If the cartridge needs additional loading that should be placed at the
primary of the SUT to load the cartridge directly. I find secondary
loading to make a cartridge behave under various situations to be a
sonic band-aid.
Years ago I found it interesting that people who
use active gain stages tend to find their MC cartridges insensitive to
loading and those who use SUT's can get fanatical about it. FWIW the loading doesn't do anything for the cartridge at audio frequencies except reduce its output. The loading is audible though, but that is because it detunes the RF resonance caused by the cartridge inductance and the tone arm cable capacitance. If the preamp is insensitive to RFI the loading doesn't do anything. 47K is therefore an effective load. I've heard loading make a difference but when you get the RFI problems sorted at the phono input, that difference goes away. While the Jensen is one of the best SUTs available, being best isn't the same as being right for all cartridges for the reasons Dave mentions above. Quality and application are two different things! But in Stu's system, the problem he described sounded very much like any phono section that isn't getting enough signal. Dynamics wake up, the sound is more vivacious when that is rectified. So comparing the Jensen which is set up for a low boost to a transformer set up for a lot more may not be about the transformers so much as it is the amount of signal presented to the input of the phono section. For that you would have to have both set up as much as possible the same way. |
There was definitely some luck involved but it offsets all the times I have been unlucky with equipment failures, red herring issues, ghosts, phantoms, and just pure stupidity! All the fun of music and audiophilia.
I would like to understand why this sounds so good, but I can live with not knowing in this case and just enjoy the music. It is a real luxury to have all you guys willing to share knowledge. Thanks to all.
Stu
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Montaldo it is great to hear your happy. Dave knows his stuff and can obviously hear music. He can do all the math and graphs, but when he is done he listens.
Part of the sound difference is in the materials and the build. Loading and step up are also in the equation. You changed multiple variables at the same time. Dave may jump in with some more thoughts. You may have got lucky and the ballpark is as goods as it gets. Regardless you seem to be excited about the results so enjoy.
Enjoy the ride
Tom
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Thanks Dave
It is one more variable in the 100's so we can black art our way to audio nirvana. If you are out at a west coast event let the forum's know. To hear your modified stacked 57's would be a delight!!!
Enjoy the ride
Tom |
Reporting back on the effect of adding Dave slagle's 1:20 Copper SUT to my Berning pre and Koetsu Rosewood Signature. In short, everything is back. The gorgeous tonal balance and graceful top end of the Bernng remain, but now all the Dynamics have been restored and the engagement and involvement is stunning. the difference is not subtle. it's as if every component of system were upgraded.
am I am I right that this huge difference can be attributed to some sort of better loading match between the Transformer and the cartridge? and maybe it is aided by the additional gain but not primarily driven by that?
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Hey Tom,
Transformer "misbehavior" (ringing etc) is a function of source and load values. With a known source (cartridge impedance) and load (47K+||100pf) the transformer can be wound such that it gives the desired behavior. This is a completely different concept than loading the cartridge and much of the confusion in the topic comes from lumping everything together into an "ideal black box"
For your 5 ohm cartridge and a need for 20X gain, a 1:20 can be done to have a low Q resonance of 3-5dB above 100Khz loaded only by the test rig. Adding the actual input impedance of 47K+ and 100pf for cable capacitance will damp this behavior down to an extended well behaved top end. Lets assume you want the cart to se 50Ω and the input resistor is 300KΩ. The turns ratio of 20 will give an impedance ratio of 400 so that 300K becomes 750Ω. Placing a 54Ω resistor at the cartridge in parallel with the reflected 750Ω will net a 50Ω load with minimal effect on the transformer behavior. From the transformer primary viewpoint, the 54Ω resistor will lower the 5Ω source impedance to 4.6Ω. The change in source impedance from 4.6 to 5Ω is well within the range of source impedances that will work for a given design. It is when you start changing the source or load impedances by a factor of 2 or more from the "design center" that transformer behavior starts to dominate the sonic signature. Take the peerless 4722 that works nicely with a denon 103 and drive it with a 2Ω SPU and that controlled top end suddenly turns into a 10+dB peak @ 22Khz. Fix that 10dB peak with a 10K secondary load and you end up with syrup.
