• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Ebay Tube Preamp Kit

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I agree with these guys; with poor quality passives (metal oxide resistors? Sheesh!), semi-unknown circuit, obscure tubes, no chassis or PS, it's not worth the trouble it'll take to make it good. Better you build your own goodness, if you got to make a chassis anyway. I have a real simple circuit that works like crazy:


I have a small schem almost finished that shows the power supply as well, if you're interested.

If it doesn't appeal to you, there are lots of other possibilities out there. The thing is, those guys aren't saving you enough (if any) work to spend the sixty bucks there. Might as well go for the gold.


Eli Duttman said:
...............A PCB of dubious quality does not whet my appetite. Also, that "kit" is far from complete. Where's the chassis? Where are the switches and controls?


bcrescen said:
I thought this looked suspect. .........

Hey, guys. A little harsh unless you have seen the preamp kit etc.!!!

I have had a couple of items from this seller.
OK, the quality of boards and components may not be top grade but...

They work, first time
Communication with the seller was excellent
dispatch was immediate
Price and postage were reasonable for what you get

What more could you ask?
You can buy transformers and there are some excellent cases around too.
As for dubious circuits, see post 4. QED!

Be constructive and objective in criticism, please.

Hey, guys. A little harsh unless you have seen the preamp kit etc.!!!


I have had first hand experience with some of these boards. I will agree with you that the communication with the seller is excellent and that the seller offers a number of items such as transformers and power supplies. I made three boards and have had questionable results on each. The circuits can be improved upon meaning the selection of parts and values are off. When the circuit is completed you will most likely have to re-engineer it to obtain the correct values to get the tube operating along the correct lines. Its not worth it....

As mentioned....the Aikido will provide a superior result. If you follow the blogs everything is laid out for you. Pick a tube and it lists the resistor values and the current draw. Its a piece of cake.
There are circuit boards available that you can purchase or you can wire it point to point if you wish.

Andy, there are a lot of well meaning guys here that are just trying to lend a helping hand. My suggestion is to follow the path they are suggesting. This will lead to a project being completed that will provide hours of pleasure and a feeling that you did something correct the first time out.
bcrescen said:
I thought this looked suspect.


I’m new to diy electronics and only meant to infer that at $50 this might be too good to be true. I have all the other parts to put this preamp together and thought it would be an inexpensive preamp for my tweaked SI T-Amp or my Magnavox console salvaged SE amp. Both amps sound pretty good with my Hafler DH 101 in front so maybe I should just leave well enough alone.

Thanks again for all the input and sorry if I offended the Ebay seller or anyone who does business with him.

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