HiFi Fever

標題: DIY Marantz 7C [打印本頁]

作者: alfcat 時間: 2007-11-25 22:52
標題: DIY Marantz 7C
In order to ease the pressure from work, I finally ordered a PCB version of Marantz 7C.

Have thought of a number of possibilities; Marantz 7, AudioNote or even Matisse and Macintosh. Saw this set at a reasonable price and finally ordered it.

Spent 4 hours going through everything in a "no hurry" manner since I learned from the terrible mistake made when modifying the CD 33.

Still looking for a good case .... that is the troublesome part. I also need a volume switch and an ON/OFF switch as well.

為了幫自己減壓, 終於忍唔住, 訂左套Marantz 7C番來玩.之前都有考慮過幾個套件; 如 Marantz 7, AudioNote, Matisse, Macintosh 等. 這個套件價格也算合理, 結果訂了回來一試.

用了四個小時來整合. 吸取了之前改CD 33 的慘痛教訓, 今次一於慢慢來.

唔 ... 重要找一個型仔case, 開闢, Volume 制.....

作者: SSWONG 時間: 2007-11-26 13:11
Hi Cat,

When u purchase this M7 pcb, is it come with schematic diagram, part list and instruction to assemble it? Do u have softcopy of it, if yes can u email it to me? I will see whether i can DIY 1 with direct soldering...

i recently had DIY a tube preamp using 6N3 tube but result not so good need a lot fine tune and study.....

ss

作者: tungming 時間: 2007-11-26 18:17
Cat,

I bought it too and finished it last week. I note that the R 14 and R30 is empty. Is it OK? :roll:

WINDWSS,

You can download it on DIYZone
http://www.diyzone.net/article.php?sid=620

作者: alfcat 時間: 2007-11-26 19:44
Dear WINDWSS,

KTChow gets ahead of me and gave you the link. I got the kit at my3c.net and the price is okay.

Dear KT,

Yes, the sockets for R14 and R30 are empty. They are used for doing measurements.

Have you power on the Pre-Amp yet? What case are you using? If you tried it out already, please tell me how do you feel about it.

What else did you buy with you, e.g. Volume control, ON/OFF switch ...

CAT

作者: tungming 時間: 2007-11-26 23:24
I bought the input selector. It is good for sorce. The sytem is a little bit hum (need to close the speaker). I am not sure my system problem or M7c because this is my first project. the power Amp is with pre amp that the high end has distortion but the middle and base is good.

作者: tungming 時間: 2007-11-26 23:29
My next prject is 6L6 and test to fix M7C high end distortion.

作者: alfcat 時間: 2007-11-26 23:39
Dear KT,

Which brand / model of CD player are you using?

Did you get a case for this Marantz 7C?

CAT

作者: tungming 時間: 2007-11-26 23:49
My CD player is Sony DVD/HDD.

I have case in ssp wf.

作者: tungming 時間: 2007-11-26 23:51
Is your M7C on? How about the sound?

作者: alfcat 時間: 2007-11-27 10:04
Dear KT,

NO, I haven't got the M7C working yet as I don't have a case.

If this M7C works fine, I MAY go and try working on a 2A3 project. However, this relies greatly on whether I have the money or not.

If I go for the 2A3, I will try doing it through direct soldering / scaffolding (搭棚).

作者: SSWONG 時間: 2007-11-27 16:41
Thanks for the link.

By the way what's the transformer specification you are using?
240V:300V? how many A?

作者: SSWONG 時間: 2007-11-27 16:45
Dear Cat,

Do u mind telling me how much u spend to purchase the M7C kit? is the price include the transformer?

作者: tungming 時間: 2007-11-27 18:25
Cat,

Case website.
http://www.vt4c.com/shop/program/main.php?cat_id=1&group_id=2&hit_cat=

作者: alfcat 時間: 2007-11-28 09:29
Dear WINDWSS,

I got the kit from www.my3c.net. They got plenty of DIY stuffs at reasonable price.

The M7C package I ordered includes the Transformer, a TIME DELAY unit, the PCB for the M7C and ALL the components. As you can see the components are not TOP grade but really acceptable. By the time I got more money, I will upgrade some of those.

From DIYZONE you can see there are quite some people using that kit to assemble M7C. They have each and every step instructions there under the Pull Down Menu on the Top "分類文章". Pretty comprehensive.

