Audio Bliss
So far I get to eat my cake and keep it. 🙂
Regards, Eric. (the happy audiophile !)
Geoff, I just turned 40, she's a couple of years older, but still very much young in mind and body, and I have several good audio systems at my repair shop, at my home and at her place, and everybody is happy. 🙂Geoff said:
So far I get to eat my cake and keep it. 🙂
Regards, Eric. (the happy audiophile !)
Afterburner Question
Hello All, I'm looking for ideas regarding an afterburner/booster stage to hang off the output of a conventional medium power amp to provide increased power and lower impedence load capability (down to 2 ohms or so.)
I am thinking along the lines of a conventional loop feedback amplifier (clean) driving either
1 - a zero loop feedback final output stage with voltage gain with its own power supply, or
2 - a local loop feedback final output stage with voltage gain with its own power supply.
Bridging output stage is ok too.
Any/all advices and experiences would be apprecited, especially regarding sonics of non loop feedback systems.
Regards, Eric.
Hello All, I'm looking for ideas regarding an afterburner/booster stage to hang off the output of a conventional medium power amp to provide increased power and lower impedence load capability (down to 2 ohms or so.)
I am thinking along the lines of a conventional loop feedback amplifier (clean) driving either
1 - a zero loop feedback final output stage with voltage gain with its own power supply, or
2 - a local loop feedback final output stage with voltage gain with its own power supply.
Bridging output stage is ok too.
Any/all advices and experiences would be apprecited, especially regarding sonics of non loop feedback systems.
Regards, Eric.
Could any you guys out there also help me? Reading so much about the 8W Monster and JLH 10W and 15W class A amps I decided to build both of them. I qucikly laid out a PCB of the Monster and ordering parts but the JLH looks to be tougher to do an PCB and I hoping some of you guys might know where or have an PCB or layout some where.
Thanks for any help!
😀
Thanks for any help!
😀
Hi FBJ,
I didn't use a PCB for the JLH 10W. I looked carefully at the photo that came with the article on the Class A website. I then laid the parts down as in the schematic and solderd them to a matrix-hole board.. I wish I had a digital camera to show you.. The board is something like 5x5cm and the power transistors are offboard on heatsinks..
I would very much like to know your procedings om the 8 watt monster... I'm also thinking about it as one of my next projects...
Greetings,
thijs
I didn't use a PCB for the JLH 10W. I looked carefully at the photo that came with the article on the Class A website. I then laid the parts down as in the schematic and solderd them to a matrix-hole board.. I wish I had a digital camera to show you.. The board is something like 5x5cm and the power transistors are offboard on heatsinks..
I would very much like to know your procedings om the 8 watt monster... I'm also thinking about it as one of my next projects...
Greetings,
thijs
I didn't use PSB also but used veroboard. Making a PSB layout shouldn't be so difficult for this amp.
- Just what version you are looking to build ,
- which transistors and how/where you want to install them ,
- what would be other component sizes like: cap can sizes, lead spacing etc.
- will you use coupling caps, parallel resistors for higher power handling etc:
Knowing all that, I could prehaps look at couple of PCB files I drew as an experiment and modify them to suit your needs.
Argo
- Just what version you are looking to build ,
- which transistors and how/where you want to install them ,
- what would be other component sizes like: cap can sizes, lead spacing etc.
- will you use coupling caps, parallel resistors for higher power handling etc:
Knowing all that, I could prehaps look at couple of PCB files I drew as an experiment and modify them to suit your needs.
Argo
FBJ
As suggested in previous replies, a pcb isn't strictly necessary; hardwiring is relatively easy for this circuit. However, there is a pcb layout for both the 1996 amp and a power supply at Jos de Weerd's website:
http://utopia.knoware.nl/users/cfw/amp/
and a commercial pcb for the 1996 version is available from Williams Hart:
http://users.classicfm.net/williamshart/classa.htm
Geoff
As suggested in previous replies, a pcb isn't strictly necessary; hardwiring is relatively easy for this circuit. However, there is a pcb layout for both the 1996 amp and a power supply at Jos de Weerd's website:
http://utopia.knoware.nl/users/cfw/amp/
and a commercial pcb for the 1996 version is available from Williams Hart:
http://users.classicfm.net/williamshart/classa.htm
Geoff
My amps are using Williamshart PCB's....
The layout is quite well made, but a little warning is in order. On the web page these are advertiesed as very high quality PCB's. The ones I received have very thin tinned tracks, no double thickness anywhere..... I ran copper wire along tracks that carry current to overcome this.
Ergo
The layout is quite well made, but a little warning is in order. On the web page these are advertiesed as very high quality PCB's. The ones I received have very thin tinned tracks, no double thickness anywhere..... I ran copper wire along tracks that carry current to overcome this.
Ergo
Ergo
Thanks for the information about the Williams Hart pcb. I have not seen one and so have been unable to judge the quality. From information supplied by another constructor, I have some other reservations about the kits they offer and I think I must now give serious consideration to removing the link to this company that is on my website.
