Circuit of Musical Fidelity A1, Any one has experiences?

siliconray · 20th October 2011, 05:42 AM

Just saw a circuit of Musical Fidelity A1 power amplifier. No part number of the transistors. Any one has experience wit this amp? I'd like to know the part no. of transistors, thanks

Tekko · 20th October 2011, 05:57 AM

Pretty standard circuit, the transistors are likely something like BC547 and BC557 and the power transistors are prolly some obsolete 2SCxxxx like the 3284 and 1302 or similar.

At only 2x18V rails, pretty much any transistors would work.

siliconray · 20th October 2011, 06:34 AM

Thanks Tekko, will build one soon

gfle · 20th October 2011, 06:49 AM

http://www.tcaas.btinternet.co.uk/mf-a1.gif

raymondo · 20th October 2011, 07:03 AM

I'm sure the power devices were 2n3055 .
There's a guy who used to work for
Mf on here who could tell u for sure.

Tekko · 20th October 2011, 07:12 AM

Which are no good for audio so replace with MJL3281 and MJL1302

siliconray · 20th October 2011, 07:25 AM

It seems that 2N3055 are not recommended for used in audio now. It's too old and too slow. In another thread about JLH amplifier many suggest MJL15003 as subsititute

jez · 20th October 2011, 12:48 PM

Quote:

Originally Posted by raymondo

I'm sure the power devices were 2n3055 .
There's a guy who used to work for
Mf on here who could tell u for sure.

I am that guy

They used 2n3055 and mj2955 complementary pairs which were labelled A1N and A1P.

Bigun · 20th October 2011, 01:17 PM

Whilst 2N3055 are no longer considered state of art and there are better devices available I believe many people have used them and been very happy with the results. If I were building a classic amp like this, I'd want to start off with devices as close to the originals as possible - otherwise I'm going to be hearing a different amp.

jez · 20th October 2011, 02:03 PM

The mj15003/15004 were used in the more powerful A100 (which is the same circuit) and will work well in the A1 also.

20th October 2011, 05:57 AM	#2
Tekko diyAudio Member Join Date: Jan 2005	Pretty standard circuit, the transistors are likely something like BC547 and BC557 and the power transistors are prolly some obsolete 2SCxxxx like the 3284 and 1302 or similar. At only 2x18V rails, pretty much any transistors would work. __________________ The point of life is to build atleast one audio amplifier before you die.

20th October 2011, 06:34 AM	#3
siliconray diyAudio Member Join Date: Sep 2011	Thanks Tekko, will build one soon __________________ www.siliconray.com High Quality Audio Enclosures, Amp Kits, Amplifiers, PCB Fab Services Chat with me

20th October 2011, 07:12 AM	#6
Tekko diyAudio Member Join Date: Jan 2005	Which are no good for audio so replace with MJL3281 and MJL1302 __________________ The point of life is to build atleast one audio amplifier before you die.

20th October 2011, 07:25 AM	#7
siliconray diyAudio Member Join Date: Sep 2011	It seems that 2N3055 are not recommended for used in audio now. It's too old and too slow. In another thread about JLH amplifier many suggest MJL15003 as subsititute __________________ www.siliconray.com High Quality Audio Enclosures, Amp Kits, Amplifiers, PCB Fab Services Chat with me

20th October 2011, 01:17 PM	#9
Bigun diyAudio Member Join Date: Jan 2009 Location: K-W Ontario Blog Entries: 2	Whilst 2N3055 are no longer considered state of art and there are better devices available I believe many people have used them and been very happy with the results. If I were building a classic amp like this, I'd want to start off with devices as close to the originals as possible - otherwise I'm going to be hearing a different amp. __________________ "The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed." Robert M Pirsig.


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20th October 2011, 06:49 AM	#4
gfle diyAudio Member Join Date: Mar 2001 Location: Athens, GREECE	http://www.tcaas.btinternet.co.uk/mf-a1.gif

20th October 2011, 07:03 AM	#5
raymondo diyAudio Member Join Date: Feb 2004 Location: manchester	I'm sure the power devices were 2n3055 . There's a guy who used to work for Mf on here who could tell u for sure.

20th October 2011, 02:03 PM	#10
jez diyAudio Member Join Date: Jan 2004 Location: n.e england	The mj15003/15004 were used in the more powerful A100 (which is the same circuit) and will work well in the A1 also. __________________ Repairs and mods to Real Hi-Fi, guitar amps and P.A. in North East England. http://www.arklesselectronics.com

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