Walnut F1
RyanM
Head-Fier
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I've just received the F1 today and I want to offer up a few tidbits of info. Firstly the clarity and power is absolutely remarkable. Not having any previous Zishan or Walnut, i have no baseline for this. I'm floored. Secondly, the volume knob is sensitive, but maybe not as sensitive as some have reported. I have noticed that running from my iPhone SE to the "Power Out", rather than "Line In" effectively bypasses the volume knob altogether. With this setup, I can use the volume through my iPhone to control the volume of the F1. It provides far more than enough power to still drive my Zen 2 balanced, while I also dont have to worry about blowing out my earphones or eardrums. I dont know if this is effectively also a "low" gain setting, but it seems to be working that way. Another thing is that I'm able to use a 3.5mm to 2.5mm adapter to run absolutely any standard earphone via the balanced port. The adapter I'm using was included with my 3.5mm balanced VE Zen 2. Anyways, this thing is an absolute marvel. I don't know what the balance out is doing behind the scenes or what percentage of it may or may not be gimmicky, but the results vs. price ratio is truly sensational.
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Ivan TT
500+ Head-Fier
What a great idea, I never even considered it!
This bypasses F1's opamp altogether, tapping into the balanced output stage (and the boost it delivers) directly.
I modded mine to feed balanced buffers into 3.5mm se out (in addition to 2.5mm balanced), only two headphone outs are soooooo last century!
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Ynot1
500+ Head-Fier
What you are doing is tying negative left with negative right when they could be at different voltage reference levels. It doesn't seem like a good thing to do. I wonder if this is similar to a scenario when you bi-amp using two amps to drive the same load. I remember in circuit theory a little bit and I think there could be race condition. But if you say it works without problems then interesting.
Current flows from pos to neg terminal, and electrons flow opposite direction. Based on this one channel could be supplying the electrons to both channels and introduce crosstalk in theory.
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Ivan TT
500+ Head-Fier
So, with this mod and Z2 the following configurations are available, they all give different sonic characteristics:I modded mine to feed balanced buffers into 3.5mm se out (in addition to 2.5mm balanced), only two headphone outs are soooooo last century!
Z2 Line Out -> F1 op-amp -> 3.5mm out
Z2 Line Out -> F1 op-amp -> buffer amp -> 3.5mm (or 2.5mm balanced) out
Z2 opamp (PO) -> F1 buffer amp -> 3.5mm(or 2.5mm balanced) out
Z2 opamp (PO) -> F1 op-amp -> 3.5mm out
Z2 opamp (PO) -> F1 op-amp -> buffer amp -> 3.5mm(or 2.5mm balanced) out,
and also a VERY interesting one: Z2 Line Out -> buffer amp -> 3.5mm (or 2.5mm balanced) out, no opamps, no volume control.
I noticed that there's a bit of noise coming from buffer output, so I reduced F1's opamp gain by adding 12kOhm resistors in parallel in feedback loop, this matched the gain of Z2's amp and gave reasonable level when bypassing opamps using last option above.
With this mod I can use buffered output can to drive headphones using extra 3.5mm socket (F1 handles up to 64Ohm easily), this is not possible with 2.5mm balanced output unless headphones are modified for balanced operation.
Effectively I can choose opamp to match the music I'm listening to on the go (currently Burson v5i in Z2, LME49860NA in F1), add extra power if needed by tapping into buffers, or listen to DAC's output (LO) + gain provided by buffers.
It also gets a bit crowded inside of my F1
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silverfishla
Headphoneus Supremus
hey, what value are those green nichicons?So, with this mod and Z2 the following configurations are available, they all give different sonic characteristics:
Z2 Line Out -> F1 op-amp -> 3.5mm out
Z2 Line Out -> F1 op-amp -> buffer amp -> 3.5mm (or 2.5mm balanced) out
Z2 opamp (PO) -> F1 buffer amp -> 3.5mm(or 2.5mm balanced) out
Z2 opamp (PO) -> F1 op-amp -> 3.5mm out
Z2 opamp (PO) -> F1 op-amp -> buffer amp -> 3.5mm(or 2.5mm balanced) out,
and also a VERY interesting one: Z2 Line Out -> buffer amp -> 3.5mm (or 2.5mm balanced) out, no opamps, no volume control.
I noticed that there's a bit of noise coming from buffer output, so I reduced F1's opamp gain by adding 12kOhm resistors in parallel in feedback loop, this matched the gain of Z2's amp and gave reasonable level when bypassing opamps using last option above.
With this mod I can use buffered output can to drive headphones using extra 3.5mm socket (F1 handles up to 64Ohm easily), this is not possible with 2.5mm balanced output unless headphones are modified for balanced operation.
Effectively I can choose opamp to match the music I'm listening to on the go (currently Burson v5i in Z2, LME49860NA in F1), add extra power if needed by tapping into buffers, or listen to DAC's output (LO) + gain provided by buffers.
It also gets a bit crowded inside of my F1
Ivan TT
500+ Head-Fier
110uf (as opposed to 220uf in stock)
RyanM
Head-Fier
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Well, I would hope that there is no negative effects to the F1, however, the alternative is blowing my eardrums out of my head on accident, so I think I'll take that risk. The sound quality is identical to my ears so no worries there.
activatorfly
500+ Head-Fier
I'd like to order the F1, please can anyone recommend a balanced silver cable for Rose Masya (2-Pin 0.75mm) earbuds?
RyanM
Head-Fier
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activatorfly
500+ Head-Fier
Is the (balanced output) configuration using: Z2/LO & "power out" on the F1 working ok?
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DBaldock9
Headphoneus Supremus
Did you try installing the LME49720NA, before doing any of the capacitor & resistor mods? How did it sound?
The reason I ask, is that I received my F1 yesterday - and the first thing I did, after charging it, was to connect it up to the Line Out of my Fiio Taishan D3 DAC (w/TOSLINK input from PC), and verify that the Balanced output would work to drive some **** PT15 earphones. It did, and sounded very good. I've also tested the Balanced output with low-ish impedance (16Ω - 32Ω) earphones, and higher impedance (115Ω - 650Ω) earbuds - all with good results.
The second thing I did, was to pop the LME49720HA (TO-99 round metal case) out of my Z1, and swap it for the OPA2134PA in the F1 (which I noticed has terrible DIP sockets - I'll be replacing them). When I turned it On, I was hearing a good deal of noise. I thought it might be due to the cover not being on the Amp, but it won't fit, since the TO-99 can is too tall. So I popped out the LME49720HA, and installed a LME49720NA, and replaced the cover - but the noise was still there.
Next, I tried a PHILIPS NE5532N (Vintage - mid-90s), and it sounded good, but also had some noise, which is audible between tracks, and during quieter parts of the music.
The last thing I did, was to install an OPA2604AP, and it sounds good, without any audible noise. Which means the two Burr Brown / TI opamps I've got, will both work well in the F1, but not the other brands / models.
So that comes back to my original question - is there something you did, which allows your LME49720NA to work in the F1, without audible noise?
Thanks,
David Baldock
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Ivan TT
500+ Head-Fier
Yes, I had a problem with background noise too, fixed it (and distortion on PO out, to a degree) by reducing opamp's gain, adding 12kOhm resistors between terminals 1-2 and 6-7.
activatorfly
500+ Head-Fier
Is the power rating of these 2 resistors critical?? I just bought 0.6W (12K Ohm) & was offered 2W as an alternative ...which seemed huge in comparison!
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