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On recommendations of several members here (Al Sekela, cdc, audionutge - thank you everybody), I decided to try Hammond 193L tweak. Let me tell you right away that it works in my system, but with two caveats:1. It can make things worse, depending on location - and this was somewhat unexpected, reading posts here.
2. By no means it does wonders, changes are rather subtle.The system: Proceed CDD, DAP, PRE are plugged into PS Audio UPC-200, and both UPC and PS Audio HCA-2 are plugged into the wall (ACME outlet), on the same line. Line is quasi-dedicated, i.e there are several outlets on it in two rooms, that don't have anything plugged into them permanently. Various aftermarket power cords, interconnects from VD and NBS. Speakers - KEF Reference 3.2.
At first, I plugged the choke into the duplex that's connected in parallel to the one the system is plugged into (both in the same in-wall box). After several days sat down to listen - the sound was unmistakable WORSE. Soundstage became flatter, and bass had less impact. Please note - both the system and my ears are relatively resolving, so there's no second-guessing if that's what I really heard.Then, I unplugged the choke and moved it to another outlet on the same line in the same room, there's probably 10 feet between them. Here, it is finally doing what it's supposed to - soundstage is marginally deeper, vocals have a little less edge to them, and midbass is slightly more articulate.
I'm not sure what the first anomaly should be attributed to - may be there's some kind of interference between the choke and UPC-200 (that has BALUN transformer inside) - they were sitting literally next to each other on the floor. Or between choke and digital amp, or speaker cables, or who knows what else.The positives are nice, but I would estimate the amount of changes as less than 50% of power cord swapping (for instance, PS Audio Statement SC and ESP Essence on amp, or Cardas Golden Ref. and VD Nite on preamp), and also definitely less than plugging components into UPC-200 as compared to directly into the wall.
On the other hand, money-wise it's about the cheapest upgrade possible, and with that in mind is definitely worth it. I'm going to try 193M next on yet another outlet, in hopes two of them will give more of the positives listed above.
FWIW.
Follow Ups:
So this can be wired across the hot and neutral without a problem?
The Elaborate DAC=Johnny's Balloon Meshplate 27 Balanced Preamp=Balanced Six Pacs=Newform Research 645
see images at: www.pbase.com/jamato8
We talk a lot about the choke so that the price of 193 increase...:))))hehe....better get few more soon , otherwise price keeps increasing...
Only PE is raising the price. Here is a better price.http://www.a1parts.com/transformers/Hammond_Chokes_193_Series.htm
Alan
Thanks, Alan. Good price.
I know that the only way is to try out, but , since we're here and i was just wondering if anyone has tried the choke for video? I have another joke on order and will try it later.
Any experiment would be greatly appreciated. I think if it works well for video too, then more chokes will be ordered...:)thanks.
Yep :)Alan
What exactly is the choke supposed to do?doggy
An ideal inductor would have impedance that rises with frequency for any frequency:Z = j * omega* L,
where j is the square-root of -1, omega is the angular frequency (twice Pi times the frequency in Hz), and L is the inductance expressed in units of henrys.
The Hammond 193L is a 5 henry choke designed for use as a filter element in a tube amp B+ supply. It has a core made of laminated steel plates, and is designed to exhibit 5 henrys of inductance with a DC current of 300 milliamperes. It will exhibit somewhat more than 5 henrys with zero DC current through it.
The winding insulation is robust and suitable for exposure to the AC line voltage. The coil resistance ("DC" impedance) is 57 ohms.
The steel plate core limits the high frequency performance. Magnetic domains in the steel have to switch their magnetic direction in response to changes in coil current in order for the choke to exhibit inductance. If the frequency of the coil current exceeds the ability of the domains to follow, the core will effectively disappear and the inductance will drop to the value that the coil alone would have due to its geometry.
This makes the choke an effective filter for RF noise present on the AC line. The inductance limits the 60 Hz current to 64 millamperes or so on a 120-volt line, but the core speed limitation reduces the impedance to RF noise.
Note that all transformers with similar construction have similar frequency limitations and can be used as RF noise filters. However, secondary windings on transformers may ring due to parasitic capacitance unless they are loaded with non-inductive resistors. Unless you are a dedicated tinkerer with access to cheap surplus transformers, the choke is the cleanest way to experiment with this kind of filtering.
