Why not just use a 20A cord, as ARC intended?
Audio Research Ref 75 SE: Replace 20A IEC inlet with 15A
Has anyone successfully replaced the 20A IEC inlet with a 15A to use a good 15A power cord? I am currently using 2 Voodoo adapters: a 20A female to 15A male + a right-angle 15A adapter due to the depth of the amp causing it to come up against the wall. Less than ideal, but works fine and sounds great.
Since the amp doesn't require 20A circuit it would be nice to replace the 20A inlet on the amp with a good quality 15A inlet for a direct connection to the power cord.
If anyone has done this, which 15A inlet did you use? Does it fit well in the amp's cutout and were you able to use the existing screw on connectors to fasten the internal wires or did you have to solder them?
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I already have a nice, and expensive, 15A power cord that I like and matches all other cabling in my systems so I'd rather not have to buy another expensive power cord of a different kind and options for 20A to 15A are limited. But, the cable manufacturer is receptive to custom modifications so you bring up a good point and maybe I'll have them replace the 15A female connector with a 20A. That is probably the path of least resistance. The annoying part is that if I move on from ARC, I have a next to useless power cord that I'll need changed back to 15A again. "First world problems" as they say.
Thanks! |
@russ69 I don't see how that would cause a future owner a problem unless they only have 20A wall socket. |
Personally I would not change the IEC inlet, I would leave it as the manufacturer intended. A change could case a hassle down the road incase of a future sale. Also many times changing the IEC is not an exact fit and that causes other cosmetic issues etc. I'd stay with the Voodoo adapters you currently use. I own several and use them regularly in various systems and they sound great. |
Well, I hate to disagree, but I must. The 75SE would very likely be just fine with a 15 amp IEC. You are correct that the size of the IEC-in this scenario-has nothing to do with the amps being delivered or the rating of the switch in the panel box. Any decently qualified tech and whole lot of amateur techs could do this for you. I hate to say it but I think ARC just thinks it is impressive to basically mandate use of a 20 amp IEC when a 15 would supply equivalent current and voltage given the circuit. The size of the IEC receptacle and plug is purely cosmetic. ARC seems to think the 20 amp IEC also provides for tighter fit but that has not been my experience at all. |
@lak Yup, agreed. Just wanted to check here to see if anyone found a 15A inlet that’s easy to swap in terms of dimensions and internal connectors. It would be a matter of turning a few screws with no modification to the chassis. Well, turns out changing the 15A female connector on my power cord is even easier. No heat shrink, all screw crimped to 3 conductors, so I will be buying a 20A female connector and changing it myself. Case closed. |
Eugene, I'm not a home wiring or amp design expert. Some mega amps have gone to 20 amp service requirement. Although I'm very unlikely to play at levels that require 20 amps, the amp manufacturer thinks that they need to wire the amp for a full 20 amp draw. Your solution of replacing the 15 amp connector with a 20 amp connector is a good solution with me guessing the power cable is over sized for 15amp usage. |
Fully resolved outcome! This amplifier power dissipation is 500 watts maximum and 230 watts at idle. Only 4 KT 150 output tubes and 2 6H30 tubes. Power storage is 520 joules. Pure curiosity, why does it have a 20 amp cable requirement? The circuit would never come close to this amperage. I wonder what the ARC 20 amp implementation rationale is. Interesting. Charles |
@charles1dad From the manual: "The AC power source for the Reference 75 SE amplifier should be capable of supplying 10 amperes for 100 or 120 volt units, or 5 amperes for 220 or 240 volt units. For the very best performance on 100 or 120 volt circuits, the Reference 75 SE should be connected to its own AC power circuit branch, protected by a 15 amp breaker." As for the reasoning: "Why does Audio Research use a 20-amp connector? Dave Gordon, brand ambassador, told me: 'The 20A IEC connector makes a tighter connection than the 15A IEC. We also spent a fair amount of time comparing 20A power cords, and we think the 20A cord sounds better.'" https://www.theabsolutesound.com/articles/audio-research-vt80se-power-amplifier @noromance I’m swapping in a 20A female connector on my power cord to fit the 20A male on the amp. |
Thanks, So it was done due to subjective listening which I completely understand. I just couldn’t envision any “technical “ explanation as 10 amps is easily managed by a 15 amp rated power cable. Charles |
@eugene81 Hi, I'm at the opposite end here, I just brought a pair of Tara Labs Cobalt 20 amp cables out of retirement when I saw a pair of the Voodoo 20 amp (cable) to 15 amp (component) adapters. Well long story short they sound better than ever! I too was thinking about re-terminating them, one is feeding my power amp and the other my power conditioner. It's not cheap to get these cables redone by Tara Labs plus the time involved. So I'm really interested to know if you do get a sonic improvement once you've changed to the 20 amp plug. I would recommend changing both ends to top quality plugs such as Oyaide. Good Luck! |
An often overlooked reason to have what appears to be an "over-kill" component where a lesser one would suffice is that its just easier to stock one item rather than two. The 20 amp will certainly work in place of the 15 amp. I am not familiar with all of ARCs current offerings, but it wouldn't surprise me if they all have the same plug. Regards, barts |
i think arc went to 20a sockets on all their ref series tube amps so the 75 got it too ... not that it is needed for its relatively modest power draw... i think arc just felt the tighter socket is a good idea, so all the amps get it my thinking is its stupid to mod such a nice and expensive amp just for the power cord... unless the owner plans to keep it forever... |
IME, a 20 amp iec works less well if placed vertically ( like most amps are designed..including the ARC REF 75) than a 15 amp iec if the 15amp iec is placed horizontally from a socket grabbing perspective. Very few amp designers place their iec’s horizontally, which means that the cable is always pulling down and away from the socket...not a very good idea IMHO. |
Swapping the cable connector is the easiest and best way to approach this. Keep the amp original. Get a good Furutech (or something similar) 20amp connector and swap it on your cable. VH Audio is an excellent source for quality connectors. Great prices and Chris can advise on what connector would fit and sound best. |
I forgot about VH! I ordered a Wattgate 350i HC Au from PartsConnexion after my last post. Lucky me, they are doing 20% on AC products for the month of April. Just going to replace the one end for now. I just overhauled 2 whole systems, and this one is for the bedroom where I'm less critical about it, so I'll give my wallet a break while I get cozy with all the new stuff. Of course it's only a matter of time before I start going down the rabbit hole of tweaks. Not sure I want to hear the difference the top end Furutech stuff brings because I might like it too much! I've got 8 power cords, not counting power conditioners, and if I really like the upgrade on one of them... well I think we all know how it goes with this disease! 😄 |
Measure the cutout dimension on the amp IEC inlet and see if any Furutech fits. https://www.vhaudio.com/acreceptacles-comp.html https://www.vhaudio.com/furutech-fi-06.pdf |