[DJ The Rocket]

No idea why you had the hit or miss experiences. I think it comes down to the power supply and whether the amp is a common ground amp.

Right, good point. I should have mentioned I only use balanced headphones for this, precisely because I don't know how one is grounded compared to the next.

Also afaik the resistor values used can make a difference. What values did you use? I just used 2 of the Rolls Pm52 boxes so i could run balanced

Resistors? Why would you want to do that?

Wait, series or parallel? Parallel would make some sense actually, but only on something with a huge output, starting at something like 75-100wpc @8ohms, depending on lots of stuff. But wouldn't that effectively double the output impedance as well? I remember the Mojo designer saying the reason the Mojo is fine to play two headphones in parallel is because of its low output impedance. If that's right then it would really depend on the amp, you'd be fine with direct-coupled designs.

I found another tuner that works this weekend (scored a JVC RX-884V for $5 at a yard sale ) with a surprisingly nice digital stepped pot, it's a shame they didn't have the remote control because it's for HT really and it's cumbersomely big. The JVC is 50wpc @8ohms (with a listed 8ohm output impedance!) but compared with my cheap Kenwood the JVC seems to sound more "musical" on my Alpha Primes (I don't know what musical really means yet).

 

[Dawnrazor]

Right, good point. I should have mentioned I only use balanced headphones for this, precisely because I don't know how one is grounded compared to the next.




Resistors? Why would you want to do that?

Wait, series or parallel? Parallel would make some sense actually, but only on something with a huge output, starting at something like 75-100wpc @8ohms, depending on lots of stuff. But wouldn't that effectively double the output impedance as well? I remember the Mojo designer saying the reason the Mojo is fine to play two headphones in parallel is because of its low output impedance. If that's right then it would really depend on the amp, you'd be fine with direct-coupled designs.

I found another tuner that works this weekend (scored a JVC RX-884V for $5 at a yard sale ) with a surprisingly nice digital stepped pot, it's a shame they didn't have the remote control because it's for HT really and it's cumbersomely big. The JVC is 50wpc @8ohms (with a listed 8ohm output impedance!) but compared with my cheap Kenwood the JVC seems to sound more "musical" on my Alpha Primes (I don't know what musical really means yet).

Balanced is best and like you I do it just so I dont have to worry

Nice score for $5

Here is a link that explains the resistors and the rationale for them especially under the additional info section

https://robrobinette.com/HeadphoneResistorNetworkCalculator.htm

 

[DJ The Rocket]

https://robrobinette.com/HeadphoneResistorNetworkCalculator.htm

Ah, the old Robinette scam

Just kidding, I actually haven't come across this guy before now, but his claims strike me as mostly dubious. I didn't even get to check his math because I couldn't figure out where he's getting all those numbers from, so curled my toes seeing him reference Ohm and Kirchoff as if to lend himself credibility. Search google for "robinette box." There isn't much, but I agree with the guy. These ideas need to die already.

So Robinette claims three reasons why using resistors is necessary: 1) matching impedance with the amp, 2) excessive gain, and 3) lack of volume control range. Of them, #3 is a legit concern, #2 sort of is but not really, and #1 is a concern for tube amps I'm told--I don't know anything about tube amps and don't really pay attention to them--but it's totally irrelevant for SS gear.

Re: #1, in SS amps, "impedance matching" means staying above the minimum impedance load. How far above doesn't matter, it's actually easier for the amp to drive a 50 ohm load than an 8 ohm load, like how 8 is easier than 4. The higher the ohms, the lower the current, and excessive current demands are what destroy amps. Again, I don't understand the limitations of tube amps where high impedance loads apparently do matter, but look at how Robinette acknowledges this: not at the very top of the page, but buried in the details. It isn't that he doesn't understand, exactly, but why is he hiding this info? Maybe because it means his page is irrelevant to most people?

