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Best 300B SE OPT?
Best 300B SE OPT?
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Old 21st September 2012, 09:24 PM   #61
needsp is offline needsp  United Kingdom
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Hi Rod

Are your SA08s encapsulated, or just open frames (with shrouds)? The encapsulated version is considerably more expensive. I know that e.g. Border Patrol use transformers which are neither encapsulated nor vacuum impregnated, as they thought they sounded better! Their SE output transformer sounds similar to the Sowter in some ways- 14 sections I think, 2.25" stack IE core, M6, 120 lam. Bigger I think- primary inductance at 75 mA 51H! But it's a 2k75 design.

The Monolith S-9's are 3k3, encapsulated, have double C-cores (this should be an advantage, if all else is equal?!), and exceptional specifications; and are, with the UKP v Euro exchange rate at the moment, cheaper than the Sowters. What to do, what to do :-)

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Old 21st September 2012, 09:35 PM   #62
andyjevans is offline andyjevans  United Kingdom
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Bud Purvine recommended to me in an email that transformers sounded better open frame "unless you wanted them to sound like the Ringland Brothers". That may be overstating the case, but there's another similar opinion.

When I use the Hammond 126C I take the end bells off it.
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Old 22nd September 2012, 10:35 AM   #63
Rod Coleman is offline Rod Coleman  United Kingdom
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Best 300B SE OPT?
Hi Paul,

Yes, mine are the SA08S, with end-bells. I can't imagine any reason to encapsulate them, unless you live in a log-cabin, or a beach hut.

The Sowters sound really fine, and they always inspire confidence with the build quality. Absolute perfect alignment of all the laminations, perfect finish. They are tested at 2500V, to boot.

Their 65kHz of bandwidth in a 25W-handling design seems as good as you could want, and leaves room to try muscle-300Bs or higher voltage SE amps. The primaries in mine measure 81 ohm dc.

Monoliths sound interesting, but how proven is the sound-performance, or the build quality?
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Old 22nd September 2012, 01:05 PM   #64
needsp is offline needsp  United Kingdom
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Hi Rod

I think most people choose encapsulated for aesthetic reasons (though personally I'm not sure personally that a plain metal box is more attractive than an open frame + bell ends), or possibly for the possible benefits of increased damping. I’d nev r thought of it as a means of climatic protection, though in e.g. SE Asia, it might well be a very good idea!

Are the Sowters’ vacuum impregnated with varnish? My Border Patrol interstages aren’t. At the moment they have thin paper in their air gaps- this slightly wider spacing gives them an almost constant primary inductance up to 35mA dc current. But it’s possible to dis-assemble the core and remove the paper- this increases the inductance at lower current (I keep meaning to do this for my 6N^ drivers which operate at 16mA- removing the paper would increase inductance from 49 to 95 H).

Border Patrol did a lot of listening tests with various designs, and found that the un-impregnated transformers sounded best to them. Does mean they act a bit like a very low efficiency speaker ....

Monoliths sound interesting, but how proven is the sound-performance, or the build quality?
Not well proven. But the claimed specs are excellent, their construction as described likewise, their designers well documented and likely highly competent, and they have customers whose testimonials are as effusive as any here. I.e. no better or worse documented than any discussed on this thread!

My Audio Note transformers are, I suspect, sonically inferior to the Sowters. But this expectation comes from a comparison of the specs and construction, not from direct comparison of the transformers in use. The ANs have also been good enough for me to easily hear the result of modifications- for instance your filament regs

So far, Andy's thread has suggested that the ANs' are middling performers as I expected. But it hasn't helped much in deciding which type to replace them with. Won't be Lundahls (I always get the impression that everything they make is god, but not great; though I have no personal experience at all, and am probably completely wrong), Japanese types (too pricy after all the hype, and also too "Zen"- you know all the mystical crap that 's associated with SE designs) or American (too costly to import); might be Sowters, Monoliths (big C-cores- good?; but encapsulated- bad?), Border Patrol (though they are 2k75) or, possibly something from SP Windings. They offer a 2k75 type of promising construction, and would, I'm sure make a 3k5 design if asked. But an even more unknown quantity?


