Leave the power on?

[pyonc]

Hi friends,When you're done with listening session, do you simply turn off the switch on your preamp, amp, CDP, LP player or plug out the main power cord as well? Some recommend just leave the gear powered on, but others say plug out the cord as well. I hear many saying one needs some warm-up time to get the best outcome from the gear, so just let the cord plugged in, even after you turn off the switch. What do you think?

[Wagner]

Hi friends,

When you're done with listening session, do you simply turn off the switch on your preamp, amp, CDP, LP player or plug out the main power cord as well? Some recommend just leave the gear powered on, but others say plug out the cord as well. I hear many saying one needs some warm-up time to get the best outcome from the gear, so just let the cord plugged in, even after you turn off the switch. What do you think?

No practical need to leave gear powered up if it is well designed and has a good power supply.
Some people think it makes things sound better (especially tubes) to leave things constantly powered on and God bless them.
I see no reason to waste power and burning up hours on equipment and tubes when no music is involved.
As for unplugging?
That's certainly the safest, especially if you live in an area as I do with shitty utility service.
Lightning too, but it would still be a personal choice as for just how "safe" you want to be.
Obviously, unplugging anything with any sort of memory sets would be problematic.
I have all of my equipment on switchable power strips and conditioners, best of both worlds.
Power on the strip then power up the equipment.

Objectively speaking? Unplugging ANY electrical device that does not require power from the mains for memory is best as far as protection is concerned, and fire prevention. (especially now with all the nice crap from overseas and the .10 cent wall warts as for fire hazards)

Other than lamps, I grew up in a home with a Father who's deal was "if you're not using it, unplug it"
He was born in the early 1920s.

[pyonc]

I have all of my equipment on switchable power strips and conditioners, best of both worlds.
Power on the strip then power up the equipment.



Actually, like you, I have all the power cords of my gear on APC surge protector that stayed powered up all the time.
But I only turn off the power switch of each gear after listening session, but not the APC.

[Ducatista47]

I do like to unplug the gear. While my gear is all new, current equipment, none of it has anything that needs resetting. A layered approach here. Whole house lightning arrestor. Whole house EMF filter. Sola ferroresonant transformer on the power supply to the whole audio system, with an on/off switch. "Unplug" it all with the flip of a switch.

Cost? Delta arrestor and facility EMF filter, $60 each. These pieces are designed to protect an entire commercial facility. Sola 250 volt amp transformer, $120 new. Shop around, the list on the Sola is over $650 now. Be patient, incredible deals online. If you need a 750 volt amp unit it can be had used for less than $90. Forget the audiophile protection equipment. Inferior and expensive. Do you want to protect your house and gear or pay for someone's spoiled daughter to go to college?

Forgot plugs, junction boxes, Romex scrap, a few feet of RV cable, switch. Around $20-$25. Half that if you really want to buy the cheap stuff for this application.

PS Don't install an EMF surge capacitor without installing the lightning arrestor first. Electricity 101. Bonus, since the EMF filter is on the service entrance, it smooths the power problems that originate outside and inside the house. Picture the refrigerator compressor or the air conditioning turning on, and those delightful florescent lights and dimmers. Even though it will do it all, in almost any scenario all that is left for the Sola to do is construct a perfect sine wave and keep it at 120 volts +/- one percent. No matter what happens, it does. If the Delta gear was not there, it would choke off the current in a surge in milliseconds and be undamaged.

The one potential downside to the Sola is it using 20% of its capacity current at idle. Its core is always saturated. Since it is only on when I am playing music, not a problem here. Hey, another reason to turn it off! Leave it on and your electric bill goes up. It does not wear out in the usual sense. The mean time between failures is 25 years in continuous - always on - use. In plain English that means it should last at least fifty years under the worst conditions.

[martin2395]

I always keep the lo-power components on all the time as they all have Class A output stages that sound the best after a warm up.

[NickH]

If its tubes I leave it off. If I lived in Florida I would probably unplug my gear when not in use. I think that's the best lightning arrestor money can buy considering how much some of these toys can cost. That being said I usually leave my sources powered up all the time.

Other then that I think its just users choice. After 20 minutes it shouldn't really matter anyways.


Just my thoughts though.

