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-   -   Is Aleph 5 modified like these? (http://www.diyaudio.com/forums/pass-labs/39031-aleph-5-modified-like-these.html)

Peleus 6th August 2004 06:01 AM

Is Aleph 5 modified like these?
 
One guy, named Wensan, suggested some modification of Aleph 5 and presented this suggestion in a Taiwan's diy forum. I need your guy any reply for the safety of these modified aleph 5, so pelease give me somg suggestion.

Wensan suggested 2 schematics of changing the capacity-coupling to directed-coupling of the active current source. He claimed these chang enhancing the quality of low frequency. Here is the shematices.

first version:
http://home.pchome.com.tw/shop/cherry1chiu/Aleph5dd.jpg

this is the spice testing result:
http://home.pchome.com.tw/shop/cherr...h5ddPSpice.jpg

And, this is another version:
http://home.pchome.com.tw/shop/cherry1chiu/Aleph5dj.jpg

the spice testing results
http://home.pchome.com.tw/shop/cherr...h5djPSpice.jpg

I have to re-address that I am not the original author, Wensan is, and I love you guy to help me if these schematics can operate safe? I am going to build my own Aleph 5 for altec 515 8G. That's right, the Aleph 5 will only push 515 for the frequency under 200 Hz.

Nelson Pass 6th August 2004 07:58 PM

Safe enough, but if you are on a real campaign to get rid of
capacitors, eliminate C4 and trim the offset by hand. C4 is not
corrected by feedback, whereas the cap that has been eliminated
is within the loop.

wensan 7th August 2004 04:31 AM

The Aleph5's low cut-off frequency is much lower than it's Active Current Source.
So, If you hope the Acitve Current Source have a better performance in low frequency area, you have to reduce the low cut-off frequency of the Acitve Current Source.

To set bias current precisely, you have to trim R4 of the first version or R31 of the second version.

Peleus 7th August 2004 06:38 AM

Hi~ Mr. Pass,

Thanks for your reply. Wensan is here! You both may talk a lot about his idea.

Hi~ Wensan,

Please forgive me that I didn't let you know I will post your ideas here. I read the threads in the PRBS Forum and the Forum (I forget its name) in China, but I really couldn't find any discussion about your this design.
And more worse, I can't find your e-mail address. So, I choose here to search helpness for your design. I wish you not mind.

Hi everybody~

I am very honor to introduce Wensan to you. He is very senior and experiened audio DIYer in Taiwan and China. He published many great ideas and designs in the Forums of Taiwan and China and inspire many DIYers of these area. Hopefully, his creation and talent also inspire DIYers here.

I am very glad to have his reply.

X.G. 7th August 2004 07:33 AM

Quote:

Originally posted by Peleus


I read the threads in the PRBS Forum and the Forum (I forget its name) in China

Hi,

I had discussed the Aleph 5 circuit with Mr.Wensan for 9 days in the China forum(you refer?),and know much about it by his help.

http://www.cndiyclub.com/bbs/dispbbs...rdID=7&ID=3440

I think the wensan's idea which advance bootstrap circuit is completely correct in theory,the actual effect whether be true should be tested/listened .

cheers

X.G.

Peleus 7th August 2004 08:16 AM

Hi, X.G.,

Just that forum! That is!

You may misunderstand my words. What I said is: there is no discussion about Wensan's ideas of getting rid of the coupling capacity of active current source, not the issue of bootstrap circuit.

I know you involved this discussion very deep, but, sorry, that is not what I need.

So, If I miss any discussion, please let me know where to find them. I have to said the forum is not convenient to me.

X.G. 7th August 2004 08:35 AM

Quote:

Originally posted by Peleus

You may misunderstand my words. What I said is: there is no discussion about Wensan's ideas of getting rid of the coupling capacity of active current source, not the issue of bootstrap circuit.

active current source substantially is current bootstrap circuit :smash: ,Mr. Pass had said.

what i say in last post is the same as yours.... ;)

Peleus 7th August 2004 08:56 AM

O.K., My purpose of this thread is not to argue "where is the discussion?" or "What is bootstrap circuit?" but concern "Can the wensan's idea be made?" Mr. Pass reply "Yes!" So, I am going to build a modified version of Aleph 5 for my new loudspeaker system, Altec 515 8G + a local made 8" full-range made by Colin's Lab with active crossover. The new version of Aleph 5 will only push the Altec 515.

If I have any result in few monthes, I will post it here.

So, be patient and wait for good news.

Cheers

Peleus


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