The PCB is pretty nice, much much better than our CD 33 PCB. It is thick, solid and well manufactured. We should be able to solder and de-solder a couple of times before we run into trouble.

CAT

作者: alfcat 時間: 2007-11-28 09:31
Dear KT,

Thanks for the link. I looked into it as well. Some of their cases are good but the price is a bit high as well.

Did you ever order anything from this site? Do they provide good service?

CAT

作者: tungming 時間: 2007-11-28 12:26
Dear Cat,

No sir. I just found it last night. Their parts are cool that I send to you.

Another tailor-make case in China. It seem wait a long time for delivery. But I'm not try it.

http://www.diybuy.net/forum-75-1.html

KT

作者: SSWONG 時間: 2007-11-28 14:01
Hi all,

Attached is the photo of the 6N3 tube preamp i recently made, since the diagram i have is not complete some of the rsistor value is not given, i'm still working to finetune it....

it's mid especially the vocal is vibrating, do you think it is because of wrong value use in low pass/high pass filter? At this moment i did not use any volume pot.

i had change the various value of the cathodr resistor but it only affect the volume not the quality of the sound.....

the vibration most serious at vocal rangr, and a bit on high frequency, low frequency is ok....

ss

作者: SSWONG 時間: 2007-11-28 14:27
this the schematic i use and measurement done as in the picture... hope some expert here can advise me why the sound at vocal range is vibrating....
thank you...

作者: cyrus 時間: 2007-11-29 15:34
Dear alfcat,

Just noticed that the website is from Taiwan, is the price listed also for New Taiwan Dollar? Can you advise how much have you paid for the whole package including mailing fee, if any?

作者: alfcat 時間: 2007-11-30 08:35
Dear WINDWSS,

Wow ... this is really DIY type. You are re-cycling old stuffs to make the case ... interesting.

My M7C is close to finish. Should be ready by Sunday. Will post the photos of each stage later.

Really regret getting a "Ladder Type" volume control. Spent over 4 hours soldering that 92 registors onto the switch. But once you know how to do it, you can do it in an hour's time.

I can't help on the schematics ... I really hope I can .. ha..ha...

CAT

作者: alfcat 時間: 2007-11-30 08:39
Dear Cyrus,

Yes of course. The company is a Taiwan firm. You can convert the $ amount into HK$. Currently should be around HK$ 1 to NT$ 4 or so.

I haven't got my VISA statement yet, so don't know exactly how much it cost me. The company is jointly organized with DIYZONE.NET
For the parts you ordered (like my M7C), there is no instructions inside, you have to download the "sharing" from Diyzone.net, suggesting how to finish the whole thing.

You can select the date of delivery. Normally, they deliver even before your selected date. I ordered on Sunday, they came on Tues afternoon.

CAT

作者: cyrus 時間: 2007-11-30 08:56
Dear alfcat,

The price is really attractive. Thanks again.

作者: Koifarm 時間: 2007-12-1 03:40

this the schematic i use and measurement done as in the picture... hope some expert here can advise me why the sound at vocal range is vibrating....
thank you...

I do not know how much amplication you need. But i here is an other proven schematic with the same tubes and voltage.

作者: deicide67 時間: 2007-12-1 05:37
[quote:b9bc1b3bfd="Koifarm"]

this the schematic i use and measurement done as in the picture... hope some expert here can advise me why the sound at vocal range is vibrating....
thank you...

I do not know how much amplication you need. But i here is an other proven schematic with the same tubes and voltage.

[/quote]

I concur that this would be a much stronger cleaner circuit, and it does not look chopped and modded like you other circuit drawing. Takes alot of guesswork out of it. If you will notice, this is a totem circuit like the 12AU7 circuit I sent you. If the 6N3 is anywhere close in charachteristic to the 12AU7, you will like this schematic.

Blair

作者: alfcat 時間: 2007-12-1 22:27
After almost a week of bit by bit hard work, I finally have my Marantz 7C FINISHED !!! So happy a man I am now ...

:

The most terrible part of the whole project is the "Ladder Style" Volume switch. I promised myself NEVER EVER to do another one. Spent over 5 hours and I am not satisfied. Learned the tricks but can do much better (if someone cheats me to make him one).

