks...which in turn were absolutely DISGUSTING compared to the Cetron (US Made) and Western Electric re-issues. Only with the latter 2 types did this amp sing, all the post-communist stuff made the amp sound like something from Sonic Frontiers! If you really want great sonic results from a Chinese triode, I'd go for the original carbon-anode Shuguang 845's. Apparently, the factory has just ceased production, so get them whilst you still can! It figures that they'd discontinue the only half-decent sounding valve they made...
I did get my MP-301 amp on Friday. Spent all day listening to it yesterday. It's very nice!
Running Altec 288 -16ohm drivers on Altec 1005 horns from ~650Hz up. Does a great job. The amp is very small and cute. Smells like fresh paint.
No noise from the amp at all. No hiss or tube rush. Not sure if any 60Hz or near harmonics would be audible on the horns, but I don't hear any. That's a solid 105dB@2.83V, so any noise should be obvious.
Chinese tubes, of course. I will tube roll a bit. 6V6 and 6AU6 are easy to find.
Although the OPT cases are marked with a diagram that shows an 8 and a 4 ohm tap, the amp has only ground and hot speaker terminals. Don't know which tap was used. The 6V6 tubes should not be heavily loaded considering the 16 ohm drivers I use.
How does it sound? Darn good. Much as other folks have stated, it's lush, maybe little too lush - and nicely dynamic. Very good tone and ambient detail. A pleasure to listen to. No idea how it does in the bass, as I don't use it there. But it does tend to make the bass sound richer, probably because of the way it handles harmonics.
I should make some measurements of FR and harmonic content, plus look around inside, but right now I'm just having too much fun listening to it.
For $200, it is a great deal.
Running Altec 288 -16ohm drivers on Altec 1005 horns from ~650Hz up. Does a great job. The amp is very small and cute. Smells like fresh paint.
No noise from the amp at all. No hiss or tube rush. Not sure if any 60Hz or near harmonics would be audible on the horns, but I don't hear any. That's a solid 105dB@2.83V, so any noise should be obvious.
Chinese tubes, of course. I will tube roll a bit. 6V6 and 6AU6 are easy to find.
Although the OPT cases are marked with a diagram that shows an 8 and a 4 ohm tap, the amp has only ground and hot speaker terminals. Don't know which tap was used. The 6V6 tubes should not be heavily loaded considering the 16 ohm drivers I use.
How does it sound? Darn good. Much as other folks have stated, it's lush, maybe little too lush - and nicely dynamic. Very good tone and ambient detail. A pleasure to listen to. No idea how it does in the bass, as I don't use it there. But it does tend to make the bass sound richer, probably because of the way it handles harmonics.
I should make some measurements of FR and harmonic content, plus look around inside, but right now I'm just having too much fun listening to it.
For $200, it is a great deal.
Thanks for the info Joe. I decided to get one of these MP310 to play with. Will do nicely on my horns until I get something better finished.
Great amp. Remove the cap that bypasses the 6J1 cathode resistor and the amp will sound astoundingly good.
No, a friend of mine has one. He's an audio designer and started his own audio company not long ago. He's also a collector of vintage amps and has great audio gear in his house. The amp sounds great. He did the mod because there was an excess gain and waveform distortion on the 6J1 stage before the 6V6 stage clips. Remove the cap and both problems disappear.
Hope he doesn't mind me posting this, maybe these posts will raise the amp's price. Hope not, haven't got one yet.
Hope he doesn't mind me posting this, maybe these posts will raise the amp's price.
Hope not, haven't got one yet.
Thanks for the info Joe. I decided to get one of these MP310 to play with. Will do nicely on my horns until I get something better finished.
Where did you get yours - I can't seem to get the Musical Paradise site working and there are none I can find on fleabay..
?
Thanks. There is too much gain for me, so this should be a good way to go.
Doing a little virtual shopping, I "think" that one could build the same or better for about the same money using Edcor iron. The chassis may be the deal breaker. Certainly if you have junk box parts to throw at it, it can be less than $200. I may try to do so and compare the two.
