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monophonic
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12-05-02
22:17:06
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daiwok
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12-05-02
17:06:02
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drwkng
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12-05-02
17:00:58
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monophonic
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12-05-02
16:58:03
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| 回覆 (5): DIY My Project Mono Phono Pre Amp with vari EQ |
I have problems to show pictures. I put in the URL link of my Server but I only see the link address but no picture.
New attempt.
The EQ Curves for Mono Vinyl 33RPM ( all 18 different curves ) and how to adjust my phono pre for correct reproduction.
Regards |
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monophonic
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12-05-02
16:56:11
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| 回覆 (3): DIY My Project Mono Phono Pre Amp with vari EQ |
Michael,
Nice to see you here, what a surprise !! I heard your MONO Phono at Uwe Brettsneider's house back November 2010. Very impressive indeed. So much that I also went down the mono route and started my own mono system 8^) |
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daiwok
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12-05-02
10:52:47
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| 回覆 (4): DIY My Project Mono Phono Pre Amp with vari EQ |
Herzlich Willkommen. Das ist gut, von Ihnen zu hören.
I am rebuilding my dual mono Tannoy phono preamp. Here is the circuit I like to share with you. I omitted all the 78s because I dont have any 78s record.
There are friends here at 1pekingroad collect mono cartidge and Lenco tunrtable for their everyday listening. Please do share with us more at this DIY thread or you can see more of LP sharing at "Idler Wheel Turntables".
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bobui
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12-05-02
09:18:38
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cpyip
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12-05-02
08:36:30
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kris
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12-05-02
08:24:50
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| 回覆 (1): DIY My Project Mono Phono Pre Amp with vari EQ |
Hello from Germany Cologne,
Since a long time i observe this wonderful webside of vintage Hifi and espacially these great DIY projects. My favourite interest is the reproduction of old mono records with the right EQ Curves.
My DIY project is a Mono phono Pre amp with variable equalization. So now I can hear my old Blue Note Jazz records and COLUMBIAS just as the artists wnted to be heared.
In the following days I will post some details and pictures.
Best regards
Michael |
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monophonic
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12-05-02
05:02:56
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| 回覆 (1): DIY My Project Mono Phono Pre Amp with vari EQ |
Hello to all DIY enthusiasts from Germany , Cologne.
I am deep impressed about your DIY Projects I observe since a long time on this wonderful webside.
So my special interest are phono pre amps. Especially Phono pre amps for correct reproduction of old Mono Records. I have searched for a long time and so my favourite in Hifi-history is the SCOTT 121C.
I build up a modern version by myself to reproduce my Jazz Records of Blue Note, Columbia etc. just as the artists wanted to be heard.
Best regards
Michael |
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| https://www.filemail.com/dl.aspx?id=SQSGEWAVBREONTN |
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monophonic
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12-05-02
04:22:00
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| 回覆 (38): DIY的大敵--自激 |
You right, you are very right! I do want to go for tube rectifier but there are three problems.
1. The HT transformer doesn't have a 5 or 4 v heater for rectifier.
2. Even if it does, not many 5V or 4v full wave rectifier can stand that voltage and current. I do have some U19 half rectifiers that are made for such high voltage but the heater requirement is 4V 4A and I need two for one channel.
3. My intention is to build an amp good enough for mid to large size maggies and that means I want lower internal impedance, lower voltage drop and fast rise time. Sicilion, on paper wise, it's way better.
I am listening and I do think I should make rooms for valve rectifier as an option. I surely would do and please tell me if you or any high hands spot anything unusual. As said, this is going to be fun for not just me. I will be well prepared to have these mono blocks ready for you guys at 1pk to have a go.
And before I forget, I do want to say "thanks" to drking for the good deal on The many 811-10s. I almost forgot to pay! Silly bobui! |
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bobui
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12-05-01
21:13:33
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| 回覆 (37): DIY的大敵--自激 |
Bobui,
It’s surprising that you would go for bridge rectification. I thought you must have a lot of NOS tube rectifiers.
