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.....

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

Dear KT,

Which brand / model of CD player are you using?

Did you get a case for this Marantz 7C?

CAT

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).

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 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

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

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

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 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

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

Dear Accphoto,

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

Please advise. Many thanks.

CAT

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

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

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

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

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

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

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

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

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

Sent an email to your company's account

CAT

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

Dear Cheaplow,

Nice Sharing.

CAT

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

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

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

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

Dear Accphoto,

I totally agree. I have thought of using Black Gate ... but I GUESS the price will be sky high. Any other good suggestion on these two?

For Icefireman,

I got everything from Sound Explorer this time.

CAT

Good, I will go for the Jensen later on.

One thing I don't get it. If you look at the PCB of the M7 I just got, there are TWO B+ Power (280V & 260V) but there is NO B- ....

Should I use the GND to act as the B-?

CAT

Dear Accphoto,

Another thing I find really strange about this M7 board. One EACH side of the board, there is a B+ 280V and another B+ 260V. From the Schematics, it suggests supplying power to BOTH and uses the GND as B-.

If that is for ONE channel, that means I have to have FOUR 280V (two will step down to 260)??

BTW, I changed the Caps to Jensen already (Power Supply)  :wink:

CAT

Dear Accphoto,

I went there yesterday but I missed that part. Ah Tong Hing said I can use a 47K resistor to step down the 280V to 260V for B2+.

Yet, when I check the output from the Matisse Retifying Board, its DC out is 310V!! I think I need a 1M to step it down to 280V DC ....

Attached is the Schematics for the LITE M7 board. I "think" I have to direct a wire (underneath the board) from LEFT B1+ to RIGHT B1+ ... same for B2+ as well. Am I right?

Dear Accphoto,

The AC voltage from the Power Supply is 310V AC. After rectification, it becomes 309V DC.

I turned the adjustment knob (potentiometer?) on the Matisse board already. 309V DC is the MINIMUM I can get. If I turn it the other way round, it gives 325V DC.

Would you mind leaving your contact number at my email achan@sjc.edu.hk? There is something I still don't quite understand.... sorry.

CAT

Dear Accphoto,

Thanks for your help. I forgot to mention that the measurement was taken WITHOUT loading. If that is the case, should it be okay?

My Physics colleague told me that I may as well take a measurement with the loading as well. He said with loading, the voltage should drop significantly.

CAT

Dear alant,

I don't mind at all. I come here to learn and any advice is welcomed.

Yes, I am in that school. If your son happened to be in 1E, 3E, 5A, 6A or 7A, I am his teacher then. If your son is not is any of these classes, then your son is VERY LUCKY ... ha..ha.

CAT

Oh, I thing I haven't fully understand yet. The Matisse Rectifying board (when not connected to the M7 output stage board) yields an output voltage of 309V DC. Now, this is an "Open Circuit", right?

So, if I want the "True" measurement, I should connect the M7 output stage board to this Rectifying board, plug in the 12AX7 TUBES and then measure the voltage at B1+ and B2+ to see if they are 280V DC and 260V DC respectively.

Am I correct? Don't want to blow the whole thing up ....

CAT

Dear alant,

Oh, your son is lucky then. I don't teach as many class as before. If he is in Science class (in the future), then the chance of him seeing me is minimal.

Usually I am very cautious about High Voltage, although I got 9 lives.

CAT

The board should be a LITE board. I don't know why they didn't print the name on the board.

CAT

Sigh .... not only you two guys, me having the same problem with my girl as well. I only got one at 10 but I never spoil her. Her studies is driving me crazy as well.

I really don't know why kids got so many problems these days. If we were like that in the past, we won't survive up to now.

We can always switch to another forum in hififever, no restriction on kids education there.

CAT

Dear alant,

You are indeed an engineer, ha..ha... Well application of your knowledge.

Frankly, I have been in the education field for over 20 years. My workload had increased more than four or five folds over these years. Unfortunately, as you said, my students get poorer and poorer; mentally, physically and morally. We spent over 50% of our time doing documentation work which I believe is useless. We stated what we are going to do and will do but ended up never got the time to do it.

Many believed that Western education is far superior than that of HK. I studied in Canada as well. The system runs more or less the same. One major difference is that kids there are NOT flooded with homework or OLE (other learning experience). Kids there got all the time they wanted to explode themselves. They are "bold" and have no fear in trying things out. That is why people got so creative and out-going.

CAT

Let's start another thread in the 發燒鎖事 ....