[IronLion]

These are my impressions of my new MPX3 SLAM after listening to it for a few days with a NOS Tung Sol driver and GE 6BL7 outputs (I have enjoyed this combination so much that I have had no desire to tube roll any of the 8+ tubes that I could use in this amp, all 5687's or 6SN7's). I don't have much to compare it to other than the amps I sampled (real listening impressions of each amp weren't possible) at the New York Headfi meet about a month or so ago and my old X-Can V3. One thing I do remember is listening to a PPX3 SLAM at the New York meet and being disappointed; I had read everywhere about how dynamic and involving it was, and about rock solid bass, etc, but to be honest when I heard it I was very underwhelmed by its sound and impact.

With this in mind, my MPX3 SLAM has everything that I thought I was going to hear in the PPX3 SLAM, with a few differences. The sound of this amp on all levels, micro and macrodynamics, is so incredibly involving that the music is intoxicating. As Mikhail told me over the phone, with a good recording, it is basically like listening to a live concert. Apparently, he not only added the Supra transformer to achieve this sound, but he said he beefed up the internal circuit boards somehow to give me the sound I was looking for. The larger amount of current running through it, he says, is why it runs warm. I know a "concert-like sound" isn't what everybody wants to hear when they listen to headphones (I say screw neutrality...) but I go to a lot of live concerts and I enjoy the overall warmth and impact of the sound. I think that my HD650/Equinox serves this purpose perfectly as well. The soundstage is very wide, maybe not as wide as with 6SN7's but I will have to do some tuberolling to confirm that. I have been dying writing final papers in school and listening to this amp nonstop, and what I have been very pleasantly surprised about is how utterly non-fatiguing this amp is. I have already listened to it for over 7 hours today and am still going strong. I think this is in large part due to how great the dynamics of it are, even at low volume levels; it is perfect for dynamic background music with the volume at 7 o'clock, move it to 9 o'clock for enjoyable listening, and if you just want to be overwhelmed and hypnotized all you have to do is move the volume to 11 o'clock. Anything beyond 11 or 12 o'clock for most recordings is simply a display of how much power this amp has. Anyways its late and I need to finish a paper. If anybody has specific questions about the sound let me know. I may post more pics later (and of the tube adapters Mikhail is now making) if I have time...

 

[Gabe Logan]

Quote:

Originally Posted by IronLion One thing I do remember is listening to a PPX3 SLAM at the New York meet and being disappointed;

I think that is the last thing i wanted to hear with mine so close to arriving.The bass impact and great sounding with rock music is what sealed the deal when i chose this amp so here is to not being disapointed

 

[Glod]

I am glad you are happy with the amp. I don't recall how many hours of operation it had before this major surgery, but I would guess that it now needs some time to at least settle in. The bass impact and speed of the amp is important to you, and I remember that my own, very modest MPX3, needed at least 80hrs before the bass got a good extension. Not until about passed ~200 hours my MPX3 seemed to not develop further.

I still wonder what Mikhail adjusted in the circuit

. Perhaps he raised the plate effect (W)? The Singlepowers are said to be very gentle to tubes and do not run them anywhere near maximum allowed effect. IIRC, he applies very low plate current in the MPX3. The plate voltage is much lower than the maximum allowed for a 6SN7GTA and slightly above the recommended level for a 6SN7GT. But, since the current is much lower, the plate effect is much lower than maximum allowed, also for GT's. Maybe somebody more knowledged can chime in here to correct me if necessary.

However, if one is seeking more impact in the sound, a layman like me would think that more juice is needed to the plates. Anybody?

 

[sacd lover]

Quote:

Originally Posted by Glod I still wonder what Mikhail adjusted in the circuit . Perhaps he raised the plate effect (W)? The Singlepowers are said to be very gentle to tubes and do not run them anywhere near maximum allowed effect. IIRC, he applies very low plate current in the MPX3. The plate voltage is much lower than the maximum allowed for a 6SN7GTA and slightly above the recommended level for a 6SN7GT. But, since the current is much lower, the plate effect is much lower than maximum allowed, also for GT's. Maybe somebody more knowledged can chime in here to correct me if necessary. However, if one is seeking more impact in the sound, a layman like me would think that more juice is needed to the plates. Anybody?

No ..... no more juice needed. He didnt change the 6BL7GT settings on the amp Iron Lion has at all. Mikhail excitedly called me to tell me about this amp/ tube set (probably since I sent him the tubes and probably so I could now stop bugging him to try the 6BL7)

..... and he said the settings for the output tubes remained the same. I am running the 6BL7/6BX7 tubes in four amps with the SAME bias and current the amps always use ...... right now ..... and they give the same kind of impact IL describes. All you need to do is go buy yourself a pair of tubes and put them in your amp and see yourself.

