[Choochoo]

Welcome back Ryuzoh.
 
I will surely order "FX Limited edition", maxxed with additional 4 BUF634s.
 
From now on, I will have to keep checking this thread to check when the preorder is formally announced.  

 

[qusp]

revisited LT1028 tonight, wow such a nice chip, the speed is pretty incredible. I dunno about you guys, but even with my JH13 I always prefer the FiQ in mid gain, rather than low, to me the sound opens up, becomes more solid and is much more dynamic. now this makes perfect sense with chips like the 797 and 1028, as they are more linear in mid to high gain than low gain. anyone else find this? of course it probably also has something to do with the fact that only the mid and high gain sections of the gain circuit are populated totally with TX2575 Zfoils

with ANOTE tants in the low gain.  I level matched to of course
 
ryuzoh: I bought the 25 turn pot for the mod you suggested, I cant believe I thought it was a different pot, I was confused because I thought there was only one, but the 797 has been in there untouched for so loing that I was picturing the layout differently to what it is. though I did open it up to pop the OPA1641 in there a couple of weeks ago, with very good results.

 

[ryuzoh]

Quote:

revisited LT1028 tonight, wow such a nice chip, the speed is pretty incredible. I dunno about you guys, but even with my JH13 I always prefer the FiQ in mid gain, rather than low, to me the sound opens up, becomes more solid and is much more dynamic. now this makes perfect sense with chips like the 797 and 1028, as they are more linear in mid to high gain than low gain. anyone else find this? of course it probably also has something to do with the fact that only the mid and high gain sections of the gain circuit are populated totally with TX2575 Zfoils

with ANOTE tants in the low gain.  I level matched to of course
 
ryuzoh: I bought the 25 turn pot for the mod you suggested, I cant believe I thought it was a different pot, I was confused because I thought there was only one, but the 797 has been in there untouched for so long that I was picturing the layout differently to what it is. though I did open it up to pop the OPA1641 in there a couple of weeks ago, with very good results.

When using super low-noise types as LT1028(A)/1128(A), LT1115, AD797......JP1/JP2 should be jumped and SW2 as ON.
If you wouldn't, might be oscillating and wasting currents

 can you check it over with oscilloscope?
 
I think the pot you mentioned might be Bourns 3296, however not 3296Y or 3296W types.
The pot should be Y or W class.
And I can make new attenuator beneath ALPS pot with tantalum resistors (discontinued Shinkoh's and called as TAF in Japan, Jam's were already applied) for you after fixing.
 
Or, you can find the pot as"3296W-202LF-ND" in digikey.

 

[FreeBlues]

I likely missed this, can someone post the dimensions of this beauty?

 

[qusp]

yes I applied all the mods and switched all switches for the 797, which has been in the amp pretty much solidly since I bought it and I was under the impression that all those settings would suit the 1028 as well. yeah I got your email with the part number for the resistive pot, I will give that a try before I send it to you, but it would have to be pretty miraculous change to transform it into a practical amp from the short play time I have now. this short time is still just enough for the short trip I must do every 2 days into the city and back, so its still serves a purpose when I feel like using the FiQ. if I was going for different R's in the pot I wouldnt go shinko tants, I wouldnt like the slightly musical edge they have applied over everything. no point using Zfoils in the gain, feedback and main signal path if i'm going to use tants in the pot, maybe something else though, this mod sounds interesting. the shiunko you talk of are a sort of grey/purple yes? nice resistors for sure, but the sort I would like to mix and match, not as an overlay over the whole signal, maybe though, i'll think on that

 

[jamato8]

The tants I used are the NOS non magnetic. The new ones have a slightly magnetic end and have a slight harsh sound compared to the NOS. I would use good carbon like Riken Ohm and tants. 
 
You are sending in the fi.Q? I get good run time on mine. I don't know how long but long enough. With the MB-1 being fed with lossless and the new SysConcept multifiber toslink (it really does improve the sound much to my surprise), I get some very excellent sounds. 
 
AudioNote UK went to the new tants for higher voltage purposes but I never had any problems in any of my tube equipment. They know they aren't the best sounding. Too bad they don't just go back to the original formula. 

 

[qusp]

I have bot ANOTE and shinko tants, I believe the shinko are NOS from PCX and are running out, I think I just prefer high end metal film R's to tants, I like a little tant flavor, but the material itself does not IMO lend itself to ultimate transparency. yeah i'll send the amp back to ryuzoh as soon as I move in a couple weeks time, so I can put an accurate return address and details on it.

 

[jamato8]

I use the tants in 2 watt. They make a difference in the sound. The current and voltage doesn't matter, I still use 2 watt. They are transparent and very neutral, to my ear but not in the .5 watt variety. 
 
