Mr Liang 845 Amplifier
Hi Kev
Thanks for that I got it now but I think I would rather do something that is on the outside of the amplifier. Some kind of Auto Transformer, which took the 240V and then stepped it down to 220V which would solve all the issues.
It would be interesting to know if the amplifier is being run overvolts and the only real way to measure that is to stick your hand inside and measure across the plate and filament to see what the working potential difference is
Yeah it took me a while to work out that there was a difference between the working voltage and the ht supply, which are the operating parameters set by the circuit and component values.
The whole thing of going inside this amplifier sort of puts me off given the voltages that are inside it and the fact that it weighs in at 41Kg about 100lbs in old money.
It would be interesting to hear what peeps think on the use of auto transformers, pretty sure I would need to go to Sowter in the UK to get one wound specially unless Hammond have one in the UK here.
In my humble opinion it should resolve all the issues with the whole thing being over run, even if it is not then it will do the amp no harm at all if it is slightly under run, it will just mean I will loose a little bit of power but that should hardly be noticeable.
I think the Tung-sol 5881s and the GE 6SJ7s have burnt in nicely the sound is much better than it was a week or so ago when I put them in not sure if the gain has increased but it seems to have done.
Just listening to Tchaikovsky 1812 Antal Dorati Minneappolis Orchestra its the Mercury Living Presence recording from late 1950s on cd with period weapons on the recording, pretty sure the orchestra is playing in the room here, sounds excellent. Lots of dynamics, bass, treble imaging great too.....it is everywhere and no where....wierd I have never heard that before.
Not bad all in all given the vintage of single ended design and the age of the tube designs correct me if I am wrong but 845s are about 1931, 6SJ7s are about 1935 and 6L6s(5881s) about 1936.
It will play anything too, it does not matter if it is classical, opera, 50s/60s pop or modern pop, I bet it will love Queen too. Oh and if the recording is of a limited bandwith which some of those 50s/60s pop recordings are it shows and it shows over use of compression on the RCA pop recordings a treat Elvis was right he said they used too much and they did.
All in all I really am very pleased with my investment and must say that this single ended thing is a whole new experience for me but in my honest opinion I was right not to build such an amplifier as this...those voltages frighten me and rightly so.
Have a nice day all!!!
Steve in the UK
Hi Kev
Thanks for that I got it now but I think I would rather do something that is on the outside of the amplifier. Some kind of Auto Transformer, which took the 240V and then stepped it down to 220V which would solve all the issues.
It would be interesting to know if the amplifier is being run overvolts and the only real way to measure that is to stick your hand inside and measure across the plate and filament to see what the working potential difference is
Yeah it took me a while to work out that there was a difference between the working voltage and the ht supply, which are the operating parameters set by the circuit and component values.
The whole thing of going inside this amplifier sort of puts me off given the voltages that are inside it and the fact that it weighs in at 41Kg about 100lbs in old money.
It would be interesting to hear what peeps think on the use of auto transformers, pretty sure I would need to go to Sowter in the UK to get one wound specially unless Hammond have one in the UK here.
In my humble opinion it should resolve all the issues with the whole thing being over run, even if it is not then it will do the amp no harm at all if it is slightly under run, it will just mean I will loose a little bit of power but that should hardly be noticeable.
I think the Tung-sol 5881s and the GE 6SJ7s have burnt in nicely the sound is much better than it was a week or so ago when I put them in not sure if the gain has increased but it seems to have done.
Just listening to Tchaikovsky 1812 Antal Dorati Minneappolis Orchestra its the Mercury Living Presence recording from late 1950s on cd with period weapons on the recording, pretty sure the orchestra is playing in the room here, sounds excellent. Lots of dynamics, bass, treble imaging great too.....it is everywhere and no where....wierd I have never heard that before.
Not bad all in all given the vintage of single ended design and the age of the tube designs correct me if I am wrong but 845s are about 1931, 6SJ7s are about 1935 and 6L6s(5881s) about 1936.
It will play anything too, it does not matter if it is classical, opera, 50s/60s pop or modern pop, I bet it will love Queen too. Oh and if the recording is of a limited bandwith which some of those 50s/60s pop recordings are it shows and it shows over use of compression on the RCA pop recordings a treat Elvis was right he said they used too much and they did.
All in all I really am very pleased with my investment and must say that this single ended thing is a whole new experience for me but in my honest opinion I was right not to build such an amplifier as this...those voltages frighten me and rightly so.
Have a nice day all!!!
Steve in the UK
Mr Liang Audio website
Dear all:
For more information about Mr Liang Audio, pls visit:
http://www.lsyx.com
or the English version
http://mrliangaudio.infinites.net
Cheers
Dear all:
For more information about Mr Liang Audio, pls visit:
http://www.lsyx.com
or the English version
http://mrliangaudio.infinites.net
Cheers
Re: Mr Liang 845 Amplifier
Installing the buck transformer external to the amplifier was my intention. Basically just a suitable box with a receptacle mounted on it to plug the amplifier into..