Re: #2 and #3, these are really the same thing as I see it, at least they have the same solution. The problem is more about the volume pot than anything else in the amp. I would want to replace the pot if it was an issue, just pick one with lots of attenuation. The simple two resistor network from the top of the linked page could do more or less the same thing, but I'm unsure about the consequences of putting them right on the output like that. I suspect the effects will vary unpredictably based on each discreet amp/headphone combination. In most of those cases, it'll cause as many problems as it solves. Maybe you ended up with one of the good combos, who knows. I bet the parallel resistor will work best without the series resistor, but I'm willing to try it out both ways and see what happens. Buying the four resistors (because his two-resistor diagram is confusingly for one channel only) will cost less than a buck, and it can't hurt anything to try.

It can't hurt to try, which is more than I can say about that crazy Robinette box. What the hell? How exactly is that supposed to work? It's no better than just plugging common ground headphones into a split ground amp! Maybe someone else can explain why this half-baked contraption is supposed to work, because I'm not seeing it. As far as I know, the safe way to use a balanced amp to drive SE headphones is not to try in the first place.

Edit: on second thought I may be getting his names for these cockamamie inventions mixed up, and I don't feel like it's worth the effort to care. You should recognize what I'm describing at least

So, I don't agree with any of his reasoning, let alone his math, and he barely even mentions the one sole reason I'm considering this, which is the thermal hiss that he misleadingly calls the noise floor. This seems to be his M.O.: saying things that technically aren't wrong, exactly, but are as misleading as possible.

I hope it doesn't look like I'm jumping on you here, @DR, I'm not. This Robinette character is a strange one though. He's pushing these snake oil ideas, yet he isn't selling anything or profiting off of them in any way I can see. I'll try to report back after picking up a few resistors

 

[Dawnrazor]

Ah, the old Robinette scam

Just kidding, I actually haven't come across this guy before now, but his claims strike me as mostly dubious. I didn't even get to check his math because I couldn't figure out where he's getting all those numbers from, so curled my toes seeing him reference Ohm and Kirchoff as if to lend himself credibility. Search google for "robinette box." There isn't much, but I agree with the guy. These ideas need to die already.

So Robinette claims three reasons why using resistors is necessary: 1) matching impedance with the amp, 2) excessive gain, and 3) lack of volume control range. Of them, #3 is a legit concern, #2 sort of is but not really, and #1 is a concern for tube amps I'm told--I don't know anything about tube amps and don't really pay attention to them--but it's totally irrelevant for SS gear.

Re: #1, in SS amps, "impedance matching" means staying above the minimum impedance load. How far above doesn't matter, it's actually easier for the amp to drive a 50 ohm load than an 8 ohm load, like how 8 is easier than 4. The higher the ohms, the lower the current, and excessive current demands are what destroy amps. Again, I don't understand the limitations of tube amps where high impedance loads apparently do matter, but look at how Robinette acknowledges this: not at the very top of the page, but buried in the details. It isn't that he doesn't understand, exactly, but why is he hiding this info? Maybe because it means his page is irrelevant to most people?

Re: #2 and #3, these are really the same thing as I see it, at least they have the same solution. The problem is more about the volume pot than anything else in the amp. I would want to replace the pot if it was an issue, just pick one with lots of attenuation. The simple two resistor network from the top of the linked page could do more or less the same thing, but I'm unsure about the consequences of putting them right on the output like that. I suspect the effects will vary unpredictably based on each discreet amp/headphone combination. In most of those cases, it'll cause as many problems as it solves. Maybe you ended up with one of the good combos, who knows. I bet the parallel resistor will work best without the series resistor, but I'm willing to try it out both ways and see what happens. Buying the four resistors (because his two-resistor diagram is confusingly for one channel only) will cost less than a buck, and it can't hurt anything to try.

It can't hurt to try, which is more than I can say about that crazy Robinette box. What the hell? How exactly is that supposed to work? It's no better than just plugging common ground headphones into a split ground amp! Maybe someone else can explain why this half-baked contraption is supposed to work, because I'm not seeing it. As far as I know, the safe way to use a balanced amp to drive SE headphones is not to try in the first place.