So your amp is being sent back? 

 

[SpudHarris]

Jam, Jeremy, I'm planning on sending mine back to Ryuzoh for an update. What is all this talk about pots and attenuator mods? What benefit does this offer?

 

[qusp]

Quote:

I use the tants in 2 watt. They make a difference in the sound. The current and voltage doesn't matter, I still use 2 watt. They are transparent and very neutral, to my ear but not in the .5 watt variety. 
 
So your amp is being sent back? 

 
yeah i'm gonna send it back and see if he can sort out this battery issue, its never been great, but has just continued to get worse, i've put up with it because the thing sounds so damn good I havent wanted to be without it, but now I have a pretty amazing sounding DIY dac/amp I can afford to give it some time for R&R. if he can do something nice with the pot that would be cool, just not sure if I want tants on the input, just a personal taste thing, after shelling out 30 bucks a piece for 0.005% matched sets of naked Zfoils i'm not all that keen on putting some tants in front of them, although I suppose they can only be better than the resistive element inside the pot. I have done pretty much all the updates, plus a few of my own (though the battery was an issue before I did any of this, so its not that) but i'm sure he'll find something to do

I do run the amp in high current high bandwidth mode with the buffers wide open as well, but that should not be causing life to be this short, I think it probably stemmed from that first incident with the charge voltage not being right and my amp being left on charge, I have made the adjustment 2 times since then, as I presume the battery continued to deteriorate and could not hold or reach the level set and would keep striving for it, just like the initial problem.
 
i'm running upgraded R's throughout the gain, bass and signal section, SMD films scattered throughout, sanyo oscons for the amp section and blackgate FK for the buffer section, both bypassed with the wimas plus smaller rifas and even smaller SMD films. i'm searching the rifa catalogue to see if any of their amazing PHE range lowZ power supply caps will fit.

 
Quote:

Jam, Jeremy, I'm planning on sending mine back to Ryuzoh for an update. What is all this talk about pots and attenuator mods? What benefit does this offer?

 
well the pot is the first resistor on the input to the amp, when signal is at its lowest and thus most susceptible to noise, the resistive element in the pot even for decent one like this is still not fantastic, so I assume that Ryuzoh will play with the shunt resistors or something, I havent looked at the internal schematic to the pots we have, but will do that in the next week. so it should lower noise, perhaps make for better channel matching and increase transparency

 

[jamato8]

On my preamp I built, with balloon 27 mesh plates from 1930, I used a bypass type of attenuator. I have a DACT in there but by using the right value to ground and in the signal path you only have that one resistor in the signal path. I learned about it maybe 8 years ago. You could use the cheapest pot available and what it is, is a shunt to ground with the signal going through the single resistor. 
 
Jeremy, I bet your batteries are shot from being overcharged. I was lucky in that mine got warm but not bad and then I adjusted it for the right voltage. I never liked the coarseness of the pot for that adjustment and need to get the one Ryuzoh suggested but it is hard to get anything here or to here on Pohnpei from many electronic companies. They want way too much for shipping. 

 

[xxoom]

Are there any alternative choices instead of "4 BG N 33uF/16V "?
They're the only ones that hard to find. Is it very important for the BG-maxxed version?
Regards.

 

[jamato8]

I heard from Ryuzoh that the 30 fi.Q's for the states are being assembled for shipment. It will be nice to read more impressions. 

 

[qusp]

Quote:

On my preamp I built, with balloon 27 mesh plates from 1930, I used a bypass type of attenuator. I have a DACT in there but by using the right value to ground and in the signal path you only have that one resistor in the signal path. I learned about it maybe 8 years ago. You could use the cheapest pot available and what it is, is a shunt to ground with the signal going through the single resistor. 
 
Jeremy, I bet your batteries are shot from being overcharged. I was lucky in that mine got warm but not bad and then I adjusted it for the right voltage. I never liked the coarseness of the pot for that adjustment and need to get the one Ryuzoh suggested but it is hard to get anything here or to here on Pohnpei from many electronic companies. They want way too much for shipping. 

yep thats what I figure too, cant just be the charge circuit needing further adjustment, not this level of problem. indeed a 25 turn pot would be better, maybe i'll suggest he use one for the replacement. will be sending it off in the next week or so, i'm at the new house now and settled in. will be great to hear more impressions of this great amp from the new batch

 

[smial1966]

How on earth does a non-technically minded audiophile order one of these superlative amplifiers?!?
 
Having messaged and emailed Ryuzoh regarding the fi.Quest to no avail, should I conclude that these amps are reserved for head-fi reviewers and not ordinary music lovers?
 
Any information would be greatly appreciated.
 
Cheers.