Marantz 7C Kit

bigger

Member
2010-09-22 6:14 am
I want to buy something made in N. America, all the offerings I see on EBAY are Chinese. I sent these people some emails and I get fast replies and they are very willing to help.

I going to give them a try and order all 3 boards they sell. It looks like a great way to put together a pre-amp quickly and on a limited budget.

I'll let you know how it works out.

I'd rather take a chance in the N. America then send my money to China.
 

bigger

Member
2010-09-22 6:14 am
Marantz 7C

After seeing the replies here, I decided to do a little research on the Marantz 7C, it looked like a well thought out circuit that has a very loyal following by many audiophiles, here and in Japan. So I took a chance and ordered a set of boards. (I just hate discounting anything without at least giving it a chance!)

The boards arrived today and I plan to start building over the next week. BTW, the build quality looks top grade.

I'll let you know how it turns out.

Is there perhaps a better area on DIYAUDIO to discuss tube type equipment? I just thought the comment that the circuit was outdated probably is due to the fact that the person replying is a solid state kind of person.

I am a tube lover, and all my main equipment has at least 1 tube in it, even my DAC!
 

SY

diyAudio Moderator Emeritus
2002-10-24 10:19 pm
Chicagoland
www.SYclotron.com
I suspect that it's fine (NP is an extremely skilled designer), but I don't know that particular circuit. Start with the question, what do you need your preamp to do?

1. What are your sources?
2. What's the input impedance and sensitivity of the power amp(s)?
3. Are there unusually long interconnects to the power amp?
4. (And here's where real self-honesty is important) Do you want the preamp to merely make a small signal larger without otherwise changing the sound or do you want it to act as an effects box?
 
Thank you for your thoughtful reply. I clearly have a lot to learn, but to answer your questions:

1. Sources are all cd players: Cal Aria and DX-1, and Sony dvp-s7700.
2. The amp is a Marantz 250 M. Input sensitivity is 1.5 v, and the input impedance is 100 kohms.
3. The interconnects are 3' long.
4. I do not want an effects box. The issue of gain is something NP discusses in his write-up for the Buffered Preamp design, and if I have it right, he feels that most preamps have too much gain designed into them to allow the amp to operate efficiently. He says that if you set your volume control to 9 o'clock it's squandering the potential of the power amp. As a beginner to DIY audio and electronics in general I am taking this at face value, but it does resonate with some other stuff I've heard.
 

SY

diyAudio Moderator Emeritus
2002-10-24 10:19 pm
Chicagoland
www.SYclotron.com
Thank you for your thoughtful reply. I clearly have a lot to learn, but to answer your questions:

1. Sources are all cd players: Cal Aria and DX-1, and Sony dvp-s7700.
2. The amp is a Marantz 250 M. Input sensitivity is 1.5 v, and the input impedance is 100 kohms.
3. The interconnects are 3' long.
4. I do not want an effects box. The issue of gain is something NP discusses in his write-up for the Buffered Preamp design, and if I have it right, he feels that most preamps have too much gain designed into them to allow the amp to operate efficiently. He says that if you set your volume control to 9 o'clock it's squandering the potential of the power amp. As a beginner to DIY audio and electronics in general I am taking this at face value, but it does resonate with some other stuff I've heard.

My apologies for this late answer, I hadn't seen your reply. It looks like you don't even need a preamp- at most, all you need is a unity gain buffer. But frankly, a passive volume control will be more than fine, and save you a pile of money and effort (which you can put into other areas of your system or, gasp!, buy music).