Which 6SN7 preamp should I build? - Page 3

ray bronk · 3rd April 2010, 04:26 PM

Quote:

Originally Posted by huskydawg9

The original thread used the 12BH7, so I went with that. Although because of your comment, I just swapped out the 12BH7's with a pair of 12AU7's and I have to admit it opened things up quite a bit.
I rolled a ton of different tubes in my "Bijou" headphone amp...and the 6H30 by far is my favorite, followed by the 6N1P

Interesting. Well, if you have something with a 6N1P in it, try using a 6CG7 as a direct replacement, and see what happens.

What is it about the 6H30 that you like the most?

Ray

huskydawg9 · 3rd April 2010, 05:26 PM

Quote:

Originally Posted by ray bronk

Interesting. Well, if you have something with a 6N1P in it, try using a 6CG7 as a direct replacement, and see what happens.

What is it about the 6H30 that you like the most?

Ray

I don't have any 6CG7's to try...but might pick some up off of ebay.

Mainly it is the level of detail. The 6H30's are the best at bringout out the finer details in the music. One thing though...the gain on the 6H30 is much lower than the others...so you need to keep that in mind.

ray bronk · 3rd April 2010, 06:25 PM

hi, Well, i've heard good tings about the 6H30 tube.

As far as the 12AU7 goes, as far as I can read, there are better tubes out there that are much more open. The 12AU7 is supposed to be fast. It wouldn't take much to convert your present 12AU7 preamp to a 6CG7. I don't know what the optimum B+ voltage is for the 6CG7.

Anyway, do you happen to know what the output impedance of the circuit is?

Ray

huskydawg9 · 3rd April 2010, 08:02 PM

Quote:

Originally Posted by ray bronk

hi, Well, i've heard good tings about the 6H30 tube.

Anyway, do you happen to know what the output impedance of the circuit is?

Ray

Here are the specs from Frank:
Specifications Line preamp:

Powerconsumption: 40W.
Weight 2 Kgs. preamp and 3.5 kgs for the PSU.

Sensitivity (IHF 0.5V)

Line: 525mV into 100K.

THD Typically better than 0.05%.

Frequency Response: 10Hz - 200KHz. +/- 0.2dB.

Noise: better than -90dB.

Input overload: Infinite.

Maximum Output level: 45V

Output Impedance: 47 Ohm.

Stereo Separation: better than 100dB at 1KHz.

ray bronk · 3rd April 2010, 08:24 PM

Hi,

Wow, sounds good. So do you have a link to the discussion on Frank's preamp? I think he calls it the ultimate preamp or something like that. There was a thread that I started to read about Frank's preamp, but I am not sure if that was the one.

So which did you build the one from Frank or Carlos?

Ray Bronk

SY · 3rd April 2010, 08:55 PM

Quote:

Output Impedance: 47 Ohm.

That's gotta be a misprint.

ray bronk · 3rd April 2010, 09:09 PM

Why do you think it is a misprint?

Ray

huskydawg9 · 09:31 PM

Quote:

Originally Posted by ray bronk

Hi,

Wow, sounds good. So do you have a link to the discussion on Frank's preamp? I think he calls it the ultimate preamp or something like that. There was a thread that I started to read about Frank's preamp, but I am not sure if that was the one.

So which did you build the one from Frank or Carlos?

Ray Bronk

Frank's Ultimate Tube Preamp.

If you go to the end of the thread...I have pictures of my build...
Look at posts 324 and 327
As far as the output impedance goes...I have no idea. Throughout the original thread he talks about the low output z... so I suspect it's correct.
Here is my build:

ray bronk · 3rd April 2010, 09:31 PM

Hi, Ok, will look at that again. I asked because you had used a 12bh7/12AU7 tube in your version. Since 6CG7's tubes might be a bit cheaper to buy, I'll try that. Meanwhile, do you have a good schem for the 6H30 tube?

Ray Bronk

huskydawg9 · 3rd April 2010, 09:37 PM

Not for a preamp. Only for the headphone amp. If you are into headphones I highly recommend it (the Bijou). I have a couple of extra boards for it (in case you are interested... at one point I was considering a balanced version).

The Bijou Headphone Amplifier

My version has regal's mod and is set up to roll tubes.

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3rd April 2010, 06:25 PM	#23
ray bronk diyAudio Member Join Date: Aug 2005	hi, Well, i've heard good tings about the 6H30 tube. As far as the 12AU7 goes, as far as I can read, there are better tubes out there that are much more open. The 12AU7 is supposed to be fast. It wouldn't take much to convert your present 12AU7 preamp to a 6CG7. I don't know what the optimum B+ voltage is for the 6CG7. Anyway, do you happen to know what the output impedance of the circuit is? Ray

3rd April 2010, 08:24 PM	#25
ray bronk diyAudio Member Join Date: Aug 2005	Hi, Wow, sounds good. So do you have a link to the discussion on Frank's preamp? I think he calls it the ultimate preamp or something like that. There was a thread that I started to read about Frank's preamp, but I am not sure if that was the one. So which did you build the one from Frank or Carlos? Ray Bronk

3rd April 2010, 09:09 PM	#27
ray bronk diyAudio Member Join Date: Aug 2005	Why do you think it is a misprint? Ray

3rd April 2010, 09:31 PM	#29
ray bronk diyAudio Member Join Date: Aug 2005	Hi, Ok, will look at that again. I asked because you had used a 12bh7/12AU7 tube in your version. Since 6CG7's tubes might be a bit cheaper to buy, I'll try that. Meanwhile, do you have a good schem for the 6H30 tube? Ray Bronk

3rd April 2010, 09:37 PM	#30
huskydawg9 diyAudio Member Join Date: Oct 2009 Location: Michigan	Not for a preamp. Only for the headphone amp. If you are into headphones I highly recommend it (the Bijou). I have a couple of extra boards for it (in case you are interested... at one point I was considering a balanced version). The Bijou Headphone Amplifier My version has regal's mod and is set up to roll tubes.