I have a huge r-core transformer from a Lux power amp I gutted. I'll try that first.
Hammond must be wondering where all of these chokes are going!
Hammond's tech staff knows...we talk often. PE on the other hand is a little confused :-)Alan
The choke cuts off odd harmonics riding on the a/c.Alan
When I started installing/using these chokes I had Auricaps installed in a Proceed CDD and two modded Powervar Medical PLCs. With the parallel filters (Auricaps) removed, the system sounded way better. It is as if the chokes are very sensitive to other parallel tweaks and filters. Also the chokes were not plug and play in my system. It takes 7 days for my system to start settling in and snapping back together.The biggest improvements have been with my Sunfire True Subwoofer Signature Sub and video. Only with my sub and video has my reaction been, "wow that is sweet!". It also seems that the more of these chokes in my system the better...so far that is. Aside that the chokes do not work well with other parallel filter devices, I have not noticed any downsides, only improvements..."in my system". Of course, as always YMMV.
Chris
I have the same thought.I first plug the choke in the same outlet where my PS Audio UO connected to.However, i don't let it stay for long. Then i move it to another outlet which is 8ft away. After 1 day, i start recognizing the change in sound: bass is punchy, mid-range is well defined....especially, the high is less edgy which irritates me most of the time.
I can't tell if it sounds better if i put it on the first outlet since i don't let it stay long on the first one. Since i hear what i like, i don't want to move it away ...:)
The only thing i don't know if it will make difference or not is that the outlet that the choke is currently plugged in is the cheap outlet. I intend to replace it with Furutech. Any suggesttion?
thanks.
The Furutech duplex will most likely effect the component plugged into it. I doubt it will effect the choke's effectiveness. Leave the choke in place for another 5 days, then see if you like it. In my system, the choke is not "plug and play". Then evaluate again a few days after. Since you liked one in your system, these chokes are so inexpensive, try adding a second one. Then report back the results.Chris
Chris,
I see some folks here use 193M . Do you think another 193L is ok with my application or getting 193M will be better?thanks.
A single 193M equals two 193L's...they sound the same. So if you want to use a 193M too...then do so...no big deal....the more the merry. You are only experiencing the first stage of a much larger concept.Alan
Very good question. I have 4 193L in my system right now. I am about to add another 193L on Wednesday (for the DVD player). I am currently using one 193L choke per component and adding them as I go along to experiment. I want to see how the chokes and other power tweaks effect my system, a step or change at a time. What I have clearly noticed/can hear in my system is that the effect of the 193L choke is cumalative, so long as they are plugged into the same circuit.The 193M is a 10 Henry choke, the 193L is a 5 Henry choke. I am going to order 2 or 3 193M chokes to experiment with. So far I have not answered your question, because I have no clue. You really have to try it in your system, at your home. The 193M is a stronger version of the 193L. Possibly Alan Maher can offer you a suggestion. Alan is currently experimenting with different combos of 193L and 193M.
Chris
OK...I will shed a little light...but only because asked...the choke can be wired many different pending your overall design application. A typical install is to just use the choke as a local and wire it across the hot and neutral of a single duplex outlet. I use this method and I strongly feel it offers the best overall effect. Another method, clustering, wires a single choke across two duplex outlets with the understanding other chokes will be plugged into the same duplex outlets. In this type of set up you have 3 components. 1. Power Cord. 2. Choke. 3. Duplex Outlets x 2. In the clustered method the effect of the split choke is less at the duplex than the method I prefer. The only component that does not see a difference in strength is the connecting power cord. So when you plug the power cord of choke 2 into the split duplex of choke 1, you now achieved the same effect as you would if you used my preferred method. I usually recommend using a 193L for a single duplex and a 193M for a split output. Recently, I have experimented with using the larger 193M on the primary of a isolation ransformer to balance the inductance level on both sides of the transformer. The secondary has 5 193L's installed....so I am currently using a pair of 193M's wired into the main power cord. So far I am extremely pleased with the results. I also use other items as pasrt of the power cord design. All items are based on increasing the conductive flow of the power cord.Alan
The problem in your first location is the parallel cap in the UPC. Parallel capacitors make the choke sound bad. I suggest a different test. Remove all filters from your system. Allow the electrical line to adjust over the next 3 or 4 days. Plug the choke back in at the a//v system and allow it 1 week to adjust on the line. The choke is not a plug and play device.Alan
Plug and play, at least in my system.I DIYed one per Al's formula with R-Cs on the secondaries. There's a failsafe switch (there's a technical name I forgot) that Al sent me, so that it would trip if there were a surge. When I flip the switch off the effect disappears almost immediately; when I flip it on the effect appears almost immediately.
