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Pass Labs Aleph 1.7 開工

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 樓主| alfcat 發表於 2008-10-29 22:36:15 | 顯示全部樓層
Let's see what I have done in the last 1.5 years.

The first M7 I made produce pretty "sweet" sound. However, the extreme ends are hard to reach. Originally, the M7 comes with WIMA caps. I later on changed them all to Auricaps. The base and clarity seems to be much better. I then sold the item to my colleague.

The second one I worked on is the Matisse, which was built many years ago by "Uncle Bun". It is very Hi Fi ... I changed all the WIMA to Jensens and the thing becomes much better. I lend it to my sister afterwards. The problem with this pre-amp is, the female aren't "feminine" enough.

Next comes the McIntosh C22. This one I kept for the shortess period of time. Not very satisfying. No outstanding performance, just an average toy. Probably some kind of design fault or so .... don't know.

Then, my current M7. Spent quite a fortune on it with separate PSupply. Unfortunately, no money to get a real hi class transformer. This one uses the Matisse rectifying board and RMG resistors together with Jensen caps. So far, this is the best Tube Pre-amp I have ever built. Sweet sound, moderate clarity, sound stage okay but not outstanding. Female vocal sounds nice and bass is not too deep.

Finally the Pass Labs. As some of you pointed out already, transistors built pre-amp gives more clarity and details. It is true. Sound stage noticably wider than the M7. More punchy bass and match with my CEC CD player well. Some Singers seem to have "improved" their singing skills when I use this Pass Labs to play their songs (tho' not true for ALL singers).

The Pass Labs still needs around 1 month to run in. See how it goes then.

CAT
autumnleaf 發表於 2008-10-29 23:18:51 | 顯示全部樓層
accphoto and alfcat,

感謝分享
autumnleaf 發表於 2008-10-30 03:24:38 | 顯示全部樓層
What kind is the sound of a "real" Matisse Reference Gold ? ..........
SSWONG 發表於 2008-10-30 09:47:58 | 顯示全部樓層
Cat Sir,

U had done a lot in 1.5years......

I'm spending a lot of time on testing cap, build and dismantle.... all are direct connection except the recently build  mrz M7 is using pcb.

So far only made 3 pcs 5687 tube buffer/preamp for friends, 1 m7 for myself.....



Dear all,

do u think iron casing will have more hum compare a aluminium casing??

I ad try my best to reduce the hum of my preamp to zero but unsuccess..

i had try floating the signal ground with 10ohm resistor, totally separate signal ground with power supply ground.... using more stage of RCR filter, use higher capacitance... but i still able to hear the hum at ~15cm from my speaker...even though this hum will not increase when volume level increase....

so any otehr suggestion? the worse is that this hum sound level will vary when use with different type of power amp, with audilab is lower hum, with quad 606 is higher hum.... fainted
accphoto 發表於 2008-10-30 12:49:36 | 顯示全部樓層
DO not  use iron casing, the better the conductivity  the better the casing, so  Copper better than -- > Aluminium better than-->  Iron.

You hum may related to wire and gounding, pay more attention to the how the wire is running, especially high tension (power ) and the heater. Beware that "resistor" is also some source of hum, do not use AB as loading resistor as they qre quite easy to introduce hum to the circuit.
SSWONG 發表於 2008-10-31 12:14:18 | 顯示全部樓層
We were always informed that cu casing better than Al casing, al casing better than iron...But what's the the output difference? quieter? better dynamic, lower background noise or??
accphoto 發表於 2008-10-31 12:45:13 | 顯示全部樓層
Simple, Copper has a better conductivity than other metal so the machines will be sheild from other interference , so the background is quieter, more detail can be revealed by the machine and most importannce is the sound quality will be more musical. It is really strange.
SSWONG 發表於 2008-11-3 10:13:35 | 顯示全部樓層
Dear Accphoto,

I follow your advice and redo the grounding for my friend's 5687 tube preamp... now very quiet .....very very minimum hum..

the only unperfection is that this tube preamp very microphonics, the casing need to be isolated very well to keep the microponic effect low... even by just softly touch on the casing, the microphonic can be heard....


any idea on reducing the microphonics effect?
accphoto 發表於 2008-11-3 15:25:35 | 顯示全部樓層
The microphonics comes from the tube , not the case. You should change another tube to see the problem still exist. If yes, use some " tube cover" to reduce the microphonics. Like this one.