Nick

[pyonc]

Thanks a lot for your valuable inputs and feedback on this issue. :applaud:
Looks like most of you prefer the gear powered up, with just the main switch off.
I'm now on the same page with you. :D

[1audiohack]

Not me! I yank the meter when I leave. ;)

I have Furman ASD120's on my main systems. If nothing else, there is just something cool about having your audio system start with the turn of a key. :)

Barry.

[Ducatista47]

It is still good form to turn on source - preamp or DAC - power amp in that order, and turn off in the reverse order. I always do that, but use my master shut-off switch to isolate everything from the electrical system, and more urgently to save electricity because of the previously mentioned Sola transformer ~50w idle drain.

I admit there can be the odd circumstance here and there. My Stax electrostatic headphones need to remain plugged in to their amplifier lest their static charge on the diaphragm leak away. It can take considerable time to fully establish it. I know it sounds unlikely that being connected to a turned off amp prevents that, but electrostatics have their own set of rules. Failing to do this results eventually in one channel becoming fainter and fainter re: the other.

[Ducatista47]

Not me! I yank the meter when I leave. ;)

I have Furman ASD120's on my main systems. If nothing else, there is just something cool about having your audio system start with the turn of a key. :)

Barry.
I visited the first experimental reactor to generate electricity. It had a start key in the control panel, like a car.

[gasfan]

My LSR&D Superamp monos take 3 hours to warm up. But even once they are at operating temp, it takes about 5 to 7 tunes before they sound their best. I have lots of amps and find it to be the case with all of them. Maybe it's just my ears adjusting?

[Wagner]

Maybe it's just my ears adjusting?
I'd say so; from ambient day to day noise and conversation to music.
A requisite 3 hour warm up to sound it's best, even for a tube amp, is..................I don't know the word?

Whenever I read threads like this (and there's a million) the first thing that comes to my mind is "how do they know it's not the associated equipment that's needing or benefiting from all that warm up time?", which I personally don't believe to be needed, but that is my experience. Might buy it with Lp playback though.

If thermal stability hasn't been reached within the first hour of use then it's a bad design or layout and that's being generous (but I do realize gear needs to be warmed up just as with any machine) 3 hours? But then it's the next 15 - 25 minutes of actual play time that brings it all together? Assume we're not talking Jazz or Classical "tunes" :)

Found the word I was looking for: incredible

Maybe I'm wrong, maybe there are systems playing in walk in freezers somewhere or outdoors on a really cold day (and windy). I'm working with an ambient temperature of between 68 and 71 degrees Fahrenheit frame of mind.

I also cry for all the hours wasted on beautiful old, "no longer in production" U.S.A. and European vacuum tubes.

I vote turn your equipment off when you're not using it and turn it on 15 minutes before you want to use it under most conditions.

[gasfan]

I'd say so; from ambient day to day noise and conversation to music.
A requisite 3 hour warm up to sound it's best, even for a tube amp, is..................I don't know the word?

Whenever I read threads like this (and there's a million) the first thing that comes to my mind is "how do they know it's not the associated equipment that's needing or benefiting from all that warm up time?", which I personally don't believe to be needed, but that is my experience. Might buy it with Lp playback though.

If thermal stability hasn't been reached within the first hour of use then it's a bad design or layout and that's being generous (but I do realize gear needs to be warmed up just as with any machine) 3 hours? But then it's the next 15 - 25 minutes of actual play time that brings it all together? Assume we're not talking Jazz or Classical "tunes" :)

Found the word I was looking for: incredible

Maybe I'm wrong, maybe there are systems playing in walk in freezers somewhere or outdoors on a really cold day (and windy). I'm working with an ambient temperature of between 68 and 71 degrees Fahrenheit frame of mind.

I also cry for all the hours wasted on beautiful old, "no longer in production" U.S.A. and European vacuum tubes.

I vote turn your equipment off when you're not using it and turn it on 15 minutes before you want to use it under most conditions.