The important thing to understand here is that the load the cartridge sees and the turns ratio of the SUT do not need to have any relationship to each other and simply mathematically attaching them to each other as a ROT generally leads to inconsistent sonic results. |
Dave I am confused on the second variable. Or what you can do to the transformer to make the cartridge not need loading.
Let's say you have 5 ohm cart. We use the 10x rule so 50 ohms is a ballpark load. We have no input resistor on the phono amp. Can you build a transformer say 1 to 20 to meet that 50 ohm need.
Or to put it another way on a 1 to 20 step up, what is the load variance window you can get by material and or winding?
Thanks Tom |
The K&K link does not "back" what Ralph says. Ralph states (correctly) that for any given source there is one load that will make the transformer act in the manner for which it was designed. The K&K link assumes the transformer to be a perfect device that simply reflects an impedance and has no other impact on the sound. It is my belief that SUT's should be designed to work optimally in an unloaded situation with 47K input resistor and ~100pf of cable capacitance being the worst case situation. If the cartridge needs additional loading that should be placed at the primary of the SUT to load the cartridge directly. I find secondary loading to make a cartridge behave under various situations to be a sonic band-aid.
Years ago I found it interesting that people who use active gain stages tend to find their MC cartridges insensitive to loading and those who use SUT's can get fanatical about it. I then went through the process of playing with loads on both the primary and the secondary of various SUT's and found that loading the secondary had a much more profound effect on the sonics. If the transformer were ideal then a 100Ω load should be a 100Ω load independent of whether it is at the cartridge directly or reflected through the transformer. Since the differences were not subtle I came to the conclusion that the load on the secondary was altering the sound of the transformer as much or more than it was the cartridge. This goes a long way to explain the "black art" label attached to loading SUT's since loading the secondary changes both the sound of the SUT and the sound of the cartridge at the same time.
dave |
Regarding the reviews for various SUTs you will find a lot on Arthur Salvatore's site, he praise ZYX CPP-1 headamp and prefers it over many SUTs. |
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chakster, you can always out board them. |
The Ortofon T30 had been praised by Jean Hiraga on a phone call we had together many years ago.
I have one.
The HM7 is a bit better sounding for me but twice the price.
If you have several carts the T30 is a top choice as can be a Air Tight ATH2 A with connections for 3 arms an different loadings. |
I tried to modify my WLM Phonata Reference phono stage by replacing the built-in SUTs. I gave up, because they are smaller than usual, maybe i will do that when i will find a better SUTs of the same size to fit in, the closest are 1:10 Lundahl SUTs that can be ordered directly from Sweden. This brand is one of the oldest SUTs manufacturer. |
Exactly Mike which I think is pretty Spendy, actually that one was $700 and there are even more Spendy examples on ebay.
And yep I will be first to admit my welding and soldering skills are woefully lacking.
Monkey 💩 springs to mind when viewing the results.... |
Uberwaltz it is very easy to put a transformer in in such a way that the phono amp can be returned to stock and nobody would ever know it had been modified.
chakster, Sowter transformers are British and are made like SME stuff. They cost about $100 per transformer which relative to transformers with a shiny face plate and chassis is CHEAP. Uberwaltz just mentioned a used Ortofon for $600! |
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More like some people do not want to modify the inside of a phono there by ruining potential resale value......
However it should be fairly easy to build a stout SUT as very simple device after all. |
@mijostyn i think we have many good SUTs available today, but the prices are sick for many of them. An old japanese SUTs are great and very cheap compared to modern SUTs, so i’m happy with my Luxman 3 in one. |
Chakster, The Sowter trandformer for low impedance cartridges is good for 1-15 ohms. 1:10 or 1:20.
Mike |
Not really Uberwaltz, most of the best cartridges now a days are very low impedance. I would just get transformers for low impedance cartridges.
IMHO an internal transformer is always better. I guess some people are not so hot with a soldering Iron. |
Which the above answers my thoughts that in the ideal world the SUT would be built and tailored exactly to the cartridge in question.