This is one interesting project for me. If I can spare some money, I will DIY probably a 2A3 amp. This time will adopt the "direct soldering" or what we Hong Konger called "scaffolding method".

CAT

作者: alfcat 時間: 2007-12-1 22:31
Power Line using Belden solid core. Connecting wire (Black & White) are Pure Silver Wire. Volume switch wires are silver clothed copper wires.

Anyone interested in buying this toy? Ha..ha... I haven't finish the case yet. Will make it pretty and nice ...

CAT

作者: tungming 時間: 2007-12-2 01:05
Congratulation!! How about the sound and where you bought the case?

KT

作者: alfcat 時間: 2007-12-2 08:28
Dear KT,

I got the case at my3c.net at last. If I buy it at the same time with the kit, I won't be paying for a second postage.

The sound is VERY VERY nice. I won't say it is excellent as there are lots of better machines around. Female Vocals are so wonderful, even better than the Matisse I am now using.

I like listening to 曼里 (Money) and 蔡琴, etc. They sound more natural and feminine using this Marantz 7C. 陳百強 was a bit too high with the Matisse. He sounds more like himself using this M7C.

Overall speaking, I will rate this as "8" and my current Matisse as "7" out of a "10" scale.

CAT

作者: accphoto 時間: 2007-12-12 13:59
Your Matisse had much more potential than your marantz preamp, i think. Matiisse had better dynamic but using WiMA will make it sound harsh. Try to use other caps on the Matisse, it will have quite a different sound.

作者: alfcat 時間: 2007-12-12 16:32
Dear Accphoto,

I don't have much money as you do la ... ha..ha...

:

If I need to change the caps, I think I will have to group several good caps together ... that will be pretty expensive.

What brand would you suggest me to use?

CAT

作者: SSWONG 時間: 2007-12-14 11:12
Dear Vash,

Thanks for guidance all the time.... i will shift to your proven 6N3 if i still not able to figure out the problem...

Dear Cat,

I got no choice in Malaysia not easy to find part or at premium price....so has to make use of all sort of available resources....

I wish to do scafffolding too but can't get the not sure where the get the coper rod....

作者: accphoto 時間: 2007-12-14 12:55
Dear CAT,

If budget is a concern, try Auricap, it will make the whole thing sound a lot different. It will cost you about a few hundred dollars, the second stage output cap , you can use 3.3U 200V instead of 400V. Jensen is of course miles better.

作者: alfcat 時間: 2007-12-15 10:27
Dear Accphoto,

Thanks for your advice. I will see how much it is going to cost me. Maybe I will go it stage by stage; that makes the thing more affordable.

Have you ever tried the GLASS capacitor from Rifa. They look really interesting.

CAT

作者: alfcat 時間: 2007-12-15 12:40
Dear WINDWSS,

I understand the harsh situation in Malaysia. It is a great countr for leisure but sometimes it is a bit "remote" to get advanced stuffs.

We ordered quite a number of things from the Internet; like www.my3c.net, www.thlaudio.com .... I think there is some good OCC copper cable at my3c and the price is also reasonable. We had a number of transactions with them and quite reliable too.

CAT

作者: viewer 時間: 2007-12-15 18:25
HI ALFCAT,

I SAY THE GLASS RIFA FILM CAP IS ENCLOSED FOR YOUR REFERENCE.
I REPLACED IT IN MY SPEAKER. ITS SOUND CHANGED CLEAR AND DETAIL.
GOOD CAP.

THANKS.

作者: alfcat 時間: 2007-12-16 08:00
Dear Viewer,

I have got 4 of those but all are 0.33u / 250V. I would like to try them on the Marantz 7. What do you think?

CAT

作者: viewer 時間: 2007-12-16 15:28
hi alfact,

I think the result is postive, sound become solid and clear.

go ahead.

thanks.

作者: alfcat 時間: 2007-12-16 15:49
Dear Accphoto,

Do you know where I can get a good deal on Auricaps?

Please advise. Many thanks.

CAT

作者: viewer 時間: 2007-12-16 18:35
Hi alfcat,
I buy it at this shop in H.K. because they are the dealer of these cap.
it price is quite reasonable.
http://www.soundexplorer.com/home/home.htm
0.1uf/400v around HK$80 each
2.2uf/400v around HK$145 each
They have 200v also it would be cheaper.
thanks.