Edit: on second thought I may be getting his names for these cockamamie inventions mixed up, and I don't feel like it's worth the effort to care. You should recognize what I'm describing at least

So, I don't agree with any of his reasoning, let alone his math, and he barely even mentions the one sole reason I'm considering this, which is the thermal hiss that he misleadingly calls the noise floor. This seems to be his M.O.: saying things that technically aren't wrong, exactly, but are as misleading as possible.

I hope it doesn't look like I'm jumping on you here, @DR, I'm not. This Robinette character is a strange one though. He's pushing these snake oil ideas, yet he isn't selling anything or profiting off of them in any way I can see. I'll try to report back after picking up a few resistors

All i know is that i bought two boxes from the pro audio world to do this. And while schematics can confuse me I think the ones for the box I bought has the same setup as the Robinette site. Values may be different but they are in the same place afaict

And it works.

Pro audio is more mission critical and Rolls wouldnt make that box if the concept wasnt sound

Anyhow here is the link but the values are zeroed out for some reason

https://www.parts-express.com/pedocs/manuals/245-1116-rolls-pm52-manual.pdf

Maybe try the resistors on amps that didnt work so well and see what happens.

 

[DJ The Rocket]

And it works.

If it works for you, that's great, and I'll probably come to the same conclusion. This is a complicated topic and I only started studying electronics seriously a few months ago. I'm making progress but here's a lot to keep in mind at any time.

What amps do you use it on, and what headphones?

Pro audio is more mission critical and Rolls wouldnt make that box if the concept wasnt sound

I'd have thought Stax wouldn't ever nerf the sound quality of their TOTL amplifier due to a misguided and short-lived FOTM trend, but I own a SRM-727A and I performed the Spritzer feedback mod on it, if you're familiar with that whole thing.

I've never had the privilege to use anything Rolls made, but great companies do sometimes make illogical decisions, is all.

 

[Dawnrazor]

If it works for you, that's great, and I'll probably come to the same conclusion. This is a complicated topic and I only started studying electronics seriously a few months ago. I'm making progress but here's a lot to keep in mind at any time.

What amps do you use it on, and what headphones?





I'd have thought Stax wouldn't ever nerf the sound quality of their TOTL amplifier due to a misguided and short-lived FOTM trend, but I own a SRM-727A and I performed the Spritzer feedback mod on it, if you're familiar with that whole thing.

I've never had the privilege to use anything Rolls made, but great companies do sometimes make illogical decisions, is all.

Sorry dude outside of them making some of the best Electrostats I dont know mich about stax or the FOTM thread.

I am using the Parasound Halo A21. Before that I had the Schitt Vali 2. Headphones are the Monolith M1060 and the M565. Both sound much better with the Halo/Rolls combo

ART has a similar box that looks like a copy of the Rolls or vice versa. Its called the HeadTap. And Hifiman has one too with different resistor values it looks like. Another company has one too but i forget its name

http://hifiman.com/products/detail/84

Now that I know the concept works I will be diying some cables with better resistors.

Anyhow good luck with your studies and let us know how it goes if you try the resistors.

 

[DJ The Rocket]

@Dawnrazor I'm listening with a modified cable right now, and I'm surprised, it really does sound better. I'm going to take it a step further and install four rheostats, so I can really hear how different values change the sound BTW I think 1/2 watt resistors are borderline for this, at least on my 50wpc@8ohms rated one. They're probably fine, but it's not like 1 watt ones cost any more.

Whoa, I can't believe how tight and accurate this bass sounds! I wonder how much more room for improvement there still is.

Turns our this is an old design called an L-pad that was (is) popular with tube amps. It was mostly used for overdriving tube amps to get that tube distortion in full swing, and also because impedance matching matters with tubes. That's more of a side-effect for SS equipment, I'd say, since SS amps are happy with high load impedances. That's one of the things different rheostat settings will change, as well as what output impedance the headphones see. Also check out T-pads, if you like that tubieness to your sound.

