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.....

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

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

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

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.

My next prject is 6L6 and test to fix M7C high end distortion.

Dear KT,

Which brand / model of CD player are you using?

Did you get a case for this Marantz 7C?

CAT

My CD player is Sony DVD/HDD.

I have case in ssp wf.

Is your M7C on? How about the sound?

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).

Thanks for the link.

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

Dear Cat,

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

Cat,

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

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

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

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

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

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...

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?

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

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

Dear alfcat,

The price is really attractive.  Thanks again.

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: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

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

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

Congratulation!! How about the sound and where you bought the case?

KT

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

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.

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

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....

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.

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

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

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.

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

hi alfact,

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

go ahead.

thanks.

Dear Accphoto,

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

Please advise. Many thanks.

CAT

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.

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.

Cat Sir



你聽人聲多Jenson啦,好嘢唔會平,一分錢一分貨.

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

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.

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.

cat sir

我只是講事實,無其他意思.

聽人聲Jensen啦.

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

DualXeon 兄,

我只是講事實

係朋友先講事實 .... 多謝!

CAT

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

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

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.