Well, that's not quite what I said. The design is also quite highly regarded; the Leach Low TIM circuit by the late Dr. Marshall Leach at Georgia Tech. The EI core transformers are 1Kva and about 10 inches long. At an ambient temp of 72, they do in fact take about three hours at idle to reach their 105F operating temp with bias set to 150ma. which is about optimum. This is why I leave them on. I have 2 pairs of the model 102. I also have 2 model 101, the stereo version with the same transformer. They all behave the same, among the best you'll ever hear. I can assure you the "tunes" I'm referring to are definitely not "looney". I know this for a fact because I leave all my other gear on 24/7 also. Fancy that!:bouncy:

Btw, I've never been among a voter turnout.

[Wagner]

Well, that's not quite what I said. The design is also quite highly regarded; the Leach Low TIM circuit by the late Dr. Marshall Leach at Georgia Tech. The EI core transformers are 1Kva and about 10 inches long. At an ambient temp of 72, they do in fact take about three hours at idle to reach their 105F operating temp with bias set to 150ma. which is about optimum. This is why I leave them on. I have 2 pairs of the model 102. I also have 2 model 101, the stereo version with the same transformer. They all behave the same, among the best you'll ever hear. I can assure you the "tunes" I'm referring to are definitely not "looney". I know this for a fact because I leave all my other gear on 24/7 also. Fancy that!:bouncy:

Btw, I've never been among a voter turnout.
I quoted exactly what you said, your question "out loud". Not your entire post I'll admit; I left out the part where you said you had a "lot of amps" and they were all that way. Do they ALL require 3 hour warm ups to sound their best?

The quote out of context doesn't appear to change anything? Sorry if it does.

Maybe it's just my ears adjusting?
Sounds like a pretty poor design to me (or a case of the snake oil Voodoo), that or some sort of placebo effect; I'm leaning more towards the oil.
That very specific target number sounds like something you were told. (the mystic of the boutique)
I never knew there was a target temperature for transformer iron beyond the cooler the better (I use the back of my hand check). If I can hold it on the iron (power supply) and count slowly to 10 then all's good, any longer, just icing on the cake.
For the OPTs? Cold would be just fine but warm will do (hold it comfortably for as long as I like).
I'm ragging on you, but look at it from my perspective: 3 HOURS for transformer iron to achieve a measurable temp only 6.4 degrees above Human body temperature?
And you know this to be the core temperature how?
Instead of the provincial tube amp cooling fan(s) you need to have Dr. Leach install some sort of secondary heating source.
I'd love to know what tube it is you are running with 150mA bias?!
What's the plate voltage and dissipation?

Post a schematic or provide a link to this amp if you would
Thanks
Thomas

[Wagner]

Well, that's not quite what I said. The design is also quite highly regarded; the Leach Low TIM circuit by the late Dr. Marshall Leach at Georgia Tech. The EI core transformers are 1Kva and about 10 inches long. At an ambient temp of 72, they do in fact take about three hours at idle to reach their 105F operating temp with bias set to 150ma. which is about optimum. This is why I leave them on. I have 2 pairs of the model 102. I also have 2 model 101, the stereo version with the same transformer. They all behave the same, among the best you'll ever hear. I can assure you the "tunes" I'm referring to are definitely not "looney". I know this for a fact because I leave all my other gear on 24/7 also. Fancy that!:bouncy:

Btw, I've never been among a voter turnout.
Forget the diagram request, I found it.
And please accept my apologies, I thought for sure we were talking tube amps! What with a 3 hour requisite warm up!
Definitely something wrong with that then, that long to get right with a sand amp (MY OPINION)
I'm going to study your toy's guts now.
Thanks
Thomas

[Wagner]

Well, that's not quite what I said. The design is also quite highly regarded; the Leach Low TIM circuit by the late Dr. Marshall Leach at Georgia Tech. The EI core transformers are 1Kva and about 10 inches long. At an ambient temp of 72, they do in fact take about three hours at idle to reach their 105F operating temp with bias set to 150ma. which is about optimum. This is why I leave them on. I have 2 pairs of the model 102. I also have 2 model 101, the stereo version with the same transformer. They all behave the same, among the best you'll ever hear. I can assure you the "tunes" I'm referring to are definitely not "looney". I know this for a fact because I leave all my other gear on 24/7 also. Fancy that!:bouncy:

Btw, I've never been among a voter turnout.
The tune reference was speaking to duration (I don't know what you listen to)
Two Classical "tunes" could easily add another hour to that warm up for example.

