Tube phono pre-amp PCB Shure M-65 VS EAR 834

[jukingeo]

The kit/complete price includes tubes. Pin 9 is grounded so in theory, if you feed 6V to both sides of the 12V port, you could run 6V from pins 4,5 to grounded pin 9. 12AU7 would replace 6N1, 12AX7 replaces 6N2. No other modifications would be necessary.
If you replace the 1M with a 1M pot, you'll vary the loading on the RIAA filter when you change the volume control. Also, a 12AX7 would give far too much gain for a preamp - You'd get about 40V out for 1V in.

However, if you wanted to, you could switch from phono at the 1M for a line input, and attenuate it with resistors, Then you could put a pot on the output of the board for volume - say 10k or so.
I also make a line/HP amp version of the board with 4 tubes instead of 8. There a link to the thread here: 6N3/6N6 headphone amp using PCB.

I am going to say that I am very tempted on the kit. Pricing is good. I am just a bit concerned about the care and feeding of this preamp down the road. 8 tubes is quite a lot. Do you have a testimonial or review page from those that have bought the preamp? I am curious to others reaction to the sound.

Geo

 

[kodabmx]

It's similar to the Aikido by Broskie but without the Aikido PSU nulling. Most people like it.

I have mine set up so it only lights up when I play records, and I expect the 8 tubes to last for years. The preamp runs 24/7 and I've only had to change the 6N6P tubes (because I run them @140V/30mA) once - they were still ok for line but wouldn't drive current into headphones anymore.

Even my power tubes last for years and I run the amplifier 24/7...

FYI. The entire 8 tube set is only 15$ @ tubes-store.com

 

[jukingeo]

It's similar to the Aikido by Broskie but without the Aikido PSU nulling. Most people like it.

Sounds pretty good.

I have mine set up so it only lights up when I play records, and I expect the 8 tubes to last for years. The preamp runs 24/7 and I've only had to change the 6N6P tubes (because I run them @140V/30mA) once - they were still ok for line but wouldn't drive current into headphones anymore.

I would say you might need a bigger tube in the follower stage, something on order of a 12BH7 or even a power tube like an EL84. That ought to do it.

Even my power tubes last for years and I run the amplifier 24/7...

Oh yeah, I have seen tube amplifiers that are run light, like jukebox amplifiers with 6L6 tubes and many (which are from the 50's) still test good today! Now in a guitar amp scenario...that it is a different story. The same tubes will last a few years at best.

FYI. The entire 8 tube set is only 15$ @ tubes-store.com

I have looked this up and couldn't find it anywhere, the 6N1 and 6N2 sell for $10 EACH.



I am going to think this over for a couple days, I am assuming you take Paypal?

 

[kodabmx]

Tubes-Store.com - Vacuum tubes, capacitors, nixie tubes, sockets. Wholesale & retail trade. Worldwide shipping.
6N1: 6N1P / 6DJ8 / ECC88 / 6922 Voskhod tube → PREAMP / DRIVER tubes → Tubes-Store.com
6N2: 6N2P / 12AX7 / ECC83 tube - wholesale price!!! → Vacuum tubes → Tubes-Store.com

NOT

www.thetubestore.com - Your online source for audio vacuum tubes. - he's the most expensive tube dealer I've seen.

6N1: Russian 6N1P-EB Audio Tubes - www.thetubestore.com
6N2: https://www.thetubestore.com/russian-6n2p-eb-6ax7

Yes, I take Paypal. If you PM the address, I'll find the shipping cost.

 

[jukingeo]

Tubes-Store.com - Vacuum tubes, capacitors, nixie tubes, sockets. Wholesale & retail trade. Worldwide shipping.
6N1: 6N1P / 6DJ8 / ECC88 / 6922 Voskhod tube → PREAMP / DRIVER tubes → Tubes-Store.com
6N2: 6N2P / 12AX7 / ECC83 tube - wholesale price!!! → Vacuum tubes → Tubes-Store.com

NOT

www.thetubestore.com - Your online source for audio vacuum tubes. - he's the most expensive tube dealer I've seen.

Heh, I remembered it wrong. However, I can assure you that Antique Electronic Supply (Antique Electronic Supply), is even more expensive.

6N1: Russian 6N1P-EB Audio Tubes - www.thetubestore.com
6N2: https://www.thetubestore.com/russian-6n2p-eb-6ax7

Yes, I take Paypal. If you PM the address, I'll find the shipping cost.

I had sent you my information in a PM, so take a peek and let me know what it would cost to ship the kit to my address.


Thank you,
Geo