Paramount Transformer Upgrade II

Gerry E.

Gerry E.

Member
Hi:

Since my original post was moved to "All things MagneQuest" I thought I would start a new thread.  The Magnequest Full Nickel BH-5s and BH-7s arrived today.  The shipping box is amazingly heavy for it's size!  Even the individual pieces are amazingly heavy for their size.  As I mentioned in my original post, a friend is going to help me install them this weekend.  I still have two questions:

1.  Any hints or tips in replacing the stock transformers/chokes with the new ones?
2.  The new OPTs and chokes seem kind of big, will they really fit underneath the chassis?

I'll have to disconnect one of the Paramounts from my system in order to flip it over and get a visual idea of how well the new units will fit in.  Thanks.

Gerry
 
I can't help you with fit but I do know that there is a direction for the plate choke.  One end should be attached to the B+, high voltage.  The choke is probably dotted, but I can't remember if the dot goes to B+ or not.  You should ask in the Magnequest area.
 
Normally, the dot goes to the high signal voltage. For both choke and output, that would be the plate of the tube.

The Magnequest parts have a thicker stack (1 1/4 inch, vs. 1 inch stock) but use the same lamination size, so they fit the same bolt holes.
 
My friend and I installed the Magnequest All Nickel BH-5 OPTs and BH-7 Plate Chokes into my Paramount 300Bs on Sunday.  Actually, my friend did 99% of the work and I was there mostly for "moral support".  We needed new sets of wires to go from the OPTs to the binding posts, so my 1% contribution was cutting those wires out of some solid-core silver speaker wire that I had leftover.

When de-soldering the connections from the stock transformers, my friend used that copper ribbon to soak up the old solder.  That's the first time I have seen that and it works great (probably old hat to most of you).  We knew the second amp would take less time than the first, but surprisingly it was LESS THAN HALF the time.

As PJ states above, the new transformers fit right in.  The BH-7 chokes have a black dot on the left side.  We assumed that's where the black wire should go and it's the same side where the black wire went to on the stock plate choke.  Please tell me we got that right (what would happen if it were wrong)?  BTW, the BH-5 OPTs that I received only have two output taps.  It looks like they are labeled 9(?) and 16 ohms.  We used the 9 ohm tap for my 8-ohm speakers.   

Given that we only were 99% sure we got everything right, I made sure to turn on only one amp at first.  No smoke, no fire, no noise, so I turned on the second amp.  We started up the CD Player and there was music, so we got it right the first time.  I'm not that familiar with my friends system, so I couldn't make any sound quality judgments at that point.  However, it sounded good.  If I had to use one word to describe the sound, it would be "smooth".  My friend uses a 211 stereo integrated amp with all Tango transformers which he inherited from his father-in-law who is Japanese.  The Paramounts were definitely in the same class/category.

I have been listening to the upgraded Paramounts in my own system for the last couple of days.  Two changes come to mind.  There seems to be better overall definition.  This is hard to quantify because I'm basing this on memory and it was already excellent to begin with, but that's the word I kept coming back to.  Also, there's a change to the high frequencies.  I believe PJ mentioned this in thread that got moved over.  I can't tell if they are more extended or just higher in level. 

I was a little concerned about this when listening to the first recording that I played, which happened to have a lot of high frequency content.  Then I switched to some of my old standby evaluation recordings and realized everything is fine.  As my system has gotten better (example: silver interconnects and speaker cables), I have lowered the cap value I use on my tweeters.  I have fine-tuned it to what sounds best to me and I'm currently using .47uF caps.  I may want to try lowering that again, but other than that, so far so good with the transformer upgrade.

Gerry                           
 
In my experience, the transformers will start the breakin process after the first 20 hours of music. They will be a majority of the way by 50 hours, with smaller improvements for another 100-200 hours.

Mike's superior materials and craftsmanship will make an improvement in the treble, not so much extension as clarity - I ascribe a lot of that to the dielectrics improving the stray capacitance. THe bigger effect is the nickel core, which produces less distortion. The distortion is made by large low-frequency signals, but it muddies the midrange and treble. With the nickel core, I often seem at first to hear less treble, then I begin to hear that it's just cleaner, less in your face but more real. People's ears vary a lot, you may hear other things.