As I pointed out you do not necessarily need to measure the plate voltage to determine whether or not the amplifier is being over-voltaged. Provided that the filament supply is unregulated you can measure it directly at the tube socket and this will give you a far better indication of the variation from nominal that you are experiencing. Please reread my previous post, you don't know with any certainty what the design range for this amplifier's plate voltage is (could be +/-10% of a nominal value you don't know except directly from the fellow who designed the amplifier) and therefore you can't make the determination you seek. Plate voltages tend to be loosely toleranced, and can vary substantially depending on the dcr of the output transformer, supply choke(s) and power transformer primary and secondary.
Note that all of this becomes irrelevant if the filament supplies are regulated and in that case you should just simply fix the bias voltage adjustment range by replacing the offending resistor values in the bias string.
Tons of people make auto-transformers I certainly wouldn't pay a premium for a sowter wound sample. I'd look on eBay UK and see what is currently listed. Surplus dealers should also be able to help. (I had a little Italian job that had taps at 110, 140V, 160V, 220V, 240V ) Also a bucking transformer as I described earlier may cost as little as a couple of quid to do this job as opposed to what you might pay for an autoformer..
Stevie342000 said:
Installing the buck transformer external to the amplifier was my intention. Basically just a suitable box with a receptacle mounted on it to plug the amplifier into..
As I pointed out you do not necessarily need to measure the plate voltage to determine whether or not the amplifier is being over-voltaged. Provided that the filament supply is unregulated you can measure it directly at the tube socket and this will give you a far better indication of the variation from nominal that you are experiencing. Please reread my previous post, you don't know with any certainty what the design range for this amplifier's plate voltage is (could be +/-10% of a nominal value you don't know except directly from the fellow who designed the amplifier) and therefore you can't make the determination you seek. Plate voltages tend to be loosely toleranced, and can vary substantially depending on the dcr of the output transformer, supply choke(s) and power transformer primary and secondary.
Note that all of this becomes irrelevant if the filament supplies are regulated and in that case you should just simply fix the bias voltage adjustment range by replacing the offending resistor values in the bias string.
Tons of people make auto-transformers I certainly wouldn't pay a premium for a sowter wound sample. I'd look on eBay UK and see what is currently listed. Surplus dealers should also be able to help. (I had a little Italian job that had taps at 110, 140V, 160V, 220V, 240V ) Also a bucking transformer as I described earlier may cost as little as a couple of quid to do this job as opposed to what you might pay for an autoformer..
Mr Liang Amplifier
Hi Jeff
In reply to hum bucking pot, nope you can not adjust it without taking the thing to pieces....but then again you do not need to there is not one once of hum or hiss from this amplifier unless you turn volume right up without any input....hum still zeroish but with just the rustle of thermal noise or hiss.
Thanks
Steve
ps oh how does it sound now that it is mostly burnt in....as described in earlier post by another membe who has been fortunate enough to visit the workshop. Bags of detail, lots of dynamics, bass good, vocals good, imaging everywhere but not unfocused just fills the room.
Hi Jeff
In reply to hum bucking pot, nope you can not adjust it without taking the thing to pieces....but then again you do not need to there is not one once of hum or hiss from this amplifier unless you turn volume right up without any input....hum still zeroish but with just the rustle of thermal noise or hiss.
Thanks
Steve
ps oh how does it sound now that it is mostly burnt in....as described in earlier post by another membe who has been fortunate enough to visit the workshop. Bags of detail, lots of dynamics, bass good, vocals good, imaging everywhere but not unfocused just fills the room.
About Mr Liang Audio
Dear all,
As I know Mr Liang Audio, if any question about the products. You are welcome to contact me at: poorstoner2006@yahoo.com.cn
Dear all,
As I know Mr Liang Audio, if any question about the products. You are welcome to contact me at: poorstoner2006@yahoo.com.cn
mr Liang 845 amplifier
Hello!
Just bought today 845 amplifier on e-bay. This is 300b version .
I would be very grateful if you could help me with advice on 6J4P replacement - amplifier
sound good - but not outstandingly better compare to Beard 30-60 . I am wondering if it is
6J4P - is chinese military valve affecting sound .
300b- is EH Gold. Many thanks in advance
Regards
Val
Hello!
Just bought today 845 amplifier on e-bay. This is 300b version .
I would be very grateful if you could help me with advice on 6J4P replacement - amplifier
sound good - but not outstandingly better compare to Beard 30-60 . I am wondering if it is
6J4P - is chinese military valve affecting sound .
