No Such Thing As An Ideal Conductor....
Probably a fine idea, but we can run it here for now, and if we feel like it we can do a cut/paste of these posts into a new thread, by all means - this is a subject that newbies need to understand.
Anyway, did you understand my previous post correctly ? - if so, good, if not, say so.
You say that you tried to make both channel mods as identical as possible BUT did you make sure that the add in pieces of wire directions are identical ?. - big question !.
I do not want any intruders to get into any wire directions debates here whatsoever, thankyou.
I say this because of experimentation results and N.P. (nuclear physicist) discussions.
Chris, by the fact that you are telling me that your NFB arrangement change has resulted in sonics change, you are telling me that you have a good enough resoloution system, and good enough ears - good.
So, drop any pretensions that you may have regarding if wire has any directional characteristic or not, and go do some experimenting with the same piece of wire in the layout, fitted in reversed direction, and note any fine changes (on music tracks you know perfectly well).
In my experience this is an additional effect, as has the alloy (or purity or plating) of the wire used, and also the solder alloy used, and that is another subject.
You can build the system so as to discount (eliminate and utilise) directional effects to fine tune the sound you want.
Chris, if you are still listening I can tell you more.
Eric.
Probably a fine idea, but we can run it here for now, and if we feel like it we can do a cut/paste of these posts into a new thread, by all means - this is a subject that newbies need to understand.
Anyway, did you understand my previous post correctly ? - if so, good, if not, say so.
You say that you tried to make both channel mods as identical as possible BUT did you make sure that the add in pieces of wire directions are identical ?. - big question !.
I do not want any intruders to get into any wire directions debates here whatsoever, thankyou.
I say this because of experimentation results and N.P. (nuclear physicist) discussions.
Chris, by the fact that you are telling me that your NFB arrangement change has resulted in sonics change, you are telling me that you have a good enough resoloution system, and good enough ears - good.
So, drop any pretensions that you may have regarding if wire has any directional characteristic or not, and go do some experimenting with the same piece of wire in the layout, fitted in reversed direction, and note any fine changes (on music tracks you know perfectly well).
In my experience this is an additional effect, as has the alloy (or purity or plating) of the wire used, and also the solder alloy used, and that is another subject.
You can build the system so as to discount (eliminate and utilise) directional effects to fine tune the sound you want.
Chris, if you are still listening I can tell you more.
Eric.
Yes its 2N1711. I will try 2SC3421 as well sometimes later. First I need to change the outputs for MJ15003 because these ST Microelectronics 2N3005s are really dull sounding compared to original Motorola devices, which I had previously but broke. Right now Power Follower I am trying out occupies JLHs cabinet. Haven’t done any serious comparisons between those two yet (I am lacking a good voltage source at the moment) but that they are definitely different sounding amps, is obvious already. JHL provided crystal clean, very detailed and sometimes even merciless sound while Power follower seems to beautify and sweeten things too much. Kind of comparing oranges to apples or better yet fresh lemon to honey.chris ma said:
Argo
Eric,
Silly me I didn't think about the direction of the wires.. there is no marking on the wire otherwise it would be easy to tell, by luck I may have them in the same direction because I cut them from the same spool used the first one to match the length and cut the second one, with both wires always between my fingers and strip them both in one go in one end and the other end stripped longer due to the fact that I want them to bend the same angle and line up the different points on the tracks to provide easier soldering, yeah I think they are in the same direction, just by blind luck that I want longer stripped on one spot on the track. I'll listen to the amp more before I'll reverse the wire though.. may be some day...but other modification/fooling around with different transistors will beome next in priority. (I do believe in wire direction BTW, just a matter of why not but no back up knowledge for the subject tough)
Argo,
I am using BD139, in my dismantled JLH1996 I used 2n1711, for some reason I think the 2N1711 sound more tube like than BD139 but can not really put my finger to it. But I want to try TimA's suggestion first then I'll try 2SC3421 too, by the way what do you mean by Power Follower, a newbie question..
Chris
Silly me I didn't think about the direction of the wires.. there is no marking on the wire otherwise it would be easy to tell, by luck I may have them in the same direction because I cut them from the same spool used the first one to match the length and cut the second one, with both wires always between my fingers and strip them both in one go in one end and the other end stripped longer due to the fact that I want them to bend the same angle and line up the different points on the tracks to provide easier soldering, yeah I think they are in the same direction, just by blind luck that I want longer stripped on one spot on the track. I'll listen to the amp more before I'll reverse the wire though.. may be some day...but other modification/fooling around with different transistors will beome next in priority. (I do believe in wire direction BTW, just a matter of why not but no back up knowledge for the subject tough)
Argo,
I am using BD139, in my dismantled JLH1996 I used 2n1711, for some reason I think the 2N1711 sound more tube like than BD139 but can not really put my finger to it. But I want to try TimA's suggestion first then I'll try 2SC3421 too, by the way what do you mean by Power Follower, a newbie question..