I know this isn't your specific model, but the information refers to this for all:
http://users.ece.gatech.edu/mleach/lsrd/lacircuit.pdf
Suggests a minimum of 15 minutes warm up for bias adjust.
http://users.ece.gatech.edu/mleach/lsrd/index.html
LNF-1 and "1A":
http://users.ece.gatech.edu/mleach/lsrd/electronicsone.pdf

Where in the hell did 3 hours come from?

[gasfan]

Perhaps you should put the bottle down?(MY OPINION)

[Ducatista47]

Different universe, but since I use JFET/MOSFET equipment for the most part, class A Nelson Pass First Watt power amps, I have his august advice to go on. The devices are designed to run in a target zone which is quite hot and cooling fans are a bad idea because the unit was cleverly designed to stabilize at that temperature. The chassis and heat sinks are set up to do that. A great example of Harry Nyquist's Fluctuation-dissipation theorem at work. I will state flatly that only fools argue with Harry Nyquist's work, and Nelson knew he could rely on it.

Nelson's advice? It sounds best after an hour in most environments, walk in freezer excepted, but they are at 95% to best sound after about five minutes. In my experience I have found that to be true of my tube gear as well. If I had a unit that took hours at idle to reach best temperature (IMO that would be a badly designed circuit, well regarded or not), I would play music to help warm it up faster. Playing music would be why I turned it on so it would be in no way an inconvenience.

Another piece of unwanted advice by me, if the chassis permits cover up your amp when you turn it off. Keeps dust out and the slower cooling lessens thermal shock to the components and boards. It cannot heat up any further when it is turned off, so there is no downside to doing this. In my high tech mode I use towels or pillow slips. They come in different colors so you can relax about how it looks.

[Wagner]

Different universe, but since I use JFET/MOSFET equipment for the most part, class A Nelson Pass First Watt power amps, I have his august advice to go on. The devices are designed to run in a target zone which is quite hot and cooling fans are a bad idea because the unit was cleverly designed to stabilize at that temperature. The chassis and heat sinks are set up to do that. A great example of Harry Nyquist's Fluctuation-dissipation theorem at work. I will state flatly that only fools argue with Harry Nyquist's work, and Nelson knew he could rely on it.

Nelson's advice? It sounds best after an hour in most environments, walk in freezer excepted, but they are at 95% to best sound after about five minutes. In my experience I have found that to be true of my tube gear as well.

Another piece of unwanted advice by me, if the chassis permits cover up your amp when you turn it off. Keeps dust out and the slower cooling lessens thermal shock to the components and boards. It cannot heat up any further when it is turned off, so there is no downside to doing this.
The smart remark about fans versus heaters was before I realized he was talking about an antiquated grad school professor's Solid State design (relatively early) from the '70s. Did not recognize the amp until I searched it and found the schematics. Ah, the Hafler years.

And thank you as well for supporting my belief that a 3 hour warm up + "about 5 to 7 tunes" didn't sound quite right. ;)

[Ducatista47]

I could add that to speed warm up leave the unit covered for the first few minutes. As long as you remember to take it off. It is similar to covering a pan of water when you want it to boil. I don't do this myself; I have time and am a patient sort of fellow.

I mean the electronics. I do cover the pan.

[Wagner]

I could add that to speed warm up leave the unit covered for the first few minutes. As long as you remember to take it off. It is similar to covering a pan of water when you want it to boil. I don't do this myself; I have time and am a patient sort of fellow.
I'm not into designs which require that much care a feeding, that's why I love good tube designs, they are nice and simple.
Easy to understand: the cooler the better.

As far as your lid on the pot to induce boiling analogy? What would that accomplish? Reduce warm up by a grand total of 10 minutes? From 15 down to 5? ;)

[audiomagnate]

At the end of a listening/viewing session I switch off my multiple BGW 602B's and the TV (if I'm using it) and leave the preamp, crossover, eq, and sources powered up all the time. I don't waste power and I don't have to worry about turn on thumps. The BGW's generate some serious heat, even idling, but I don't worry about the rest of it.