I, however, am even using a less powerful **** gain tube that has a more airy sound than the 5687. The impact is still present but the 6BL7/6BX7 throws a huge soundstage with a 6sn7 or **** tube. The 5687 for gain might up the impact slightly. But the 5687 will not throw the soundstage of a 6sn7 or **** tube and there is still major impact using the tubes even with a less powerful gain tube. On the other side .... wait until those wanting more soundstage hear what the 6BL7/6BX7 does with a dimensional gain tube. My Supra's throw the largest single ended soundstage I have come across. In fact, the soundstaging is NEARLY EQUAL to the balanced Supra I auditioned a couple weeks ago. Woodcans can attest to this. We listened to the amps on November 19th when he came down for a mini-meet. The 6BL7/6BX7 can do much more than just add bass and dynamics.

 

[sacd lover]

Quote:

Originally Posted by Gabe Logan I think that is the last thing i wanted to hear with mine so close to arriving.The bass impact and great sounding with rock music is what sealed the deal when i chose this amp so here is to not being disapointed

I dont know what SLAM IL listened to ..... or what it was hooked up to ..... but I have essentially the same amp he does and the SLAM PPX3 has excellent bass impact by any measure. Perhaps the SLAM had a 6sn7 (which dilutes the dynamics some and adds soundstage) rather than a 6cg7 for gain.

But the standard SLAM PPX3 has a weighty powerful bass with loads of impact and drive. Plus, the SLAM IS great for rock. I think I called the SLAM PPX3 " the hardest rocking Singlepower yet" in my signature for awhile. I highly doubt you will be disappointed Gabe.

 

[Glod]

Quote:

Originally Posted by sacd lover No ..... no more juice needed. He didnt change the 6BL7GT settings on the amp Iron Lion has at all. Mikhail excitedly called me to tell me about this amp/ tube set (probably since I sent him the tubes and probably so I could now stop bugging him to try the 6BL7) ..... and he said the settings for the output tubes remained the same. I am running the 6BL7/6BX7 tubes in four amps with the SAME bias and current the amps always use ...... right now ..... and they give the same kind of impact IL describes. All you need to do is go buy yourself a pair of tubes and put them in your amp and see yourself.

I guess I will have to do that

Sounds almost too good to be true: better dynamics with the same bias.

And then also a better soundstage. I guess the 6BL7GT is a more efficient design than the 6SN7GT.

 

[sacd lover]

Quote:

Originally Posted by Glod I guess I will have to do that Sounds almost too good to be true: better dynamics with the same bias. And then also a better soundstage. I guess the 6BL7GT is a more efficient design than the 6SN7GT.

A couple quick points before I head out. The 6BL7/6BX7 definitely has more potential. The fact they perform so admirably at lower bias and voltage is a plus. Your suspicions the tubes can be better is certainly valid. With more voltage .... say 450 volts .... and likely more bias .... I have no doubt these tubes can be even better. The problem for now is what gain tube can take 450 volts? The 6SN7GTA maybe. But the best tubes like the 6SN7GT/ 7N7/6CG7 and 5687 cant handle that voltage. You would need a split power supply to send 300 volts to the gain tubes and the higher voltage to the 6BL7/6BX7. You could use three 6BL7's I suppose. But then you limit tube choices almost completely.

Furthermore, these tubes are circuit dependent like any other tube. My basic Supra with the identical setup has a completely different sound with these tubes. The Supra running at only 265 volts ...... while very good .... is not on par with the other amps in regard to bass and dynamics. The sound is more neutral and extremely natural sounding ...... and I do mean extremely. The soundstaging with less bass emphasis is outstanding. This tube looks to be able to satisfy many different priorities. I have been enjoying the basic Supra as well if not more than the other amps with a lot of music.

Still this points to the tube performing better at higher voltagte and bias. The Supra-X ..... which incidentally I found runs at 300 volts .... and the mpx3's have more bass and impact. The Supra-X adds the soundstaging of the basic Supra but with this amps more powerful bass and warmer tone the amp doesnt sound subjectively as airy as the basic Supra. I amvery curious what a fully optimized amp will sound like. I may have to take one for the team.

However, I am not ready to concede the "best tube" title to the 6BL7/6BX7 just yet. The 5687's have an amazing sound in the Singlepower amps. The 5687 has a bit more warmth .... along with the impact .... some may prefer. Atleast this is true as the amps are currently tuned. The 5687 is also so quick ..... and concentrated so to speak ...... so dont underestimate how involving the 5687 can be.

Anyway, get a pair of these tubes and try them out .... you will be glad you did.

 

[philodox]

Quote:

Originally Posted by sacd lover However, I am not ready to concede the "best tube" title to the 6BL7/6BX7 just yet.

6H30

Though you would need to change the amp significantly and wouldn't be able to use any of the other tubes any more.

 

[IronLion]

Quote:

Originally Posted by Gabe Logan I think that is the last thing i wanted to hear with mine so close to arriving.The bass impact and great sounding with rock music is what sealed the deal when i chose this amp so here is to not being disapointed

As I said before, listening conditions at the NYC meet were less than ideal. Also, I can't remember if the SLAM there was using 6CG7's or 5687's. Don't listen to me though, judge for yourself, I doubt you will be disappointed. All I am saying was that I personally was not that impressed at the NYC meet, given the conditions and the music I heard through the SLAM (which was probably not very impactful music anyways). I seem to have very very high expectations though when it comes to amps (I can always imagine something better sounding than any amp/headphone combination I've ever heard, including the Orpheus)...