作者: viewer 時間: 2007-12-16 18:42
hi alfcat,

I feel the rifa glass cap high notes is little bit better than Auricaps.
mid range and bass Auricaps is better.
Auricaps is very balance cap no suprise to me.
rifa's cap is very good in high notes so if for female voice is better.
you can replace to rifa caps first, because you got it aldy.
the costs of Auricaps is few hundred la !!!!!!!!
just for sharing.

作者: DUALXEON 時間: 2007-12-17 05:36
Cat Sir

你聽人聲多Jenson啦,好嘢唔會平,一分錢一分貨.

作者: alfcat 時間: 2007-12-17 09:28
DualXeon 兄,

好耐無見, 一切可好?

唉, 我都知 JENSEN 好, 但真是能力有限 .... :cry:

多謝提點 :wink:

CAT

作者: accphoto 時間: 2007-12-17 23:01
The original circuit of marantz using 0.01 and 0.22 as the by-pass cap.Just bear in mind that the original design was with early LP in mind, so everything under 70 hz was cut. I have played with the marantz circuit for more than 10 years, my experience is that if you are using modern caps, the original value of 0,22 will make the amp sound harsh. I suggest you to replace 0.01 with 0.1 and 0.22 with 2-3U. i have play with kimper caps, the high are not smooth enough, and the MIT caps which is too hi-fi.
If you are aware that Sid Smith 7, the amp that sell for 30,000+ are using Auricap with the above suggested value. The top version is using Jensen silver cap ( 4K each) and selling for 100K. so, there is virtually no secret to good sound, a good design with good material. Good design is no secret nowadays and the key is to get good material. You kit supply with WIMA cap, which is not very match to tube in my opinion.

作者: accphoto 時間: 2007-12-17 23:02
I had not try RIFA caps, however, a lot of factory like cello, Mark , using RIFA as by pass caps. My feeling is that it sound a little bit harsh on the highs like a lot of transistor amp. I had already replace those even though my DAC using RIFA caps.

作者: DUALXEON 時間: 2007-12-18 04:44
cat sir

我只是講事實,無其他意思.

聽人聲Jensen啦.

作者: alfcat 時間: 2007-12-18 11:17
Dear Accphoto,

Thanks for your opinion. I will check those caps out later as the Marantz 7 is not with me for now. I lent it to my colleagues for a try out.

I would very much like to change the WIMA caps on both pre-amps. I got the "authorization" from my colleague already .. ha..ha.. that I can modify the Matisse he lent me.

CAT

作者: alfcat 時間: 2007-12-18 11:53
DualXeon 兄,

我只是講事實

係朋友先講事實 .... 多謝!

CAT

作者: kkwan18 時間: 2007-12-19 04:04
Hi Cat,

Whats the Marantz 7C sounds like with the ladder type volume instead a normal Alp pot, is it worth the extra $$$$ , because i like to put together the Marantz 7c but not that good at soldering all those resistors on to that Pot, is there a Phono amp part for it?

kkwan

作者: alfcat 時間: 2007-12-19 09:39
Dear KKwan,

I haven't try what difference it makes with the ALPs as I haven't got one. Frankly, I DON'T really like the ladder type. It is not very convenient. As it goes step by step, not exactly continuous.

I like the ALPS in the Martisse. Don't know how much it costs now but it worked fine for over 10 years.

If you happened to look at my previous photos, I mentioned never in my life I want to solder another ladder type again. I like soldering but this thing is indeed a headache. I now managed to obtain some "tricks" in doing this thing. IF and only IF I have to do one more, it should take around half the time I took last time. For a first timer, better off get one already done with good workmanship.

The Marantz 7C I got has NO phono part. The WIMA capacitors definitely can be replaced for better listening pleasure.

There are numerous versions of the Marantz 7 around. Some comes with Phono Amp part. You just have to pay for it.

Will be able to get your remote by tomorrow night.

CAT

作者: accphoto 時間: 2007-12-19 12:04
Ladder type volume of course had a significant difference in the sound. CAT using Dale resisitor so the sound is very neutral. while holco resistor and RMG resistor will give you a detailed and sweet sound. Most high value gears using ladder type volume. The difference is more than the different of $300 against $60. ha....ha..... All my pre-amp are using ladder type now. Actually William have some ready-made ladder volume pot with Dale resistor , you can buy direct from him. I think it is below $ 300.