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SSWONG 發表於 2008-11-3 16:53:19 | 顯示全部樓層
Yes shifu, it come from the tube, when touch the casing, the vibration transfer to the tube.... the tube is act like microphone....

so far this issue only occurs for 5687 tube..... other tube don't have this problem....

i was told by some otehr DIYER that 5687 tube is quite microphonic...
 樓主| alfcat 發表於 2008-11-12 17:58:59 | 顯示全部樓層
Autumnleafcat,

Tell us what differences it makes after changing the resistors in the Aleph 1.7 please.

CAT
autumnleaf 發表於 2008-11-13 11:51:20 | 顯示全部樓層
The test takes time, since I have to replace all the rsisitors on the VOL board. I will listen to the original VOL board before I make the change. I hope the change could improve the low frequency response.
 樓主| alfcat 發表於 2008-11-13 11:57:23 | 顯示全部樓層
Dear Autumnleafcat,

Of course it takes time, ha..ha.. Take your time, no hurry.

Just eager awaiting your answer.

Did you manage to get all the values for those resistors? All Holco or some other brand?

CAT
autumnleaf 發表於 2008-11-13 15:16:21 | 顯示全部樓層
Dear alfcat,

I only bought holco and luckily I could get all the values. If a single value is missing then the whole volume control board cannot be built. The sound of holco is good enough, even 40k preamp using holco as vol control pot.

From some other preamp circuit, the volume resistance is much higher than Aleph. So I would like to scale up the volume resistance of Aleph preamp volume board. In theory this could improve bass response.

All values scale up 5 times, 62R -> 300R, 120R -> 620R and so on ...

Aleph preamp low frequency is not solely determined by vol resistance but also the output node impedance which is around 2k ohm by calculation.

I have measured the volume input-output attenuation relationship and found that at mostly used position the volume impedance is 200 ohm.

Low frequency response f = 1/{(2pi)(RC) = 1/{(2pi)(2.2k)(30u)} = 2.4 Hz

Still pretty good !

If scale up 5 times volume resistance, expected vol imp = 1k ohm, then new low frequency response = 1/{(2pi)(3k)(30uF)} = 1.8Hz

Though only go a bit lower, I hope to have a notable deeper bass. Let see !

BTW, do you notice the bass of Aleph preamp is not puncy enough?
 樓主| alfcat 發表於 2008-11-15 10:33:30 | 顯示全部樓層
Too busy these days. Just turn on the two Aleph by turn to run them in. No chance sitting down there and listen.

Anyway, I don't really like "punchy" bass; that is why I mainly have female vocal CDs. My speakers can adjust the base level by narrowing or widening the gap at the bottom. I set it to minimum bass too.

Situation will be better after next week. Then I can have more time to play with the toys and assemble the third Aleph for my colleague.

CAT
SSWONG 發表於 2008-11-17 09:07:22 | 顯示全部樓層
Bad luck....my transformer in my tube preamp burned...

i had use the same brand, same spec of the power transformer, it work fine for ~3-6month then the secondary coil of the transformer will burn...any idea or suggestion? So far had burn 3 pieces... all burn after working for several months...
autumnleaf 發表於 2008-11-17 12:57:42 | 顯示全部樓層
Maybe your transformer working at close to maximum rating. The accumulated of heat melt the insulation or fuse the wire. Try to use a double rating one instead. Otherwise, your cicuit has some unstable.
 樓主| alfcat 發表於 2008-11-17 23:29:38 | 顯示全部樓層
The TWO Pass Labs 1.7 I have made.

Spent two hours today to change the front panel to the one at the bottom.
Haven't got Chloroform at home, so I can't fix the back plate for the Volume Switch yet. Will try to get some Chloroform tomorrow to have it done.