Paul N
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Old 22nd September 2012, 03:24 PM   #65
andyjevans is offline andyjevans  United Kingdom
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Here are some comparative pieces of data from various people. At least these are A-B comparisons. Not science, but rankings do have their uses:

"Let me explain about amorphous cores. There are three kinds of audio transformers:
1. Si-Fe type
2. Ni-Fe (permalloy)
3. Amorphous - composed of Fe-Ni or Fe-Co

Amorphous is not an alloy. It has no regular crystals of metal. Physically, it is like glass and quite brittle but Tamura got around this with special manufacturing technology. The other challenge that Tamura had to overcome was that amorphous material saturates even more easily than permalloy or pure nickel, so here again special techinques were employed. I find the amorphous core to be excellent throughout the frequency range, however, its extremely clear sound requires color and power elsewhere in the amplifier

F5002 good detail in all frequency, really sensitive to associated parts, lack of bass
I highly recommend you use top of the line F-5002, even the cost is .... But you will never use lower grade trainee.
Compare between M6 and Amorphous, the Amorphous on the high resolution lousdspeaker possess a lot more low level detail and resolution over M6
Go for the Tamura F-475!!! I have 3 pairs and using 2 pairs at the monent. They are absolute the best buy in Tamura opts. I am using them in my Sun Audio SV-VT25 amp and they are better sounding then the Tamura opts in Sun Audio amp. I also compared them with Tamura F-5003, and I am surprise then the F-475 shares the same sound quality of the F-5003 but without the detail and not as musical, but considering the F-5003 is 5 times the price!!!
For people with listening experience with the Tamura amorphous trans. Is the bass really light? I am getting incredible midrange and high end - one of the cleanest, most real (neutral) sound. But the bass seems very light. I wonder if this is a characteristic of the Tamura output (Sakuma-san made some comments about it in SP)

To my ears Tamuras are the best. To save money get the ElectrPrint as they are the cheapest of the good sounding ones. Hashimoto’s my other favourite, but they are pretty pricey as well

Here is our Thailand shotout. (DIY Audio) We test on 2A3 first.
1. Tamura F-2007
The one that was installed on the chassis. Neutral, clear bass and good impact in LF. Detail and HF is fair.
2. Tamura F-7003
Connected for 5K. Sweet and pleasingly musical. It made female vocal more sweet and seem to be younger. Unfortunately, bass is not as clear as the F-2007 but good enough.
3. Tango NY-15-3.5s
Same tone of F-7003 with a bit of added detail in the HF. The vocals are the same as F-7003. We 're surprised that NY-15.3.5s is so close to the F-7003, much more so than other series of the same brand.
4. Tamura F-5002
Superb detail. Vocal is very clear but not as sweet and pleasing as both permalloy transformers. Lacks the bass of all the above. But we have some magic.
5 LL1623
Very economic. Less detail and clarity than a Japanese trans. Bass is same as F-2007 with the same character, punchy and full. We didn't listen to this trans as much 'coz it worse than any Japanese transformer.
6. DIY trans 3k
Less clear than LL1623 but tonal balance is same. Nothing to talk about. We have to experiment much more.
After the first round we concluded the "sound of the core" made the difference. Hi-B give neutral and full bass with impact. Bandwidth is less than others. Permalloy adds something good to vocals. Less full and clear in the bass. Amorphous very detailed and clear with less impact of bass. Bandwidth is so wide. Second round started with the VV52. We focused on F-7003 and F-5002 only. The result still the same but the owner of F-7003 said "I feel the detail of F-7003 was hidden somewhere". So, we moved both OPT to the Spk terminal to use #35 SWG 20cm long of Spk cable and used 5 meter for HV cable from VV52 to OPT. Believe it or not, both OPT gained in detail and F-5002 showed more volume and clearer bass than the F-7003, even better than F-2007, I think. I thought this contradicted the idea that F-5002 has weak bass.