作者: kkwan18 時間: 2007-12-19 21:08
Hi Cat,

How much was the Marantz 7c kits cost u in total, I will be back in hong kong in Chinese new year so that i can pick 1 up....

Excuse my ignorance accphoto, where can i get the ladder type volume from as you mention (William)

kkwan

作者: accphoto 時間: 2007-12-19 23:38
WIllian is the admin of HiFiFever......

作者: kkwan18 時間: 2007-12-20 01:30
Hey thanks accphoto for telling me......

作者: alfcat 時間: 2007-12-20 07:42
Dear KKwan,

I got my Marantz 7C from www.my3c.net. The price there is in NT. Divide it by 4 and you get $ amount in Hong Kong. They ship worldwide. The KIT includes Transformer, Delay output unit and ALL parts like capacitors, resistors, vacuum tubes, etc.

My3c.net is associated with www.diyzone.net. From DIYZONE, they have passages teaching you (from different people) how to assemble the kits, very comprehensive.

There are lots of items for you to shop around from my3c.net. You can also find the Ladder Type Volume control there, either in KIT (DIY) or finished product.

In Hong Kong, you can find many shops selling these ladder type VR as well. They range from HK$ 4xx to over HK$ 2K.

I will bring your remote up to China now. If I am home early, will tell you about the news.

CAT

作者: cyrus 時間: 2008-1-14 17:04
Hi Alfcat,

Are the components you used (Holco/Dale resistors, WIMA/BHC capacitors, the transformer, etc) came with the package? If not, where can you buy all those components? Are they all matched with the circuit? Is there any odd value resistor (e.g. 82K) that you can't find? If true, can you share how you resolve this?

Best rgds,

作者: alfcat 時間: 2008-1-14 17:43
Dear Cyrus,

Sure, I can share my experience with you.

Almost everything comes with the Package; Transformer, Delay output unit, tubes, capacitors, resisotrs ....

Items not included: On/Off switch, Case, Volume control, wiring (mine is pure silver). The RCA sockets and the Balance output socket comes with the case. The cover of the case (Entry100) has NO holes drilled! Be aware of this.

I did changed the CAPACITORS of the pre-amp. Very common ones and I used Auricaps. You can for sure find those in "Hoi Wan" down in 558 Nathan Road or so. Changing ALL the caps will cost you around HK$ 900.
I changed them because my colleague (who is the owner of this M7C now) would like to have more BASS.

You can order the whole thing from www.my3c.net. One word of reminder. Another active member said this set of Marantz 7C is not the best around as the voltage is a bit low. However, for just under HK$ 2000 with everything for a DIYer, it is worth as a beginner project.

Hope this helps.

CAT

作者: cyrus 時間: 2008-1-15 00:30
Thanks much, alfcat.

作者: alfcat 時間: 2008-1-16 13:07
Dear Cyrus,

Any interests in constructing one? This set is very easy to do with good instructions downloadable from the net.

Hi Fi Fever also got this M7 kit. You have to give them some time to pack everything for you. The price is a bit higher but the quality is much better!

CAT

作者: cyrus 時間: 2008-1-16 13:49
Hi alfcat,

Really wanna get 1 but I want to attend a pre-amp training from Hifi Fever first, cos I know nothing about building an amplifier. As you know, the PCB and Schematic won' tell you how to connect wires from/to transformer, RCA sockets, volume controls, selectors etc..., that's part of the amplifier. After I gained the experience, I'll try to build 1 by myself.

作者: accphoto 時間: 2008-1-16 13:54
Cyrus,

Don't build this one, it sound so so, ask William to get you a real Marantz 7 kit from China, the pcb layout and it is using original value. or try Matisee reference.

作者: alfcat 時間: 2008-1-16 16:43
Dear Cyrus,

What Accphoto said is true. This one is just a BUDGET model. Good only for a try out. If you want something that will last .... get the better one.

Remember, this one is just HK$ 2K or so. A much better one cost around double to triple the price. You have to pay to get a better one ...

:

Joining Hi Fi Fever course is fun. If I can spare the time (& of course $$$), I would like to meet with them again.

