"Sweetie" What - are you cruizing for a piece of ... ?
"Help" implies attempting to assist towards the achievment of a goal. You are not contributing toward the achievment of any goal - simply pointing out a possible problem - which you cannot know yourself. It is more likely that you are trying to HELP YOURSELF financially.
If I say this 100 more times will it eventually get through?
"Help" implies attempting to assist towards the achievment of a goal. You are not contributing toward the achievment of any goal - simply pointing out a possible problem - which you cannot know yourself. It is more likely that you are trying to HELP YOURSELF financially.
If I say this 100 more times will it eventually get through?
Hi Sweetie,
I really only offerred my kit products to give a FINE example of what could be achieved and make it available at minimal cost to DIYers. I have given this forum a great deal in a short time despite the troglydite's smarting. I don't need to do it - but I have - for the education of those interested in my field of endeavour and who want to best their system! Unfortunately, in this country, there are no positions that pay state wages to produce 'free to air' product designs so I have to retrieve something for mine!
If you're complaining about my miniscule prices for the trouble of dealing with scurrilous commercial vendors then I'm terribly sorry! If you want me out of here because I challenge your belief regime I'm here forever! There are people out there who want better audio not blinkered belief.
Only trying to help.
Cheers,
Greg
I really only offerred my kit products to give a FINE example of what could be achieved and make it available at minimal cost to DIYers. I have given this forum a great deal in a short time despite the troglydite's smarting. I don't need to do it - but I have - for the education of those interested in my field of endeavour and who want to best their system! Unfortunately, in this country, there are no positions that pay state wages to produce 'free to air' product designs so I have to retrieve something for mine!
If you're complaining about my miniscule prices for the trouble of dealing with scurrilous commercial vendors then I'm terribly sorry! If you want me out of here because I challenge your belief regime I'm here forever! There are people out there who want better audio not blinkered belief.
Only trying to help.
Cheers,
Greg
There are many DIYers who appreciate my advice. THEY don't have a narrow defensive mindset. Goodbye.
Greg.
Greg.
Could you two just arrange to meet up somewhere and beat the cr@p out of each other. You sound like a pair of petulant teenagers.
P-Spice file can be found here:
http://www.delta-audio.com/temp_jens/leach_spice.rar
Sharing is part of the joy 🙂
\Jens
http://www.delta-audio.com/temp_jens/leach_spice.rar
Sharing is part of the joy 🙂
\Jens
Hi Terry,
Of Mr Pass' power amp designs I have only built the Aleph 3, however judging from the result I got I would not use this as a reference amplifier. It falls at the "characterful" end of the audio spectrum IMHO.
I have a V4.5 Leach amp built in dual mono on Prof. Leach's pcbs. I would regard this as an accurate amplifier and find that the treble quality is good.
Cheers,
Dave
My favourite "straight wire with gain" type amp is the Leach. My favourite "sprinkling of MSG" type amp is the AKSA.
The Aleph sounded "wrong" to my ears (and those of two friends whose opinions I value more highly than my own!) and in my system. No offence intended to Pass fans.
Dave
The Aleph sounded "wrong" to my ears (and those of two friends whose opinions I value more highly than my own!) and in my system. No offence intended to Pass fans.
Dave
Dave S said:
Hi Dave,
After more listening, I would agree that the term harsh was not well chosen. The highs are probably very clear. I was intentionally using music with prominent highs to test the different amps. I also used some recordings with very prominent bass to test the low end as well. The Leach is very articulate. So much so that some recordings I have do not sound good on it. It has a way of accentuating the flaws in recordings. I think the harshness I was hearing is in the recording and not in the amp.
I agree that he Krell is more musical than the Leach and probably not near as accurate. I guess it depends on what you will use the amp for.
Blessings, Terry
A bit OT, but has anyone built a pair of AmpGuru's amplifiers?
If so please let us know how it sounds.
If so please let us know how it sounds.
still4given said:
A number of people have criticised the bass peformance of the Leach. I have not found it wanting. The power supply has a strong influence on the low end performance of power amps and I like to use a large transformer with modest value caps (1KVA (separate windings for each channel) and 10KuF per rail) in my Leach - I find this gives a good combination of speed, tunefulness and depth/power.
The other critical aspect in any amp is grounding. You mention you have one transformer and two rectifier bridges. If you transformer does not have separate windings for each channel you must ensure you have both channels correctly start earhterd to the same point (and theoretically the channels must occupy the same physical space).
Regards,
Dave
Dave S said:
Hi Dave,
I have no complaints about the bass in the Leach. It is very strong and clear.
Here's a pic of the inside of mine. You can see that I have one star ground for everything.
Blessings, Terry
while tube amps excell in the mids and to some extent highs, i found these leach amps best all around, from bass to highs.
and the leach super amps are very honest amps!😀
and to think that prof. leach gave this to the audio diy world for a song, what more is there to say?
there are those who would spin hypes about a certein topology, but i doubt they can do what prof leach has done!
and jens's pcb design brought these leach amp a couple of notches higher. very excelllent layout.
and the leach super amps are very honest amps!😀
and to think that prof. leach gave this to the audio diy world for a song, what more is there to say?
there are those who would spin hypes about a certein topology, but i doubt they can do what prof leach has done!
and jens's pcb design brought these leach amp a couple of notches higher. very excelllent layout.
