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Author Topic: FR-2LE service manual?  (Read 973 times)

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Offline borjam

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FR-2LE service manual?
« on: June 13, 2018, 11:55:58 AM »
Hi,

I've got a Fostex FR-2LE. Nice preamps but the headphone output really sucks. I wonder,
is it possible to find a service manual anywhere?

Thanks!
"Don't worry about the drums. I'm a percussionist, I can play on carton boxes" - Peer Wyboris

Offline Fatah Ruark (aka MIKE B)

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Re: FR-2LE service manual?
« Reply #1 on: June 13, 2018, 12:24:59 PM »
From what I remember from mine, the headphone output is pretty useless. I don't think it's fixable, it just came that way.
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Offline borjam

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Re: FR-2LE service manual?
« Reply #2 on: June 13, 2018, 12:33:27 PM »
From what I remember from mine, the headphone output is pretty useless. I don't think it's fixable, it just came that way.
Exactly :)

Not meaning to "fix" it, but maybe to replace its amplifier with something better.

"Don't worry about the drums. I'm a percussionist, I can play on carton boxes" - Peer Wyboris

Offline heva

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Re: FR-2LE service manual?
« Reply #3 on: June 13, 2018, 02:58:18 PM »
It could be that the headphone amp is in the cirrus CS42L51 chip.
Not much to improve if so.

Offline borjam

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Re: FR-2LE service manual?
« Reply #4 on: June 13, 2018, 04:48:59 PM »
It could be that the headphone amp is in the cirrus CS42L51 chip.
Not much to improve if so.
Ouch! You are right, looking at the datasheet it's clear that "line out" is derived from the headphone output as well!

Pity that the chip is a bit limited.

https://statics.cirrus.com/pubs/proDatasheet/CS42L51_F2.pdf

Only possibility would be to reduce the gain of the output stage (which means snooping on the I2C or SPI bus and replacing certain commands) and adding a proper amplifier. Cheaper to upgrade to a MixPre 3 or a Zoom F4 but might do it for fun.



« Last Edit: June 14, 2018, 02:40:29 AM by borjam »
"Don't worry about the drums. I'm a percussionist, I can play on carton boxes" - Peer Wyboris

Offline borjam

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Re: FR-2LE service manual?
« Reply #5 on: June 14, 2018, 12:42:11 PM »
Now this is odd. That chip is used in music players with (reportedly) good audio.

Has anyone explored options? (Not intending to reinvent the wheel) :)
"Don't worry about the drums. I'm a percussionist, I can play on carton boxes" - Peer Wyboris

Offline John Willett

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Re: FR-2LE service manual?
« Reply #6 on: August 22, 2018, 11:30:35 AM »
From what I remember from mine, the headphone output is pretty useless. I don't think it's fixable, it just came that way.
Exactly :)

Not meaning to "fix" it, but maybe to replace its amplifier with something better.

Don't do this.   :alert:

The FR-2LE had a better headphone amp. than the FR-2.

But the headphone amp is like this for a reason - it's all down to current draw and battery life.  A better amp. would draw more from the battery and shorten the recording time and the recorder is a field recorder, so the longer running time the better.

The best headphones to use with the FR-2 and FR-2LE are the Sennheiserr HD 25 which are very efficient and give a good output at lower gain levels than other headphones.

I asked this question to Fostex in detail when the first FR-2 came out and I wrote the first review of it for LineUP magazine and they told me the reason at the time.

So - you may put in a better headphone amp., but at the expense of draining the batteries faster and limiting the recording time.

I found the HD 25-1 (in my case) an excellent match for the FR-2 and FR-2LE and they did not display the nasties that less efficient and higher impedance headphones did.

Offline borjam

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Re: FR-2LE service manual?
« Reply #7 on: August 23, 2018, 06:02:57 AM »
Don't do this.   :alert:

The FR-2LE had a better headphone amp. than the FR-2.
Was the FR-2 even worse? Amazing!

Quote
But the headphone amp is like this for a reason - it's all down to current draw and battery life.  A better amp. would draw more from the battery and shorten the recording time and the recorder is a field recorder, so the longer running time the better.
Of course it would increase power consumption, that's a given :) I won't do it because I got a SD MixPre 3. It drains power like there's no tomorrow
but everything is amazing.

I will sell the FR-2LE including a new Tamiya compatible battery and charger.

Quote
The best headphones to use with the FR-2 and FR-2LE are the Sennheiserr HD 25 which are very efficient and give a good output at lower gain levels than other headphones.
I was using Ultrasone HFI-650 which are quite efficient. I also tried the Sony MDR-7506 lately and I think these are more efficient than the Ultrasones.

Quote
I asked this question to Fostex in detail when the first FR-2 came out and I wrote the first review of it for LineUP magazine and they told me the reason at the time.
I know Fostex are far from idiots and there was a reason. I haven't opened it but I imagine they used the codec-and-all chip.

Nowadays there are better components :) Anyway I won't do it finally, better to sell it.

"Don't worry about the drums. I'm a percussionist, I can play on carton boxes" - Peer Wyboris

Offline John Willett

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Re: FR-2LE service manual?
« Reply #8 on: August 23, 2018, 03:04:20 PM »
The Sony 7506 are very inefficient compared to the Sennheiser HD 25.

The HD 25 are 120dB efficient, the Sony only 106dB - the Sennheisers are 14dB better.

I found no problem at all using the HD 25 in the FR-2 and used mine for quite a few years before I sold it on and upgraded to a Nagra VI.

I used the FR-2 as a master recorder for several CDs.

Yes, I had problems with less efficient and higher impedance headphones - but teh HD 25 seemed a perfect match for me (I actually said most of this when I originally reviewed the FR-2).

 

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