Geoff
Thanks for the information about the Williams Hart pcb. I have not seen one and so have been unable to judge the quality. From information supplied by another constructor, I have some other reservations about the kits they offer and I think I must now give serious consideration to removing the link to this company that is on my website.
Geoff
one question not related to JLH amp
Williamshart seems to be one of very few places to have
Motorised Alps Blue Velvet 50K.
Does anyone know any other sources for this part? The postage charge from WilliamsHart to Estonia was not very good.....
I have a remote kit waiting for decent motorised pot for months now, but I haven't found good source.
Ergo
Williamshart seems to be one of very few places to have
Motorised Alps Blue Velvet 50K.
Does anyone know any other sources for this part? The postage charge from WilliamsHart to Estonia was not very good.....
I have a remote kit waiting for decent motorised pot for months now, but I haven't found good source.
Ergo
Ergo
I'm glad to see you have used the JLH preferred position for the compensation capacitor rather than the usual cap between the collector and base of the VAS.
Geoff
I'm glad to see you have used the JLH preferred position for the compensation capacitor rather than the usual cap between the collector and base of the VAS.
Geoff
I like this method of compensation too. Until now it's more of a gut feeling, but it seems there are guys out there who confirm this. Hugh Dean also said that the cap between base and collector of voltage amp degrades sound more.
Well, we have a plan with a friend to buy Welleman PC Scope and Signal Generator. With this setup it will be possible to measure freq/phase response up to 1MHz. Then I think it will be very informative and I will post the results.....
It will also help to fine tune the cap even further. Current measurements of phase were done with dual channel scope and it's quite hard work 🙂
Ergo
Well, we have a plan with a friend to buy Welleman PC Scope and Signal Generator. With this setup it will be possible to measure freq/phase response up to 1MHz. Then I think it will be very informative and I will post the results.....
It will also help to fine tune the cap even further. Current measurements of phase were done with dual channel scope and it's quite hard work 🙂
Ergo
Thanks everyone for the feedback and so quickly.
argo & tschrama - I am interested in the 1996 version. And it really doesn't matter what layout size or parts sizes and shapes, I was going to layout my own PCB, with the PCBExpress general pricing PCB size (3, 3.8 in X 2.5 in PCBs for $65.00 including shipping). I just like PCBs, to me my projects looks more professional. My time frame for finishing these amps will be a while cause I have many other projects I have been putting on hold either because I have not have time and money or cause I like my projects in really nice enclosures and to find a machine shop that won't take 4 months to do one or two of what I want.
Thanks Geoff, your web site is great and I found most of all the info I seen on the net there. I will try those sites. I wouldn't remove Hart site from your web site they do have good info but maybe a warning about their PCBs might be better.
ergo - I don't know if Germany is any cheaper for you but I know Borbely Audio sells motorized ALPS pots and some of the others Germany sites named in this forum does too.
argo & tschrama - I am interested in the 1996 version. And it really doesn't matter what layout size or parts sizes and shapes, I was going to layout my own PCB, with the PCBExpress general pricing PCB size (3, 3.8 in X 2.5 in PCBs for $65.00 including shipping). I just like PCBs, to me my projects looks more professional. My time frame for finishing these amps will be a while cause I have many other projects I have been putting on hold either because I have not have time and money or cause I like my projects in really nice enclosures and to find a machine shop that won't take 4 months to do one or two of what I want.
Thanks Geoff, your web site is great and I found most of all the info I seen on the net there. I will try those sites. I wouldn't remove Hart site from your web site they do have good info but maybe a warning about their PCBs might be better.
ergo - I don't know if Germany is any cheaper for you but I know Borbely Audio sells motorized ALPS pots and some of the others Germany sites named in this forum does too.
Not that i wan't to earn money on you guys, but if you could get a bunch of people together.. Then I or Geoff or anyone else could order boards from a PCB manufacture!?
Then you could get your boards done like you all wanted them => 110um copper thickness! And buy them at a good volume price (when buying a total of 50 - 100units). It is not more like 25 - 50 stereo amps.
Sonny
Then you could get your boards done like you all wanted them => 110um copper thickness! And buy them at a good volume price (when buying a total of 50 - 100units). It is not more like 25 - 50 stereo amps.
Sonny
JLH
Geoff, is the output stage of this thing supposed to be a quasi-complementary?
Lets review:
Common emmitter output
Class A operation
Two voltage gain stages
Am I the only one that thinks this thing looks pretty close to a BJT version of the Aleph amplifiers......
H.H.
P.S. My favorite JLH design
Geoff, is the output stage of this thing supposed to be a quasi-complementary?
Lets review:
Common emmitter output
Class A operation
Two voltage gain stages
Am I the only one that thinks this thing looks pretty close to a BJT version of the Aleph amplifiers......
H.H.
P.S. My favorite JLH design
Attachments
JLH
Thats Jennifer Love Hewitt......and if my wife see's the picture I will be typing with a broken arm!
H.H.
Thats Jennifer Love Hewitt......and if my wife see's the picture I will be typing with a broken arm!
H.H.