Here is the best version I have assembled.
The pcb are compact and well done, it is a pnp version with "modern" output
device.
Honestly I do not understand why it works better than the other but it is really a notch with a good psu.
https://www.aliexpress.com/item-img...22716.html?spm=2114.10010108.1000017.2.ShmrgT
The pcb are compact and well done, it is a pnp version with "modern" output
device.
Honestly I do not understand why it works better than the other but it is really a notch with a good psu.
https://www.aliexpress.com/item-img...22716.html?spm=2114.10010108.1000017.2.ShmrgT
Yes, I have that tiny PCB in a kit that came with Sanken 2SA1216 outputs. At the price, I only assume they are genuine. It is certainly a very small and useful board because it can mount on the heatsink. This could result in a very low profile, suitable for squeezing in either side of the power supply in a small Ebay type enclosure with the heatsinks either side.
An interesting feature is that the board is double sided and grounding is via an obvious central star point. this is new for the original JLH'69 design and is worth some consideration.
https://www.aliexpress.com/item/GZL...32798795176.html?spm=2114.13010608.0.0.PKuHMT
An interesting feature is that the board is double sided and grounding is via an obvious central star point. this is new for the original JLH'69 design and is worth some consideration.
https://www.aliexpress.com/item/GZL...32798795176.html?spm=2114.13010608.0.0.PKuHMT
Do you have the schematic? The PCB is interesting and I will investigate it soon. But I saw 2k7 carbon composite resistors. Putting Allen-Bradley in feedback path will give a very different sound. Impressive I think. But in the long run its too much for my ears and I prefer not to use such resistor in feedback.
Hi
I would replace the blocking capacitor with these type of Philips capacitor.
2pcs Philips 3300UF 3300MFD 16V 105°C ELEC ALUMINUM AXIAL CAPACITOR 16x30mm AX | eBay
I know many people does not believe one capacitor can be better than the other- believe me I tried in my SEWA build a lot of different caps and these type gave me most natural and well controlled (the best) sound.
One of the main reason I want the build the high power version that does not use blocking caps before the speaker.
That capacitor quality has a huge effect on the amplifier over all performance. If you have you at your hand some other type of caps please test them.
Just an advise... Not because Elna is bad may be other type will feet your taste better.
Have ordered this module
https://www.aliexpress.com/item/32810285409/32810285409.html?shortkey=V3QJzyUb&addresstype=600
With mje15024, do i need to use speaker protection and softstart with this amp?
Am going to use 24-0 and 24-0 transfer with 4A
Please let me know if anything need to consider/change
https://www.aliexpress.com/item/32810285409/32810285409.html?shortkey=V3QJzyUb&addresstype=600
With mje15024, do i need to use speaker protection and softstart with this amp?
Am going to use 24-0 and 24-0 transfer with 4A
Please let me know if anything need to consider/change
Great sound! Nice amp it match that speaker well. My taste
By any chance do you have some picture from inside the amp....
div diy - Side 15
HI
I'm seriously interested on these version (JLH2003) If someone knows a PC boards layout that would be a great help.
I know on Ebay readily available and cheap but that does not feet my heatsink.
Thanks for any help.
Greets.
I have made version with 2 pairs of transistors per channel out of fun. It is so good and powerfull that I have decided to give it nice Yamaha case
http://www.diyaudio.com/forums/soli...ur-solid-state-pics-here-519.html#post5084031
I often see these Philips axial lead caps supplied in JLH 69 kits but there is a small problem fitting them to the pads meant for a radial type, on the PCBs in the kit referred to. You could stand them up and run the top lead to the output connector or drill another hole in the output trace for the same purpose but in any case where the cap is wired off-board, a connection to the 10k charging resistor still should be made there, at the speaker side of the cap.(see the 1970 update article which shows a 2k resistor instead)
100% agree with you .
i have a big collection of capacitor polarized and no polarized .
I have not yet investigated why this resistance carbon but it will come because I have not yet traced the schematic of this pcb
Hi Gabor,HI
I'm seriously interested on these version (JLH2003) If someone knows a PC boards layout that would be a great help.
I know on Ebay readily available and cheap but that does not feet my heatsink.
Thanks for any help.
Greets.
It the ckt confirmed to work as it is? I havent readup on this amp yet. I am willing to make a layout.
reg
Prasi
Hi Prasi
First of all thank you for the offer
You can read it hear
Jlh-2003-amplifier | adolfo martinez - Academia.edu
It advised to use metal can power transistors, I don't know ON semi and Sanken has some high power not metal can transistor if those can deal with the heat..
I hope some other people interested to build these amp not just me. We could do a small GB in that case, Otherwise only home brew PC boards.
It would be the best if you could make it about 32Cm long
Thanks
Yes, the maximum output will be lower, what is the load impedance likely to be?
If you use the secondaries in parallel, or separate secondaries for each amp, after the regulator you only have approx 16V power rail which will give you 4watts into 8 ohms. If you connect the secondaries in series it will give you 32V and 16 watts into 8 ohms, I think this is too high a voltage for an 8 ohm load though, the maximum is 27V I believe.
Standard range toroidal transformer voltages are really too wide to meet the optimum supply requirement. Now there are only 12V, 15V, 18V windings followed by a large step to 25V, 30V etc. If you can still find a 2 x 22V transformer, this can be rectified with a diode bridge to 30VDC, which makes a good power supply for 6-8 ohm speakers and allows a tad more output than the usual 10W max. power output before clipping.
Edit: For class A operation with less mechanical hum noise due to the constant high load, it is better to use a quality transformer with at least 2 x the required bias current rating. That is, if the bias requirement is 1.25A DC per channel, the transformer winding should have a rating of around 3A or more, meaning at least 120VA, preferably 160VA total transformer rating in this case.
Edit: For class A operation with less mechanical hum noise due to the constant high load, it is better to use a quality transformer with at least 2 x the required bias current rating. That is, if the bias requirement is 1.25A DC per channel, the transformer winding should have a rating of around 3A or more, meaning at least 120VA, preferably 160VA total transformer rating in this case.
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