CAT

作者: accphoto 時間: 2008-1-16 21:58
Actually, it should not cost that much. I had build a Marantz 7 ( the real circuit with 膽穩壓，using auricap and Elna Cereine ,it cost about 3K without the tube.

作者: cyrus 時間: 2008-1-16 23:52
That sounds good, can't wait to have my own one!!!

作者: kkwan18 時間: 2008-1-17 07:27
Hi Cat,

Thanks for the remote, its working fine now...

According to every body here its better to get a more expensive version of Marantz 7 then the 7c, or should i try the new LS7 Preamp kit {kit-ARCLS7} from hififever shop, it seem that the LS7 is a near identical copy of the original Audio research LS7, will it go with my Antique soundlab AQ1004 power amp to complete the system.

kkwan

作者: accphoto 時間: 2008-1-17 08:32
LS7 sound quite different to Marantz 7, it is a matter of taste. LS7 sound like modern tube amp which have more dynamic, extension and faster. It does not sound like a tube amp. The default kit using bennic capacitor which need to be changed. For the Marantz 7, if appropriate run-in and with better parts, it is more musical and sound "thicker". Your power amp i also important because sometimes it is a mix and match.

作者: alfcat 時間: 2008-1-17 09:11
Dear Cyrus,

I mixed up Marantz 7's price with something else. The Marantz 7 should be around $ 3K without tubes and case, just like Accphoto said. And with that budget, the components are already very good ones.

CAT

作者: cyrus 時間: 2008-1-17 11:15
Thanks to Alfcat and Accphoto.

I'm planning to join the pre-amp course, do you recommend any models other than Marantz 7? They are now offering AudioNote M7, ARC LS-7, Conrad Johnson PV-3, Marantz 7, GG and 禾田茂氏.

作者: accphoto 時間: 2008-1-17 21:39
A lot of people like GG, but I need manage to get really good sound from this circuit. It is quite simple in effect and good for really beginner. From a design point of view, marantz 7 is the best because the cathod follower will result in lower output impedence. I had not tried audio note m7 and conard johnson , so I am unable to comment on it.

作者: alfcat 時間: 2008-1-18 08:38
Dear Accphoto,

How do you feel about the McIntosh C22 from www.my3c.net? One of my colleagues is interested in this kit. He is thinking of buying it and wants me to assemble it for him.

I think it is better to check with you as you have more knowledge on this field.

BTW, I fixed the EL34 (one side). The sound is not impressive. As it was too late last night, no time for the second block. Will see if I can complete both tonight and have it assembled and go for a test.

CAT

作者: accphoto 時間: 2008-1-18 12:07
C22 is basically a Marantz 7 with different value. I think Marantz 7 will be better.

I have a Jadis JP-200 half finished, I do not know whether your friend will be interested, you can finished it off for him. I am using premium parts like MIT and Philips Cap, just like the original one. .......Please PM me to discuss if your colleagues interested. I have PCB, tube stabilizer, transformer and case available at the moment.

作者: alfcat 時間: 2008-1-18 15:22
Sent an email to your company's account

CAT

作者: SSWONG 時間: 2008-1-30 13:53
Accphoto,

Need your advice.

Recently i DIY a 5687 tube pre amp, when use on DVD player as a source, no hum/very little hum but when use Bada tube CDP as source will have high hum.

the hum sound is ngggg at woofer only. then i disconnect my grounding in my tube CDP, hum sound become worst, got eee sound from the tweeter as well (much more distortion).

i didn't ground my supply to the filament.

Besides, what shall i adjust if i replace the 12AX7 in M7 to 12AU7?

TQ

作者: accphoto 時間: 2008-1-30 14:22
Oh, it is a ground different between two devices. You need to check whether your tube CDP and your pre-amp had ground the 水線 to the case of the device or some even connect to the 水線. It is better to connect both 水線 to the case.
For filament supply, there is normally two ways in reducing the hum sound, some will ground one filament, other method will connect a high voltage ( say 100V) to the filament and float the filament from the ground, both ways should be ok to reduce hum.

For change the 12AX7 to 12AU7, it is not that simple as these tube had different operating condition. Need to change the bias resistor and the 陰極電阻。I will check my circuit with me tonight and let you know.