300b- is EH Gold. Many thanks in advance
Regards
Val
Mr Liang 845 Amplifier
Hi Dan I think sorry if I got it wrong
I am sure you will not be dissappointed with this amplifier...the amp as a warning sounds harsh and hard and limited in some areas when first out of the box....I have mine connected to the Cable TV so the whole thing is on pretty much all day....a great way to burn in amps too......
Do not as a word of warning leave it unmonitored or powered on when not around...but that goes for all equipment.....as for your question as to what the tube line up is.......
In my version the tubes are 6J4P (6SJ7, 5693), 6P3P(6L6GC, 5881, KT66 watch heater currents here) and 845......I use General Electric 6SJ7s and new production Tung-sol 5881 with standard 845s....which I am changing shortly to Shuguang 845B which are Amperex replicas and the nearest you can get to RCA NOS.......I hope that helps......
You will not regret this purchase I am sure...my advise to you is to get the tubes and/or wait about a month before changing them if you have it switched on for long periods you will notice the change in sound and it does change.....for sure....once it all starts to sound nice and you will now then change the valves/tubes.....for me even with it on for about 8 hours a day it took some time...and I am not sure now if it is has finished burning in yet some components might take 6 months........
A word of warning those input tubes might start to have a small lightning display if your model is not the latest 300B version which has a second delay circuit and choke...mine is an earlier version and does not have 300Bs or the second delay something that could be put in.....but it suggests to me with the firework display that those input tubes go over volts until the heaters have warmed up.....which is why I changed mine...but the other reason not to change the input tubes is of course the guarantee might be invalidated or you might waste money on expensive replacements.....
Of course the reason I say to wait is to let the components burn and when you switch those tubes you will see the difference, pretty sure I lost a bit of gain when I changed the tubes too....which is why I say to wait to...if we stick to the same program we can then advise others better too....I hope that all helps
Steve in the UK
Hi Dan I think sorry if I got it wrong
I am sure you will not be dissappointed with this amplifier...the amp as a warning sounds harsh and hard and limited in some areas when first out of the box....I have mine connected to the Cable TV so the whole thing is on pretty much all day....a great way to burn in amps too......
Do not as a word of warning leave it unmonitored or powered on when not around...but that goes for all equipment.....as for your question as to what the tube line up is.......
In my version the tubes are 6J4P (6SJ7, 5693), 6P3P(6L6GC, 5881, KT66 watch heater currents here) and 845......I use General Electric 6SJ7s and new production Tung-sol 5881 with standard 845s....which I am changing shortly to Shuguang 845B which are Amperex replicas and the nearest you can get to RCA NOS.......I hope that helps......
You will not regret this purchase I am sure...my advise to you is to get the tubes and/or wait about a month before changing them if you have it switched on for long periods you will notice the change in sound and it does change.....for sure....once it all starts to sound nice and you will now then change the valves/tubes.....for me even with it on for about 8 hours a day it took some time...and I am not sure now if it is has finished burning in yet some components might take 6 months........
A word of warning those input tubes might start to have a small lightning display if your model is not the latest 300B version which has a second delay circuit and choke...mine is an earlier version and does not have 300Bs or the second delay something that could be put in.....but it suggests to me with the firework display that those input tubes go over volts until the heaters have warmed up.....which is why I changed mine...but the other reason not to change the input tubes is of course the guarantee might be invalidated or you might waste money on expensive replacements.....
Of course the reason I say to wait is to let the components burn and when you switch those tubes you will see the difference, pretty sure I lost a bit of gain when I changed the tubes too....which is why I say to wait to...if we stick to the same program we can then advise others better too....I hope that all helps
Steve in the UK
Hi
http://mrliangaudio.infinites.net/Pricelist.htm
I want to go to live in China !
The link of Circuit diagrams doesn't go?
http://mrliangaudio.infinites.net/Pricelist.htm
I want to go to live in China !
The link of Circuit diagrams doesn't go?
Gold_xyz said:Hi
http://mrliangaudio.infinites.net/Pricelist.htm
I want to go to live in China !
The link of Circuit diagrams doesn't go?
Hi that works out at about £282 which is about what I paid for it...if you look at page two and maybe 3 of this thread you will see schematics for the two versions the latest version which uses the 300B is slightly different it has a second delay circuit and a choke in the 300B HT supply....
However I will not attempt to attach all the versions of the circuit that have.....or at least the latest version for other see above...
Steve in the UK
Attachments
Mr Liang Amplifier
Hi All
As this is a diy group I am submitting this design...it is well worth the building, there is nothing special about the circuit...apart from it's simplicity...there is no need for expensive components in a well executed circuit after all they will not ressurrect what is not there..half decent capacitors are more than adequate....anyhow back to the circuit below is the latest version using 300Bs and second delay circuit etc etc etc.