It's not dramatic, but it's noticeable in my system, which has several other RFI filtering devices in parallel mode as well. My kids heard it clearly as well. Things sharpen up, not brighten up, but clarify.
I didn't find the tranny solution to be as location dependent as you describet the Hammond choke to be, but I also don't have some of the other AC devices you're using in the system either.
FYI, if you find a surplus house this tranny/R-C device is cheaper than the Hammond Choke device, from all your descriptions of pricing.
Dear Bartc,What kind of tweak you are talking about : isolation or balanced transformer ?
For my CD player and DAC, I had installed Jon Risch's DIY power line filter and isolation transformer with the R-C filter configuration as suggested by Al. The result is very good.
I also have a JR Iso Tranny for my digital front end, but that's not what I'm talking about.A year or so ago when the Hammond choke tweak appeared Al Sekela clued me into how to make a device with a similar effect using an EI transformer that I had lying around. He perfected it with the addition of R-Cs across the secondaries. He put it into his system where it worked well; I put it into mine, where it also worked very well. According to Al, the effect should be pretty much the same as what the Hammond choke does (he can tell you the theory).
He's refered to it in several recent posts here.
It's simply another form of parallel AC filter. Just uses a 2 wire plug into an ordinary transforme on the primaries, then the R-Cs on the secondaries. Nothing plugs into that device; it exists as a parallel device plugged into whatever your system is fed by.
Don't know whether this is considered balanced or isolated or whether that even matters here.
How big must the transformer be, to be effective? 1KV, or size doesn't matter? Also, does it have to be step down transformer or 1:1 isolation transformer will do?
Is it not the same as the JR DIGITAL FILTER with back to back secondaries and caps in the middle (but no resistors)? Thanks.
I've got a 1 KVA filament transformer wired as a parallel AC filter. Choose the biggest transformer that will remain quiet, and be sure to use a circuit breaker or fuse in the primary circuit.The secondary has to be loaded to keep it from ringing. This is done with an R-C network, so the higher the secondary voltage, the smaller the C required. The transformer will absorb AC line spikes, so you do not need X-rated capacitors.
This is similar in concept to the first two stages of the JR filter, but there is no power delivered with it. It absorbs AC line noise as a parallel filter.
Dear Al,Thanks for your explanation again. I find your previous discussion on this topic.
http://db.audioasylum.com/cgi/m.mpl?forum=tweaks&n=138441&highlight=bartc&session=
You mentioned that "Please do not use an electrolytic capacitor for AC service: these are polarized and cannot withstand significant reverse voltage. They can explode if used incorrectly!"
I had some 50V, 100uF Black Gate non-polar electrolytic capacitor. Can I use them as a parallel R-C filter in the 12V secondary of the filament transformer ?
Also how many such "filament transformer AC filter" should be used in the audio system ?
Thanks.
You would need a 1.2-ohm resistor to look like 120 ohms at the primary. A half-watt size should be adequate.As to how many, again this is trial-and-error. Any unused outlet may be a place where a filter can take energy out of the house wiring RF resonances. I would make a few and try them in different locations.
Thanks Al. Another question. For those of us who already have like a 2KV isolation transformer, can we add the RC filter at the secondary and then connect an outlet at the end of the RC filter so that the power to the components are passing thru the RC filter instead of just the isolaton transformer, or are the filters better just as plug-ins.
Will the RC filter also work with a balanced transformer (JR signal D2 transformer recipe).
The R-C filter is best used as close to the AC outlet as practical. If your isolation transformer has sufficient core losses, it may already provide most of the benefit that an R-C filter would. The only way to tell is to try.I don't think the R-C filter would help much on the secondary side of the isolation transformer.
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