Autocostuire Fenice 20a & hiss problems - Page 2 - diyAudio
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Old 8th September 2005, 08:23 PM   #11
Pano is offline Pano  United States
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Quote:
Originally posted by plovati
Who is the real manufactor of these boards and where I can get documentation about it?
I will ask the manufacturer if they wish to be identified.
Autocostruire is the dealer. I do have the schematic, I'll ask if I can publish it. Shouldn' t be a problem.

Quote:
Finnegann
There clearly is/was something wrong with this board to start with. Maybe the missing parts were the cause, maybe not.
Maybe not, none of my Fenice boards had any problem other than the hiss. This was simply due to the missing cap C31* that decouples the +5V. Once that cap is installed, the hiss goes away and the board is as silent as the Sonic Impact, perhaps more so.

*C32 is also missing, it decouples the Sleep function.
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Old 10th September 2005, 06:27 PM   #12
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Thanks for the comments.

I've soldered some 0.1uF's onto the board and all is ok, it is currently burning in.

Stoat
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Old 19th September 2005, 07:07 AM   #13
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Replacemenet board provided by Autocostruire, my confidence in the italians is up to 100% again.

Quote:
panomaniac: "I'll post more in another thread, if anyone is interested."
I am indeed interested in.
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Old 27th September 2005, 08:56 AM   #14
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Default Same problem with Class-t-amp-2020-m ?

Hello !

I seem to have a similar problem with my Class-t-amp-2020-m kit from Autocostruire (a very loud hiss from the speakers). Since I am not exactly experienced in these things could anybody please tell me what is happening and what I can do about it in not-too-technical terms ?

Thanks !

/Mirland
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Old 14th December 2005, 03:03 AM   #15
BStrum is offline BStrum  United States
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Default Initial Fenice20 Impressions

I received a Fenice20 yesterday and hooked it up using a lab grade regulated DC power supply driving my cheap bench speakers.

No mods yet and very bad connections it sounds better then my gainclones. Not as much volume of course.

I am going to use them as the biamp to drive my Raven3s. 800hz crossover using a Marchand I built.

They are rated at 100db so they should crank. I tried it with a frind'd tricked out Red Wine and and the sounded incredible.

Id like to hear what type of input mods people have done with this board.

Bill Strum
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Old 14th December 2005, 04:46 AM   #16
Pano is offline Pano  United States
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Replace the 2 onboard electrolytics, they're junk.
I'll try to post pics of the input mod later. Very easy to do. A DC offset circuit is also easy to add.

A nice board and plenty of room for mods.!
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Old 19th December 2005, 01:10 AM   #17
BStrum is offline BStrum  United States
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Default Fenice 20 Mods.

Click the image to open in full size.
I've moved to stage two. I have mounted the Fenice on a perf board with two 3/4" brackets I drilled out for RCA jacks and bining posts.

Power is comming from a lab quality commercial power supply.

Batterys come later.

Panomaniac Says Replace the 2 onboard electrolytics, they're junk.

I agree. I measured the diameters of the current electrolytes they are .3 " ~ 8.5mm This is a lot samller then the Black Gates or Elna Cerafines.

Is the answer ugly fit or do you have a recomendation for another replacement?

For input mods it appears C5 - C8 get replaced with 2uf each of a film or other audio friendly cap.

Any recomendations here?

By the way the Fenice sounds good as it sits.
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Old 19th December 2005, 10:39 AM   #18
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For the electrolyitcs I like Panasonic FM series 680uF 16V. You can get them at Digikey. Get the thin ones (8mm diam), I don't think they stock the fat ones any more.

You can remove the SMD inputs caps from the pads and solder something like a Blackgate in place. Each input has 2 SMD caps in paralelle. You can bridge either pad, or both.

If you want to use a big film cap, then remove and bridge the SMD caps, remove the jumper tabs where it says "close no pot", and connect your input cap to the center hole of the pot pads. Input ground can stay where you have it.

Be sure to check for DC at the outputs before you connect speakers!
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Old 23rd December 2005, 08:52 PM   #19
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Default Proposed mods to the Fenice

Original Feince20 Input circuit
Click the image to open in full size.
Proposed modifications
Click the image to open in full size.

I am not 100% sure of my approach and invite suggestions:

a. Remove C6 and C7 and Jumper, this gets rid of the 1uf SMD caps

b.Remove the pot jumper and use the pot thru wholes for mounting a 2uf "audio" (non polarized) cap Suggetions??



Not shown are bypass caps on the output side (C10 and C11) they would be replaced with Pansonic FS caps. the Blackgates won't fit.

And now my big question. C25 is a 10uf cap the forms a high pass filter (DC blocking) this is obviously in the signal path. should I ( think I should) pull it and the 100K resistor and use a good film cap and a quality resistor. They would be point to point wired and with the cap lead being the be input and the resistor soldered to the ground input pad.

All suggestions are appreciated.
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Old 28th December 2005, 06:29 AM   #20
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Hey Panomanic,

I was wondering where I get the Feince 20 boards from the manufacturer. Is there a number or website I can go to? Is there a certain quanity that I need to order? Thanks for your time, Kevin. The obbligato oil caps are awesome by the way. Much better than auricaps.
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