Makes it a bit of a pain if you swap carts a lot though...... I can just swap SUTs for almost any LOMC because smart manufacturers like Luxman made at least 3 different toroidal silver plug-in SUTs for one base connected to the arm and phono stage, very easy to swap in 5 seconds. On that page you see 2 of them, but there was actually one more in the middle (8025 for 3-40 Ohm). There is a SUT for any situation, for carts under 3 Ohm, for carts over 3 Ohm til 40 Ohm, for carts over 40 Ohm. But most of my favorite LOMC are all low impedance, anything from 0.17 mV works fine. Any modern manufacturer can offer something like that ? |
Which the above answers my thoughts that in the ideal world the SUT would be built and tailored exactly to the cartridge in question.
Makes it a bit of a pain if you swap carts a lot though......
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That's a bit of a surprise- your response on AudioAsylum lead me to believe otherwise. I can point you to a number of other examples should you need more proof. I think we are missing each other on a few of these things. I have no doubt that assuming enough inductance and a reasonably competent transformer design that for a given cartridge an acceptable network can be found to give flat response. My contention is those networks put in place to account for a mismatch also do some sincere damage to the sound quality. We agree that SUT's can never be "universal plug and play" and while you say issues can be fixed by loading, I contend while that is technically true, this imparts a rather large sonic compromise. While on this topic I will add that in a perfect world I would install the "ideally matched" SUT into the front end of the phono stage but then what happens when you want to compare a Lyra Atlas to a Van Den Hul Colibri? In my world you would need a new SUT and in Ralph's world you would need to hope that there is enough inductance to support the VDH and then adjust the load accordingly. In either case with an internal SUT this becomes a difficult task which is why i advocate for using external devices as the best option for this situation. |
@intactaudio 47K is a silly value for the input of a phono stage when considering a SUT. Selecting a turns ratio on the reflected load of that 47K is misguided.
I install a 300K at the input of my LR phono and I believe shindo used 100K so no everyone adheres to that antiquated 47K value.
Very Interesting. I can confirm that higher load resistor value in MM input for SUT is harmless, at least to for my ears. I was concerned about it simply because most of my MM phono stages already upgraded with 100k Ohm Vishay instead of some cheap stock 47k Ohm resistors manufacturers installed by default in MM input. But i was a bit afraid to use SUT since 47k Ohm recommended, not 100k Ohm. However, i tried and it was OK. Actually it's a good news. Luckily my favorite JLTi phono stage was upgraded by the manufacturer upon my request too (internal resistors is 500k Ohm), so i can use parallel RCA plug resistors of 47k Ohm (or 100k Ohm), i can go even higher if needed. The only problem is that i don't have higher than 100k at the moment, but i could buy to try. The reason why i like this JLTi phono stage so much is the flexibility and convenience. |
My largest concern here is that it sounds like it is the optimal to
build the sut to suit one cartridge so when/ if you do the cartridge
square dance ideally you would need change sut too? No. You simply have to load it correctly for that cartridge. I still don't believe you :-) That's a bit of a surprise- your response on AudioAsylum lead me to believe otherwise. I can point you to a number of other examples should you need more proof. A SUT or line level transformer driving a gate/grid of an active device
is a different situation where any load or network required is a
function of a compromised transformer design and not part of the
transformers "job description" SUT's typically drive the input of a phono section, where the input standard is 47Kohms. In this situation, the inductance of the cartridge and the capacitance of the interconnect cable form a resonant circuit. This resonance might have to be snubbed else it can cause troubles for the preamp, if the preamp has poor RFI immunity. That's what the loading resistor is for. However, driving a SUT with its additional inductance this peak is a bit different. If you don't deal with it it might cause the transformer's response to not be flat- depends on if the transformer is designed specifically for a certain cartridge, but if the transformer is mounted in the preamp as is the case with this thread where the transformer is expected to work with *any* cartridge then loading should be set up. I have found that when operating as balanced care must be taken with
the cable layout to adhere to the balanced standard and simply attaching
an XLR connector to an existing tonearm wire is hit or miss when it
comes to hum pickup.