作者: alfcat 時間: 2008-1-31 22:01
Dear Accphoto,

My colleague gave me a difficult question. He asked how is my Matisse stands up to your JP200? Which wins in what aspect?

Do you think you can make a comparison?

CAT

作者: accphoto 時間: 2008-1-31 22:11
no, i can really give you any comment as i have not finished the kit yet. But base on circuit design, Matisse is more dynamic and hifi and JP-200 should be more lay back and musical. It is really until you finish it and you do not really know how it sound. Does it sound chanllaging?

作者: oldbeandad 時間: 2008-2-2 12:14
Hi folks,

May I join in to bring your attention to a good pre-amp which is not as popular as the M7 and Matisse do. It is called "Magus" of which the circuit was designed by Bruce Moore. I have my Magus built 20 years ago and it is still with me now. It has the phono stage, so I hook it up to my turntable. For listening to CDs, I have the Matisse which was built almost 18 years ago if I am not mistaken.

There are 5 common tube pre-amp circuits introduced in the Audiophile (The high end audio journal of Hong Kong). You guys may be interested in.

作者: alfcat 時間: 2008-2-3 09:24
Dear Cheaplow,

Nice Sharing.

CAT

作者: SSWONG 時間: 2008-2-4 11:15
Dear Accphoto,

Since the preamp i make is in a wood box, so no grounding to the box. all grounding connecr to the main ground on the 3 pin plug.

for my CDP, the ground of the pcb is connected to a capcitor then to the chasis (to reduce rf) so the chassis is actually not grounded.

作者: accphoto 時間: 2008-2-4 15:15
Wooden box is always a problem for grounding. Did you got any metal plate on the wooden box, you can ground the earth to the metal plate to replace interface. Alternative, you can remove the cap on the cpd and ground it to see it will better or not.

作者: alfcat 時間: 2008-2-6 10:36
之前我也想過用亞加力膠片做 case, 因為好有型. 但想到 Grounding 問題, 結果都係放棄 ....

CAT

作者: SSWONG 時間: 2008-2-18 10:44
Dear all,

My tube preamp is using 5687 tube (circuit close to audionote M7 but i run B+ at 130V only).
The noise reduce a lot after i do the following changes:

1) change to metal casing
2) restructure the grounding (use star grounding)
3) add in another C-R-C (total 4 CRC in series)
4) Reduce plate resistor ( increase the voltage supply)

Thank you everybody here for advice.

作者: accphoto 時間: 2008-2-18 21:18
130V is too low. I suggest you to increase the plate voltage to 200v and use the orignal value of resistor. You will find the ' 動態" is much better. For power supply, it is better to use CLC rather than CRC and you will find the noise is much lower when you use CLC. About 10 H coke will be better and cost very low ( about $ 100 if you buy local).

作者: cyrus 時間: 2008-2-19 11:11
Hi all C Hing,

Would like to know what is CRC and CLC.

作者: accphoto 時間: 2008-2-19 11:50
CRC = Capacitor + Resistor + Capacitor
CLC = Capactior + Coke + Capacitor

Ways to reduce ripples in power supply.

作者: cyrus 時間: 2008-2-19 18:35
Oh I see, thanks.

作者: alfcat 時間: 2008-2-19 19:58
Dear Accphoto,

I think you mean "CHOKE", ha..ha... caught your mis-typing.

I agree with you, CLC should be better than CRC. But need to reserve room for the choke. It will be easier if DIY as we fix the dimensions ourselves. But if doing modification, depends on whether the case got room for a good choke, right?

CAT

作者: accphoto 時間: 2008-2-20 01:14
ka ka ka....... yes , I mean choke.... instead of coke......ka ka ka....

作者: SSWONG 時間: 2008-2-21 17:13
no source of cheap choke in malaysia at this moment..

i'm think instead of choke can i just use the inductor 10mH?

maybe use 1 C-RC follow by 1 CLC....

作者: accphoto 時間: 2008-2-23 00:32
One famous local manufacturer selling choke of 10H 100ma , for only $80 (about USd 10.00), Sound ok but of course not up to those japanese one like tango or tamura.

I know someone tried to use inductor but its effect is weak when compare to choke. I can help you to buy one or two .