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limage
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12-05-01
20:26:50
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| 回覆 (36): DIY的大敵--自激 |
Here is a bit more info for sharing. In the making of this amp, I will adapt the proper and normal way by
1. Find the voltage swing required for the desire output which is limited by the output cow.
2. Go about making the 6j5 and 6bx7 to ensure the swing requirement and other essentials are well met.
3. Conduct testing on a scope and hopefully a distortion analyzer to have all the details written down.
For now, I can share with you that the sowter I have is 7k anode to anode 100 watts, 200ma per side cow. That also means each valve will see a load of 7k in a PPP arrangement. The HT also been set and limited by the acquired mains cow which has a 500AC secondary translate to 500 X 1.41= 705dc. I will be using silicon rectifier and under loaded HT would be roughly 0.93 of 705dc due to transformer loss. The available current will be less than 500ma since i need to use a bridge rectifier which would not be a huge problem if most of output is in Class A.
I won't go into details in the heater arrangement as this is pretty standard. Just AC with a center ground return define by two 47 ohms resistors. Because of the highly accurate resistor we can buy off the shelve in 21st century. I don't believe it's necessary to use a variable resistors. A Fluke measured 47ohms gives you much better accurate readings for hum killing.
I am considering all voltage gain and phase splitter valves in dc heater arrangement to minimize hum. Any advice, feel fee. |
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bobui
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12-05-01
18:16:42
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| 回覆 (35): DIY的大敵--自激 |
Its been so long la and now is the right time to get a kick start on this hundreds of Watts project. The 811-10 PPP mono amp offering 800 watts class A into 0.3 ohms.
Opps! Easy easy guys! Forgive me la! They were typos only, ok? No bullshit, ok! Should be 100watts Class AB2 into 8 ohms.
The second chassis arrived on last friday. Rough layout looking like below.
Major components line up:
British Gresham 500ma C-core mains cow for 811-10 output stage
USA Thordarson 3.5H 500ma choke for output stage only
British Gresham faliment cow 6.3V 5A X 4 for the four per channel 811-10
British Partridge 150ma C-core cow for the driver stage
British Partridge 10H 100ma choke for the driver stage
British Sowter 100Watt output
USA Western Electric 100ma current meter X1
Deutsch Chassis from Klangfilm with handles X 2
Deutsch HT filter caps F&T X plenty
Hong Kong born circuit valve line up is 6J5 input stage and then 6BX7 indriectly heat troide driving four 811-10. Overall feeback of roughly 10db is optional. The 811-10 will be running at 650V, 80ma, 52W (pa). Fixed bias at around -34V.
Circuit, gain calculation, damping factor etc will be coming real soon. And I beg you please share your thoughts and advice before I make a fool of bobui.
Made in Hong Kong
Danke, Thanks a lot, Great, 謝謝你, !
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bobui
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12-05-01
13:54:49
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| 回覆 (35): DIY的大敵--自激 |
當我用我Audio 分析仪觀察時，发現很严重的高頻自激！
當無輸入信号時，輸出已有10几伏的輸出！怪不得火牛發热。
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i bet the original ST20 does not behave like this^-^ |
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drwkng
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12-05-01
13:52:27
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| 回覆 (34): DIY的大敵--自激 |
最近朋友交上來一台EL84 PP機，是別人代焊的。
朋友告訴我問題：聽约一小時的時間，火牛滾热達不可触摸的程度。其他没有細講。
打開分析：哦原來是仿Leak ST20，前三支X7，后四支EL84。
當我用我Audio 分析仪觀察時，发現很严重的高頻自激！
當無輸入信号時，輸出已有10几伏的輸出！怪不得火牛發热。
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cpyip
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12-05-01
10:01:27
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| 回覆 (33): DIY 自作派同好同學會 |
Oh, tell me about it! I have heard and seen DIYers claiming houdreds of SE watts in class A from a transmission valve without knowing what grid current is. "The mains transformer is huge and I have the output cow special made, what grid current? no worry".
Basic characterics info of a valve is written clean and ready for anyone to study for free. |
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bobui
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12-04-30
17:27:04
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limage
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12-04-30
16:28:58
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| 回覆 (31): DIY 自作派同好同學會 |
I am not fond of the 12.1 but it does claim it has only 0.1 percentage distortion. Ah, did they have a distortion analyzer in the late 50's?
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and yes. i measured one and it is as stated. i think before we sneeze at those amps of the bygone age, we better take a good look. these beat many of the so called great diyed amps. well, at least they are normal and balanced. |
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drwkng
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12-04-30
16:22:44
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| 回覆 (30): DIY 自作派同好同學會 |
I am not fond of the 12.1 but it does claim it has only 0.1 percentage distortion. Ah, did they have a distortion analyzer in the late 50's?