Right now my amp is seeing 8 ohms, so it's putting out a lot more current than it would with the 49 ohm headphone drivers. I'm going to have to draw out the circuit to calculate how much of that current the headphone drivers are actually seeing, and how much is turning into heat.

Ironically, when I was reading about this in some forum somewhere, I remember seeing one guy insisting vehemently that no one's ever tried an L-pad on an SS amp before. He didn't see any reason to, and I understand why. It was invented for a totally different purpose, and it's crazy that this works like it does. Definitely worth looking into further!

 

[Dawnrazor]

@Dawnrazor I'm listening with a modified cable right now, and I'm surprised, it really does sound better. I'm going to take it a step further and install four rheostats, so I can really hear how different values change the sound BTW I think 1/2 watt resistors are borderline for this, at least on my 50wpc@8ohms rated one. They're probably fine, but it's not like 1 watt ones cost any more.

Whoa, I can't believe how tight and accurate this bass sounds! I wonder how much more room for improvement there still is.

Turns our this is an old design called an L-pad that was (is) popular with tube amps. It was mostly used for overdriving tube amps to get that tube distortion in full swing, and also because impedance matching matters with tubes. That's more of a side-effect for SS equipment, I'd say, since SS amps are happy with high load impedances. That's one of the things different rheostat settings will change, as well as what output impedance the headphones see. Also check out T-pads, if you like that tubieness to your sound.

Right now my amp is seeing 8 ohms, so it's putting out a lot more current than it would with the 49 ohm headphone drivers. I'm going to have to draw out the circuit to calculate how much of that current the headphone drivers are actually seeing, and how much is turning into heat.

Ironically, when I was reading about this in some forum somewhere, I remember seeing one guy insisting vehemently that no one's ever tried an L-pad on an SS amp before. He didn't see any reason to, and I understand why. It was invented for a totally different purpose, and it's crazy that this works like it does. Definitely worth looking into further!

See DJ! You cant escape the Robinette scam. It will consume you...

Glad you tried it and man now you wont go back to a headphone amp. My uneducated guess is that more current is getting through and at least on my planar speakers, current is very helpful so probably is here too.

One day I will take the plunge and make some cables with resistors and ditch the Rolls. I bought them to test the concept and not knowing what to expect the attenuator was a plus. But now I know its not needed so it will be ditched.

The Halo also has autosensing so I just boot up the computer and viola upon playing a tune the amp turns on!

And man when i hooked up that amp and went balanced it was a whole new level and these M1060s are phenomenal after a rather long burnin. Super transparent and well the Parasound amp just drives the crap out of them. ClassA and smooth!!!


Be interested to see if bad experiences with some amps you used before can be reversed with the new cables.

My 2nd Parasound is going in my computer setup to replace the Vali2

 

[Dawnrazor]

@Dawnrazor I'm listening with a modified cable right now, and I'm surprised, it really does sound better. I'm going to take it a step further and install four rheostats, so I can really hear how different values change the sound BTW I think 1/2 watt resistors are borderline for this, at least on my 50wpc@8ohms rated one. They're probably fine, but it's not like 1 watt ones cost any more.

Whoa, I can't believe how tight and accurate this bass sounds! I wonder how much more room for improvement there still is.

Turns our this is an old design called an L-pad that was (is) popular with tube amps. It was mostly used for overdriving tube amps to get that tube distortion in full swing, and also because impedance matching matters with tubes. That's more of a side-effect for SS equipment, I'd say, since SS amps are happy with high load impedances. That's one of the things different rheostat settings will change, as well as what output impedance the headphones see. Also check out T-pads, if you like that tubieness to your sound.

Right now my amp is seeing 8 ohms, so it's putting out a lot more current than it would with the 49 ohm headphone drivers. I'm going to have to draw out the circuit to calculate how much of that current the headphone drivers are actually seeing, and how much is turning into heat.