Chris
I'm afraid it's on hold at the moment. I was hoping to use a JLH design for my refurbishment of some antique powered Advents, but heatsinking proved to be too big an issue. I'm putting ESP3As into the Advents instead, then I'll revisit the JLH. I'm kind of glad I shelved it for a bit with the new information recently posted in this thread. I had one channel running but will probably start again with the latest suggested changes.chris ma said:paulb
How is your JLH progressing btw?
Chris
It’s an Andrea Ciuffoly's Power Follower 99 - SE class A mosfet amp. http://www.audiodesignguide.com/my/Follower_99c.gifchris ma said:
It's a source follower, like emitter follower - or cathode follower, with the gain less than 1, so it requires an additional voltage amplifier stage first. I just built it out of curiosity into the housing of JLH amp because I had some mosfets and big power transformator already. It needs some more heat sinks than ordinary JLH amp though.
So if I decide to keep it will have its own housing. It’s a very simple design with a little twist, as is JLH amp and sounds marvelous too, but different.
Argo
Just some observations:-
Having blown one channel of my Elliott Death of Zen (a JLH lookalike) from what appeared to be thermal creep and an unoticed too-small TO3 mica insulator, I decided to make some tweaks when repairing. Even though I loved the sound, I thought I could improve on it, so I replaced the existing MJ15003's (Hfe=70) with higher gain and better matched MJ15003's (Hfe=125) on the output. (I'd made that switch from 2N3055's to MJ's shortly after completing the amp a while back and it definitely makes a difference). I also replaced the existing NTE373 (2SC3421 substitute) driver & current source which were Hfe=100 with JE180's (BD139 substitutes) with an Hfe=250.
The net result is the amp just sounds hard, dry and seems to have lost the magic. As I know the MJ's aren't the issue, I'll be reverting to the NTE373's or will try to find some 2SC3421's.
The only other change I made, because I'm now using 4 ohm speakers, is I've dropped the voltage and raised the current (18V rails @ 3A quiescent instead of 40V@1.7A. Once I get a new toroidal xformer I'll raise the rails to 30V and drop the current a little). I have noticed that the JE180's run cold with this lower voltage configuration whereas the NTE373's ran warm previously and wonder if there's any sound coloration going on due to that? So I'll probably fix the power supply first before I do the transistor switchout as I'm concerned that the lower Ic max of the NTE373's may be an issue in a 4 ohm configuration. If the sounds still off once the power supplies where I want it (30V@2.5A) I'll revert to the 373's/2SC3421's. I'll update later if anyone's interested
Having blown one channel of my Elliott Death of Zen (a JLH lookalike) from what appeared to be thermal creep and an unoticed too-small TO3 mica insulator, I decided to make some tweaks when repairing. Even though I loved the sound, I thought I could improve on it, so I replaced the existing MJ15003's (Hfe=70) with higher gain and better matched MJ15003's (Hfe=125) on the output. (I'd made that switch from 2N3055's to MJ's shortly after completing the amp a while back and it definitely makes a difference). I also replaced the existing NTE373 (2SC3421 substitute) driver & current source which were Hfe=100 with JE180's (BD139 substitutes) with an Hfe=250.
The net result is the amp just sounds hard, dry and seems to have lost the magic. As I know the MJ's aren't the issue, I'll be reverting to the NTE373's or will try to find some 2SC3421's.
The only other change I made, because I'm now using 4 ohm speakers, is I've dropped the voltage and raised the current (18V rails @ 3A quiescent instead of 40V@1.7A. Once I get a new toroidal xformer I'll raise the rails to 30V and drop the current a little). I have noticed that the JE180's run cold with this lower voltage configuration whereas the NTE373's ran warm previously and wonder if there's any sound coloration going on due to that? So I'll probably fix the power supply first before I do the transistor switchout as I'm concerned that the lower Ic max of the NTE373's may be an issue in a 4 ohm configuration. If the sounds still off once the power supplies where I want it (30V@2.5A) I'll revert to the 373's/2SC3421's. I'll update later if anyone's interested
Sidney
And while you are there (I mean transformator change, power supply redesign and everything) maybe you can try to modify the whole thing even a little bit further and try out one of the JLH versions. I have always been interested to make some comparison between those two but newer managed to build DOZ myself.
Argo
And while you are there (I mean transformator change, power supply redesign and everything) maybe you can try to modify the whole thing even a little bit further and try out one of the JLH versions. I have always been interested to make some comparison between those two but newer managed to build DOZ myself.
Argo
Class A
Drafance007
YESTER-ME. YESTER-YOU, YESTERDAY /Stevie Wonder (paul mcCartney "Michelle/Yesterday"
i am no sherlock holmes
but you should keep asking these "Solidarity poland" guys
anything
and the lord will help you to have a little nice
Classy amp, after Christmas, January/February
I have built
my own mono class a design
that can deliver 4 Watt pure into 8 ohms
i love it!
will make another one for stereo at summertime!
