Speedskater Posted January 22, 2019 Share Posted January 22, 2019 I think that those measurements might be what electricians call phantom voltage (very different from microphone phantom power). A DMM has a very high impedance on the voltage ranges and can pick-up all kinds of stray voltages. The isolated Hot/Neutral is not referenced to the Safety Ground or chassis. Link to comment
Bdht Posted February 15, 2019 Share Posted February 15, 2019 When using smaller units(I have a 91092-12 and 91092-31), is it recommended to put anything between the wall and the transformer? i.e. UPS, AVR, or additional surge protection? I have 1a or 2a fuses at the input but thats it. Link to comment
diecaster Posted February 15, 2019 Share Posted February 15, 2019 250VA units aren't good for much. Assuming a power factor of 1, that is 250 watts. A power factor of .8 is more likely and that is only 200 watts. You don't need or really want anything between the wall and the transformer. They "reduce a 6,000 volt spike to an insignificant 0.0030 volt." Link to comment
Bdht Posted February 15, 2019 Share Posted February 15, 2019 51 minutes ago, diecaster said: 250VA units aren't good for much. Assuming a power factor of 1, that is 250 watts. A power factor of .8 is more likely and that is only 200 watts. You don't need or really want anything between the wall and the transformer. They "reduce a 6,000 volt spike to an insignificant 0.0030 volt." Using em with headphone systems so I dont think to much wattage is necessary? Had assumed as much as well with stuff between the wall just wanted to ask, thank you. How bout power cabling, since usage is for digital devices is having the low inductance quadrapole cabling between the wall and the transformer beneficial, between the transformer and the equipment as well? Link to comment
oneguy Posted February 15, 2019 Share Posted February 15, 2019 More than enough VA to power a DAC or some preamps like the Freya. Link to comment
gererick Posted February 16, 2019 Share Posted February 16, 2019 Hi: I've bought a Elgar model 2.5-13. It is 2.5kVa and .0005 pfd. It appears to be the same as or very similar to a Topaz 91002-31. The input (from the wall outlet) is wired. The output has to be wired. Would the black and the white wires go in the same position that they are wired in the input? Link to comment
Speedskater Posted February 19, 2019 Share Posted February 19, 2019 On 2/14/2019 at 10:49 PM, diecaster said: You don't need or really want anything between the wall and the transformer. They "reduce a 6,000 volt spike to an insignificant 0.0030 volt." The transformer will have no significant effect on a Hot to Neutral spike! Link to comment
Speedskater Posted February 19, 2019 Share Posted February 19, 2019 On 2/14/2019 at 10:49 PM, diecaster said: 250VA units aren't good for much. Assuming a power factor of 1, that is 250 watts. A power factor of .8 is more likely and that is only 200 watts. Yep! About all a 250VA transformer is good for is reducing ground loop problems on poorly designed hi-fi components. Link to comment
diecaster Posted February 19, 2019 Share Posted February 19, 2019 6 hours ago, Speedskater said: The transformer will have no significant effect on a Hot to Neutral spike! One of major points that Topaz specifically called out for their isolation transformers was electrical surge suppression.......as I quoted in my post. Link to comment
Speedskater Posted February 20, 2019 Share Posted February 20, 2019 That's for Common Mode suppression! a Hot to Neutral spike is Differential Mode. A transformer can't suppress it and be a transformer. Link to comment
Superdad Posted February 20, 2019 Share Posted February 20, 2019 23 hours ago, diecaster said: One of major points that Topaz specifically called out for their isolation transformers was electrical surge suppression.......as I quoted in my post. Sorry, @Speedskater is mostly correct. Isolation transformers do not suppress differential spikes at frequencies below about 10KHz. But a lot of the energy in high power surges is contained in high frequency components, which do get suppressed by the very low capacitance of the specialty Topaz transformers. But generally one can not consider an isolation transformer as serving the same function as a surge suppressor. Bdht 1 UpTone Audio LLC Link to comment
Bdht Posted February 20, 2019 Share Posted February 20, 2019 8 minutes ago, Superdad said: Sorry, @Speedskater is mostly correct. Isolation transformers do not suppress differential spikes at frequencies below about 10KHz. But a lot of the energy in high power surges is contained in high frequency components, which do get suppressed by the very low capacitance of the specialty Topaz transformers. But generally one can not consider an isolation transformer as serving the same function as a surge suppressor. Thanks for the response. So would you recommend a ups/surge unit before the topaz? I'm also wondering about the switching off of the amplifier(from an outage) while headphones are connected. Link to comment
