The Pinnacle

If they glow, this is the place to be
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Ray P
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Re: Transcendent Mini Beast Build

Post by Ray P » Wed Oct 03, 2018 11:04 pm

BTW Ali, why the Pinnacle and not a scratch build of the 300B SE-OTL? Is it just the extra Watts?

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Ali Tait
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Re: Transcendent Mini Beast Build

Post by Ali Tait » Thu Oct 04, 2018 12:58 am

Partly, don’t have room for big horns at the moment lol.
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Wolfgang
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Re: Transcendent Mini Beast Build

Post by Wolfgang » Thu Oct 04, 2018 3:50 am

The TS 300B OTLs have their very typical sound no matter if it's the SE AC/DC or the PP. Rather in the direction of bright with very transparent upper mids, lacking a bit of foundation in the lower mids, but with deep, dynamic, and very articulate bass (never muddy). All this with Lowther DX4 Medallion II, C-Horns, and Klipsch La Scala II, Nordost speaker cables and acoustically treated listening room.

Four 300Bs in parallel sound very different compared to a single 6C33. The reason for this is that each tube behaves a little different no matter how precisely matched they are. It appears as constant fluctuations of the Ip between the tubes and on the positive side as some very open soundstage. But the instruments are not 100% stable in their virtual position compared to a single output tube OTL like the 6C33. This can be fixed with quite some effort to some degree in the 300B OTL DC. I did this in addition to Ray's version. If each 300B has exactly the same Ip it sounds almost like a single output tube OTL. The extra wide and deep virtual soundstage shrinks a little and the brightness is a bit reduced, the sound gets a little darker and the instruments are more stable in position. With the 6C33 OTL the soundstage doesn’t lose any width and depth and the instruments are 100% stable but with some extra “air” or space around them. Very close to live music. The 6C33 OTL has many more advantages but I think this is not so interesting in this context.

The SE 300B AC with 15Hz AC for the filaments (I refer to my version with adjustable sine generator and class AB amp, not the class D amp at 25Hz that the original TS kit used) sounds somehow closer to the Pinnacle than the SE DC version. What I miss in both amps is the foundation in the lower mids and the precise location of the instruments on the virtual sound stage. I became aware of this only after I had listened to the 6C33 OTL for a while. But the overall difference between the Pinnacle and the SE is less than one might expect and without the mods in the SE DC version I would always go for the Pinnacle.

For 8 ohm speakers I would only recommend the Pinnacle. Less than 8 ohm I wouldn’t even try with any of these 300B OTLs as they cannot show their wonderful qualities. Depending on the loudspeakers (single driver or x-over) I would recommend additional improvements for the Pinnacle.

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Ali Tait
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Re: Transcendent Mini Beast Build

Post by Ali Tait » Thu Oct 04, 2018 8:22 am

Ok thanks, will probably build it stock with some better caps etc to start with, let it run in, then will seek your advice on worthwhile mods.
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Re: Transcendent Mini Beast Build

Post by Clive » Thu Oct 04, 2018 10:58 am

Wolfgang, many thanks for explaining your experience, which is clearly significant. The lack of lower mid foundation is something I've had the impression that Bruce's amps do in general. I don't know whether this includes the Mini Beast which Ali has. Like Ali, I too am very interested in Pinnacle.

So that I can even better position the comments you made about the lack of lower mid foundation aspect can I ask your view on how Pinnacle melded with your speakers and cables? I can't comment at all on the C-Horns and La Scalas...as for the Lowthers, yours are very probably well implemented but...I heard some (there are many variations of Lowthers) exhibit a coolness in the lower mid so if the amps lack lower mid I can see this wouldn't be an ideal match. I'm sure your other speakers help with identifying the sound of the amps and of course the C-Horns and La Scalas will sound different to the Lowthers.

My experience of Nordost cables ended with Red Dawn and Blue Heaven, I found them very clear but bright and lacking bass weight, probably due to their being configured as aerials. Again this would not be great synergy if the amps are a little bright. I expect your cables are much more recent so will sound very different to the ones I had. It sounds like I'm being critical of your kit; I'm not and I'd be surprised if your kit has the foibles I experienced 10 to 15 years ago but I wanted to check to further my understanding. The cost of the Pinnacle kit plus eight 300Bs mean I want to be very sure before committing. I my case I need about 3W or 4W into 16R so Pinnacle is a bit more power than I need.

I very much get the purity which a single output device (or pair of devices in PP) brings so the 6C33 is really interesting but probably not enough power for my 100db 16R speakers.

Thanks again for your descriptions and advice.

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Ali Tait
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The Pinnacle

Post by Ali Tait » Thu Oct 04, 2018 11:57 am

Thought I’d start a new thread so we’re not taking over Steve’s.
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Wolfgang
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Re: Transcendent Mini Beast Build

Post by Wolfgang » Fri Oct 05, 2018 4:03 am

Clive, the Pinnacles work really well with the 8ohm and the 15 ohm DX4 in Medallions and C-Horns and with the Nordost speaker cables. IMO BLH with Lowther DX4 don’t show signs of coolness, extra brightness, or lack of bass per se but for sure those speakers are like a magnifying glass that shows the difference between good and bad or new and old recordings. I wouldn't recommend them if one listens primarily to rock music. For Jazz and classical music, New Age, Ethnic or World Music I cannot think of anything better. With the 6C33 OTLs this magnifying glass effect is somehow less dramatic than with TS OTLs as the upper bass/lower mids seem to be more naturally represented in the overall sound. This couldn’t be achieved with the TS OTLs by simply boosting these frequency bands with an EQ because that would make other recording sound too bass heavy or would create too much room resonance. It’s simply the “sound” of this amp, the sound of the 6SN7/6C33 tube, and that’s why I think it’s ideal for the 15ohm DX4. But the TS OTLs work of course also very well with these speakers.

The Medallions benefit from the more powerful Pinnacles which is clearly noticeable at dynamic peaks. Bass is deep and very fast. The bass with the Pinnacles seems to be more focused on the dynamic side, the bass with the 300B SE DC more on the tone itself. I don’t know if that makes sense but it is very obvious and it appears to me as the main difference. Micro details sound different too. Again: the Pinnacles are focusing more on the transients of the sound event which really can create some very nice extra “sparkle”, the SE DC are developing more the character of the tone.

For the C-horns with 15 ohm driver this advantage over the SE DC is no longer there. Here I prefer the SE DC (especially with reduced NFB) because these amps deliver more of the tone character but now also with very fast transients at dynamic peaks. That doesn’t mean that the Pinnacles don’t sound very good but somehow they cannot deliver the “essence” of a single tone in the same way as the SE DC.

For 16R/100dB drivers, especially for single driver speakers, I would rather recommend the 6C33 OTL with which you get both qualities: lightning fast dynamics and tone character in abundance. But don’t take only my word for it let’s see what Ray has to say when he has finished his amp.

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Ali Tait
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Re: Transcendent Mini Beast Build

Post by Ali Tait » Fri Oct 05, 2018 9:22 am

Nick, could you move this part of the discussion to the Pinnacle thread please, don’t want to crap more on Steve’s thread. :)
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Ali Tait
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Re: The Pinnacle

Post by Ali Tait » Fri Oct 05, 2018 11:09 am

Thanks Nick.
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