Ironically, when I was reading about this in some forum somewhere, I remember seeing one guy insisting vehemently that no one's ever tried an L-pad on an SS amp before. He didn't see any reason to, and I understand why. It was invented for a totally different purpose, and it's crazy that this works like it does. Definitely worth looking into further!

Oh what cans and what amp?

 

[DJ The Rocket]

Mr. Speakers Alpha Prime / JVC 884-whatever. I tried on the Kenwood 3070 I've been using to drive the Alphas for most of a year, and though the Kenwood sounds better straight, the JVC blows it away with the L-pad. (I won't call it that other name anymore and L-pad is the proper name anyway)

I spent about 60¢ on four 100 ohm pots with 25-turn screws, and they all measured the same at a little more than 4 ohms per rotation. I haven't made a cable with them yet, but everything is ready to go for it. I'm also working on a high-pass filter for my car stereo, so I might not get to the L-cable immediately.

Robinette's problem was making everything about himself. And a box might not be the best format for this either. L-Cable is a way better name for it, and audiophiles already love buying and changing cables. You could make an SMD version that's identical to any other cable, with the resistors sitting in the plug housing! Still though I doubt there's enough interest for the L-Cable as a product without an extensive marketing campaign. I'm not so sure I'm about to give up headphone amps either, but this could be a real alternative for a lot of people.

I wonder how it would sound on a really quality amp, even a cheap one like an Adcom or something

 

[Dawnrazor]

Mr. Speakers Alpha Prime / JVC 884-whatever. I tried on the Kenwood 3070 I've been using to drive the Alphas for most of a year, and though the Kenwood sounds better straight, the JVC blows it away with the L-pad. (I won't call it that other name anymore and L-pad is the proper name anyway)

I spent about 60¢ on four 100 ohm pots with 25-turn screws, and they all measured the same at a little more than 4 ohms per rotation. I haven't made a cable with them yet, but everything is ready to go for it. I'm also working on a high-pass filter for my car stereo, so I might not get to the L-cable immediately.

Robinette's problem was making everything about himself. And a box might not be the best format for this either. L-Cable is a way better name for it, and audiophiles already love buying and changing cables. You could make an SMD version that's identical to any other cable, with the resistors sitting in the plug housing! Still though I doubt there's enough interest for the L-Cable as a product without an extensive marketing campaign. I'm not so sure I'm about to give up headphone amps either, but this could be a real alternative for a lot of people.

I wonder how it would sound on a really quality amp, even a cheap one like an Adcom or something

I can tell you the Parasound Halo is a quality amp and it sounds amazing driving the headphones

Interesting you mention the cable idea. I plan to do that very thing instead of boxes. If you want plug and play the rolls is cheap and easy.

Not sure what you read on the Robinette site. I got nothing like he was making it about himself but only read the one page with the resistor calculator and theory. Maybe I filtered it out.

Anyhow glad you are making progress

 

[BobG55]

Need someone's help, please. For a couple of years now I've been wanting to listen to my headphones from the speaker outputs on my vintage int. amp. First I want to state a fact & it's not easy for me to admit this, I don't understand technical stuff. I'm not good at assembling electronics, I'm not a handy man and it's not about learning how to do these things. I'm in my sixties and know by now that there are some things I'm just not able to understand let alone do. It was the same in school with math. Never got around solving the understanding part past basic math.

So, I'm asking if anyone on this thread is willing to help me out, first by telling me if this "Tap Monitor Level Converter" is safe & worth getting : https://www.parts-express.com/open-...hone-tap-monitor-level-converter--86-245-1116

My vintage amp is a Sansui AU-719 & these are it's specs (from HiFi Engine site) :

Specifications

Power output: 90 watts per channel into 8Ω (stereo)

Frequency response: 10Hz to 20kHz

Total harmonic distortion: 0.015%

Damping factor: 110

Input sensitivity: 2.5mV (MM), 200mV (line)

Signal to noise ratio: 88dB (MM), 100dB (line)

Channel separation: 65dB (MM), 70dB (line)

Output: 200mV (line)

Speaker load impedance: 8Ω (minimum)

Dimensions: 430 x 168 x 395mm

Weight: 16kg

Year: 1980

My headphones : HD600 & HD650, 300 ohms; Grado PS1000 (original), 32 ohms & AKG K340, 400 ohms.


