What are you going to do with half a million old transistors? I'd make a start on selling those you won't be needing now because it may take many years to clear them if you hope to make a profit through internet sales.
It seems likely that the audio electronics nostalgia wave we are riding, will pass in the coming years and you could wind up with a pile of worthless semis instead of saleable ones. Keep an eye on realistic prices for your particular stock.
It seems likely that the audio electronics nostalgia wave we are riding, will pass in the coming years and you could wind up with a pile of worthless semis instead of saleable ones. Keep an eye on realistic prices for your particular stock.
I am going to take pictures of the packaging of the low power transistors, just that is too beautiful, in any case I had never seen such packaging before.
Yes, a lot of Thomson but also US and Japan references and even some Cosmos references.
@Ian: a few years ago (more than two decades) I had received a huge batch of tubes (radio, tv, bf) but at the time I had no interest in tube devices and I have sold almost the entire lot.
today not a month goes by that I do not regret having sold them, I certainly will not do it again.
I know that a lot of references are not used or totally obsolete (germanium among others) but who says that "tomorrow" I will not use them because I too would have evolved.
The good example is the jlh69, before knowing this diagram, I had no interest in the 2n3055 and other MJ15003 15024 etc etc, but now more than ten years after having assembled my first, I must have 5 or 6 kg ...
moreover, now i'm self-employed in HIFI electronic troubleshooting and i'm always surprised by what i am led to repair, devices which for me have no value, neither in their operation, nor in their design , nor in their construction, but people love them for a whole bunch of reasons and I make money by repairing it and everyone is happy.
Yes, a lot of Thomson but also US and Japan references and even some Cosmos references.
@Ian: a few years ago (more than two decades) I had received a huge batch of tubes (radio, tv, bf) but at the time I had no interest in tube devices and I have sold almost the entire lot.
today not a month goes by that I do not regret having sold them, I certainly will not do it again.
I know that a lot of references are not used or totally obsolete (germanium among others) but who says that "tomorrow" I will not use them because I too would have evolved.
The good example is the jlh69, before knowing this diagram, I had no interest in the 2n3055 and other MJ15003 15024 etc etc, but now more than ten years after having assembled my first, I must have 5 or 6 kg ...
moreover, now i'm self-employed in HIFI electronic troubleshooting and i'm always surprised by what i am led to repair, devices which for me have no value, neither in their operation, nor in their design , nor in their construction, but people love them for a whole bunch of reasons and I make money by repairing it and everyone is happy.
Strange intermittent 'Brr noise' during music passages
I built the Siliconray 15W JLH Class A a few years back. Very happy with it except the 20,000 uF per rail PSU (one PSU per channel) I purchased off Ebay was not up to the task (hum levels around 50 mV from memory and audible).
Recently I replaced the dual PSU with a single Bonsai's 'Ripple Eater' (with one 10,000uF cap per channel). Measured the 50 Hz level below 1 mV, checked the sine and square wave performance, tweaked the offset voltage and bias (1.5A) and put it back into service.
On switch on, no hum from the speakers now
Started playing some music from my PC (ASUS sound card) and enjoyed until I suddenly heard a short duration 'Brrr' from the speakers
Carried on playing a few songs and heard this intermittent 'Brrr' coming through every 60 seconds or so. Music was not at high volume nor was the volume 'peaking' when the noise came through.
Though perhaps it might be the PC/sound card or other.
Switched to Bonsai's xK amplifier (same wiring etc) listened to the same tracks, no 'Brrr'.
Back to the 15W and again noticed the same brief 'Brrr' noise (< 1 second) at odd occasions No expert at determining frequency but seems quite low (< 1 KHz).
Seems like an intermittent oscillation?
I have recently 'rearranged' the HiFi equipment in my office and now have a 5m RCA cable from my (very basic) passive preamp to the 2 amps (JLH and Ovation). Not sure if this could be a factor IRO the JLH?
The JLH does not have a Zobel Network on the output (it didn't before anyway) but there is one available on the ripple eater. Perhaps I should try that but, as the amp was working 'OK' before, I wanted to explore any additional possibilities before opening up the Amp case again. I also think (?) the Zobel is only effective at higher frequencies anyway?
Thoughts, suggestions appreciated.
