Great sounding Tube preamplifier kit recommendation!!

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Dear DIYaudio members,

I am in need of your help and recommendation for a great sounding tube preamp kit in the sub range 1500k. I had several good DIY built amplifiers so I only need a good tube preamp to pair with.

So far my searches and studies through multiple sources come out to 2 candidates below

1. Bottlehead BeePre 300B Preamplifier Kit (1200k - 1400k)
2. Tube4hifi SP14 preamplifier (1000k for dissembled kit)

Have anyone already built or owned these kits, do you have any feedbacks/reviews in term of their sonic quality ?

Do you have any other recommendations for other tube preamp kits that comparable or better than the 2 options that I have found in term of cost and sonic quality.

I really appreciate your time reading my post and your precious help and recommendation.

Most warmest regards and thanks from a happy DIY audio builder :)
Tom
 
Which sources do you use, and what power amplifier and speakers?

hi Rayman,
My sources are DIY Pass F4 Solid state current amplifier and Class A Alelph J poweramp. Speakers are JM Focal lab full range about 92 dB sensitivity.

Pass F4 amp is very special amp since it has no voltage gain, it's a current gain Class A amp, so pretty much 100% output sonic quality depends on the active preamplifier stage.

Thanks,
Tom
 
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Joined 2011
hi Rayman,
My sources are DIY Pass F4 Solid state current amplifier and Class A Alelph J poweramp.
Speakers are JM Focal lab full range about 92 dB sensitivity.

Do you use phono, and is it tube? Do you use CD?

With a CD source, just a 10k pot will be fine with the Aleph J.
With phono and the F4, you will certainly need at least moderate preamp gain,
perhaps up to 20dB, depending.
 
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Do you use phono, and is it tube? Do you use CD?

With a CD source, just a 10k pot will be fine with the Aleph J.
With phono and the F4, you will certainly need at least moderate preamp gain,
perhaps up to 20dB, depending.

hi Rayma,
I used both CD and Phono. For Phono, I have built multiple phono stages in the past both opamps and JFET versions. My top pick are DIY Pearl2 and Salas Folded Simplistic Phono. I'm not a big fan of tube phono stage. For CD, i'm using an external Schitt multibit DAC feeding into B1 pre and Alelph J.

So far, i'm using PASS B1 preamp feeding into Alelph and PASS B3 active preamp feeding into F4. As you can see most of my builds are SS, I'm starting to get into tube. I want to at least try out good active tube preamp feeding into F4 to see how differences is the sound compared to what I had in my system. That's the whole reason behind this thread.

Another sidetrack/minor point, I have ordered Tube lab SE and SSE PCB amps but did not have a chance to build them. Probably, i'll find some time to get to it after finishing Tube preamp kits.

Thanks,
Tom
 
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Joined 2011
i'm using PASS B1 preamp feeding into Alelph and PASS B3 active preamp feeding into F4.
As you can see most of my builds are SS, I'm starting to get into tube. I want to at least
try out good active tube preamp feeding into F4

Then you want to keep a ss phono stage, and try using a tube line stage?
The F4 is 47k input impedance, so it's somewhat low for best results with a tube line stage.
The Aleph J is 242k, and will be fine.

Be sure that the line stage you choose won't output large voltage transients during
power up/down or during a power outage. It could damage the amp.

First, I would encourage you to try a good 10k volume pot with the Aleph J,
with both your ss phono stage and your CD player, in place of an active line stage.
 
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Their "Smash" kit not appeal to you?

jeff

Jeff,
Their "Smash" kit's price point is very appealing but the spec output impedance at 1.6k is a major turn off for me. High output impedance will not be a good match for alot of amp out there. That's just my only 2 cent. Unless, I miss something here!

Did you have a chance to own or build their Smash or Bepre ? any advices ?

Thanks,
Tom
 
Then you want to keep a ss phono stage, and try using a tube line stage?
The F4 is 47k input impedance, so it's somewhat low for best results with a tube line stage.
The Aleph J is 242k, and will be fine.

Be sure that the line stage you choose won't output large voltage transients during
power up/down or during a power outage. It could damage the amp.

First, I would encourage you to try a good 10k volume pot with the Aleph J,
with both your ss phono stage and your CD player, in place of an active line stage.

Thank you for the advice, Rayma! You are right, input impedance of F4 is pretty low and alot of tube preamp out their has pretty high output impedance as I look into their specs
 
Rayma,
So what you are suggesting is to use a lower output bypass capacitance values to keep the bass
from rolling off and to compensate for the higher output impedance of most of tube preamp ?

It's difficult in general for a tube line stage to drive lower impedances.
The load should be greater than five times the resistor used for the output tube,
whether it's a common cathode or cathode follower.

Also, the output capacitor must be large enough to place the LF pole low enough.
For a 2Hz corner into 47k, you need about 2uF for the output capacitor.
 
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Jeff,
Their "Smash" kit's price point is very appealing but the spec output impedance at 1.6k is a major turn off for me. High output impedance will not be a good match for alot of amp out there. That's just my only 2 cent. Unless, I miss something here!

I did notice that, but might not be an issue unless you're using longish IC's.

Did you have a chance to own or build their Smash or Bepre ? any advices ?

No, but the 4P1L does interest me as a preamp tube.

jeff
 
Dear DIYaudio members,

I am in need of your help and recommendation for a great sounding tube preamp kit in the sub range 1500k. I had several good DIY built amplifiers so I only need a good tube preamp to pair with.

So far my searches and studies through multiple sources come out to 2 candidates below

1. Bottlehead BeePre 300B Preamplifier Kit (1200k - 1400k)
2. Tube4hifi SP14 preamplifier (1000k for dissembled kit)

Have anyone already built or owned these kits, do you have any feedbacks/reviews in term of their sonic quality ?

Do you have any other recommendations for other tube preamp kits that comparable or better than the 2 options that I have found in term of cost and sonic quality.

I really appreciate your time reading my post and your precious help and recommendation.

Most warmest regards and thanks from a happy DIY audio builder :)
Tom

Built Smash with CCS upgrade and the Sp14 / Aikido like, and Ph14.

Of course I modified all of them later, however if you want an unbiased review, the Ph14 and Sp14 can be built and are ready to sound like a commercial product of high quality. The bottlehead amplifiers have a very special sound, it is hard to describe, the positive about their kits is that it is a good introduction to p2p wiring and involve some transistors in upgrade kits which is nice to see the schematic and the workings.
 
Tom,
Not sure if you have checked out the link from Hearinspace, but I can speak from experience that the Mir Linestage Preamplifier designed by Kevin at K&K Audio is a wonderful sounding piece of gear. I have owned several other preamps in your price range, both tube and solid state, and have found the Mir to be a great match with my equipment and music preferences. The kit was straight-forward, with detailed instructions and photos. I highly recommend giving it a look.

Steve
 
Here is my point to point version, alps blue mono and 3 channels selector.
Ez81 rectifier and a choke which was replace by internal resistors, the power supply is unregulated.

The weakest point in the amplifier is the volume pot probably. I am very satisfied overall.

You can place any type of tube for the cathode follower output, which is nice, but it benefits from tightly matched sections and high performing input tubes.

The input tube grid bias is very strange at -1.5V which yields the best results with small input signals amplified up to 5 Vrms output.
 

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