Tube preamp for car

[Megabyte]

Hello, I would like your opinion on building a tube preamp for my car, this is going in the head console which is something I have never seen before, each parts has to be under $50. So far I've been looking at a few ebay/aliexpress kits, let me know your thoughts, thanks.

Kits so far:
https://www.ebay.com/itm/313757694352?var=612529018280
same kit but on Aliexpress: https://www.aliexpress.com/item/2255799850275299.html?spm=a2g0s.8937460.0.0.fa832e0eg3hQZ8
https://www.ebay.com/itm/325203864221?var=514101376212
https://www.ebay.com/itm/125318368510
https://www.aliexpress.com/item/2251832832888687.html?spm=a2g0s.8937460.0.0.fa832e0eg3hQZ8
https://www.aliexpress.com/item/2251832694961293.html?spm=a2g0s.8937460.0.0.fa832e0eg3hQZ8

 

[barry4]

From what I remember as a kid, a lot of valves (tubes) can be microphonic if subjected to high vibration levels. Also the acoustics in most cars are pretty bad. Is it worth the effort?

 

[KeesB]

We used to have car radio's - no microphonics at all; besides you're using it at line level. The most likely candidate seems to be the last one with the 6sn7.
Concerning the acoustics, these are in a car often better than at home, almost like a headphone as you are completely surrounded by it. So I would give it a try.

 

[Megabyte]

From what I remember as a kid, a lot of valves (tubes) can be microphonic if subjected to high vibration levels. Also the acoustics in most cars are pretty bad. Is it worth the effort?

I don't know what kinda car you have, but mines a Mazda 2 and it has a Tang Band W5-2143 5
running on cheap Class D amp board > Fiio BTR5 and sounds pretty good, I can tell the car is not the limiting factor. I just want more musical and warmth.

The Mazda 2 below is something similar to what I have. Anyone with good knowledge on circuit I would like your opinion on which board to invest in with potential in upgrading caps etc... It's worth it! Thanks.

Car sound deadening materials will be used for this build: Siless Liner 157 mil

FYI I am a proud owner of a Yaqin MC13s/ Mullard 34B and it sounds amazing! 🙂

 

[Megabyte]

I'm back! 🤓 thanks for your input KeesB, I'm going to get the last one for the car "DC12V 6N8P (6H8C 6SN7)" I saw another which is quite interesting.

Hifi 6Z4 +12AX7 SPreamp Board /Kit Base on France JP200 Preamplifier:​

https://www.ebay.com/itm/164561341392?var=464128057395

Let me know what you guys think, the seller recommended these transformers:
https://www.ebay.com/itm/164561307729
However I'm wondering if there's anything better that would improve the sound, what transformer and 6Z4 tubes do you recommend?

 

[picowallspeaker]

There's something wrong if you say transformers...in a car!
Probably you want to install a DC/AC converter, so 12 VDC>120 AC then Transformers!
An elegant way is to take power for HT directly from 12 V DC and use a switching circuit to elevate potential to 200-300 V.

But you don't need it!
The warmth & sweetness of the sound don't depend on the particular circuitry, well, substantially you would want to use transistors where they're needed ( line level) and tubes for power.

 

[Megabyte]

There's something wrong if you say transformers...in a car!
Probably you want to install a DC/AC converter, so 12 VDC>120 AC then Transformers!
An elegant way is to take power for HT directly from 12 V DC and use a switching circuit to elevate potential to 200-300 V.

But you don't need it!
The warmth & sweetness of the sound don't depend on the particular circuitry, well, substantially you would want to use transistors where they're needed ( line level) and tubes for power.

The second one is not going in the car.. It's for home. So you can recommend some parts.

 

[stocktrader200]

The 7 pin pentode 6n1 or 6n3 is about 1 inch tall easier to fit 2 into the head unit as opposed to 12ax7. A small buck boost circuit can do the B+ of 40 to 50v. The 12v may work for line levels.

 

[kodabmx]

I think you mean 6J1 and 6J3? 6N1 and 6N2 are 9 pin dual triodes.