Speedskater Posted February 21, 2019 Share Posted February 21, 2019 Surge suppression should be dealt with where the AC power enters the building. Using a whole home suppression unit. Make that a 'UL' rated/listed unit. Been reading on the electricians pages about unlisted units going up in flames. Ralf11 1 Link to comment
Jud Posted February 21, 2019 Share Posted February 21, 2019 1 hour ago, Speedskater said: Surge suppression should be dealt with where the AC power enters the building. Using a whole home suppression unit. Make that a 'UL' rated/listed unit. Been reading on the electricians pages about unlisted units going up in flames. Since the whole home units use MOVs (as far as I know), is there any possible issue with them losing effectiveness over repeated use, or even "going up in flames"? One never knows, do one? - Fats Waller The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature. Link to comment
Speedskater Posted February 22, 2019 Share Posted February 22, 2019 With MOV's there is always a small possibility of failure. It was un-rated units that went up in flames. Go with top shelf name brand units from an electrical supplier and replace them every decade or two. Everything in your AC power system should be 'UL' rated. Jud 1 Link to comment
skatbelt Posted February 24, 2019 Share Posted February 24, 2019 Question: in one of his latest videos in YouTube, PS Audio's Paul McGowan states that switch mode power supplies are happier with single ended power as opposed to balanced power. He does not explain why. Is this true? And if so, can anybody explain it technically (in terms that I as a generalist can understand.... 😉)? The reason I ask this is because I use an isolation transformer in a 230V country, wired for balanced output to power all audio components of which two use switch mode power supplies. Streamer dCS Network Bridge DAC Chord DAVE Amplifier / DRC Lyngdorf TDAI-3400 Speakers Lindemann BL-10 | JL audio E-sub e110 Head-fi and reference Bakoon HPA-21 | Audeze LCD-3 (f) Power and isolation Dedicated power line | Xentek extreme isolation transformer (1KVA, balanced) | Uptone Audio EtherREGEN + Ferrum Hypsos | Sonore OpticalModule + Uptone Audio UltraCap LPS-1.2 | Jensen CI-1RR Cables Jorma Digital XLR (digital), Grimm Audio SQM RCA (analog), Kimber 8TC + WBT (speakers), custom star-quad with Oyaide connectors (AC), Ferrum (DC) and Ghent (ethernet) Software dCS Mosaic | Tidal | Qobuz Link to comment
skatbelt Posted February 25, 2019 Share Posted February 25, 2019 17 hours ago, skatbelt said: Question: in one of his latest videos in YouTube, PS Audio's Paul McGowan states that switch mode power supplies are happier with single ended power as opposed to balanced power. He does not explain why. Is this true? And if so, can anybody explain it technically (in terms that I as a generalist can understand.... 😉)? The reason I ask this is because I use an isolation transformer in a 230V country, wired for balanced output to power all audio components of which two use switch mode power supplies. Anyone? @JohnSwenson for instance? Streamer dCS Network Bridge DAC Chord DAVE Amplifier / DRC Lyngdorf TDAI-3400 Speakers Lindemann BL-10 | JL audio E-sub e110 Head-fi and reference Bakoon HPA-21 | Audeze LCD-3 (f) Power and isolation Dedicated power line | Xentek extreme isolation transformer (1KVA, balanced) | Uptone Audio EtherREGEN + Ferrum Hypsos | Sonore OpticalModule + Uptone Audio UltraCap LPS-1.2 | Jensen CI-1RR Cables Jorma Digital XLR (digital), Grimm Audio SQM RCA (analog), Kimber 8TC + WBT (speakers), custom star-quad with Oyaide connectors (AC), Ferrum (DC) and Ghent (ethernet) Software dCS Mosaic | Tidal | Qobuz Link to comment
ray-dude Posted March 9, 2019 Share Posted March 9, 2019 Folks, forgive the newbie question, but I'm lost a bit in the various wiring scenarios for the Topaz Ultra Isolation transformers. I've tracked down a 91018-31T and 91002-31 on eBay. I'm US-based (120V) so I have H2/H4 (neutral) jumpered and H1/H3 (hot) jumpered on input, and X2/X4 (neutral) jumpered and X1/X3 (hot) jumpered on output. My question is where to wire ground on input and output. On one unit, ground was jumpered to H4 (neutral) on input and X4 (neutral) on output. On the other unit, ground was only connected to X4 on output (not jumpered to H4 on input) Should ground stay floating from the primary and secondary, or should it be grounded to the secondary or should it be grounded to both primary and secondary? ATT Fiber -> EdgeRouter X SFP -> Taiko Audio Extreme -> Vinnie Rossi L2i-SE w/ Level 2 DAC -> Voxativ 9.87 speakers w/ 4D drivers Link to comment