Many thanks
I built the Siliconray 15W JLH Class A a few years back. Very happy with it except the 20,000 uF per rail PSU (one PSU per channel) I purchased off Ebay was not up to the task (hum levels around 50 mV from memory and audible).
Recently I replaced the dual PSU with a single Bonsai's 'Ripple Eater' (with one 10,000uF cap per channel). Measured the 50 Hz level below 1 mV, checked the sine and square wave performance, tweaked the offset voltage and bias (1.5A) and put it back into service.
On switch on, no hum from the speakers now
Started playing some music from my PC (ASUS sound card) and enjoyed until I suddenly heard a short duration 'Brrr' from the speakers
Carried on playing a few songs and heard this intermittent 'Brrr' coming through every 60 seconds or so. Music was not at high volume nor was the volume 'peaking' when the noise came through.
Though perhaps it might be the PC/sound card or other.
Switched to Bonsai's xK amplifier (same wiring etc) listened to the same tracks, no 'Brrr'.
Back to the 15W and again noticed the same brief 'Brrr' noise (< 1 second) at odd occasions No expert at determining frequency but seems quite low (< 1 KHz).
Seems like an intermittent oscillation?
I have recently 'rearranged' the HiFi equipment in my office and now have a 5m RCA cable from my (very basic) passive preamp to the 2 amps (JLH and Ovation). Not sure if this could be a factor IRO the JLH?
The JLH does not have a Zobel Network on the output (it didn't before anyway) but there is one available on the ripple eater. Perhaps I should try that but, as the amp was working 'OK' before, I wanted to explore any additional possibilities before opening up the Amp case again. I also think (?) the Zobel is only effective at higher frequencies anyway?
Thoughts, suggestions appreciated.
Many thanks
Thanks for your reply Kozard,
The Siliconray PCB components were pretty much similar to the JLH-2005 board
ones and has the same filter as per your diagram.
BTW There is also an RFI filter (inbuilt) on the IEC mains input socket.
I should mention that the mains transformer is 15-0-15 160VA - unchanged from the previous 'incarnation'.
I never managed to get the jlh siliconray to work properly with the components selected by the "designer" it was still oscillating in a strange way.
before putting it away in a cupboard then in a box where it is always there, I had tried slower transistors and it did not oscillate but did not have much interest in listening compared to the original 69, that's why it's always in its box.
before putting it away in a cupboard then in a box where it is always there, I had tried slower transistors and it did not oscillate but did not have much interest in listening compared to the original 69, that's why it's always in its box.
Perhaps narrow down the changes and the sequence of changes.
Did you:
- Change the power supply (to ripple eater)
- Change the preamp
- Change the location of the amplifier
- Change to a 5 meter long input cable
Can you connect a clean source to the amplifier (in the present location) using a short high quality input cable? (Without the preamp and without the 5 meter long input cable.) Do you still get the "burr" sound?
Now for some humor: You didn't move the amplifier to your desk and then rest your mobile phone on top of the case of the amplifier or preamp did you?
There is one discrete pre-amplifier that I got from AliExpress (called "Marantz Circuit J74 K170 A970 C2240") which I have never been able to stop all the R2D2 sounds. You just move your hand around the circuit board to change all the whistling and other noises.
Hi guys, another test of my 1969 JLH (10W) "CLASS A" PURE.
Now with 2A BIAS.
Temperature test on components and heat sinks.
Spectacular audio!
Power supply:
Transformer: 110 / 220V • 18V AC • 6A
Rectifier bridge: 8A
Capacitor: (1x) 22,000uF (63V)
Power: 18V DC
I.Q. (BIAS) = 2A
Speaker = 6 ohms
Power (no distortion) = 7W RMS (per channel)
MONOBLOCK
TESTE #8 - Amplificador "CLASSE A" PURO ? JLH 1969 (10W) ? 18V DC e BIAS de 2A - MONOBLOCO - YouTube
Now with 2A BIAS.
Temperature test on components and heat sinks.
Spectacular audio!
Power supply:
Transformer: 110 / 220V • 18V AC • 6A
Rectifier bridge: 8A
Capacitor: (1x) 22,000uF (63V)
Power: 18V DC
I.Q. (BIAS) = 2A
Speaker = 6 ohms
Power (no distortion) = 7W RMS (per channel)
MONOBLOCK
TESTE #8 - Amplificador "CLASSE A" PURO ? JLH 1969 (10W) ? 18V DC e BIAS de 2A - MONOBLOCO - YouTube
That's sad news. I was quite happy with mine (other than the hum) before I changed the rudimentary dual PSUs for the single ripple eater. Perhaps it's something to do with that change - i.e. a common PSU for both amps...