 

[PFKMan23]

If you're talking SLAM amps, then the 5687 outputs are a given (more or less), the key I think is the driver tube, whether you're using the 6sn7 or 6cg7 or another type. Although meet conditions, I woudln't necessarily call something you should use as a key consideration for a purchase. See if you can demo it in a smaller, less congested setting.

 

[Rhydon]

HAAaaaaa, i love you guys

 

[PFKMan23]

Quote:

Originally Posted by Rhydon HAAaaaaa, i love you guys

Umm ok....

 

[IronLion]

Quote:

Originally Posted by sacd lover No ..... no more juice needed. He didnt change the 6BL7GT settings on the amp Iron Lion has at all. Mikhail excitedly called me to tell me about this amp/ tube set (probably since I sent him the tubes and probably so I could now stop bugging him to try the 6BL7) ..... and he said the settings for the output tubes remained the same. I am running the 6BL7/6BX7 tubes in four amps with the SAME bias and current the amps always use ...... right now ..... and they give the same kind of impact IL describes. All you need to do is go buy yourself a pair of tubes and put them in your amp and see yourself.

So did I misunderstand Mikhail when he said he beefed up my circuit board? Or are you implying that he was exaggerating or even lying to me? I just don't know why he would say that if he didn't mean it. When did you talk to him about the amp/tube set, and are you sure that he was referring to my amp specifically when he said the settings for the ouput tubes were the same? He told me about this yesterday, and from what I gathered it was something he did to achieve the particular sound I was looking for.

 

[sacd lover]

Quote:

Originally Posted by IronLion So did I misunderstand Mikhail when he said he beefed up my circuit board (not sure what part of it...)? When did you talk to him about the amp/tube set, and was he referring to my amp? He told me about this yesterday, and from what I gathered it was something he did to achieve the particular sound I was looking for.

I am not really sure of where in the order of things he was when I spoke with him. I do know he was telling me about your amp and it was last week sometime. You had the amp and posted a couple days after we had our discussion. The 6BL7 tubes in your amp came from me. I also know he spent hours fine tuning the the amp because he told me he stayed up until 4:00am playing with the bias points. In particular, he definitely spent a lot of time optimizing the 5687 for gain. I also know he tried various bias points with the 6BL7's and decided to leave the amps settings exactly like the are on all the Singlepower mpx3's currently out in the field. I asked about the 6BL7's specifically because I was curious ..... and I know your amp has the same operating parameters for the output tubes as any mpx3.

He was originally working on the amp with three 5687 and was very pleased with that tube trio. I dont know for sure .... but he must have decided to try the 6BL7 at this point. I have been suggesting he try the 6BL7's for awhile now.

After installing the 6BL7's he was pumped up by how much better the amp sounded.

Moving on ..... I am wondering if he meant/ said ...... he beefed up the circuit vs the circuit board. What he stated to me made a big difference was increasing the 5687 tubes gain to drive the 6BL7's. The more he increased the 5687's gain the better the amp sounded. The increased drive from the 5687 is what apparently made the 6BL7's sing their best. He clearly increased ..... or "beefed up" the amps gain stage drive capability for the best dynamics. He is not lying about anything and I would never imply such a thing.

Finally, the Supra transformer requires some reworking too because of the much higher current draw and this could also be what he was referring to when he talked to you. By the way, the added current draw from the Supra transformer is another reason your amp will run hotter. The Supra transformer on my SLAM MPX3 does heat up the amp more. This amp always runs warmer than my other mpx3's.

 

[IronLion]

Quote:

Originally Posted by sacd lover I am wondering if he meant/ said ...... he beefed up the circuit vs the circuit board.

Yeah, it could have been one or the other I can't say I remember, I had slept 4 hours from the previous night due to finals and sort of vaguely remember what he told me. Which one of these would seem to make more sense? I certainly don't know, I was just trying to re-iterate what he said.

Quote:

Originally Posted by sacd lover Finally, the Supra transformer requires some reworking too because of the much higher current draw and this could what he was referring to when he talked to you. By the way, the added current draw from the Supra transformer is another reason your amp will run hotter. The Supra transformer on my SLAM MPX3 does heat up the amp more. This amp always runs warmer than my other mpx3's.

Yeah maybe this is what he was referring to, especially seeing as I asked him why the Supra transformer has a tiny, tiny hum to it that I can hear only when I put my ear to it. My amp definitely runs warm as you said, not only is the case warm but the volume knob is even pretty warm. It seems to be warmest around the transformer, which would make sense.

Earl you seem to be as knowledgable about the effects of different tubes in the different positions; I have some NOS Sylvania 5687's in a whitish/yellow box, I have an RCA 5687 and another one I can't identify. What difference could i expect tube rolling these in the driver slot when compared to the NOS Tung Sol? Also, what recommendations would you have for 6SN7's in either the driver or output positions? I still have my old Ken Rad and Sylvania GT's around and I haven't tried them yet with the BL7's or the 5687s.