The MQ DS-025's are in my primary system (2A3). I had the Tango U-808 in this system previously. While both were wonderful, I settled on the DS-025's has having a tigher low end

I just installed the Hasimoto 20 3.5 on my tubelab SE. I was using the James before. It's another planet

I'm using a pair of Hashimoto H-20-3.5U transformers. The highs and midrange were very good, but the bass is a little woolly. To my ears it sounds very similar to the James JS-6123H. I don't have experience with their more expensive transformers. I built a drd about 8 years ago with some excellent iron from Electra-Print. It's my favorite to date.

I have used Audio Note, Bartolucci, Electra Print, MQ (both parafeed and FS-030), and James. I think James is the best for cost vs. sonics, but MQ is hard to beat at any price. The SE transformers I still have on hand are MQ and James, the rest sold along the years.

I'd put them up against Tango. I've used original Dyna from the SCA-35 (very good), UTC LS-52 (also very good), and James (excellent). My own bias is toward James, if you can get 'em. Very mixed experience with Hammond. Good experience with Edcor.

6115HS – sounds better than Daburu to one poster
JS-6123HS is “quite good” like 3.5/5 where Tango/Tamura are 4.5 or 5. Nearly a clone of XE20S which scored 4, but cheaper. LOOK-AUDIO MATERIEL AUDIOPHILE

I have a pair of Daburu I bought a couple of years ago and yes I like them a lot - better than James? tricky...they do do the business and I'd be happy to buy more...
I had a pair, which were better sound than the AN Trans-15? (presume 152)
I have used James Output transformers in two projects now - 300b and 2A3SE - and couldn't be happier. I have compared them in similar designs to trasnformers by AN, ElectraPrint and Bartolucci and I'd say you'd have a hard time beating them at 2x or 3x the price. I preferred the AN and James over the others - and so did a good friend who is a musician

I did directly compare James and ElectraPrint. The EP's are currently in use in my amp while I sold the James

6113HS for my tri-amp is good (10Y/50/300B amplifier) and I'm very satisfied. Sounds fantastic and I believe it's in the same league as my Tamura F-475 (45 amp) and MagneQuest DS-025 (2A3 amp).

I have used Plitron's 3035SE OPT in my 300B mono's for few years. It has very good frequency response upto almost 100KHz. However, I don't like the sound of it much. The Lundahl 1620AM amorphous OPT has much more natural sound breathing out music. With Lundahls amorphous sounds better han nickel to me.

The Silk transformer has everything the very expensive Tamura has - something is less, something is more but not 8 times difference as the price suggests. I use their 5K OPT and I love it. Took about 200 hours of burn in before it got to it's best but even brand new it was amazing.
On the far-east iron front I've found that James is OK , Silk very good , Valab suspect (no nickel and high capacitance) and the grey stuff like the anonymous c-core 5k transformers I got from Hong Kong complete shite.

Over the last few years I purchased a Daburu 5K 10W SE, Eastern Audio 3K/5K 20W SE and 10K/50W SE. Fit and finish very good. They are better then all variety of Hammonds but not as good as the smaller James 6115HS (from Euphoria Audio) which sounds much better to me

The most detail can be heard from the silver secondary Electraprint iron, the best tone from the Onetics, Lv3
Lundahl LL1620/60mA. Lacks the refinement of the O-netics on strings and voices, but it does have quite good tone to instruments. A loss of micro-detail compared to the O-netics. Bass was strong but less defined in tone

AN Trans 152 About the same level as the Lundahl above - smoother and more rounded but a further slight loss of micro detail. Bass again strong but less defined in tone than the O-netics

My Malaysian agents imported some Bartolucci outputs on trial, but found they did not sound as good as the "James" transformers they were already getting from Taiwan and had some finish quality problems as well. Allen Wright

In the ETF shootout the James was beaten by a Tango, which isn't too shabby. The Softone beat another Tango 3.5K (which knocked out a LL1664), which says something for the Softone! The Silk beat a Van der Veen toroid - not too informative.

Hard to say how "equal" the comparisons were, but going from the above and very loosely and unscientifically:
- Tamura sound best, with amorphous clearest but lighter in the bass.
- Second to this seems to be Tango and Hashimoto, depending on the models
- James seems to come in at this point and also Electra-Print in different ways.
- Silk, O-netics and Magnequest are floating around somewhere here as well, but comparisons are difficult. Softone may also be at this point.
- Daburu seems to come in behind these
- Lundahl probably next, though their amorphous cores should jump up a few places. AN Trans-152 about the same level as straight Lundahls.
- Bartolucci has had some bad comments from users which I won't reproduce, though others rate them.
- No actual comparative info on Sowter so far. Same with AE, Monolith and some others.