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bobui
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12-04-30
15:40:54
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| 回覆 (29): DIY 自作派同好同學會 |
All you get from using a pentode as a gain stage are lots of gain & distortion
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in the hands of master, they can do magic. just look at Western electric and old german gears. it is just us mere mortals who can't make anything good out of them. |
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drwkng
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12-04-30
15:04:34
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Derek2A3
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12-04-30
14:44:40
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| 回覆 (27): DIY 自作派同好同學會 |
Pulse condition is what the scanned pages of the PL509 were trying to tell. Probably more relevant to TV application. I wouldn't torture myself lor! And I don't even have the bolts and nuts to get into radio frequency yet!
Nevertheless, reading the first few chapters on radio frequency already offer me an awful lot of bonus knowledge!
Here is an example: Tons of valve preamps and power amps from the hey day of valve/tube time were based on EF86, 6AU6 and EF37A as input gain stage, right? I have heard comments that these pentodes were the main killer for the lack of high frequency in all these classic amps. "bobui, throw them away if you want to hear high frequency in your DIY amps".
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bobui
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12-04-30
13:21:55
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| 回覆 (26): DIY 自作派同好同學會 |
This is taken from one of the tube manuals I grabbed years ago, possibly from Philips.
At the time I was using the EAR549, all I did was to check every PL509 to make sure it operated up to the spec and as a user, I supposed that would be good enough.
I do not profess to understand anymore than 20% of its contents and the graphs, instead of shedding light to help my vision, only leave me with more questions than answers!
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limage
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12-04-30
12:25:35
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bobui
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12-04-19
16:59:42
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| 回覆 (24): DIY 自作派同好同學會 |
| Very serious DIY from Netherlands. The power tube isTB3/1000, equivalent to 833A made by Philips. The tve in the mddel fo frthe chassis is a 300B. |
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bobui
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12-04-19
16:58:30
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bobui
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12-04-19
16:49:28
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bobui
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12-04-19
16:46:41
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| 回覆 (21): DIY 自作派同好同學會 |
Is that a pair of 3/5A?
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Ah, they were used as steps for my old cat bill to stop him from hurting his arms/legs when jumping off from the wardrobe. And they are the 3/5A long lost cousins, Linn Kan! |
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bobui
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12-03-26
12:22:11
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icefox
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12-03-26
12:10:54
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| 回覆 (19): DIY 自作派同好同學會 |
bobui, don't bring in the leak until you've got the room acoustic & speaker placement figured out
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See guys, i do have friends in 1PK! |
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bobui
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12-03-26
11:49:41
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| 回覆 (18): DIY 自作派同好同學會 |
| bobui, don't bring in the leak until you've got the room acoustic & speaker placement figured out |
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Derek2A3
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12-03-26
11:46:07
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| 回覆 (17): DIY 自作派同好同學會 |
bobui, you know that I am always honest
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I know, thats why i sometimes want to kill you.
Should Lowther stay or should Lowther go? Emmmmm, I think i should work hard to apply effectively on all the planned adjustment to the listening environment before a judgement call.
And let me be honest to you too! Yesterday was the first time I cooked pasta in pesto. Glad you like it! |
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bobui
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12-03-26
11:33:36
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| 回覆 (16): DIY 自作派同好同學會 |
bobui, you know that I am always honest .......... your DIY caliber on this "thing" certainly set a high standard for your DIY Hi-Fi, ^__^!
Now you know what to do when you need to summon a crowd to your den auditioning your DIY Hi Fi for comments!!!
The new route to D-bay is indeed quite a nice ride. I prefer that than going from the sea. Thanks, it's a nice present day!
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icefox
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12-03-26
10:23:48
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limage
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12-03-11
14:32:59
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dd845
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12-03-10
09:18:25
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| 回覆 (14): A day of sorrow |
9th March 2012, a day where Mrs bobui choose to play a keyboard version of the Handel Largo Xerxes for a bobui family member "bill". He passed away in peace this afternoon at the age of 13. Equivalent to a human of 65.
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bobui
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12-03-09
18:32:36
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daiwok
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12-03-03
08:31:18
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dd845
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12-03-03
07:02:32
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