[gasfan]

The smart remark about fans versus heaters was before I realized he was talking about an antiquated grad school professor's Solid State design (relatively early) from the '70s. Did not recognize the amp until I searched it and found the schematics. Ah, the Hafler years.

And thank you as well for supporting my belief that a 3 hour warm up + "about 5 to 7 tunes" didn't sound quite right. ;)

Circa 1980. You didn't find it btw. Many respected brands use the topology. There's quite a large following at DIY.

[Wagner]

Circa 1980. You didn't find it btw. Many respected brands use the topology. There's quite a large following at DIY.
Wasn't knocking it.

My remarks were all inspired by your (in MY OPINION) bizarre claim.
That led me to wanting to take a look at your amplifier.

I acknowledged that initially I was incorrect by assuming that you had a tube amp. Lots of Voodoo in the tube world.

[gasfan]

Wasn't knocking it.

My remarks were all inspired by your (in MY OPINION) bizarre claim.
That led me to wanting to take a look at your amplifier.

I acknowledged that initially I was incorrect by assuming that you had a tube amp. Lots of Voodoo in the tube world.

Still not sure you understood my post. Outside of warm up time(without playing music), I find it takes about 5 cuts by the time the amp is at it's best regardless which one I'm using among several ss brands.

As you can see, the transformer and heat sinks are quite massive in both the model 102 seen here, and also the 101 which is identical, but stereo.

[Wagner]

Still not sure you understood my post. Outside of warm up time(without playing music), I find it takes about 5 cuts by the time the amp is at it's best regardless which one I'm using among several ss brands.

As you can see, the transformer and heat sinks are quite massive in both the model 102 seen here, and also the 101 which is identical, but stereo.
I agreed with you in post #12 when I responded to your stream of consciousness thinking out loud question and told you why I said what I said
The rest of it's bull shit, EXCEPT, possibly, that the amp is so worn out that maybe it does take three hours to sound like anything
I wouldn't know, I know nothing about your example
But, on another note:
Can't see what's going on with boards, but from the looks of your photos, you're about due for a re-cap, everything appears to be original.

Read that literature I posted; more than one issue(s) with the large value caps, shorts and leaks (although the black ones seemed to be more problematic) as well as a mounting improvement was in there somewhere
I just skimmed the articles; go educate yourself about your amps. Fresh caps might help you with that protracted "warm up" time as well.

My apologies to the OP of this thread for the hi-jack and derail
Sorry
Thomas

[gasfan]

I agreed with you in post #12 when I responded to your stream of consciousness thinking out loud question and told you why I said what I said
The rest of it's bull shit, EXCEPT, possibly, that the amp is so worn out that maybe it does take three hours to sound like anything
I wouldn't know, I know nothing about your example
But, on another note:
Can't see what's going on with boards, but from the looks of your photos, you're about due for a re-cap, everything appears to be original.

Read that literature I posted; more than one issue(s) with the large value caps, shorts and leaks (although the black ones seemed to be more problematic) as well as a mounting improvement was in there somewhere
I just skimmed the articles; go educate yourself about your amps. Fresh caps might help you with that protracted "warm up" time as well.

My apologies to the OP of this thread for the hi-jack and derail
Sorry
Thomas

It's fully rebuilt except for the main caps. As I noted, you didn't find the amp. The LNF-1 and 1A are different amps; earlier examples. You really need to put that bottle down:blink:

[Wagner]

It's fully rebuilt except for the main caps. As I noted, you didn't find the amp. The LNF-1 and 1A are different amps; earlier examples. You really need to put that bottle down:blink:

You really are annoying and don't read worth a shit. Look at the circuits and service notes (those link thingies). WAIT! DING! The oven timer just went off, I think your amp's done!


