Comments on: Marantz 7 Phono Pre/ Passive Line Preamp

By: chris

chris — Fri, 29 Jul 2022 17:28:40 +0000

In reply to Joe. i built it myself from scratch

By: Joe

Joe — Fri, 29 Jul 2022 17:25:46 +0000

Hi Chris, what is the model of the power supply your using for this build.

Thanks,
Joe

By: Bruce Matesso

Bruce Matesso — Tue, 25 Jan 2022 19:32:38 +0000

In reply to Tom Fine.

Hi Tom,
I read your post, Please contact me off line about SS circuits and parts. I would like to build a line stage that gets me to a higher level than what I have been able to achieve with tubes. I’d love to hear / see what you are seeing and build a circuit that I have not come across yet. please reach out.
– Bruce

By: admin

admin — Mon, 25 Nov 2019 12:57:53 +0000

In reply to Noonan.

hello, it’s a rect circuit from an old marshall combo…one cap…4 IN4007… the resistors are just ground reference. generally u end up with around 6.5v DC on the filaments. The schem is widely avail on the ‘net if u search for ‘DC filaments’. good luck

By: Noonan

Noonan — Sat, 23 Nov 2019 16:44:19 +0000

Really enjoyed reading about your build.
Would love to know how you handled creating the 6.3VDC? I see what I assume is 6.3v tap going through what appears to be a bridge rectifier, 3 resistors and a couple of smoothing caps. What voltage did you end up with feeding the filaments?

By: David

David — Thu, 13 Jun 2019 03:07:16 +0000

In reply to Andrew Linton. I think he only made the phono part of the diagram, without the bass/treble controls, which is the left side. So each channel gets a 12AX7 and then they share the third tube for the 280V cathode follower output. It's much clearer if you compare the schematic from his first build to the Marantz service schematic. In the marantz schematic they label the tubes clearly for left and right, and they share the 280V tube 3.

By: chris

chris — Fri, 06 Jul 2018 18:59:31 +0000

In reply to Andres. Hi Andres, yes, I used a 6X5, I tend to use these in most small projects. CR

By: Andres

Andres — Tue, 03 Jul 2018 22:34:42 +0000

Chris , you use a 6×5 rectifier in this build? greetings from argentina !

By: Andrew Linton

Andrew Linton — Mon, 03 Jul 2017 20:58:42 +0000

I don’t understand how it is stereo .. you only are using 3 tubes …

By: Paulo

Paulo — Tue, 23 Apr 2013 03:47:18 +0000

In reply to chris. Thanks for the advice!!! Wonderful job!!!!