One and a half Posted March 10, 2019 Share Posted March 10, 2019 20 minutes ago, ray-dude said: Folks, forgive the newbie question, but I'm lost a bit in the various wiring scenarios for the Topaz Ultra Isolation transformers. I've tracked down a 91018-31T and 91002-31 on eBay. I'm US-based (120V) so I have H2/H4 (neutral) jumpered and H1/H3 (hot) jumpered on input, and X2/X4 (neutral) jumpered and X1/X3 (hot) jumpered on output. My question is where to wire ground on input and output. On one unit, ground was jumpered to H4 (neutral) on input and X4 (neutral) on output. On the other unit, ground was only connected to X4 on output (not jumpered to H4 on input) Should ground stay floating from the primary and secondary, or should it be grounded to the secondary or should it be grounded to both primary and secondary? My Topaz was delivered with H4 connected to GND, and was swiftly removed. Thou shalt use but only one connection from GND to the neutral, and that's at the main panel. Things get complex for generators in the same installation, let's assume you don't have one, so kick the connection from H4 to GND. So the green wire from the wall, connect it to the H part of the box to GND. At the X part on the other side of the transformer, best for now to jumper X4 to GND, and the green wire to the connected loads. The GND should pass all the way through the structure of the transformer from the H to the X boxes, please check it with a mulitmeter. There should be some more wires connected to the GND terminal internally, these go back to the GND, don't float these shield wires. You have the connections right for the hot and neutral on both sides. H1 is the black and H4 the white. X1 is the hot (black) and X4 (white) on the output. AS Profile Equipment List Say NO to MQA Link to comment
ray-dude Posted March 10, 2019 Share Posted March 10, 2019 Thank you @One and a half! I appreciate the quick reply. To confirm, leave neutral on the primary disconnected from ground, but connect neutral on the secondary to ground. Ground and shield should be continuous through the transformer (per the graphic). Can you add some color on the motivation/implications of leaving neutral disconnected from ground (except at the main panel)? Is the intent of connecting neutral on the secondary to ground to mimic the same connection at the main panel? ATT Fiber -> EdgeRouter X SFP -> Taiko Audio Extreme -> Vinnie Rossi L2i-SE w/ Level 2 DAC -> Voxativ 9.87 speakers w/ 4D drivers Link to comment
One and a half Posted March 10, 2019 Share Posted March 10, 2019 12 minutes ago, ray-dude said: Thank you @One and a half! I appreciate the quick reply. You're Welcome. 12 minutes ago, ray-dude said: To confirm, leave neutral on the primary disconnected from ground, but connect neutral on the secondary to ground. Ground and shield should be continuous through the transformer (per the graphic). Yes leave the incoming neutral disconnected from GND, just connect to H4. 12 minutes ago, ray-dude said: Can you add some color on the motivation/implications of leaving neutral disconnected from ground (except at the main panel)? Is the intent of connecting neutral on the secondary to ground to mimic the same connection at the main panel? Oh, simple. Rules are Rules, it's in the NEC code, @Speedskater could cite the exact enforced clause that applies. It's not that leaving the neutral off is the complication, it's the leaving it on is the problem. AS Profile Equipment List Say NO to MQA Link to comment
Speedskater Posted March 10, 2019 Share Posted March 10, 2019 Everywhere (with the exception of the secondary of an isolation transformer) the only place that the Neutral and the Safety Ground/Protective Earth may be connected together is at the main breaker box and this connection is required. ray-dude 1 Link to comment
Speedskater Posted March 10, 2019 Share Posted March 10, 2019 Oops, with regard to: (with the exception of the secondary of an isolation transformer) This only applies if the transformer is wired as a Separately Derived System. ray-dude 1 Link to comment
Ralf11 Posted March 10, 2019 Share Posted March 10, 2019 On 2/21/2019 at 5:54 PM, Speedskater said: With MOV's there is always a small possibility of failure. It was un-rated units that went up in flames. Go with top shelf name brand units from an electrical supplier and replace them every decade or two. Everything in your AC power system should be 'UL' rated. also check for any known issues - one US brand had a number of problems but did not issue a recall Link to comment
diecaster Posted March 10, 2019 Share Posted March 10, 2019 20 hours ago, ray-dude said: Folks, forgive the newbie question, but I'm lost a bit in the various wiring scenarios for the Topaz Ultra Isolation transformers. I've tracked down a 91018-31T and 91002-31 on eBay. I'm US-based (120V) so I have H2/H4 (neutral) jumpered and H1/H3 (hot) jumpered on input, and X2/X4 (neutral) jumpered and X1/X3 (hot) jumpered on output. My question is where to wire ground on input and output. On one unit, ground was jumpered to H4 (neutral) on input and X4 (neutral) on output. On the other unit, ground was only connected to X4 on output (not jumpered to H4 on input) Should ground stay floating from the primary and secondary, or should it be grounded to the secondary or should it be grounded to both primary and secondary? I'd go look at posts #854 to #872 in this thread. ray-dude 1 Link to comment
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