Still haven't finish yet. Will try it make it better tomorrow, just ran out of time today. Will need also to spend some time to shop for screws to make the front panel looks even better.  :wink:

CAT

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SSWONG 發表於 2008-11-18 12:40:11 | 顯示全部樓層
Dear ALC,

The transformer i use is 350V-0-350V,100mA at secondary... preamp normally run below 50mA right? anyway the wire in 2ndary seem really thin... i think u r right, i shall use a bigger 1.....

I try to use the foil inductor again, but this round i use opposite direction then sound seems not as fast as last time....
Modify speaker seems much more difficult than amp & cdp, just little bit of changes can make a lot diffrences and result can be worse most of the time....
 樓主| alfcat 發表於 2008-11-23 23:21:40 | 顯示全部樓層
Tried different hook up wire for the Pass Lab 1.7

8N copper (Tara Labs), Military Silver Plated OFC copper wire and finally 99.9999 pure silver wire.

The pure silver wire gives the best clarity and sound stage. The 8N copper is a bit sluggish, I still don't understand why. The worst is the silver plated copper. Good only for power supply.

However, I still use the 8N copper for the Grounding. Save me some money, ha...ha... :

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DUALXEON 發表於 2008-11-24 02:46:44 | 顯示全部樓層
Cat sir

Where you bought Taralabs wire. it is expensive.
 樓主| alfcat 發表於 2008-11-24 09:00:25 | 顯示全部樓層
Dear DualXeon,

The TaraLabs were bought at SSP Wing Shing. Yes, you are right, they are not cheap (around $ 36 - 38 / foot). Connecting everything inside the Pass 1.7 requires around 2 feet.

The Silver ones are around $ 70 / foot --- doubled the price.

CAT
DUALXEON 發表於 2008-11-24 23:27:30 | 顯示全部樓層
Cat Sir

Thanks for you info.

I have bought Tara labs cable today.for my headphone amp


 樓主| alfcat 發表於 2008-11-25 12:31:39 | 顯示全部樓層
Dear DualXeon,

Might have "mis-led" you. My Pure Silver Wire is NOT from TaraLabs.  The silver wire is a bare wire. I have to put in Telfon or heat shrinking wrap.

CAT
 樓主| alfcat 發表於 2008-11-29 20:57:05 | 顯示全部樓層
My Pass Lab 1.7 in "Night Vision" mode.

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SSWONG 發表於 2008-12-2 15:08:32 | 顯示全部樓層
CAT,

Your PASSL really beautiful especially at night.....
 樓主| alfcat 發表於 2008-12-3 09:58:45 | 顯示全部樓層
Dear WINDWSS,

It looks best after I DIMMED the display and just let the side on. It is easy to do and the result is very fascinating.

CAT
autumnleaf 發表於 2008-12-17 17:12:15 | 顯示全部樓層
小弟劣作

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autumnleaf 發表於 2008-12-17 17:17:22 | 顯示全部樓層
power supply:

1. Nippon Chemicon 400V 470uF SMH series
2. Cheap Choke 10H/0.2A
3. On-semi Schottky 20A 100V diode
4. Wondor cap 3uF 425V

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autumnleaf 發表於 2008-12-17 17:21:58 | 顯示全部樓層
Toroid Transformer

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autumnleaf 發表於 2008-12-17 20:34:08 | 顯示全部樓層
What can I do with this?

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autumnleaf 發表於 2008-12-20 12:04:26 | 顯示全部樓層
cdpro2

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autumnleaf 發表於 2008-12-20 12:06:11 | 顯示全部樓層
DAC1955PRO

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autumnleaf 發表於 2008-12-21 14:25:11 | 顯示全部樓層
早前燒左 P1.7 house keeping power supply 粒 opto-coupler ...

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autumnleaf 發表於 2008-12-21 23:09:39 | 顯示全部樓層
Circuit replacing opto-coupler

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autumnleaf 發表於 2008-12-23 17:26:01 | 顯示全部樓層
Manepan 1.6 impedance

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autumnleaf 發表於 2008-12-24 02:25:46 | 顯示全部樓層
amp out

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autumnleaf 發表於 2008-12-28 03:15:19 | 顯示全部樓層
MG1.6 schematic

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goldlighta 發表於 2009-7-20 00:57:34 | 顯示全部樓層
WhiteCat 兄,

小弟想請問 DIP_SW 3 腳係去 IN+ 的 AGND 定係 IN- 的 AGND??
塊底板 DIP_SW 個位同 D 腳好似唔係好順, 吾知有無砌錯.

