choky said:whatza initial DC offset for Aleph amp (from cold) ?
do we and when we will have chance to see J service manual?
The cold DC figures for an Aleph are usually less than 500 mV.
I don't know about the J service manual - I haven't written in,
and I'm still shipping the product.
Compensation caps.
Well,
Its Friday, so I could not resist checking the Aleph jfet compensation caps tonight with my computer square wave generator. It was only able to use a 1Khz square wave not 10Khz.
After trying 5 through 10 pF, it looks like 10 pF was the best with out any ringing as Mark had shown previously. I tried 9 pF but there was a tad bit of ringing at 1Khz, so I guess the verdict is in for the jfet amp. 10 pF seems to be the best for no ringing on the square wave tests.
I did not have any oscillations while checking it and did not need the mpsa18 base to collector either with the .001 uF (1 nF) cap to stabilize the Aleph jfet, so I left it out.
I noticed touching the board caused extrenious noises, so perhaps that was the problem over at Mark's home.
I still need to check the AC current gain, but I think the jfet conversion is finished. I would like to try it one more time over at Mark's to see what he thinks along with Lyndon and then I could go ahead and write a pdf on what the end results were to build this conversion. 🙂
Mark may be out of town though, because I have not heard from him all week. He may be stuck in Wyoming again on a theatre install repair.
Bill
Well,
Its Friday, so I could not resist checking the Aleph jfet compensation caps tonight with my computer square wave generator. It was only able to use a 1Khz square wave not 10Khz.
After trying 5 through 10 pF, it looks like 10 pF was the best with out any ringing as Mark had shown previously. I tried 9 pF but there was a tad bit of ringing at 1Khz, so I guess the verdict is in for the jfet amp. 10 pF seems to be the best for no ringing on the square wave tests.
I did not have any oscillations while checking it and did not need the mpsa18 base to collector either with the .001 uF (1 nF) cap to stabilize the Aleph jfet, so I left it out.
I noticed touching the board caused extrenious noises, so perhaps that was the problem over at Mark's home.
I still need to check the AC current gain, but I think the jfet conversion is finished. I would like to try it one more time over at Mark's to see what he thinks along with Lyndon and then I could go ahead and write a pdf on what the end results were to build this conversion. 🙂
Mark may be out of town though, because I have not heard from him all week. He may be stuck in Wyoming again on a theatre install repair.
Bill
Nelson Pass said:
with delay circ for ldsp out in range of 1 minute,that's nice even for Lowthers
regarding manual-just take your time;
children are already spoiled too much
Re: Re: Compensation caps.
Maybe, I will have you do my complete schematic layout of what I did. I then could incorporate that into my pdf and send it to you to post eventually.
I would still like Mark to check my bandwidth for higher frequency oscillations when he gets back, since my computer signal generator is bandwidth limited on doing a nice square wave.
Thanks again.
Bill
PS now it is time to just listen and burn the Aleph 3 jfet in for a while.
choky said:
If you need any help that I can give, just buzz
Maybe, I will have you do my complete schematic layout of what I did. I then could incorporate that into my pdf and send it to you to post eventually.
I would still like Mark to check my bandwidth for higher frequency oscillations when he gets back, since my computer signal generator is bandwidth limited on doing a nice square wave.
Thanks again.
Bill
PS now it is time to just listen and burn the Aleph 3 jfet in for a while.
Member
Joined 2002
Any one care to see the New SMD Alephs ?
Here is a link to a hand full of picture's..
Yes it took lot's of time and patiance to do these 🙂
http://gallery.jasesspace.com/main.php?g2_itemId=487
Here is a link to a hand full of picture's..
Yes it took lot's of time and patiance to do these 🙂
http://gallery.jasesspace.com/main.php?g2_itemId=487
Re: Re: Re: Compensation caps.
yes!!!
attaching file is easy:
keep it under 100KB, allowed formats are :gif jpg png txt zip jpeg pdf
for pics is smart to keep it under 1000xsmaller pixels
when you write reply (or post) on bottom of the page is line "attach file" and "browse" button.........
simple,isn't it?
anyway,I'm here 😉
BillWW said:
yes!!!
attaching file is easy:
keep it under 100KB, allowed formats are :gif jpg png txt zip jpeg pdf
for pics is smart to keep it under 1000xsmaller pixels
when you write reply (or post) on bottom of the page is line "attach file" and "browse" button.........
simple,isn't it?
anyway,I'm here 😉
I've tried attaching photos before, but nothing shows up on the board. Do I have to have a photo account?
Bill
Bill
Member
Joined 2002
It will be a while before I write the pdf.
I would still like Mark and Lyndon hear the amp one more time with the 10 pF compensation cap to see if they like it.
Bill
I would still like Mark and Lyndon hear the amp one more time with the 10 pF compensation cap to see if they like it.
Bill
Member
Joined 2002
Member
Joined 2002
choky said:
Sure..
Here is 5 pages of pictures 🙂
http://gallery.jasesspace.com/main.php?g2_itemId=371
Sorry.. Here is more pictures of it in action.. http://gallery.jasesspace.com/main.php?g2_itemId=169
I dont have them in cases yet. But i do have 8 of these 4 challes SMD 4 channels Through Hole.
jleaman said:
hehe,I saw that allready😉
you didn't see quote to Bill's post 😉
anyway-I like those snakey cables
Member
Joined 2002
Want a set >?choky said:
I make them 🙂
konst said:
To me the SMD stuff sounds WAY WAY WAY better. That is why i pushed so hard to get smd aleph's done. They just sound so cleaner faster and much much more detail.
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