It is time to klone another great amplifier. I think Accuphase has many fantastic amps but it is very few schematics available. And for me best is this one from Chinese site:
£ÛÒôÀÖ֮Ȫ£Ý·ÂÈÕ±¾½ðɤ×ÓP1000£¬£±£°£°£×£ª£²¶¥¼¶Ð¡¹¦·Å£¬Ïɵ¤-Ó°ÒôµçÆ÷ - ÌÔ±¦Íø
£ÛÒôÀÖ֮Ȫ£Ý·ÂÈÕ±¾½ðɤ×ÓP1000£¬£±£°£°£×£ª£²¶¥¼¶Ð¡¹¦·Å£¬Ïɵ¤-Ó°ÒôµçÆ÷ - ÌÔ±¦Íø
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i can confirm this is not real accuphase schematic. it is modified by some chinese from accuphase prototype in public manual.
Various classic Accuphase schematics are available at Jan's site
Welcome to Audio Circuit Denmark
The accuphases are pretty complicated and a clone would certainly need a prototype and tweaking for modern parts.
Have fun, Hannes
Welcome to Audio Circuit Denmark
The accuphases are pretty complicated and a clone would certainly need a prototype and tweaking for modern parts.
Have fun, Hannes
These old schematic are not interesting for me, I would like to build clone of P350, P370, P450, P550, P650 or P700. They are based on same topology and are "quite simple". But where to find real schematic? Maybe this chinese schematic is get from real amplifier?
Check out the URLs by post #11 and #16 about
http://www.diyaudio.com/forums/soli...sen-jikken-yearly-index-1924-2009-wanted.html
concerning feedback through an opamp
For the aim of diy I would not choice the Accuphase topology and no other mirror symmetry circuit topology, because particulary by this topology the demand for high coincidence between the positive and negative half is very high. Because I haven't conditions like a circlotron (CSPP), the residual differences are too large, because NPN and PNP devices only in the schematics itself have a nice symmetrc behaviour.
Much more better results without horrible selection of transistors of the voltage gain stages you will get with Lavardin's topology or with that one from Renardson (MJR-Amp)
http://peufeu.free.fr/audio/memory/memory-8-complete.html
http://www.angelfire.com/ab3/mjramp/amp8.html
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"The front end is typical of their symmetry in design and the they do send the feedback through an opamp, which when I tried that it does correct some non-linearties but at the cost of noise."
No, the op amp is to servo out any DC offset. R14//R15 set the main amp gain.
This is a current feedback topology amplifer ('CFA') -Accuphase like CFA because of they generally have less phase distortion and wider bandwidths than VFA amps. They use CFA in their line preamp stages as well.
The first circuit has a few idiosyncracies - I'd avoid it - clearly whoever is trting to copy the Accuphase has pretensions of being an audio amp designer but seem to have wandered off the track a bit. The second one looks more like an Accuphase. I like their products and they are very well engineered - great sounding and looking stuff.
No, the op amp is to servo out any DC offset. R14//R15 set the main amp gain.
This is a current feedback topology amplifer ('CFA') -Accuphase like CFA because of they generally have less phase distortion and wider bandwidths than VFA amps. They use CFA in their line preamp stages as well.
The first circuit has a few idiosyncracies - I'd avoid it - clearly whoever is trting to copy the Accuphase has pretensions of being an audio amp designer but seem to have wandered off the track a bit. The second one looks more like an Accuphase. I like their products and they are very well engineered - great sounding and looking stuff.
regarding schematic of e-210 in post 5 - I think that C22 shouldn't be there (instead should be a straight wire)
Hello
greetings does anyone have ACCUPHASE P-370schematic to share with me
warm regards
andrew lebon
greetings does anyone have ACCUPHASE P-370schematic to share with me
warm regards
andrew lebon
Probably you mean this amp:
Accuphase/kensonic P-370
As I know, Accuphase releases all service manuals from obsolete models.
A clone isn't easy (despite easy and good to understand circuit topologies) because the used topology requires a high standard in the selection of the components like transistor matching regarded to similar values of hfe and Vbe.
Otherwise you will not obtain the wanted THD results, even if the amplifier works.
Actually this is not entirely true, the matching of the transistors help for dc offsets but very little concerning distortion and youll find that just a little mismatch actually helps keep distortion down when it comes to the vas (complementary vas fighting effects). As all accuphase amps have DC servo the dc offsets are of no concern.
Never heard of vas fighting. Maybe try a search here, many have posted their experiences here on the subject.
Mean you the topogies by post #1/#44 about
http://www.diyaudio.com/forums/solid-state/209658-has-anyone-seen-front-end-before.html
and
http://home.tiscali.nl/data.odyssey/Super_TIS.html
Such topologies I hate, because all commercial products, where such topogies are in use, don't sound good in all respects (nevertheless nearly perfect measuring results).
the only full complementary front-end, that sounds good for me, is that one from the AVM Monoblock of the "Evolution" series.
The main reason therefore is the fact, that here only one voltage gain stage is in the NFB loop (mostly you will find two, the input LTP and VAS stage).
Functional schematic you will find by follow URL:
http://www.diyaudio.com/forums/solid-state/88515-cfp-vas-8.html
go to post #73
More about the AVM topology:
http://www.diyaudio.com/forums/solid-state/27644-stereoplay-1988-monoblock-guenter-mania.html
http://www.diyaudio.com/forums/soli...ody-burmester-avm-schematics.html#post2598494
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Youre confusing me now, any push pull vas suffers to some extent from this, the avm is also a complementary push pull vas.
You have to keep in mind that the topologies that you say dont sound good are accurate, the problem being probably in your input or speakers ie cd player or other. I dont understand these views where the amp is solely responsible for the sound of a system, its ridiculous. How about next time purchasing a amp and changing the cd player till you find one that sounds good with the amp ?? Most cd players sound thin and lifeless and when you couple this to a blameless type amp yes it doesnt sound good at all, but a good cd player does the opposite. Using a expensive phono I have found that blameless amps can sound very good indeed.
I like the topology on the avm,, wish I had more info or the whole article, maybe jacco has all the pages.
You have to keep in mind that the topologies that you say dont sound good are accurate, the problem being probably in your input or speakers ie cd player or other. I dont understand these views where the amp is solely responsible for the sound of a system, its ridiculous. How about next time purchasing a amp and changing the cd player till you find one that sounds good with the amp ?? Most cd players sound thin and lifeless and when you couple this to a blameless type amp yes it doesnt sound good at all, but a good cd player does the opposite. Using a expensive phono I have found that blameless amps can sound very good indeed.
I like the topology on the avm,, wish I had more info or the whole article, maybe jacco has all the pages.
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Here are a couple of pages => Klang einer MOS Endstufe straffen?, Elektronik - HIFI-FORUM
Total is 25-30 pages, most not exactly interesting (bit of an Amp101 course for mag readers flavour), i'll see if i can scan the lot.
Total is 25-30 pages, most not exactly interesting (bit of an Amp101 course for mag readers flavour), i'll see if i can scan the lot.
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