Musical Fidelity F16 problem/Schematic

Smiffy · 6th December 2003, 01:58 PM

HI All
Little problem with a Musical Fidelity F16 power amp.Keeps coming through distorted on one side and occasionally completely cuts out.Takes a while to happen suggesting temp related but if you raise the input level it cures it possibly suggesting a dodgy capacitor somewhere.Have checked for dry joints.Also does anyone have a schematic for the above.Musical Fidelity will not sell me one.Thanks for any help.Smiffy

Netlist · 6th December 2003, 03:18 PM

I would start replacing caps.

/Hugo

Smiffy · 7th December 2003, 08:12 PM

Thanks for the advice Hugo
Still hoping for a schematic but it shouldn't be to hard to work out signal/power caps.There are only about 7 caps on the power amp boards.May replace them with Black gates at the same time really.There is a 220uf non polarised right on the input.Shame MF are so tight with their circuit diagrams.\Lovely amp though.
Smiffy

Lenin · 19th May 2004, 09:56 AM

Hi Smiffy,

The F16/F19 circuit is apparently a tidied up version of the MF P270/A370 circuit.

The original amps ran VERY hot and were unreliable (I can attest to that! There is nothing quite like the smell of smoke coming from your amplifier to convince you that things might not be quite right!).

The Mk II versions cured the overheating (and some of the reliabilty) problems, while the F16/F19 were the best implementation of the circuit MF could possibly achieve, finally taking advantage of the oppotunity to incorporate acres of heatsinking and space for a huge supply. (400w AB/50w A in an elegant, good-looking chassis is no mean feat! Its also one of the few commercial amps I would buy in a flash).

I've a copy of the A370 circuit (the P270 is the same, with just 3, rather than 5 pairs of output devices).

I'll dig it out and post it here.

Lenin · 5th June 2004, 12:28 AM

Too big to post, I'm afraid.

E-mail me and I'll send it.

mirlo · 5th June 2004, 03:56 AM

Lenin,

Your email through diyaudio is disabled at the moment ...

Please email me a copy of the schematic. My father has a P270 and I'd be curious to see how things have changed in that amp after some refinement.

Thanks!

-- mirlo

mickey_s · 10th June 2004, 07:17 AM

Good afternoon!

Is there somebody who has a service manual or even schematic diagram of NAD 314 Integrated Amp?

I have scratching sound coming out of either the left or right speaker about 2 years ago. Later, it worsened with distorted sound from either left or right channel when music passages are low yet when the volume control was cranked up the music would be normal.

I suppose I have same symptom similar to Smiffy (Musical Fidelity F16 problem/Schematic ).

I started replacing capacitors when the bass sounded thin. The sound improved for a few days before the bass sounded anemic again.

thanks for any helping hand you can extend.

[I]

Lenin · 15th August 2004, 10:04 PM

Here you go...

http://www.audiodesignguide.com/doc/...elity_a370.jpg

ckwong99 · 10th December 2006, 04:39 PM

Quote : The F16/F19 circuit is apparently a tidied up version of the MF P270/A370 circuit.

Do you meat F19 circuit is revised version of A370 ?

Based on A370 circuit how to adjust the DC bias and zero DC offset ?

6th December 2003, 01:58 PM	#1
Smiffy diyAudio Member Join Date: Aug 2002 Location: UK	Musical Fidelity F16 problem/Schematic HI All Little problem with a Musical Fidelity F16 power amp.Keeps coming through distorted on one side and occasionally completely cuts out.Takes a while to happen suggesting temp related but if you raise the input level it cures it possibly suggesting a dodgy capacitor somewhere.Have checked for dry joints.Also does anyone have a schematic for the above.Musical Fidelity will not sell me one.Thanks for any help.Smiffy

19th May 2004, 09:56 AM	#4
Lenin diyAudio Member Join Date: Feb 2002 Location: London	I hope this helps... Hi Smiffy, The F16/F19 circuit is apparently a tidied up version of the MF P270/A370 circuit. The original amps ran VERY hot and were unreliable (I can attest to that! There is nothing quite like the smell of smoke coming from your amplifier to convince you that things might not be quite right!). The Mk II versions cured the overheating (and some of the reliabilty) problems, while the F16/F19 were the best implementation of the circuit MF could possibly achieve, finally taking advantage of the oppotunity to incorporate acres of heatsinking and space for a huge supply. (400w AB/50w A in an elegant, good-looking chassis is no mean feat! Its also one of the few commercial amps I would buy in a flash). I've a copy of the A370 circuit (the P270 is the same, with just 3, rather than 5 pairs of output devices). I'll dig it out and post it here.

15th August 2004, 10:04 PM	#8
Lenin diyAudio Member Join Date: Feb 2002 Location: London	MF schematic - better late than never... Here you go... http://www.audiodesignguide.com/doc/...elity_a370.jpg

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6th December 2003, 03:18 PM	#2
Netlist diyAudio Moderator Join Date: Jan 2003	I would start replacing caps. /Hugo

7th December 2003, 08:12 PM	#3
Smiffy diyAudio Member Join Date: Aug 2002 Location: UK	Thanks for the advice Hugo Still hoping for a schematic but it shouldn't be to hard to work out signal/power caps.There are only about 7 caps on the power amp boards.May replace them with Black gates at the same time really.There is a 220uf non polarised right on the input.Shame MF are so tight with their circuit diagrams.\Lovely amp though. Smiffy

5th June 2004, 12:28 AM	#5
Lenin diyAudio Member Join Date: Feb 2002 Location: London	Too big to post, I'm afraid. E-mail me and I'll send it.

5th June 2004, 03:56 AM	#6
mirlo diyAudio Member Join Date: Jul 2002 Location: San Diego	Lenin, Your email through diyaudio is disabled at the moment ... Please email me a copy of the schematic. My father has a P270 and I'd be curious to see how things have changed in that amp after some refinement. Thanks! -- mirlo

10th June 2004, 07:17 AM	#7
mickey_s diyAudio Member Join Date: Jun 2004 Location: quezon city, metro manila in the Philippines	Good afternoon! Is there somebody who has a service manual or even schematic diagram of NAD 314 Integrated Amp? I have scratching sound coming out of either the left or right speaker about 2 years ago. Later, it worsened with distorted sound from either left or right channel when music passages are low yet when the volume control was cranked up the music would be normal. I suppose I have same symptom similar to Smiffy (Musical Fidelity F16 problem/Schematic ). I started replacing capacitors when the bass sounded thin. The sound improved for a few days before the bass sounded anemic again. thanks for any helping hand you can extend. [I]

10th December 2006, 04:39 PM	#9
ckwong99 diyAudio Member Join Date: May 2005 Location: HK	Quote : The F16/F19 circuit is apparently a tidied up version of the MF P270/A370 circuit. Do you meat F19 circuit is revised version of A370 ? Based on A370 circuit how to adjust the DC bias and zero DC offset ?

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