Actually you treat it like any other balanced source. The '+' and '-' outputs of the cartridge travel in a shielded twisted pair, the shield is the tone arm ground (pin 3 on DIN connections, pin 1 on XLR connections). If you set it up this way (assuming that the arm itself is actually connected to the ground) there will be no hum whatsoever. |
Dave didn't believe me when I commented on AudioAsylum some years back that interwinding capacitive coupling is affected by loading, and thus to get flat frequency response loading is a pretty important aspect of transformer use.
I still don't believe you :-) I think this was in reference to a transformer inside an ampex deck that showed different behavior than I had seen from other line level transformers. This particular transformer showed a critically damped but rolled off top end and when loaded the midband gain was reduced without effecting the high frequency corner which in "extended" its bandwidth. I still believe that designing for the specific situation is the best approach and only rely on the load to control things if it is the main purpose of the transformer. Power delivery to a speaker necessitates a load, working in a 600Ω professional environment also necessitates a load. A SUT or line level transformer driving a gate/grid of an active device is a different situation where any load or network required is a function of a compromised transformer design and not part of the transformers "job description" I have seen the age old 'all cartridges are balanced' along with the 'all cartridges are current generators' and rather than bicker about a technical definition, I look at the primary as a two terminal generating device that inherits its mode of behavior from whatever you hook it up to. I have found that when operating as balanced care must be taken with the cable layout to adhere to the balanced standard and simply attaching an XLR connector to an existing tonearm wire is hit or miss when it comes to hum pickup. dave |
I think I was better off when I knew nothing at all.... At least I was blissful in my ignorance!
My largest concern here is that it sounds like it is the optimal to build the sut to suit one cartridge so when/ if you do the cartridge square dance ideally you would need change sut too?
Ming boggling..... |
Ralph, I will ask Dave Slagle what he thinks about my setup and loading.
The original sound tradition Hashimoto hm-7 I tried had an even higher
winding ratio such as 1:30 I think. It sounded pretty amazing with 29dB
gain. But it was a little too big and "in my face." This will be 26 dB
on top of 46 dB of my linestage, which seems reasonable. Dave didn't believe me when I commented on AudioAsylum some years back that interwinding capacitive coupling is affected by loading, and thus to get flat frequency response loading is a pretty important aspect of transformer use. He's a believer now. BTW his updates on the H/K Citation 2 are excellent. Hang on guys, some transformers have multiple taps and others do not.
You have to check on the wires coming out of the transformer. Most are
color coded. While having multiple taps gives you flexibility. I think
but I am not entirely sure that a single ratio transformer is
theoretically better. Ralph may be able to comment on this. Sowter has
multiple tap transformers but I have always avoided them. May be just a
knee jerk assumption. My brain hates unused wires. Multiple taps don't do anything to degrade performance, but they do allow you to use the transformer in a more flexible manner. The Jensen transformers in the OP's preamp have as commented earlier three different setups that can be used. The wires don't hang unused- they have to be connected together to form either parallel or series arrangements. This affect they way they respond to inter-winding capacitance so the loading requirements change as well. A nice little side note: All phono cartridges are balanced sources and most of the time are run as if they are single-ended. But when you do this you wind up with that odd 'ground wire' that other single-ended sources don't seem to need. That ground wire is pin 1 of the XLR if you were running balanced. All transformers are capable or running balanced or single-ended input or output, so if you have an SUT you can run balanced from the tone arm to the transformer and single-ended from the transformer output if your phono section is single-ended. The advantage here is that the tone arm interconnect cable ceases to be as critical in the overall system sound; if you had to audition this cable to find the right one for your system you know exactly what I mean. So you can take another step closer to neutrality by doing this, although you will have to find a place to install the XLR connections to the transformers... again, a fun little fact :) |
Dave
Thank you very much indeed, something even my poor simple head can grasp and comprehend!
Dialog with Manley will commence!