謝謝!
goldlighta 發表於 2009-7-23 22:46:25 | 顯示全部樓層
Hi c-hing,

小弟的 1.7 將接近完成, 請問 D 散熱片同零件中間使唔使加片絕緣件??
唔加會唔會 short 野??

thx!
 樓主| alfcat 發表於 2009-7-25 08:53:02 | 顯示全部樓層
Heat Sink + MOSFET 中間是有雲母片的. 唔係我怕會 short.

之前 dip switch 問題 solve 了麼? 這幾天較忙, 沒上來.

我以前 d 相好似都有 pos t過 dip switch 邊隻腳要接邊隻腳...
goldlighta 發表於 2009-7-25 14:12:13 | 顯示全部樓層
[quote:53b59e680d="alfcat"]Heat Sink + MOSFET 中間是有雲母片的. 唔係我怕會 short.

之前 dip switch 問題 solve 了麼? 這幾天較忙, 沒上來.

我以前 d 相好似都有 pos t過 dip switch 邊隻腳要接邊隻腳...[/quote]

thak you 師兄,

咁我諗都係加返雲母片安全 D 好.

""""我以前 d 相好似都有 pos t過 dip switch 邊隻腳要接邊隻腳...""""""""
真係, 要揾來對一對先!


另外小弟的 preamp 1.7 剛開聲, 用 RCA 接 CDP, 但出來效果好似好細聲咁, 最大 75, 但我要開到 6x (六十幾) 先夠聲. 唔知發坐乜事??

請指教
 樓主| alfcat 發表於 2009-7-25 20:20:20 | 顯示全部樓層
你有無 set 好 d dip switch 同有無 measure 個兩粒 100 ohm 電阻是否 set 了在 0.42?
goldlighta 發表於 2009-7-27 12:15:24 | 顯示全部樓層
[quote:3590a0185c="alfcat"]你有無 set 好 d dip switch 同有無 measure 個兩粒 100 ohm 電阻是否 set 了在 0.42?[/quote]

thx!

d DIP Switch set 好了, 真係細 output 好聲 D , 細緻 D



"""同有無 measure 個兩粒 100 ohm 電阻是否 set 了在 0.42?""""""

請問指邊兩粒??
用乜野 tools 去 measure?
點解要 set 0.42??

sorry, I am 新手, 問題較多.


另外請問那裡有 DAC 套件現貨出售???
香港  or  深圳都可以
accphoto 發表於 2009-7-27 13:50:58 | 顯示全部樓層
你唔加雲母,可能已經燒左。
 樓主| alfcat 發表於 2009-7-28 22:10:07 | 顯示全部樓層
你可以 follow 這個 link:

http://i517.photobucket.com/albums/u331/alfchanys/Reading.jpg

我應該重有張相在那兒.

你個 dip switch d 腳有無銲埋?
goldlighta 發表於 2009-8-3 00:44:09 | 顯示全部樓層
[quote:7a33bae7ee="alfcat"]你可以 follow 這個 link:

http://i517.photobucket.com/albums/u331/alfchanys/Reading.jpg

我應該重有張相在那兒.

你個 dip switch d 腳有無銲埋?[/quote]

thanks!
but what is the purpose to set o.42??
follow specification?
goldlighta 發表於 2009-8-31 12:18:17 | 顯示全部樓層
thx all c-hing! my 1.7 is working fine

now my friend ask me to do 1 more unit for him, but seems some accessory is out of stock.

any c-hing know, where can buy WIMA MKP4 10uF cap. and BC 1500uF 水塘?? 之前買那店沒貨.

thx!
sunsvc 發表於 2009-10-31 21:35:26 | 顯示全部樓層
[quote:bd7dc69d36="alfcat"]WINDWSS,

Please check your email[/quote]

Would like to know where to get the kit?
 樓主| alfcat 發表於 2009-11-22 16:08:30 | 顯示全部樓層
Where are you located? Hong Kong or other parts of the world?

CAT
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