Was your amp constantly oscillating or intermittently like mine?
1, 3,4 all at once. Perhaps also point 2 - It's a while since I used it having built the kX amp. I might have been running it from a JLH headphone amp (with headphone input from the ASUS sound card on my PC).
I'll see what I can do about running it from a different source closer to the amp. When I built it, it was to be used basically as a 'single input' Amp and I have a Volume control mounted to the front panel for this purpose. Ergo I can change the volume without a preamp.
Talking of humour, I said the sound is like 'Brrr'. In actual fact if you've heard someone give one of those long 'burps' it's almost identical - minus the last 'p'.
Thanks for your help!
sensitive to everything, at one time I even thought of moving the power supply transformer to another room
also sensitive to the signal but also to the music and the preamp and cd player, in short sensitive what.
on the other hand he never burped but a lot hissed and buzzed
I'm trying not to pre-empt anything at present so as not to influence any responses. The though had crossed my mind that possibly the 10,000uF per channel on the Ripple Eater is insufficient and perhaps there's some 'break-through' of 50 Hz on the output of the PSU?
Is there a way to detect any unusual DC output when the amp is running? Having checked the output of the amp with the inputs shorted I didn't see any perturbations on the output while setting the output to 'zero' (< 10 mV) - but that's under quiescent conditions.
Just fuses as per the original design unfortunately. When I made up the amp I had a soft start module and a separate ground lift circuit - so there was little room left. I'm now using the ground lift on the Ripple Eater and have removed the soft start as it wasn't really necessary. Perhaps I should rather look at an electronic DC protection... Problem with the majority of these 'speaker protection' circuits is that they operate at different (lower) voltages to the Amp PSU. However I do have one now (DiyAudio one) that maybe I could install.
Thanks for the reminder.
Bingo!
Thanks, Kozard and others
Running the Amp direct from my Marantz CD player the 'Brrr' sound has gone (thus far anyway). (Reminder that I built in a 10K log pot into this amp so it could be used without a preamp).
With the Ripple Eater the sound seems less 'contaminated' and clear (albeit with my old Celestion DL6s at this stage). But then playing music from a decent CD player is also going to have its advantages too of course.
Anyway, it sounds the best that I can remember now.
Remarkable little amp given its design simplicity and age.
Now I know where to look to improve/correct the system
Hi everyone. Wondering if I can get a little advice for my build. I have finished my amp boards and am looking at the chassis arrangement and power supply.
I am using an old amplifier chassis with perforations underneath and on top. I was thinking of using four separate heatsinks (one for each output transistor) arranged in a circle with a 200mm brushless 12v fan that I have to enhance cooling. I have tested the fan with lesser voltage and it runs right down to about 4V just slower. The fan is quiet when run off a regulated lab power supply.
I have a transformer which puts out 12.15V DC rectified with no load. I was thinking of just putting some decent capacitance across it and running the fan directly. I feel I don't need to be able to control speed of fan given fairly stable heat dissipation of Class A. What do you think? Should I just try something like a good 10000uf cap and if the fan makes no audible noise then go with it?
The mains will be split to power both this transformer and my main transformer powering the amp. A less than perfect psu for the fan won't affect the sound quality from the amp will it?
I am using an old amplifier chassis with perforations underneath and on top. I was thinking of using four separate heatsinks (one for each output transistor) arranged in a circle with a 200mm brushless 12v fan that I have to enhance cooling. I have tested the fan with lesser voltage and it runs right down to about 4V just slower. The fan is quiet when run off a regulated lab power supply.
I have a transformer which puts out 12.15V DC rectified with no load. I was thinking of just putting some decent capacitance across it and running the fan directly. I feel I don't need to be able to control speed of fan given fairly stable heat dissipation of Class A. What do you think? Should I just try something like a good 10000uf cap and if the fan makes no audible noise then go with it?
The mains will be split to power both this transformer and my main transformer powering the amp. A less than perfect psu for the fan won't affect the sound quality from the amp will it?