So what to draw from this? If we exclude the top Audio Notes, Tamura, Tango and Hashimoto on price, then the "superior but good value" cohort seems to include the cheaper O-netics Level 1, Electra-Print, Magnequest, James, Silk and Softone, and possibly Daburu slightly behind these. How they actually compare under identical conditions who knows. For Sowter and AE and Monolith I have no way of telling, but they may be equal or superior to the above "good value" group.

I don't know if that takes us any further!
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Old 22nd September 2012, 04:02 PM   #66
needsp is offline needsp  United Kingdom
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There's an interesting article about SE output transformer design on the Electra Print Audio website-

Electra-Print.com Tech Blog

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Old 22nd September 2012, 04:09 PM   #67
needsp is offline needsp  United Kingdom
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Hi Andy

I don't know if that takes us any further!
Neither do I, but thanks for trying!

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Old 22nd September 2012, 07:20 PM   #68
fullrangeSR is offline fullrangeSR  Canada
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Originally Posted by andyjevans View Post
Could you give us an idea of the sound quality of the James OPT compared with the Transcendar please?
I haven't had the time to try James output transformers. The other day there was an ad on Canuck Audio Mart, the fellow was selling James transformers and I went to buy a pair since the price seemed right. How right? To this day I think that Mr. Patrick Turner is the most honest transformer winder on this planet, for one simple reason – he doesn't hide what's inside his transformers: wires, insulation, iron, layers, strategies etc. No other winder does that, period. If shipping charges from Australia were not brutally expensive, I'd own a pair or two of his transformers (I still might if the time is on Mr. Turner's side – long you live old man!).
On one of the websites it's said that James JS-6132 weighs 5.2kgs (it turns out later that the actual weight is 4.8kgs...) and the dimensions are 106/96/130mm. I then checked those dimensions against a similar (5.2kg) transformer that Mr. Turner has for sale and concluded the following: James trafo with enclosure and potting compound is still smaller than Mr. Turner's transformer of the same weight without enclosure and potting compound. Smaller diameter wires? I thought... Still, not far off and the price was nice and the sale was local and...
Once inside the man's basement - I was shocked. Ten plus amps, all with James transformers, many many boxes full of James and other transformers, a room full of electronic instruments, boxes full of tubes... Talk about a kid in a candy shop... The man told me how ten years ago he ordered two thousand pounds of James transformers from Taiwan... I was looking at what was left. I knew then it was now or never again, so I – in addition to two output transformers – bought two James chokes and a power transformer. Now that the initial euphoria is over I'm still positive I've done the right thing. Double C-core, relatively heavy, reputable engineers... No, I'm not throwing my 20W Transcendar pair away, it simply shines in plate-to-plate FB circuits (EL84, 6V6,), in Tubelab Simple SE, and in 2A3 circuits...
Very interesting discussion about output transformers can be found here: Magnequest DS025 and Tamura 5002 real world assessments - AudioBanter
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File Type: jpg transcendar-james.jpg (81.0 KB, 2040 views)
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Old 4th October 2012, 07:34 AM   #69
MQracing is offline MQracing  United States
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Originally Posted by kevinkr View Post
Sounds like prose from Mike LaFevre of Magnequest.

Magnequest iron was quite good, I'm not sure what is going on with MQ these days, but I recently tried to find a source for his plate chokes and was unable to do so.
Sorry if you had trouble reaching me. I'm still at acrosound@aol.com and MQ has two different forums where you can ping us if need bee.

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Old 26th October 2012, 04:28 PM   #70
needsp is offline needsp  United Kingdom
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Hi All

I've decided to order a pair of the Monolith Magnetics Summit S-9 C-core 3k5 300B SE transformers I mentioned. I'll report back when I've installed them and had a good listen. I'll be able to offer a comparison with the Audio Note 152 types at least

Paul N
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