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Indeed the 47K is there for MM inputs to properly load a MM cartridge. The 47K value is not a liability for an active MC stage but when the turns ratio of a SUT is considered things change. The 47K value reflects to the Cartridge as 47K/Turns ratio squared. The perfect example of where this becomes an issue is with the Altec 4722. This is a 30/200:40K mic transformer that found a cult-like following because it is a great match wired 1:18 (120:40K) for a denon 103. The interesting thing with this combo is you get essentially the same gain out of a 103 in both the 1:18 hookup and the 1:36 hookup. This happens because assuming 47K, the reflected load of the 1:18 is 145Ω which is fine for a 103 but moving to 1:36 nets a 36Ω load which is less than the 40Ω internal impedance of the 103 which results in a 6dB loss which roughly offsets the 6dB gain from doubling the turns ratio. If the 47K resistor were increased to say 200K suddenly the increase of gain by doubling the turns ratio would be returned however the transformer behavior would also change which may be better or worse. It is interesting to note that some people do prefer the sound of the 1:36 connection with the 103 which has two possible expanations. 1) the transformer has no ringing and is critically damped. 2) loading a cartridge with its internal impedance reduces IM distortion and increases high frequency tracking (Peter Moncrief IAR #5)
Since with the SUT connected the secondary of the transformer serves the purpose of the grid resistor, it can in theory be removed completely. The problem with this is if the SUT is external and the interconnect gets unplugged or has a fault the phono stage can immediately become unstable and wreak havoc with a system with the tweeters usually becoming a casualty. The better solution is to increase the 47K value to the largest value that still keeps the phono stage stable with an open input. This becomes a situation where it is wise to open a dialog with the manufacturer and then have a competent tech change the value retaining the original part to replace if the unit is to ever be resold. I should also point out that increasing the value from 47K serves no purpose if the SUT is relying on that value (and possibly an additional Zobel) for controlled response.
I install a 300K at the input of my LR phono and I believe shindo used 100K so no everyone adheres to that antiquated 47K value.
dave
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Dave
Complete novice here on SUT so bear with me please.
"47k is a silly value for an input of a phono stage"
Bearing in mind that is the figure majority of MM phono stages come with and the likely application what figure do you suggest is NOT silly and how to go about making it so?
Hope that makes sense as genuinely intrigued as yep I am running a SUT through a 47k phono stage right now...….
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Over a decade ago I made the below linked post and still stand by it 100% today. https://forum.audiogon.com/discussions/thoughts-on-cartridge-loading-with-a-sut?highlight=intractaudiohttp:// Some basic takeaways I have found. -Loading the secondary is the worst thing you can do to a transformer. With a known source / load combo an optimal transformer can be designed. -47K is a silly value for the input of a phono stage when considering a SUT. Selecting a turns ratio on the reflected load of that 47K is misguided. -Turns ratio and cartridge load should have zero connection to each other when selecting a SUT. Turns ratio should be set for appropriate gain (with careful attention to possible overload). Load resistor should be also as high as possible. Any needed cartridge load should be placed directly at the cartridge. -Zobel Networks are a Band-Aid for a source to load mismatch of a transformer. They will make the test equipment happy but always leave the music feeling something is amiss. -high Q resonant behavior of a SUT at 30Khz is audible and objectionable yet Low Q resonant behavior above 100Khz seems audibly benign. dave |
Hang on guys, some transformers have multiple taps and others do not. You have to check on the wires coming out of the transformer. Most are color coded. While having multiple taps gives you flexibility. I think but I am not entirely sure that a single ratio transformer is theoretically better. Ralph may be able to comment on this. Sowter has multiple tap transformers but I have always avoided them. May be just a knee jerk assumption. My brain hates unused wires. |
Name came from a big night out when I lived in London and we were drinking Barolo wine. As long as the leads have not been cut too short it can be done. How easily is something you'll have to determine. Go to their web page and there are three docs, one each for 8:1, 12:1 and 24:1 ratios. There is also a doc for the zobel networks, dependent upon single ended or balanced configuration, step up ratio and internal impedance of cart to be used. I don't remember if that doc is on the website. Good luck.
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Barolobrain: Firat of all you may need to explain your username to me (expiring minds want to know).
