Almarro A205A A205 MK-II Single Ended Integrated Amplifier - what Upgrade Steps are the best ?

[tiefbassuebertr]

On the web are to find a lot of different upgrade versions.
But I miss a replace of the electrolytic caps after the rectifier (for anode voltage).
Who can recommend most important upgrade steps to get most enhancement in sound quality ?
What is the aim of the air coil inductor in image 7-9 ?

Thank you very much

some URLs:
https://www.almarro.com/products.html
https://web.archive.org/web/20030320085610/http://www.almarro.com/
https://hifihaven.org/index.php?threads/almarro-a205a.808/
http://www.audiosuite.net/PRODUKTE/almarro/A205AMKII.pdf
https://jeffsplace.positive-feedbac...ntegrated-amplifier-duelund-coupling-cap-mod/
https://6moons.com/audioreviews/almarro4/mk2.html (incl. schematic)
https://6moons.com/audioreviews/almarro4/mk2_2.html
https://www.audioasylumtrader.com/c...rro/A205A-MKII/with-factory-cap-upgrade/24563
https://www.audiocircle.com/index.php?topic=181077.0
https://www.diyaudio.com/community/threads/almarro-a205a-as-experimentation-platform.227038/

 

[alanhuth]

I have the same question. Bump.

 

[6A3sUMMER]

A schematic is worth 1,000 words, and worth 100 Posts.

No schematic = A blindfolded Archer trying to hit the Bulls Eye.
Help Us Help You.

 

[Zitronenfalter]

There is a structual schematic in the review on 6moons
-> https://6moons.com/audioreviews/almarro4/mk2.html

Unfortunaly without information on the components values.

Regards Eberhard

 

[vinylkid58]

No schematic = A blindfolded Archer trying to hit the Bulls Eye.

That's pretty much it. These amps have been around for some time now. You'd think if there was anything special about this design, someone would have stepped up and drawn a schematic.

jeff

 

[6A3sUMMER]

teifbassuebertr,

Those partial schematics of 6Moons in Post # 4 does not show any Air Core inductors on that amplifier.

Did you purchase one of those used amplifiers that has been modified?
Did you get those pictures off of the web?
Do you have the amplifier? Then kindly and carefully make a complete and accurate schematic of the amplifier that you have (that will answer the question of what the air core coils are.

I don't think anyone reading this thread is going to reverse engineer that amplifier for you, if we only have pictures.

Please let us know the whole truth before we waste our time.

 

[huggygood]

maybe this one on the first post

 

[6A3sUMMER]

The are Air Core coils or transformers that are pictured in Post # 1, are not shown in the schematics of Post # 7 . . .
Unless this is:
Either a super-tweeter amplifier;
Or has special filtering of the power supply to meet VDE EMI regulations;
Or they are an inductor in series from the output transformer secondary to the output connector, just like the solid state Dyna stereo amplifiers used (to make the amplifier stable with loudspeaker cable's capacitance and loudspeakers capacitive reactance) Quad electrostatics, anybody?

Oh, perhaps the Air Core coils are part of a speaker-crossover that is built inside the amplifier (customer modification).

Just my opinions as an RF Engineer, and as a Power Supply Engineer.

Challenge: can you think of another use for such air core coils inside that amplifier?

 

[Zitronenfalter]

Or they are an inductor in series from the output transformer secondary to the output connector...

Exactely what i deducted from the picture🙂

 

[tiefbassuebertr]

teifbassuebertr,

Those partial schematics of 6Moons in Post # 4 does not show any Air Core inductors on that amplifier.

Did you purchase one of those used amplifiers that has been modified?
Did you get those pictures off of the web?
Do you have the amplifier? Then kindly and carefully make a complete and accurate schematic of the amplifier that you have (that will answer the question of what the air core coils are.

I don't think anyone reading this thread is going to reverse engineer that amplifier for you, if we only have pictures.

Please let us know the whole truth before we waste our time.

A friend of me have purchase this amp in not perfect condition and before he start troubleshooting he wants exact and detailed information in advance like circuit description amount of versions etc. This is the reason, why I have start this thread.
Most easy way to find out this would be a call to the still exist company - by a member from Japan, of course:

Almarro Products
3488-24 Kitagata Iida-shi,Nagano 395-0151 Japan
Phone: +81 265 25 8188

Maybe there are even an owner of the same model here on diyaudio, who know any details.

P.S.: The previous history is not known, since the last owner no longer has any contact with the first owner and has also made no effort to get this information.

 

[6A3sUMMER]

The very best thing to do, is to go to all the trouble to make a full and accurate schematic of the Exact amplifier your friend has.
Nothing less than that can help us to make the amplifier the best it can be (or discover that it already is the best it can be).

If any previous owner has done any non factory modification to the amplifier, then Almarro Products will not know that.
I am just saying.