TTFN
Steve in the UK
Hi All
As this is a diy group I am submitting this design...it is well worth the building, there is nothing special about the circuit...apart from it's simplicity...there is no need for expensive components in a well executed circuit after all they will not ressurrect what is not there..half decent capacitors are more than adequate....anyhow back to the circuit below is the latest version using 300Bs and second delay circuit etc etc etc.
TTFN
Steve in the UK
Attachments
Wondering about the copyright provisions on those schematics, hopefully you checked with the vendor prior to posting all of them here. Links to a schematic on someone's site is one thing, posting actual schematics of current production commercial kit is another.
IMO This a good inexpensive commercial design, not one I would necessarily want to replicate as a DIY project.
The CF design is a compromise at best. Were I to use a CF I would run high enough currents to allow for some level of A2 operation. More likely I would use transformer based driver circuit with a much less expensive dht, the choice of a 300B in this implementation seems marketing driven, I'm sure it performs well, but is hardly an ideal choice for a follower. (A low mu, moderate transconductance triode run at low currents - I'd choose pretty much the opposite or even a pentode.)
A separate filament transformer would be worthwhile as would better filtering and/or regulation on the dc filament supplies.
IMO This a good inexpensive commercial design, not one I would necessarily want to replicate as a DIY project.
The CF design is a compromise at best. Were I to use a CF I would run high enough currents to allow for some level of A2 operation. More likely I would use transformer based driver circuit with a much less expensive dht, the choice of a 300B in this implementation seems marketing driven, I'm sure it performs well, but is hardly an ideal choice for a follower. (A low mu, moderate transconductance triode run at low currents - I'd choose pretty much the opposite or even a pentode.)
A separate filament transformer would be worthwhile as would better filtering and/or regulation on the dc filament supplies.
Mr Liang 845
Hi Kevin I think
Your right I did not check but thought that it was unnecessary as they were freely available in the public domain..if they are copyrighted it is not marked or if it is it is in Chinese which of course I do not read.......
I did not see anything wrong with listing them it was more for information than anything else, If someone chooses to build one then they could do that freely enough from circuit diagram....on the same hand when the Audio Note Ongaku came out was that circuit diagram freely available? Many people have built replicas of that one too......
You can find it on line now if you look and I am pretty sure that that would be copyrighted they used to charge you to get a list of the various circuit diagrams from them here in the UK.
Not sure what the position is on any of them or what the laws are online copyright......I was on the understanding that you could not really copyright anything if it is published in the public forum which the internet is.........
I do however agree with you on the power supply...it could do with a little work....but it is more than adequate in this circuit application.....it might run out of steam or so might those output tubes........I assume they are biased in class A1......
Well I will be more careful in the future......
thanks
Steve in the UK
Hi Kevin I think
Your right I did not check but thought that it was unnecessary as they were freely available in the public domain..if they are copyrighted it is not marked or if it is it is in Chinese which of course I do not read.......
I did not see anything wrong with listing them it was more for information than anything else, If someone chooses to build one then they could do that freely enough from circuit diagram....on the same hand when the Audio Note Ongaku came out was that circuit diagram freely available? Many people have built replicas of that one too......
You can find it on line now if you look and I am pretty sure that that would be copyrighted they used to charge you to get a list of the various circuit diagrams from them here in the UK.
Not sure what the position is on any of them or what the laws are online copyright......I was on the understanding that you could not really copyright anything if it is published in the public forum which the internet is.........
I do however agree with you on the power supply...it could do with a little work....but it is more than adequate in this circuit application.....it might run out of steam or so might those output tubes........I assume they are biased in class A1......
Well I will be more careful in the future......
thanks
Steve in the UK
Mr Liang Amplifier
Hi all
OOops sorry about that...hit the return button ....let me continue...I was about to say I thought it was ok to post the circuits and I had said before that you could not have built them for what I paid for them......
If you were going to make them then you would need to spend a lot of money on the transformers and making that slightly better.....but why build them when you can get them for virtually free.....
Well worth the money and well worth the risk....I was merely trying to tell people how much improvement there had been in the Chinese designs.
If you come across one my advise is to buy it if you are in China and you can get to the factory go and listen to it before you buy it....you will not be dissappointed...
Have a nice day all
Steve in the UK.
Hi all
OOops sorry about that...hit the return button ....let me continue...I was about to say I thought it was ok to post the circuits and I had said before that you could not have built them for what I paid for them......
If you were going to make them then you would need to spend a lot of money on the transformers and making that slightly better.....but why build them when you can get them for virtually free.....
Well worth the money and well worth the risk....I was merely trying to tell people how much improvement there had been in the Chinese designs.
If you come across one my advise is to buy it if you are in China and you can get to the factory go and listen to it before you buy it....you will not be dissappointed...
Have a nice day all
Steve in the UK.
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