My LSR&D Superamp monos
LSR&D and Electronics One Amplifiers

This page is authored by W. Marshall Leach, Jr.
LSR&D: In the latter 1970s, three engineers who worked at the Georgia Tech Research Institute approached me with the idea of forming a company to manufacture and market audio power amplifiers. This was the beginning of LSR&D, Inc. The letters L, S, R, and D were the first letter of the last name of the original four partners. One of the partners soon dropped out, but he was replaced soon after that. Our first product was a stereo amplifier which we called "The Leach Amp." It was rated at 160 watts per channel into 8 ohms. It was based on a circuit which I had published in Audio Magazine in 1976 and1977 in two papers titled "Build a Low TIM Amplifier." The earliest LSR&D amplifiers can be identified by a dark colored E-I core transformer immediately behind the front panel to the right of the switch. We soon replaced this transformer with two round toroid transformers. Although the toroid transformers were lighter, I always thought that the E-I core transformers made a "stiffer" power supply. A mono amplifier was introduced later. We called it "The Leach Superamp." It was based on a circuit I published in Audio Magazine in 1980 titled "Build a Double Barrelled Amplifier." The Superamp was rated at 300 watts into 8 ohms. Our company went out of business in the mid 1980s. The three things that doomed us were financing, marketing, and squabbling among partners. The two links below contain circuit diagrams and servicing hints for the two amplifiers. Unfortunately, I do not have a parts layout for the circuit board. I don't have any of the LSR&D amplifiers, but I work with someone who has managed to collect several of them.

The Leach Amp (http://users.ece.gatech.edu/mleach/lsrd/lacircuit.pdf). Circuit diagram, parts list, and hints for servicing.
The Leach Superamp (http://users.ece.gatech.edu/mleach/lsrd/superamp.pdf). Circuit diagram and parts list. See hints for servicing for the Leach Amp above.
Electronics One: In the early/mid 1970s, a former student of mine who was working part time at the company Electronics One, Inc. contacted me about manufacturing an audio amplifier I had been working on. Electronics One was a very small company consisting on one engineer, one technician, and part-time help when needed. The company offered electronics consulting services and it manufactured small-scale electronic components and systems under contract with customers. I signed an agreement to allow Electronics One manufacture and sell audio amplifiers based on circuits I had published in Audio Magazine. These were stereo amplifiers rated at 100 watts per channel and were called "Leach LNF-1 Amplifier" and "Leach LNF-1A Amplifier." The LNF-1 models were housed in a shoe-box style chassis. The LNF-1A models were in a rack-mount chassis. I don't think that the company was ever financially sound because of the uncertainty of the contract electronics business. The owner was looking for a product, and he hoped the amplifiers would fill that need. But the company failed and the owner sold it sometime in the latter 1970s. It had closed, vacated its building, and the owner had left town before I knew anything about the failure. The drawings linked below are all I have on these amplifiers. There are some modifications that I recommend to improve reliability. I have the prototype Electronics One LNF-1 and LNF-1A amplifiers in my lab and both are still working after all of these years.
I have seen two LNF-1A amplifiers sold on Ebay which had an auxiliary circuit boards mounted inside the chassis to convert the stereo amplifier into a strapped mono amplifier. I never knew that any amplifiers were sold with this modification. I recommend removal of the auxiliary circuit boards and operating the amplifiers as stereo amplifiers.

Leach LNF-1 and LNF-1A Amplifiers (http://users.ece.gatech.edu/mleach/lsrd/electronicsone.pdf) once manufactured by Electronics One
Home (http://users.ece.gatech.edu/mleach/)
This page is not a publication of the Georgia Institute of Technology and the Georgia Institute of Technology has not edited or examined the content. The author of this page is solely responsible for the content.

[BMWCCA]

Now children! :scold:

Might be a good time for a time-out for both of you until you learn how to reply without the insults. :dont-know:

[gasfan]

You really are annoying and don't read worth a shit. Look at the circuits and service notes (those link thingies). WAIT! DING! The oven timer just went off, I think your amp's done!


