Listening to 300b paramounts

[Jim R.]

Well, I'm listening to my first pair of bottlehead amps.  Thanks to the generosity of fellow bottlehead, Paul (paswen) I have his 300b Paramounts on loan for a couple of days and am enjoying them quite a bit.  This particular pair has stock iron, the triad choke in the PS, v-cap coupling cap and mundorf SiIO for the parafeed cap.  It also has a new, not yet broken-in pair of the Shuguang Treasure 300bs.  Initial thoughts are that these amps are respectably quiet, very dynamic and have wonderful tone.  My only complaint is my general complaint with the 300b in that leading edges seem slightly blunted which in combination with my resonant cabinet speakers, makes the overal sound a bit too warm for my tastes.  No fault here on either part, just that I don't think this will be an ideal long-term pairing.  Detail and bottom end articulation are extremely good for a 300b though.  Please keep in mind that I've been listening to 2a3s for the last couple of months, so that too may skew my findings.  Overall excellent amps though.

Next Paul will be bringing his SR45s over for a listen, and then sometime after that, his Paramour IIs, but so far I'm really impressed with the quality of the amps.

I'm also expecting my Carina back this week, so it will be interesting to hear that (SE EL84) ihn comparison to the DHTs I've been listening to.

-- Jim

[Doc B.]

Hey Jim,

Yes, I think that speaker resonances are an issue that can be "amplified" by a 300B. We had some upper bass humps that made my 300B Paramount driven woofer system sound slow. PJ felt that the issue was the speakers and not the amps. When I thought about how fast Paul Stubblebine's 15" woofers in his Magico system sound with 300B amps I saw his point. Retuning the ports in the woofer boxes took care of the the problem, and after coming back from CES I felt like the bass in my room was up with the better rooms we heard there in terms of attack and speed, though not in terms of pure pants leg flapping audiophile punch - as they are just 6.5" woofers

[Jim R.]

Dan,

I may have jumped the gun on tuning my speakers and will later on try going back to the small baffles on the tonians.  When I put the medium baffles in, the bass did come up somewhat but as you say, tend to make things sound a bit slower.

Fortunately it's only a 2-minute job to swap the the different plates on the back of the speakers.

I'll report back later when I've had some more time to listen with that setup.

-- Jim

[Paully]

Of course, as I am sure you know, you can always build the Paramounts in 2a3 configuration if you think they are a quality amplifier.  I have had mine configured for both at one time or the other.

[Jim R.]

Yes, that is something to consider, and I'm definitely thinking in that direction.

I did swap the tuning baffles in my speakers yesterday and things got significantly better and I could certainly live with this for some kinds of music, but bass-heavy source material still feels a bit thick in the upper bass and lower mids -- again, I'm certain that this is more of a speaker issue, or speaker/300b issue than anything else.  Mind you, in the overall picture, this is still a really good sounding combination.  Even the vocals on some of the poorly produced CDs out of Africa that have always tended to be unintilligible and harsh, are now tolerable and far more understandable.  The high-res 24/88 and 24/96 stuff is awesome.

Wonder how much of a difference the iron upgrade makes and in what ways...

-- Jim

[Doc B.]

Hey Jim,

If the Tonians have 8 ohm woofers and the Paramount secondaries are wired for 8 ohms, ask the owner of the Paramounts if he will let you temporarily reconfigure the output transformer secondaries to four ohms. That can often tighten up the bass a bit.

[Jim R.]

Dan,

Not sure that I want to put Paul in that position as that's the kind of thing I'd play around with with my own amps.  I also know from breaking in the Treasre 2a3s that the bass can be flakey and soft at first and really starts to tighten up after 100 hours or so.  These Treasure tubes sound quite good out of the box, but when they're through their sometimes fickle break-in, they outstanding.  Paul did warn me that these are very new.

I'm also going to put the brass feet back on the speakers to see if that tightens things up a bit as compared to the ebony blocks that are under there now, which tended to warm the sound a bit when they were installed.  I also still know I need some more room treatments before a destination sound is found.

-- Jim

[Rick58]

In the OP, Jim said "This particular pair has stock iron, the triad choke in the PS ..."

Sorry, I have been away from this forum for a while, but can someone explain the 'triad choke in the PS' concept?

Ah, I see - Triad is a magnetics company ... does that mean just a different brand/type of choke in place of FC-1?

Thanks!

[Paul Joppa]

Sounds like a confusion between Paramour and Paramount. The Paramour II 2A3 upgrade moved the Triad 10-henry plate choke to power supply duty when the plate choke was replaced.

In the other recent thread started by Rick58 I posted a circuit for an impedance switch to use with the stock Paramount iron, for those who want to experiment with speakers and drive impedance. The upgrade iron is the same for Paramount and Paramour II, and has 8 and 16 ohm taps so a simple switch is suitable, or even a third binding post. In all cases, you'd have to drill a new hole to mount the switch or binding post.

[Jim R.]

No, no confusion, but you'd have to ask paswen for an explanation.  These were definitely paramounts and the triad was added to the B+ supply in place of a resistor.  It's mounted on top over the FC1, which is still in place as far as I know.

How this compares to the stock paramount, I have no idea as this was the first one I ever heard.

-- Jim

[Paul Joppa]

OK, sorry for the mistake - I lose track of all the variations people try! Now that you remind me, I do remember some discussion of this change on the forum.

It's true, the Paramount has a 270 ohm power supply resistor just like the Paramour, and for the same reason- the Triad choke (270 ohms DC resistance) can substitute for a quieter power supply. It does require some creativity to find a spot for that extra choke in a Paramount, whereas with Paramour (which does not have a filament choke) there is a spare mounting spot.

[Doc B.]

To clarify, yes the power supply will look more "quiet" on the scope, that is, it will have less ripple. But that ripple will only be less than the already minimal ripple. The Paramount is exceptionally quiet as-is, and I don't imagine the choke will make a noticeable difference in the noise floor.

[Rick58]

Paul, Jim, Doc,

Thanks for the explanations!  Maybe one day I might try this for fun. Good information to have.