Second, I did not realize these Jensen Transformers had optional configurations. If I could have mine required to 1:12 or 1:24 that would be interesting to try. Is the procedure difficult or could any tech do it, with insrtructions from Jensen?
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@montaldo I have a diy SUT with Jensen AT 347 trannies. These can be wired for 8:1, 12:1 and 24:1 gain. I run a Dynavector XVT-1s at 24:1 into the MM of a Zesto Andros 1.2 phono pre. You might want to ask Berning if your trannies can be rewired to 12:1 which should be enough of your cart's output.. That being said, not sure what is the MM gain of your unit. If you go to the Jensen site, you can see the schematics for the three different gains. The loading will not have that much impact on gain but it definitely helps to experiment as it relates to the sonics. I used the zobel circuit that Jensen recommends for the 347 at the gain used.
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Ralph, I will ask Dave Slagle what he thinks about my setup and loading. The original sound tradition Hashimoto hm-7 I tried had an even higher winding ratio such as 1:30 I think. It sounded pretty amazing with 29dB gain. But it was a little too big and "in my face." This will be 26 dB on top of 46 dB of my linestage, which seems reasonable.
As fas the loading issues I still don't understand all those variables so I will continue to listen to you guys and talk to Dave Slagle as well.
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Ralph, Sowter offers different step up ratios and tells you what cartridge impedance range the transformers were designed for. Is that enough in and of itself to get you headed in the right direction? I have installed them in the past and as far as my ears can tell they worked fine. |
Ralph, you would think the transformers would be designed for a 47K load
which is pretty standard for MM phono stages. If not 47K how would you
figure out what it was? Just a meter? Also why the capacitor. Wouldn't
just a resistor do? I know you might have to change capacitive
loading for a MM cartridge but why the transformer? @mijostyn They are designed for 47K, but any transformer designer worth his salt knows that the transformer isn't going to work perfectly with that- and that it will also change depending on what cartridge is used. IOW they know that it has to be loaded correctly (if they don't, they are leaving performance on the table). The capacitance has to do with the fact that you will likely get a peak somewhere that might not show up from simple ringing of the transformer with a square wave. @montaldo If you don't get the transformer loaded correctly, you will hear differences but they won't tell you anything about which transformer is better! On top of that 20:1 is very different from 8:1. To get to the right loading values for the transformer you have to talk to the manufacturer of the transformer. The only way I know to do this empirically on the bench is to apply a square wave in series with the cartridge and look at the output of the transformer on an oscilloscope and vary its load to get a very slight amount of overshoot. The problem here is that the capacitance of the tone arm interconnect cable is a variable, as well as the capacitance of the cable at the output of the square wave generator, and you run the risk of damaging the cartridge by deguassing it. This is why I like working with Jensen, as they have demonstrated over and over again that they know and care what they are doing. Most SUT manufacturers can't tell you how the unit works with every cartridge out there. |
After after all our exchanges, which I appreciate so much, I decided an experiment might be useful. So I am buying a used Intact Audio 1:20 copper SUT to just try and see how different it sounds from my internal 1:8-ish Jensens in my Berning pre. I will report back this weekend.
Stu
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Mike the the formation so far has been confusing at best. You might be best served talking again to Dave at intact and call Kevin at K+K audio. The ratio of the step up is squared then divided into the 47,000 resistor. So 10 to 1 is 10x10=100 then 47,000÷100=470. So the cart is seeing a 470 ohm load. There are ways to parallel resistors to lower that value but not increase it. The cap is use if you want a zobel network. Some guys like others do not.
If you really want total control with step up ratios and cart loading you need have your friend bypass the 47,000 and play with various resistors externally. Then when have what you want you could replace the 47k with the new value. If you sell the phono stage latter you could put back the 47k.
Without total control of the step up and loading you never really know what your cart is capable of. And of course the transformers also have a sound of their own.
Maybe Dave or Kevin will build you a sut box that you can plug in different resistors and easily change step up ratios. Then bypass the 47k in the phono stage and you are good to go.
Enjoy the ride
Tom |
Ralph, you would think the transformers would be designed for a 47K load which is pretty standard for MM phono stages. If not 47K how would you figure out what it was? Just a meter? Also why the capacitor. Wouldn't just a resistor do? I know you might have to change capacitive
loading for a MM cartridge but why the transformer?