If it's not a safe or good converter, would someone be willing to build an L pad for me that would be safe for my headphones & amplifier. I will pay for all of the parts/ material + your time & of course the s&h.
If someone would be willing to do this please message me.

Thank you,

Bob Gosselin
Milton, NS
Canada

 

[richard51]

Bob the headphone output of your Sansui is probably like mine already very good.... If you add some new electronic parts to the amp I am not quite sure that it will be better... I try to drive my he 400 orthodynamic , then with no impedance matching problem with my Sansui, directly from the speakers tap, but without converter, and the result were good yes,but the volume control were very difficult, the margin between high volume and minimal volume was very delicate...Then the danger to blow up the headphone.... I come back to my headphone out and I was very please... You dont have orthodynamic headphones that pose no problem with the impedance matching, perhaps your actual headphones will sound very good out of the headphone out .... Sansui put very good headphone out on their amplifier.... But like you I am not an electronically knowledgeable guy...It is only my 2 cents... By the way the AKG 340 are very sensible headphone and I am pretty certain that there will be no advantage to power them with the speakers output even with a converter.... At the time that AKG created this headphone they think it with an headphone out in mind, it is an headphone difficult to drive yes,but the Sansui is perfect for driving them with his headphone out...But it is only my 2 cents...This converter seems ok and is not high price, if you want to try it....I had already think to buy this converter, if you try it report to me , and perhaps I will buy one .... But like I have said the headphone output of my AU-7700 is so good with no hum or noise than I never go on with the idea to buy a converter...If someone with experience with this converter give his impressions we will listen for sure...

 

[Sonic Defender]

I suspect, but I don't know this for sure, that like many amps Sansui would have just put a bunch of resistors in between the output stage and the headphone output so not sure if that qualifies as anything special. My concern with older gear is that components can drift out of value. As for the volume play on the gain dial, it might have enough increments, but again that depends and I have no way of knowing. There is no reason that you couldn't simply go directly from the speaker terminals without anything in-between, and I believe when this is an option, it is better to do so. Less is more, so the less circuitry needed to do the job if it is working as it should then that is the way to go.

A concern, and like you both, I am not very technically sound with electronics, is that the amp will be noisy if using headphones from the speaker terminals. Exactly what specifications will reveal this are unclear to me, but that is the first question you should seek technical input on, will your amp be so noisy that at lower volumes, or during quiet passages in music the noise detracts enough from the listening pleasure to make it not worthwhile. Again, something I know is a possibility and important to consider, but I don't know how to direct you further.

I guess another question would have to be why do you want to try this? Is it because you believe the Sansui will provide a significant sound quality boost due to more power, or do you simply want to try it and see? My gut tells me that unless there is a very particular sonic signature to the amp that you are seeking to take advantage of, the odds of the technology from the 80s being better able to produce quality headphone driver control, sonics etc, then decently designed dedicated headamps available today is low, IMO. Many factors to consider for sure.

I went this route as my NAD M3 was a pretty current integrated at the time, and according to a few very knowledgeable members who looked over the specifications in detail for me felt that it would have no issues with noise. So I had this amp that I loved the sound signature of, but it had no headphone input so no way to use it unless I went the speaker tap route. It cost me close to $500 Canadian (actually that was a discounted price) to have Norne Audio make me a really nice, two piece, 12 foot long speaker tap cable. It has been great and I have driven planar and dynamics without the slightest hint of a problem.

So that is my input. I think as was already stated, if you find the headphone input already sounding good with your headphones, I'm not sure that you will gain much by going directly off the speaker terminals because that is really what is happening internally anyway in all likelihood with just some resistors in the signal path. The possible sound advantage that could be gained by going directly from the speaker terminals with no adapter inbetween comes down to how much you believe the resistors in the circuit impact the sound? That said, you were considering doing so by using an external device before the speaker terminals anyway so not entirely sure what the advantage would be?