In any case, keep the reports coming as the breaking progresses!
 
Gerry,
This is an upgrade that I've also considered and would most appreciate if you as PJ suggested keep the reports coming.
Thanks,
John
 
Hi John:

I did a fair amount of listening over the weekend and the Paramounts are sounding better and better.  I clearly hear improvements in definition, dynamics and treble response.  That little bit of extra high frequency energy that I heard the first few days after the upgrade has now completely balanced out and the amps sound amazing.

Even at this early point, I can easily recommend the All Nickel upgrade when time and/or funds permit.  BTW, who made the stock transformers?  I was under the impression that it was Magnequest, but someone told me that's not correct.

I
 
Interestingly the top end response of both transformers measures about the same. The bottom end is where the MQ iron should edge out the stock stuff and also in terms of microdynamics due to the boutique materials used. The stock transformers are our own design, wound by another American company.

I think you said all you needed to say about Mr. Medwin when you said "Jeff preaches".
 
Doc B was posting at the same time, but here's my reply anyhow - not much different.

The stock iron is made custom for us, more or less to my design - that is, I do the winding sequence but consult with our winding house to be sure I haven't gone off the deep end, and that it is easy to build inexpensively. They have given me some good ideas, especially for the power transformers. We use their standard materials (wire, insulation, etc.) and they wind on modern machines, up to 24 coils at a time. We've done business with them for a long time now and have a good relationship.

We have not had any nickel core units made for us, because machine stacking is not practical for nickel and hand stacking is expensive (labor intensive). We use M6 grain-oriented silicon steel for audio iron.

When Magnequest does a transformer, Mike selects specific materials for their sonic properties, and his coils are all (I believe) wound one at a time by a master winder on a classic machine. The coil designs are of course different, but Mike and I have many similar prejudices about how to do things; I sometimes adjust a design to make it less sensitive to the insulation materials. Mike also always stacks by hand, and he has a wide variety of core materials available.
 
Paul Joppa said:
Normally, the dot goes to the high signal voltage. For both choke and output, that would be the plate of the tube.
Click to expand...

Hi:

I finally got around to taking some photos of the upgraded Magnequest plate choke and OPT installed into one of my Paramounts (see below).  The choke is on the right side of the first photo and the black wire is connected to the terminal with the black dot.  From these photos, can anyone confirm that the choke connections were made correctly?  Thanks.

Gerry

bh2.jpg


bh1.jpg

 
Thanks PJ.  It may look obvious but I didn't want to make any assumptions.

Debk - I purchased this pair of Paramounts already built and they came with both the V-Caps and big Mundorf Silver/Oil already installed.  Therefore, I never heard them without the upgraded caps, so no comparsion is possible.

It was an amazing coincidence that the amps came with those caps because those are the same two brands of caps that I had been using on the tweeters in my speaker system (first the Mundorfs and then the V-Caps).  I didn't even know that the amps came with those caps until I got to the seller's house and flipped them over.  As you can imagine, it was a nice surprise.  :)

Gerry       
 
The set of transformers and plate chokes that Mike sells is for a pair of monoblocks. And BTW I'm not sure where the term "irons" came from, but when we started talking about big ol' transformers in single ended tube amps the slang was "iron" - singular - as in Heavy Iron. My hunch is that some well meaning folks from Asia may have confused the pluralization when they posted on the internet - a common mistake going from a language that makes it all easy by saying "one man, ten man" to English, the most rehashed, complex, constantly evolving crazy language there is. Woman = Wu-mun, Women = Wi-min! Having said that, society dictates what the current terminology may be. Perhaps my perspective is anachronistic.
 
Gerry E. said:
... the BH-5 OPTs that I received only have two output taps.  It looks like they are labeled 9(?) and 16 ohms.  We used the 9 ohm tap for my 8-ohm speakers.                       
Click to expand...

I have my 300B Paramounts similarly wired, to the 9 ohm tap.  What, if anything, could/should be done to run 4 ohm speakers, or is this impedance mismatch to be avoided completely?
 
You can leave the MQ plate chokes in, however, a little extra inductance will certainly work well with either the BH transformers or the MQ transformers.

-PB
 
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