Mike
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Thank you Atmasphere! the Berning preamp has loading plugs for the
moving coil section but if I understand what you're saying correctly
those are for the INPUT side whereas you think the Jensen transformers
themselves may need loading on the output side. Is that correct? I can't speak to the Berning as I'm not familiar with its innards but to the last question, any and all SUTs should be loaded on the output side and the cartridge should never be loaded at all since the SUT is doing all the loading via its ability to transform impedance. So when its loaded correctly (with the cartridge at its input) there is simply no need to load the cartridge. As an additional note, cartridge loading is for the benefit of the preamp not the cartridge. If the preamp has good RFI immunity no cartridge loading will be needed. When the SUT is used, it blocks RFI generated by the cartridge inductance and tonearm cable capacitance, so no need for cartridge loading. Clear as mud? An additional note: the amount of gain you ask of a transformer also degrades its performance. So the least amount of gain you get from it will always be the best. Also, if you use a different turns ratio the correct loading will change. Until you are able to sort out this loading issue, its quite pointless to compare transformers!!! Some transformers are designed to be fairly well loaded when presented with a 47K load and a nominal cartridge resistance, others are not (IMO Jensens fall into the latter category; they assume that you are going to pay attention and get the loading right). In a nutshell you would then be comparing apples to oranges. Any SUT comparison needs to have the SUTs on an even playing field; both need to be properly loading which will not be the same values! The transformer manufacturer should **always** be able to to supply you with the correct loading values (which will usually be a combination of a resistor and capacitor). |
montaldo,
You can try contacting Isao Asakua of Hashimoto, he can help you in getting the right transformers for your application. Isao Asakura, support@obsinc.us. I was going to go with Hashimoto SUT’s myself until I found a pair of MU Audio SUTs, they have Stevens and Billington transformers inside. The Hashimoto are excellent, definatly superior to the Jensen’s, and the MU audio are better still. If you have to add loading its going to drop your gain and degrade the sound. Better to avoid that if possible. If you have a good tech, he can install the Hashimoto’s in your phono pre if there is space and you are good to go.
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Please read Ralph's comments with attention - that's atmasphere.
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I like to add as little gain as possible. My phono/pre has a LOT of headroom, right on the edge of using no boost at all (accomplished with multiple devices in parallel). For many records, that is sufficient. For some, the Lundahl is useful, and easily the best I’ve tried (includes Koetsu’s own, Hashimoto, and Sowter; but not Jensen).
The 1931AG adds the least gain. That would be my suggestion for a KRS. The fine fellows at K&K Audio (no affiliation, just a satisfied customer) are very good guides - talk to them about your system. So is Mr. Lundahl, a gentleman of the first water.
If you can’t afford the silver, I’ll bet the 1931 with copper windings would be better than anything else you could buy - but remember, SUT’s don’t wear out. You only buy them once. |
Again my ignorance raises its head, but would the ideal windng ratio for the non-platinum be different? I believe the impedances are the same but the output is .4mv for mine, not .3mv (platinum). I imagine the answer is yes as long as there would be "enough" overall gain?
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I use the most revealing Lundahl silver SUT with my Platinum. That's the 1931AG IIRC. Not cheap - but they are almost as good as a noiseless gain stage.
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I use a 1:20 step up with my Koetsu RSP and it is a perfect match.
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Thank you Atmasphere! the Berning preamp has loading plugs for the moving coil section but if I understand what you're saying correctly those are for the INPUT side whereas you think the Jensen transformers themselves may need loading on the output side. Is that correct?
If so it sounds like I should contact Jensen and ask what kind of loading should be added to mate with the koetsu Rosewood signature.
Since the consensus is that the Jensen Transformers are excellent and the 8:1 winding is not a huge mismatch, this output loading is a hypothesis that might explain what I was hearing with the Hashimoto transformers. So maybe the Hashimoto simply had a better loading match and weren't necessarily superior sounding. Maybe is a road to fixing this.
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