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Old 15th September 2014, 06:45 PM   #1
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Default Cheap and upgradable preamp

Hi all,
I am looking for an upgrable, good and not so expensive tube preamp for my modded TPA 3116.

I know aikido have some reputation but I red bad reviews as well....
GlassWare Audio Design Software
I had a look on this one:
Yuan Jing Audio - 6Z4 Tube Pre-Amplifier Board [ Maratz 7 ] [ No 6N4 ] - $26.20
I think I can upgrade the tubes and capcitors with better quality.

What do you think? Is this pre can be upgraded? or is there other good alternative?

Thanks all!
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Old 15th September 2014, 08:03 PM   #2
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If you want really upgradeable (and I don't mean just swapping caps and stuff) you better not go with a PCB.

Have soldering strips on the chassis and go point to point. Pick a common enough socket for the tubes (octal or noval) and have one tube socket per channel - that way you can go balanced at some point, with dual triodes.

Leave a lot of room, so you can add different plate loads, CCS tails for balanced, and source follower output buffers at some point.

Then begin with a simple all resistors and capacitors and tubes kind of a setup, and get experimenting!

The single most significant thing in a preamp is not the tubes you use, not the capacitors you use but the topology. Leave room to change that (most significantly, to go balanced).
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Old 15th September 2014, 08:05 PM   #3
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Also I would put the input-output section on small separate plate that is screw mounted on the back of the preamp. That way you can make changes to that (XLR balanced input/output for example).
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Old 15th September 2014, 09:06 PM   #4
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Quote:
Originally Posted by MrCurwen View Post
If you want really upgradeable (and I don't mean just swapping caps and stuff) you better not go with a PCB.

Have soldering strips on the chassis and go point to point. Pick a common enough socket for the tubes (octal or noval) and have one tube socket per channel - that way you can go balanced at some point, with dual triodes.
Thanks for answer,
what kind of schema do I use? Do you have some links and advertise?

Thanks!
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Old 15th September 2014, 09:08 PM   #5
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Hi,

First of all I don't understand why anyone would want a preamp where all it takes is a source selector, a volume control and, if you need to drive long capacitive cables, a well designed buffer stage?

Anything else thrown in only just degrades the sound further, surely?

So, O.K. you want a preamp to add some even harmonics to that sterile digital sound......

Anywho, of the two I'd rather put my beans on the Aikido than on a dubious clone of a circuit that sounds like someone has pulled a sock over your ears.....

@McCurwen: you make leaps and bounds but from what the TS expresses I'm not sure he's still with you....

Ciao,
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Old 16th September 2014, 03:06 AM   #6
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What Frank said!

No gain / low gain, source selector and volume control.
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Old 16th September 2014, 06:07 AM   #7
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Let's assume he has a signal source giving some 300 mV but the output amplifier needs 1 V to be driven full.

I would build something like this:

https://www.dropbox.com/s/u8ngp55qcf...A4d_G.GIF?dl=0



Non-inverting, low THD and adjustable gain ( with P1).

Last edited by artosalo; 16th September 2014 at 06:15 AM.
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Old 16th September 2014, 07:47 AM   #8
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Quote:
Originally Posted by artosalo View Post
I would build something like this:

https://www.dropbox.com/s/u8ngp55qcf...A4d_G.GIF?dl=0



Non-inverting, low THD and adjustable gain ( with P1).

Well, it looks good,
But I am not sure to be able to do it.
This is why my first intention was to look for a kit.
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Old 16th September 2014, 10:40 AM   #9
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How about this ?

6J4 6P6P 6Z5P Class A HiFi Tube Preamp 110V 220V Vacuum Tube Preamp Kit 1set | eBay

Click the image to open in full size.
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Old 16th September 2014, 11:21 AM   #10
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Quote:
Originally Posted by artosalo View Post

Looks easiest for me.
Do you think it is a good start?
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