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In Reply to: RE: Ignore the doubters! posted by Garg0yle on September 20, 2015 at 21:58:27
I am a big fan of raw data collection and feel anecdotes (like the pierre sprey wire direction test) are very important to remember. The thing I don't like (and most people take issue with) is the assigning of merit (good or bad) to a particular data set.
It typically goes like this. I listen to some vintage WE transformers and am amazed by the wonderful sound. Some of the claims mad as to why are:
-Age annealed laminations
-Age annealed wire
To me (assuming the transformers really contain magic) those just focus on the obvious... old wire old core but discussion rarely goes beyond that into something that seems a bit more plausible. As the laminations go it is reported that WE used "power supply" iron in many of their coveted designs. The key factor for me in this is WE (allegedly) used EI laminations and PS lams are a non-oriented material. The supporters of C-cores claim their superiority because the grain is always in line with the core material in a wound tape core but in a Stamped lamination the uptight of the "E" is always cross grain. The thing to note here is if you use a non-oriented material (like PS iron) the claim of superiority of C-cores by optimized grain direction goes away. (the one thing C-cores allow you to do is very thin laminations but that is for another day)
As for the wire. With the increasing popularity of recycling of copper the thing I wonder is if older wire is simply of better "quality" It seems entirely possible that wire that was mined and refined 50 years ago has a consistent nature whereas the recycled copper of today comes from a questionable pedigree. Sure recycled copper can be refined to the utmost of purity but at what cost and is it ever done in todays money driven economy?
Anyways.... got a bot off topic there.... As for your silver experiment, I say give it a try and send it around as a blind test to see what happens. In other words collect the data then have a statistics guy crunch the numbers. I think raw data and statistics can be both powerful and honest and I was shocked how increasing the sample size cahnges things. 6 out of 10 pretty much makes it a coin toss, 58 out of 100 is similar but by the time you get to 550 out of 1000 it starts to become meaningful even thought the difference in percentage has gotten smaller.
dave
Follow Ups:
One other note should be made as regards WE vintage transformers and that is that when these designs were penned... the grain oriented core materials (M6) had not yet been introduced to the commercial marketplace.
MSL
Builder of MagneQuest & Peerless transformers since 1989
Correct and the empiricist in me really makes me wonder if the "better" lams are really an improvement just like Push pull was an improvement over SE and solid state was an improvement over tubes. Since the generally accepted premise in this small sector of the asylum is based on an antiquated concept, it really surprises me how many people are willing to dig moats in the sand.
dave
From the vantage point of magnetic parameters M6 is a vast improvement over M19.As I said earlier the core losses in M6 are less than one third of the losses in M19.
M19 is only available in 26 and 24 guages. M6 is available in the thinner 29 guage standardly. This would decrease eddy currents.
Perm is much greater with m6 if used in a non airgapped application.
Max permissible Flux is greater (giving the designer more options on sizing the transformer to achieve their mix of design goodness.
Harmonic distortion generated by the core will be reduced with M6 vs M19.
No load exciting current will be reduced with M6 vs M19
Thicker guages of lams (M19) tend to be mechanically noisier than the thinner M6.
Except for lower costs I do not see any advantages to M19 over M6 (and even more so with M4, M3 or M2).
MSL
Builder of MagneQuest & Peerless transformers since 1989
Edits: 09/24/15 09/25/15 09/26/15
many of the "coveted" WE audio transformers such as the 171A output trans the core was a C and I configuration (both the C and I being stamped from 26 guage (.0185") M19 material. The two c's are closed around the I which is located in the middle.The C and I arrangement is not very efficient from the vantage point of having many gaps of high reluctance.
M19 has triple the core losses than M6 and just a fraction of M6's superior (i.e., greter) permeability. And has less power handling capacity to boot.
That same 171A coil wrapped in a modern core (such as M6 or better) will have much better performance specs.
Two other quick thoughts. You mentioned "thin" lams... you can get M6 stamped from. 006" material... though as with all of the thinner core materials the penalty is having a poorer stacking factor... so that, in practice, you've reduced the core cross section area... which raises the flux density (and by extension reduces power handling). I don't see it as being advantageous in audio transformer designs.
A point to consider as regards c cores is that they tend to have large (uninterrupted) air gaps versus an interleaved EI core. Take the same transformer and build one with EI's and one with c-cores (using the same grade of lam)... then measure the no load exciting current for each... and tell me what you've discovered.
I fail to see any magic in c-cores and whenever possible will build with an EI (or other stamped lam shape) which can be assembled and fitted by hand stacking for an optimum fit with the wound coil.
MSL
Builder of MagneQuest & Peerless transformers since 1989
Edits: 09/21/15 09/21/15 09/21/15 09/21/15 09/21/15
Hello, Mikey and Dave.I used to service nearly all W.E. stuff. I serviced Movie Theatres, and later bought and built theatres of my own, and also built stadium-type theatres for new owners.
W.E. gear I ran into a lot. At first, when servicing an older theatre, I would remove the W.E. model 91A amps, or some of their bogus attempts at making push-pull amps, remove the speakers and their drivers, give the junk away and replace the amps with McIntosh MC-60's (which I lightly modded), and the speakers with clean, sonically and directionally ACCURATE units such as ALTEC or JBL.
Later on, the Japanese went bonkers over historic W.E. gear, and we saved the old junk and sold it to them-- we sure didn't like to listen to it.. Interestingly, MGM pictures boycotted ALL W.E. gear in their theatres because it totally butchered the "live", accurate, sonic presence that MGM wanted for their theatres. I believe a Mr. Jim Lansing was hired to design something better, and he surely did!
The point of this is that I got better sound-- a lot better-- without the W.E. gear. Today, one can also get better sound by avoiding the misdesigned 300B tube, unless it is one that is made symmetrically with vertical filament structures by EML, etc.
Love you guys, keep up the good work!
---Dennis---
Edits: 10/08/15
hey... just to have some fun here...
That same 171A coil wrapped in a modern core (such as M6 or better) will have much better performance specs.
by what definition of performance?
Re thin lams....I have some .006" thick nickel and it is fragile as hell but with C-cores even .001 is rigid. I'm not making a judgement just noting differences between the stamped vs. tape wound topologies. I typically use non-oriented materials and tend toward stamped laminations where the only two main differences between the cut core and stamped lamination are lam thickness and gap size. I'm not saying thinner lams are better... just making the observation and in the case of amorphous material which is .001" thick, a c-core is the only option.
Now when we move onto gap size, the Cut cores have two discrete gaps that cover the area of the core. This means that the smallest gap possible depends on the finish of the mating surface. A while back there was a company offeing cut tape wound cores with a stepped surface to increase the surface area of the gap which makes it effectively smaller. With stamped laminations you have the option of alternately stacking the laminations which greatly increases the surface area of the gap making far smaller gaps possible than with cut cores. So to answer your question... for a given coil and core geometry a power transformer stacked with 1X1 EI laminations will have far less magnetizing current than a pair of C-cores in a shell configuration since the stamped laminations allow for a much smaller effective gap.
For years people have asked me to use 80% nickel C-cores for my autoformer since 'C-cores are better'. I try to explain that if I were to move to a cut core I would end up with a maximum of 1/10th the possible inductance of a 1X1 stacked EI configurtation. If all your sources are 50 ohms then it isn't an issue but in the real world we need to do some pretty nasty stuff to meet that goal so I opt for the EI lams as the best option.
dave
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