LSR&D and Electronics One Amplifiers

This page is authored by W. Marshall Leach, Jr.
LSR&D: In the latter 1970s, three engineers who worked at the Georgia Tech Research Institute approached me with the idea of forming a company to manufacture and market audio power amplifiers. This was the beginning of LSR&D, Inc. The letters L, S, R, and D were the first letter of the last name of the original four partners. One of the partners soon dropped out, but he was replaced soon after that. Our first product was a stereo amplifier which we called "The Leach Amp." It was rated at 160 watts per channel into 8 ohms. It was based on a circuit which I had published in Audio Magazine in 1976 and1977 in two papers titled "Build a Low TIM Amplifier." The earliest LSR&D amplifiers can be identified by a dark colored E-I core transformer immediately behind the front panel to the right of the switch. We soon replaced this transformer with two round toroid transformers. Although the toroid transformers were lighter, I always thought that the E-I core transformers made a "stiffer" power supply. A mono amplifier was introduced later. We called it "The Leach Superamp." It was based on a circuit I published in Audio Magazine in 1980 titled "Build a Double Barrelled Amplifier." The Superamp was rated at 300 watts into 8 ohms. Our company went out of business in the mid 1980s. The three things that doomed us were financing, marketing, and squabbling among partners. The two links below contain circuit diagrams and servicing hints for the two amplifiers. Unfortunately, I do not have a parts layout for the circuit board. I don't have any of the LSR&D amplifiers, but I work with someone who has managed to collect several of them.

The Leach Amp (http://users.ece.gatech.edu/mleach/lsrd/lacircuit.pdf). Circuit diagram, parts list, and hints for servicing.
The Leach Superamp (http://users.ece.gatech.edu/mleach/lsrd/superamp.pdf). Circuit diagram and parts list. See hints for servicing for the Leach Amp above.

Electronics One: In the early/mid 1970s, a former student of mine who was working part time at the company Electronics One, Inc. contacted me about manufacturing an audio amplifier I had been working on. Electronics One was a very small company consisting on one engineer, one technician, and part-time help when needed. The company offered electronics consulting services and it manufactured small-scale electronic components and systems under contract with customers. I signed an agreement to allow Electronics One manufacture and sell audio amplifiers based on circuits I had published in Audio Magazine. These were stereo amplifiers rated at 100 watts per channel and were called "Leach LNF-1 Amplifier" and "Leach LNF-1A Amplifier." The LNF-1 models were housed in a shoe-box style chassis. The LNF-1A models were in a rack-mount chassis. I don't think that the company was ever financially sound because of the uncertainty of the contract electronics business. The owner was looking for a product, and he hoped the amplifiers would fill that need. But the company failed and the owner sold it sometime in the latter 1970s. It had closed, vacated its building, and the owner had left town before I knew anything about the failure. The drawings linked below are all I have on these amplifiers. There are some modifications that I recommend to improve reliability. I have the prototype Electronics One LNF-1 and LNF-1A amplifiers in my lab and both are still working after all of these years.
I have seen two LNF-1A amplifiers sold on Ebay which had an auxiliary circuit boards mounted inside the chassis to convert the stereo amplifier into a strapped mono amplifier. I never knew that any amplifiers were sold with this modification. I recommend removal of the auxiliary circuit boards and operating the amplifiers as stereo amplifiers.

Leach LNF-1 and LNF-1A Amplifiers (http://users.ece.gatech.edu/mleach/lsrd/electronicsone.pdf) once manufactured by Electronics One

Home (http://users.ece.gatech.edu/mleach/)
This page is not a publication of the Georgia Institute of Technology and the Georgia Institute of Technology has not edited or examined the content. The author of this page is solely responsible for the content.

I'm actually very well versed on the history of these amps. Hence my correction of your erroneous identification back there. I see you finally figured it out? Well done!:applaud:Now how about a nice little nap. Thaat's it. Bu bye.:)

Not interested in reading your pm you just sent btw. Why don't you just display it for all of us?

[audiomagnate]

Perhaps you should put the bottle down?(MY OPINION)


It's fully rebuilt except for the main caps. As I noted, you didn't find the amp. The LNF-1 and 1A are different amps; earlier examples. You really need to put that bottle down:blink:

Did you really think that's such a witty remark that it bore repeating?

[gasfan]

Did you really think that's such a witty remark that it bore repeating?

Excuse me, but I'm not trying to be witty or funny. What do You think he should do with it? Or do you think there was no 'influence' in his responses and attitude? Would you like me to forward you the pm he sent, which I did not open btw? You could peruse it and direct me on whether I should read it.

Oh my! Musn't upset the drunk!

[audiomagnate]

Excuse me, but I'm not trying to be witty or funny. What do You think he should do with it? Or do you think there was no 'influence' in his responses and attitude? Would you like me to forward you the pm he sent, which I did not open btw? You could peruse it and direct me on whether I should read it.

Oh my! Musn't upset the drunk!

Wow.