The Leach is a benchmark.
Whenever the local high-end emporium got in their latest and greatest toy they were bragging about, I would drag in my Leach.
Built around 1980 with three pair of MJ15011/12 and MJE15030/31 running on ±63V, it was clearer, cleaner, imaged better, and hit harder than anything.
There were certain aspects of the Electrocompaniet Amplifier that I liked, the regulated supply for the voltage gain stages. The Threshold S300 has a very nice midrange, I think the lack of global feedback, and loop feedback from the pre-drivers does this.
My Leach did not have feedback from the pre-drivers (like the Threshold and the v4.5 Leach), my next one will, and I intend to try the Threshold output stage with the Electrocompaniet front-end regulator.
On a side note, if you like 'warm' bass, just leave off the 22µF main supply bypass caps, and if you like 'soft' highs, just leave off the 0.1µF bypass cap on the main feeback cap. It now sounds a lot like a Bryston!
Whenever the local high-end emporium got in their latest and greatest toy they were bragging about, I would drag in my Leach.
Built around 1980 with three pair of MJ15011/12 and MJE15030/31 running on ±63V, it was clearer, cleaner, imaged better, and hit harder than anything.
There were certain aspects of the Electrocompaniet Amplifier that I liked, the regulated supply for the voltage gain stages. The Threshold S300 has a very nice midrange, I think the lack of global feedback, and loop feedback from the pre-drivers does this.
My Leach did not have feedback from the pre-drivers (like the Threshold and the v4.5 Leach), my next one will, and I intend to try the Threshold output stage with the Electrocompaniet front-end regulator.
On a side note, if you like 'warm' bass, just leave off the 22µF main supply bypass caps, and if you like 'soft' highs, just leave off the 0.1µF bypass cap on the main feeback cap. It now sounds a lot like a Bryston!
Hi Terry,
Here is my concern:
When you connect a signal source you will get a ground loop I.e. L source -> L input -> L power star on pcb -> Main power star -> R power star no pcb -> R input -> R source. This loop area could be subject to induced current by the mains transformer and could also be prone to high frequency interference. You could also have a conflict because the pcbs appear to have a power ground (by virtue of the large rail caps on board) as well as the busbar on your main smoothing caps. Please also do not believe that a separate bridge rect for each channel gives you some sort of isolation - when the diodes are conducting the L+R power rails are connected to each other through a low impedance.
Because Jens has put the large electrolytics on the pcbs (and therefore a power star) you don’t really have the option to build a stereo amp with just one supply - and critically one power ground. Therefore I think you need to go dual mono.
If you look at Prof L’s layout he is fully aware of these issues and he places the L+R inputs physically close to avoid large loop areas. He also has just one power ground star.
If I could make a suggestion - it may be best to remove the busbar and associated caps, and fit another mains transformer in the vacated space. Then build a dual mono using the pcb power ground as speaker return etc.
Here is my concern:
When you connect a signal source you will get a ground loop I.e. L source -> L input -> L power star on pcb -> Main power star -> R power star no pcb -> R input -> R source. This loop area could be subject to induced current by the mains transformer and could also be prone to high frequency interference. You could also have a conflict because the pcbs appear to have a power ground (by virtue of the large rail caps on board) as well as the busbar on your main smoothing caps. Please also do not believe that a separate bridge rect for each channel gives you some sort of isolation - when the diodes are conducting the L+R power rails are connected to each other through a low impedance.
Because Jens has put the large electrolytics on the pcbs (and therefore a power star) you don’t really have the option to build a stereo amp with just one supply - and critically one power ground. Therefore I think you need to go dual mono.
If you look at Prof L’s layout he is fully aware of these issues and he places the L+R inputs physically close to avoid large loop areas. He also has just one power ground star.
If I could make a suggestion - it may be best to remove the busbar and associated caps, and fit another mains transformer in the vacated space. Then build a dual mono using the pcb power ground as speaker return etc.
Update
Terry,
I have just spend some time listening to my ref amp and the leach clone with 10 transistors..... I found that the light sounding track was sounding more or less the same on both amps, so I hope that there is no need for you to worry about EQ 🙂
I will do some DC current measurements and try different current settings in the output stage to see if the current makes a lot of difference.
I will update again when I know more.
Regarding grounding, I find that adjusting the DC current Up/down in the output stage and listening to any change in hum levle in the speakers tends to reveal if the grounding is ok. If the hum levle goes up with current you need to change your grounding, if not don't bother youself with redoing it!
\Jens
Terry,
I have just spend some time listening to my ref amp and the leach clone with 10 transistors..... I found that the light sounding track was sounding more or less the same on both amps, so I hope that there is no need for you to worry about EQ 🙂
I will do some DC current measurements and try different current settings in the output stage to see if the current makes a lot of difference.
I will update again when I know more.
Regarding grounding, I find that adjusting the DC current Up/down in the output stage and listening to any change in hum levle in the speakers tends to reveal if the grounding is ok. If the hum levle goes up with current you need to change your grounding, if not don't bother youself with redoing it!
\Jens
Correctly designed kit for amateurs must also contain good directions for building, Jens... " too much space " for building experiments isn't good, how we can persuade here again and again... 😉
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