 

[BobG55]

Bob the headphone output of your Sansui is probably like mine already very good.... If you add some new electronic parts to the amp I am not quite sure that it will be better... I try to drive my he 400 orthodynamic , then with no impedance matching problem with my Sansui, directly from the speakers tap, but without converter, and the result were good yes,but the volume control were very difficult, the margin between high volume and minimal volume was very delicate...Then the danger to blow up the headphone.... I come back to my headphone out and I was very please... You dont have orthodynamic headphones that pose no problem with the impedance matching, perhaps your actual headphones will sound very good out of the headphone out .... Sansui put very good headphone out on their amplifier.... But like you I am not an electronically knowledgeable guy...It is only my 2 cents... By the way the AKG 340 are very sensible headphone and I am pretty certain that there will be no advantage to power them with the speakers output even with a converter.... At the time that AKG created this headphone they think it with an headphone out in mind, it is an headphone difficult to drive yes,but the Sansui is perfect for driving them with his headphone out...But it is only my 2 cents...This converter seems ok and is not high price, if you want to try it....I had already think to buy this converter, if you try it report to me , and perhaps I will buy one .... But like I have said the headphone output of my AU-7700 is so good with no hum or noise than I never go on with the idea to buy a converter...If someone with experience with this converter give his impressions we will listen for sure...

I suspect, but I don't know this for sure, that like many amps Sansui would have just put a bunch of resistors in between the output stage and the headphone output so not sure if that qualifies as anything special. My concern with older gear is that components can drift out of value. As for the volume play on the gain dial, it might have enough increments, but again that depends and I have no way of knowing. There is no reason that you couldn't simply go directly from the speaker terminals without anything in-between, and I believe when this is an option, it is better to do so. Less is more, so the less circuitry needed to do the job if it is working as it should then that is the way to go.

A concern, and like you both, I am not very technically sound with electronics, is that the amp will be noisy if using headphones from the speaker terminals. Exactly what specifications will reveal this are unclear to me, but that is the first question you should seek technical input on, will your amp be so noisy that at lower volumes, or during quiet passages in music the noise detracts enough from the listening pleasure to make it not worthwhile. Again, something I know is a possibility and important to consider, but I don't know how to direct you further.

I guess another question would have to be why do you want to try this? Is it because you believe the Sansui will provide a significant sound quality boost due to more power, or do you simply want to try it and see? My gut tells me that unless there is a very particular sonic signature to the amp that you are seeking to take advantage of, the odds of the technology from the 80s being better able to produce quality headphone driving, headphone driver control, sonics etc, than decently designed dedicated headamps available today is low, IMO. Many factors to consider for sure.

I went this route as my NAD M3 was a pretty current integrated at the time, and according to a few very knowledgeable members who looked over the specifications in detail for me felt that it would have no issues with noise. So I had this amp that I loved the sound signature of, but it had no headphone input so no way to use it unless I went the speaker tap route. It cost me close to $500 Canadian (actually that was a discounted price) to have Norne Audio make me a really nice, two piece, 12 foot long speaker tap cable. It has been great and I have driven planar and dynamics without the slightest hint of a problem.

So that is my input. I think as the was already stated, if you find the headphone input already sounding good with your headphones, I'm not sure that you will gain much by going directly off the speaker terminals because that is really what is happening internally anyway in all likelihood with just some resistors in the signal path. The possible sound advantage that could be gained by going directly from the speaker terminals with no adapter inbetween comes down to how much you believe the resistors in the circuit impact the sound? That said, you were considering doing so by using an external device before the speaker terminals anyway so not entirely sure what the advantage would be?

Thank you both, Richard51 & Sonic Defender for your very good advice & suggestions. I've read both of your replies carefully & more than once. I've decided to keep listening from the headphone output jack since the sound is already pretty darn good anyways.