how to keep them firm while tightening ; you'll get everything else from picture , too:
When using these ribbon connectors, how do you (and Papa) assign the various pins? I assume parallel many pins together or alternate ground and signal?
2 pins for each route , except for rails , where I'm using 4 pins
no special care about arrangement/assignment of pins ...... it simply lay-outs by itself
no special care about arrangement/assignment of pins ...... it simply lay-outs by itself
Hardly that I invent anything there
when in doubt , take a look at Papamp
then do it better
(if ya can)
when in doubt , take a look at Papamp
then do it better
(if ya can)
Hi all,
What Idss do you recommand for match Quad of 2sj74 (Q1a and Q1b) for the Aleph J
thanks in advance!
What Idss do you recommand for match Quad of 2sj74 (Q1a and Q1b) for the Aleph J
thanks in advance!
8mA and upward
they'e biased with CCS to 5mA or so , so Idss is not so critical , as in some other Papamps
they'e biased with CCS to 5mA or so , so Idss is not so critical , as in some other Papamps
ok , great! as the toshiba are quite hard to get, so far looking for them i have not found any bellow 9mA or above! and that woudl be suitable for a F5 also i guess then !?
The Aleph J is up and running and sounds great! While troubleshooting I made all the internal wiring extra long and that needs cleaning up, which might explain the slight hum I’m getting. Turn on is quiet, and turns off with just a gentle bump. Thanks to many for the help especially 6l6. We all know 6l6 deserves his own call out! Also Papa!
Attachments
Those input wires are too close to the transformer. Run them close to the sides of the case away from the transformer and see if that helps with the hum.
Indeed they are wdecho! Part of what needs cleaning. Thanks for your observation, I can use all the help I can get.
Regarding the hum, I just noticed that there is just a whisper of hum except when I am standing by the turntable, seems my hand near the needle is the source of the slight hum I was referring to. Perhaps with some wire clean up this Aleph J will be silent. I’ll report on that later. The sound of this amp is quite pleasant, easy to listen to.
Regarding the hum, I just noticed that there is just a whisper of hum except when I am standing by the turntable, seems my hand near the needle is the source of the slight hum I was referring to. Perhaps with some wire clean up this Aleph J will be silent. I’ll report on that later. The sound of this amp is quite pleasant, easy to listen to.
Thats a beautiful amp! I love the blue indicators near the knob - a great touch.
Please keep us informed with what works and doesn't work with the hum mitigation.
Again, a fantastic job! 😀 😀 😀
Please keep us informed with what works and doesn't work with the hum mitigation.
Again, a fantastic job! 😀 😀 😀
Excellent build! You could further maximize the distance between the transformer and the inputs by moving the transformer ALL the way to the front of the chassis combined with a slightly longer shaft for the attenuator. Rectifier bridges can come to the center. Also you can experiment rotating the transformer while listening for hum to find the minimum field lobe. Perhaps one more twist at the input connector and bend the tab a little closer to further reduce the loop area (ode to the late AndrewT!). Good luck and enjoy!
BK
Pass DIY Addict
Joined 2000
Paid Member
Beautiful looking build! Might help to twist those primary wires on the transformer as well as the AC wires from the EIC input to the terminal block. This is likely to help reduce radiated noise and might help with hum.
The hum when hand is close to the phono cartridge is not related to the amplifier but more to do with turntable grounding. Not something I would do much detective work on solving myself if only occurs when hand is close. Short the inputs of the amplifier and see how much hum is present to check the amplifier for hum internally. Having input wires close to transformers or any AC source will cause hum, sometimes very significantly. Just a slight amount of moving input wires can make a lot of difference.
Thank you 6l6, couldn’t have done it without you!
Bk856 what you are suggesting sounds almost like a rebuild! Which of course I will enjoy doing! You are making some really good suggestions here. Funny I couldn’t see this while planning and building. I have to admit that once finished I was wishing there was more to do.
Eric, thanks for your suggestions. Wdecho, thank you again.
If there is anyone curious about the labeling it’s from Vinyl Lettering | Custom Vinyl Lettering - DoItYourselfLettering.com. One of the features I am pleased with is the volume knob. It is turned from 3.125 diameter aluminum with a little metal lathe I have. I had what I thought was a clever idea while making the knob to get a nice finish. After turning I chucked the knob up in my drill press the used an abrasive sponge to create the finish that you see.
Thank you all for your suggestions and comments.
Bk856 what you are suggesting sounds almost like a rebuild! Which of course I will enjoy doing! You are making some really good suggestions here. Funny I couldn’t see this while planning and building. I have to admit that once finished I was wishing there was more to do.
Eric, thanks for your suggestions. Wdecho, thank you again.
If there is anyone curious about the labeling it’s from Vinyl Lettering | Custom Vinyl Lettering - DoItYourselfLettering.com. One of the features I am pleased with is the volume knob. It is turned from 3.125 diameter aluminum with a little metal lathe I have. I had what I thought was a clever idea while making the knob to get a nice finish. After turning I chucked the knob up in my drill press the used an abrasive sponge to create the finish that you see.
Thank you all for your suggestions and comments.
Just finished my Aleph J build. Put it in the F5X chassis I never got to. Powered it up and it is fantastic immediately. Very quiet and dynamic, air around the performers. Listening with OB Lowthers and 15 inch eminence. A bought F6 is driving the bass. The Aleph is overshadowing it, significantly. Listening to Ricky Lee Jones "Pop Pop".
Thanks 6L6, Zen Mod, all the other builders and questioners/contributors, and of course Nelson Pass.
Thanks 6L6, Zen Mod, all the other builders and questioners/contributors, and of course Nelson Pass.
Pass DIY Addict
Joined 2000
Paid Member
I aspire to be a Sissie, too 😉 I have a few projects already in the hopper - J is 3rd or 4th on the list, behind the VFet2, M2, and something else will likely pop up by then...