作者: SSWONG 時間: 2008-2-28 11:03
Hi, Accphoto,

Can i have your email so that easier for me to contact you. Thne i can make arrangement with you to buy the choke....

thank you.

作者: SSWONG 時間: 2008-3-6 14:26
Hi,
attached is the 5687 tube pream/buffer i made.

Using the attached schematic but some changes
1) use only 4.7k plate resistor
2) B+ = 175v
3) chatode resistor =470R
4) SOLID STATE half wave rectifier
5) 1uF cap
6) C-R-C filter

next will make another 1 using
1) ~250v B+
2) 10K plate resitor
3) choke
4) 0.47uF mundorf ZN
5) separe box for power supply
hopefully sound will be much better

作者: sjh327 時間: 2008-3-16 19:10
M7的DIY文章又整理了9篇，大家可以參考下。

http://yunwt.u111.net/2wz2.html

作者: SSWONG 時間: 2008-3-18 11:31
云外天,

The tube preamp i made is same as your post 5687单管胆前级 in your web but i change the 1M to 470k.

plate resistor audionote using 50k, vt4 using 10k.

do u know what is the effect of th eplate resistor and the cathode resistor?
i understand that by using higher plate resistor can get better dynamic, how about cathode resistor and cathode capacitance? how's the value will affect the sound?

Do u think a DIY marantz M7 is much better than this 5687?

作者: sjh327 時間: 2008-3-18 12:45
謝謝你對我的信任，我英文不好，還是說用中文回復你吧，我用的是原廠的電路，屏極電阻是50K（兩個100K 2W電阻並聯），陰極電阻是470歐，輸出端是2微法（MKP）＋0.1微法（油浸）＋0.01微法（油浸）電容組合，聲音我還是很滿意的，聲音比較有活力和彈性，M7的優點是中頻，聽LP，FM，卡座估計會很合適的，但是高低頻略有欠缺。當然也可以通過調整耦合電容值的大小來進行補償。

作者: SSWONG 時間: 2008-3-18 16:53
No problem, i like to read mandarine/chinese. Sorry for inconvenient as i do not has software to key in chinese word.

By the way may i know your your voltage measurement on the position below during idle:

1) voltage before the 50K resistor
2) voltage after the 50k resistor (on the plate)
3) wht's teh value of capacitor (uf) at the chatode
4) voltage at chatode

作者: abelwoo 時間: 2008-5-12 09:52
[quote:90f23bdba0="WINDWSS"]no source of cheap choke in malaysia at this moment..

i'm think instead of choke can i just use the inductor 10mH?

maybe use 1 C-RC follow by 1 CLC....[/quote]

bro u try to find at FARNELL location at Subang Jaya.

http://my.farnell.com/inductors-chokes-coils

作者: icefireman 時間: 2008-5-12 22:24
To accphoto and alfcat,

You mentioned before that M7 cost around HK$3k (not include case and tube). What components are included in it such as switch, colume control (which type), etc? Is it used auricap and Elna? Is it hard to solder all the things by myself? Thank you.

Icefireman

作者: alfcat 時間: 2008-5-12 23:10
Dear Icefireman,

The one I got from www.my3c.net is NOT the best around. I think HiFiFever got a much better version of the Marantz 7. The price may be a bit higher but it also depends on the caps and other stuffs you use.

I am now building another one based on the LITE Marantz 7 board. This time I use:

Two cases: small one for power supply, large one for M7
One LITE transformer
Rectification stage using Matisse design (transistors type), not tube
All Jensen caps on M7
Cardas RCA sockets
NO volume switch as I got one
ALL RMG resistors

The whole thing cost around HK$ 4,500 or less.

Where are you located? Hong Kong?

CAT

作者: icefireman 時間: 2008-5-13 00:47
Yea, I am living in Hong Kong. I am just planning my next target. Because I just finished my UCD180. Need a pre-amp later. So that's why I want to get more info. Are you living in Hong Kong too, Alfcat?

Icefireman

作者: alfcat 時間: 2008-5-13 10:15
Dear Icefireman,

Yes, I live in Hong Kong as well. I oredered the My3c.net M7 from their website. It is just an okay product; depends on how much you want to spend and your other components.

The following photos are the parts for my new M7.

CAT

歡迎光臨 HiFi Fever (http://hififever.com/dz/)