Tube Buffer Preamplifier

[Audiodoc]

Yes the line outs of most CD players is around 2v rms that should be good for the B1. Basically most amplifiers will run from 2v rms directly from the CD player if there is no problem with impedance matching which is relatively rare in recent designs, however a good preamplifier definitely improves the sound stage and depth and are the best place to introduce a decent volume control in the audio chain.

 

[miroflex]

Hi Audiodoc and Captrajesh,

I would need something more than a buffer and a switch between various sources. A gain of unity would not serve my purpose as I need to positively boost signals from MM/MC cartridges.

Can you suggest a good DIY pre?

Regards.

 

[Audiodoc]

Check the DIY solid state preamplifier which uses dual OPA627 opamps and provides amplification of 6x and 11x. Have used the same to upgrade my Norge 1000, sounds really good.

http://www.ebay.com.my/itm/220826714830?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

 

[sachu888]

Hi Audiodoc and Captrajesh,

I would need something more than a buffer and a switch between various sources. A gain of unity would not serve my purpose as I need to positively boost signals from MM/MC cartridges.

Can you suggest a good DIY pre?

Regards.

You will need a good Phono pre.I have PCB's available for this http://www.hifivision.com/phono-turntables/20115-batery-powered-diy-cnc-phono-stage.html
This will work with MM and HOMC carts.

Regards,
Sachin

 

[captrajesh]

Hi Audiodoc and Captrajesh,

I would need something more than a buffer and a switch between various sources. A gain of unity would not serve my purpose as I need to positively boost signals from MM/MC cartridges.

Can you suggest a good DIY pre?

Regards.

May be OT for OP and hope he wouldn't mind.

Transcend Grounded Grid pre-amp: Transcendent Sound Grounded Grid Preamp

Aksa GK1 Pre-amp: ::: Aspen Amplifiers :::

Bride of Son of Zen Pre-amp:
An article by Nelson Pass: http://www.passdiy.com/pdf/balzenpre.pdf
Project showcase: http://www.parttimeprojects.com/audio/diy/BOSOZwebpage.php
Pre-amp PCB: PASS LABS CLONE - ALEPH 3 Amplifier PCB
Power supply PCB: XCCS - BOSOZ POWER SUPPLY - DIY X-BLS-CCS PREAMPLIFIER PCB
Check with Sharon for the parts and build instructions: [email protected]

 

[miroflex]

Hi Audiodoc, Captrajesh and Sachu,

From the various suggestions given, which would be the best in terms of sound quality, ease of sourcing and construction and value for money vis a vis the quality of what is available in the used market, mostly older NADs in the Rs. 5k to Rs. 10k range? I would prefer a valve pre to a solid state one, other things being equal.

Looking for detailed responses.

 

[Audiodoc]

All are good designs and sound very good however you have to choose depending on budget and relative complexity will only be able to comment when I build the pass. presently using the OPA627 and OPA2134 opamps both sound pretty good.

 

[captrajesh]

All are good designs and sound very good however you have to choose depending on budget and relative complexity will only be able to comment when I build the pass.

Absolutely correct. I fully agree.

@Miroflex, if you do some searching, you will find that all of them have rave reviews.

BOSOZ is said to be the best pre-amp design given by Nelson Pass to DIY community.

Original GG has been made by GeorgeO and a Chinese clone by Gobble. You may check with them.

 

[miroflex]

Captrajesh and Audiodoc,

Thank you very much for your very helpful posts.

Sachu,

I will send you a PM.

Regards.

 

[Audiodoc]

I already have a pass design preamplifier board based on jfet 2sk170. That is the red one in the center also in the picture are 3 LM3886 mono blocks for my 5 channel amp and a input selector circuit as well as a SMD NE5532 / Dual OPA627 preamplifier.

 

[dansplace]

Greetings All:
I am very new to tube diy please excuse my lack of experience. I purchase one of these
kits, mounted in AT power supply case. Does not look good but works fine with my lm3886. I have made a pcb of the tube side of the circuit but nor the power supply. It is not verified. If anyone would like to have files please e-mail.
Thanks

 

[Audiodoc]

Can you post a few pictures.

 

[dansplace]

Here is pix of my amp and buffer, also a pdf of the tube part of buffer circuit.
I have not made the power supply at this time, soon
Regard
Dansplace

 

[Audiodoc]

Looks similar to my buffer circuit the only difference is that my buffer has an on board power supply which uses 12V ac input and increases the voltage to 60V. You will need to make a 30-0-30 V power supply to power the buffer circuit.

By the way the amplifier looks good can you post a few more pictures.

 

[dansplace]

Greetings:
Thank you! My first kit worked well, but, my second kit intended for my granddaughter failed??? The signal waves in and out like a siren, I use the same kite, transformer and I don't see any physical change between the two,
one works, the other does not. The only thing I can think of is the tube or voltage regular. Any and all suggestions would be appreciated.
Best Regards, be well
Dansplace

 

[Audiodoc]

Reflow the solder joints, check for shorts, check voltages, and isolate the signal ground.

 

[dansplace]

Thank you, I will do that promptly, my grand daughter thinks I can build her an Ipod dock.
Got to figure how to do that?
Again, Thank you . be well

 

[Audiodoc]

Get some good cheap ones from Fiio.

FIIO