/halojoy home of music and for real chess brains
helloDrafance007 said:
Drafance007
YESTER-ME. YESTER-YOU, YESTERDAY /Stevie Wonder (paul mcCartney "Michelle/Yesterday" i am no sherlock holmes
but you should keep asking these "Solidarity poland" guys
anything
and the lord will help you to have a little nice
Classy amp, after Christmas, January/February
I have built
my own mono class a designthat can deliver 4 Watt pure into 8 ohms
i love it!
will make another one for stereo at summertime!
/halojoy home of music and for real chess brains
Re: Jlh poasted by Les is not Class A methinks
In Oct 2002 a cct was posted by Les as the JLH 1996 Class A amp. It looks Class B to me. Shouldn't the speaker be connected to the low Voltage rail by a capacitor and not to Ground as shown!? In the 1996 JLH article the speaker was connected to -V through a cap. I am just tryin' to learn this stuff again, but I did do 3 years of EE 20 years ago before dropping out so pardon me if I am wrong. Thanks.
Greg
In Oct 2002 a cct was posted by Les as the JLH 1996 Class A amp. It looks Class B to me. Shouldn't the speaker be connected to the low Voltage rail by a capacitor and not to Ground as shown!? In the 1996 JLH article the speaker was connected to -V through a cap. I am just tryin' to learn this stuff again, but I did do 3 years of EE 20 years ago before dropping out so pardon me if I am wrong. Thanks.
Greg
Temp Measurements
Thanks to one of our member posted the thermometer model from Radio Shack in another thread that I went and bought one and now do not have to use my hand to test the heat.
The measurements are for my JLH for ESL between both mono blocks, if anyone can foresee a protential problem please let me know and warn me about it, thanks.
8 Output transistors case temp MJ15003 best to worst, 63C-67C
8 Heat sink temp for MJ15003, 48C-52C
4 Bridge Rectifiers case temp, 63C-67C
2 Transformer(22-0-22 300VA) top plate temp, 52C
4 Regulators LM338K no worries, did not take measurement.
Supply rail after regulation is 20V and Iq bias at 4A. All measurements were taken after 2 hours at room temperature of 21C.
Thanks in advance,
Chris
Thanks to one of our member posted the thermometer model from Radio Shack in another thread that I went and bought one and now do not have to use my hand to test the heat.
The measurements are for my JLH for ESL between both mono blocks, if anyone can foresee a protential problem please let me know and warn me about it, thanks.
8 Output transistors case temp MJ15003 best to worst, 63C-67C
8 Heat sink temp for MJ15003, 48C-52C
4 Bridge Rectifiers case temp, 63C-67C
2 Transformer(22-0-22 300VA) top plate temp, 52C
4 Regulators LM338K no worries, did not take measurement.
Supply rail after regulation is 20V and Iq bias at 4A. All measurements were taken after 2 hours at room temperature of 21C.
Thanks in advance,
Chris
JLH PCB
Hi Argo
yes an other newbie
Hope you Can Help
I Have Been looking at the Diy audio forms with great interest on what you guys have to say on the JLH class an Amps And hoped that you world consider giving me a little help as I have a grate interest in building this amp and would be most indebted to you
But I mead some help with the PCB fig 3
update for this amp A Constant current source ccs relating to Vr2 Q7 Q8 R12 fig3 update page but not being that good at adding this upgrade into the PCB I got some info from Geoff the ccs was built as a sud board And
I Thought that as you are more experienced in the electronics field than I am you May help by letting me have a pcb overlay drawing of the ccs part of the circut and the connection points into the pcb overlay in fig 3 on the
JHL Class A Amp for the Quad ESL57 page Or mabe the fulley updated overlay of this pcb if you have one
I thankyou and would be most gratefully for the help
Regards
Colin
Hi Argo
yes an other newbie
Hope you Can Help
I Have Been looking at the Diy audio forms with great interest on what you guys have to say on the JLH class an Amps And hoped that you world consider giving me a little help as I have a grate interest in building this amp and would be most indebted to you
But I mead some help with the PCB fig 3
update for this amp A Constant current source ccs relating to Vr2 Q7 Q8 R12 fig3 update page but not being that good at adding this upgrade into the PCB I got some info from Geoff the ccs was built as a sud board And
I Thought that as you are more experienced in the electronics field than I am you May help by letting me have a pcb overlay drawing of the ccs part of the circut and the connection points into the pcb overlay in fig 3 on the
JHL Class A Amp for the Quad ESL57 page Or mabe the fulley updated overlay of this pcb if you have one
I thankyou and would be most gratefully for the help
Regards
Colin