Monogram Build.

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chris65

  • Jr. Member
  • Posts: 4
Monogram Build.
« on: 15 Jul 2013, 12:19 pm »
Hi,
First post here, but have been reading the forum for a while. Been wanting to build a Monogram for some time & finally got the board from Jim.
I have a small collection of 78's, but wanted a tube based stage to provide variable Eq.
There doesn't seem to be many who have built this, so thought I would share:



Upgraded some of the components from the parts list: Solen & Vishay caps in the signal path, Vishay & Holco resistors
Wiring is vintage Western Electric except on the power.



Chassis is Hammond, powder coated in a nice vintage grey. Not quite complete yet, front panel & some other cosmetics to finish, but I was pretty pleased when when worked first time. Been tube rolling a little, with some NOS tubes to play with (Brimar, Mullard, RCA).







I have a few questions, but I'll leave that for another time. Thanks to Jim for a great design & sharing his ideas.
Chris


david62

  • Jr. Member
  • Posts: 145
Re: Monogram Build.
« Reply #1 on: 19 Jul 2013, 09:01 pm »
Nice neat build.You do nice work! Enjoy.
Dave

Jaxn

  • Jr. Member
  • Posts: 7
Re: Monogram Build.
« Reply #2 on: 21 Jul 2013, 02:51 pm »
Nice work.....enjoy!

chris65

  • Jr. Member
  • Posts: 4
Re: Monogram Build.
« Reply #3 on: 9 Aug 2013, 12:32 pm »
Thanks for the comments.
Fully finished now, here running Brimar CV4004, JAN Philips 6189's & Osram U50. Some more tube rolling planned.



As I am using vintage GE RPX & Clement cartridges, the output from these can be as high as 30mV. So, I do find the gain a little too much.
Tried using a 5751 tube replacing the 12AX7, but not really any difference.
My question is, can a 12AT7 (mu of 60) or even a 12AY7 (mu of 45) be used to reduce some of the gain. The volume pot is 50k, maybe a 100k would also help?

Thanks, Chris