It must sound a lot better than it looks.. The layout looks terrible IMHO, but it is pretty inexpensive. (The OPTS appear to be very far away from the output tubes, undoubtedly in an effort to keep the power transformer as far away from them as possible.)
The EL-156 amplifier looks very interesting and comparatively not badly designed. Aesthetically it is quite good for the money, some level of aesthetics is necessary in any commercial design IMO and the lack of symmetry in the MP301 is disturbing to this fan of Palladio.
The EL-156 amplifier looks very interesting and comparatively not badly designed. Aesthetically it is quite good for the money, some level of aesthetics is necessary in any commercial design IMO and the lack of symmetry in the MP301 is disturbing to this fan of Palladio.
I have one of these, and have yet to try it with speakers. With headphones it's very detailed, and dynamic, but gets very harsh as the volume is increased? Not sure if it's clipping I hear or what. Perhaps if the unit is documented, some forum gurus may offer suggestions. I may try that cap mod.
LOL. I thought the 6J1 was triode connected but the resistor value is 781k.
Screen taking the B+ supply from the anode? Haven't seen this before.
Well, the reason why this amp sounds special must be the absence of gNFB. It does have local feedback and guess what kind... ta ta! yes, it's a la Schade. Hehe, whatever you want to call it but it works great. I have just build a PP EL84 amp with this type of local feedback and no gNFB. So far it's my best experience with a pentode amp. I think that I could live with it, that is, in the daytime -night is for triodes only.
Screen taking the B+ supply from the anode? Haven't seen this before.
Well, the reason why this amp sounds special must be the absence of gNFB. It does have local feedback and guess what kind... ta ta! yes, it's a la Schade. Hehe, whatever you want to call it but it works great. I have just build a PP EL84 amp with this type of local feedback and no gNFB. So far it's my best experience with a pentode amp. I think that I could live with it, that is, in the daytime -night is for triodes only.
Please help?
Would someone please point out the referenced capacitor to me in the photograph bellow?
Thanks in advance, Bill!
Would someone please point out the referenced capacitor to me in the photograph bellow?
Thanks in advance, Bill!
Attachments
Results and more questions.....
Alright, I've removed these capacitors in addition to the MP's Alps volume pot from the circuit (as I am using this amp in combination with a DIY passive pre). As a result of these mods there has been a definite reduction in the amps gain (still plenty left to spare, even when using my passive pre). Also, as advertised the distortion at higher volume has now disappeared (to my ear) as well.
However, I now wonder if simply removing the cap from the RC circuit was the best way to go about achieving these results, or would it have been better to have recalculated the RC circuits component (cap and resistor) values and actually have replaced the RC circuit instead?
I also would like to hear opinions regarding whether or not any significant sonic improvements could be achieved by replacing the stock capacitors with different brand caps and if so which brands in which positions specifically, would one use to achieve this?
Thanks in advance, Bill!
Alright, I've removed these capacitors in addition to the MP's Alps volume pot from the circuit (as I am using this amp in combination with a DIY passive pre). As a result of these mods there has been a definite reduction in the amps gain (still plenty left to spare, even when using my passive pre). Also, as advertised the distortion at higher volume has now disappeared (to my ear) as well.
However, I now wonder if simply removing the cap from the RC circuit was the best way to go about achieving these results, or would it have been better to have recalculated the RC circuits component (cap and resistor) values and actually have replaced the RC circuit instead?
I also would like to hear opinions regarding whether or not any significant sonic improvements could be achieved by replacing the stock capacitors with different brand caps and if so which brands in which positions specifically, would one use to achieve this?
Thanks in advance, Bill!
You would have to change the plate resistor and screen resistor also if you want to keep the bypass cap, different R will change the current but the gain will be more or less the same. It's a pentode with Schade feedback so those mods are not recommended.
As for the rest, I'm no cap expert so no comments.
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