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esims89 24th November 2008 09:43 AM

Pre-amp for BeoMaster
Hi there,
I'm totally new to this whole tube amp thing,
My family and I are in the process of moving, and I found our old audio setup under in storage. It's a Beo Master 5000 amp, and turn table combo.

I've also been listening to my grandfather's old 50's record player / Tube amp, and I've really fallen in love with the tube sound.

So my question is, I'd like to find a reasonable ($<150) DIY pre-amp to work with the Beo master amp and turntable. But also, I'd like to be able to plug in my laptop which has the majority of my music into the tube pre-amp as well.

I'm completely lost in this whole tube thing, so any advice will be greatly appreciated.

Thanks in advance

Eli Duttman 25th November 2008 12:10 AM


You are not going to come close to your wish list for $150, sorry. To put things in perspective, the Bottlehead Seduction phono preamp kit costs $279, plus shipping. You could not make a worse choice, for a scratch built 1st project, than a phono preamp. :( You could be OK with the kit, but it's too expensive.

I suggest you leverage that which already have as your 1st project. Your B&O equipment has a built phono section and (apparently) a dual tape monitor loop. For the budgeted sum, you could construct a tubed buffer that picks up the selected source and feeds the RCA style tape in jacks. Use the tape monitor feature to "massage" the signal before it gets to the volume control circuitry.

If by happy chance the unit has preamp-out/amp-in capability, you could completely bypass the internal line level circuitry. Can you post a photo of the available jacks?

esims89 25th November 2008 05:35 AM

Looks like we're in luck, there is a pre-amp out for this BeoMaster.
See the picture here

anyway, so does that solve the phono issue?
I should now be able to plug everything into the BeoMaster like normal now, except rather than outputting to the speakers, it will run it through the pre-amp then back into the beomaster and then to the speakers.

Am I understanding this?

Anyway, so if this is true, what pre-amp should I get?
(My budget is somewhat flexible, yet I'd like to stay close, also I do have some experience with electronic, soldering and such.

Thanks again for your help!

esims89 25th November 2008 06:41 AM

maybe its not a pre amp out...
actually I just read in the manual:
"you can connect an equilizer via the jack relay 1 and the looped phono plugs marked line in/out"
Could use line in/out for the preamp? (because right now as you can see in the picture, there's just a relay in those plugs)
I'm confused

Eli Duttman 26th November 2008 12:57 AM


If you can post a scan of the schematic, it would be a BIG help. I can't be sure if those jumpers are part of a preamp-out/amp-in feature or a signal processor loop. My hunch (sadly) is that it is the later. Otherwise, why would there be a separate set of preamp-out jacks?

There definitely is a phono section in the unit. That grounded binding post is for the "5th wire" from the TT.

Assuming that things are inflexible, you can build a tubed circuit that plugs into the jacks now occupied by jumpers. Yes, it's a signal processor of sorts. You add a touch of 2nd harmonic distortion to the signal hoping that some "warmth" is picked up.

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