Hi all,
I stumbled upon this discussion board via google. I've been collecting audio gear for quite some time, spending lots of hard-earned cash in the process. I recently gathered up enough courage to assemble a small, kitchen table work station, where I can practice my soldering skills, with the hope of eventually assembling better sounding gear for cheap. My first goal is to build a standalone preamp that will better the internal pre in my CJ PV-15. Any help along the way would be greatly appreciated. I welcome unsolicited advice and encouragement. I have steady hands and a willingness to learn from my mistakes.
I stumbled upon this discussion board via google. I've been collecting audio gear for quite some time, spending lots of hard-earned cash in the process. I recently gathered up enough courage to assemble a small, kitchen table work station, where I can practice my soldering skills, with the hope of eventually assembling better sounding gear for cheap. My first goal is to build a standalone preamp that will better the internal pre in my CJ PV-15. Any help along the way would be greatly appreciated. I welcome unsolicited advice and encouragement. I have steady hands and a willingness to learn from my mistakes.
Hi guy. For first instance, what is the amplification needed from your stuff, impedances, voltage supply available, +, +/-, etc.
Ortofon 2m black specs:
Technical data
Output voltage at 1000 Hz, 5cm/sec. 5 mV
Channel balance at 1 kHz 1 dB
Channel separation at 1 kHz 26 dB
Channel separation at 15 kHz 15 dB
Frequency range at - 3dB 20-31.000 Hz
Frequency response 20-20.000 + 2 / - 0 dB
Tracking ability at 315Hz at recommended tracking force 80 µm
Compliance, dynamic, lateral 22 µm/mN
Stylus type Nude Shibata
Stylus tip radius r/R 6/50 µm
Tracking force range 1,4-1,7g (14-17 mN)
Tracking force, recommended 1,5 g (15 mN)
Tracking angle 20°
Internal impedance, DC resistance 1,2 kOhm
Internal inductance 630 mH
Recommended load resistance 47 kOhm
Recommended load capacitance 150-300 pF
Cartridge colour, body/stylus Black/Black
Cartridge weight 7,2 g
Replacement stylus unit 2M Black (interchangeable with 2M Bronze)
Specifications
PV15
Gain: 28.5 db
Maximum output: 5.5 vrms
Distortion: less than 1% THD
Frequency response: 2 Hz to 10OKhz
Hum and Noise: 95 dB below 2.5 V
Phase: phase inverting
Tube complement: 2 x 6C4 / 8080
Dimensions: 13.75D x 19W x 3.315H inches
Total weight: 15 lbs.
Presumably I will still be using the line stage of the CJ for the phono stage.
I may have to wait a bit longer to give you the info on my handmade tube amp. It was built by Jimmy Nicholls, an 8 EL-34 tube amp. I'll have to pm him. BTW, I may at some point want to switch to low output mc, complicating matters I know, but there it is.
Technical data
Output voltage at 1000 Hz, 5cm/sec. 5 mV
Channel balance at 1 kHz 1 dB
Channel separation at 1 kHz 26 dB
Channel separation at 15 kHz 15 dB
Frequency range at - 3dB 20-31.000 Hz
Frequency response 20-20.000 + 2 / - 0 dB
Tracking ability at 315Hz at recommended tracking force 80 µm
Compliance, dynamic, lateral 22 µm/mN
Stylus type Nude Shibata
Stylus tip radius r/R 6/50 µm
Tracking force range 1,4-1,7g (14-17 mN)
Tracking force, recommended 1,5 g (15 mN)
Tracking angle 20°
Internal impedance, DC resistance 1,2 kOhm
Internal inductance 630 mH
Recommended load resistance 47 kOhm
Recommended load capacitance 150-300 pF
Cartridge colour, body/stylus Black/Black
Cartridge weight 7,2 g
Replacement stylus unit 2M Black (interchangeable with 2M Bronze)
Specifications
PV15
Gain: 28.5 db
Maximum output: 5.5 vrms
Distortion: less than 1% THD
Frequency response: 2 Hz to 10OKhz
Hum and Noise: 95 dB below 2.5 V
Phase: phase inverting
Tube complement: 2 x 6C4 / 8080
Dimensions: 13.75D x 19W x 3.315H inches
Total weight: 15 lbs.
Presumably I will still be using the line stage of the CJ for the phono stage.
I may have to wait a bit longer to give you the info on my handmade tube amp. It was built by Jimmy Nicholls, an 8 EL-34 tube amp. I'll have to pm him. BTW, I may at some point want to switch to low output mc, complicating matters I know, but there it is.
So you want to make a standalone phono preamp? I can say from experience that the Pass Pearl 2 is stunning. Really quite wonderful. It's not the easiest project, but there is lots of support available on this forum. Here is the link -
http://www.diyaudio.com/forums/pass-labs/204336-building-pearl-2-a.html
And if you really want an amazing bang-for-the-buck DIY project, build a Pass F5 amplifier. There is a reason why there have been a huge amount of them made, they are simple, easy to source parts, fairly inexpensive, and are a fantastic amplifier. Link -
http://www.firstwatt.com/pdf/prod_f5_man.pdf
http://www.diyaudio.com/forums/pass-labs/188691-illustrated-guide-building-f5.html
http://www.diyaudio.com/forums/pass-labs/204336-building-pearl-2-a.html
And if you really want an amazing bang-for-the-buck DIY project, build a Pass F5 amplifier. There is a reason why there have been a huge amount of them made, they are simple, easy to source parts, fairly inexpensive, and are a fantastic amplifier. Link -
http://www.firstwatt.com/pdf/prod_f5_man.pdf
http://www.diyaudio.com/forums/pass-labs/188691-illustrated-guide-building-f5.html
Thanks 6L6 for the info. I think I'll stick with my JMW tube amp, but will investigate the pearl.
Jim just shot an email re my amp:
hey Greg,
the one thing about my units is they are very, very easy to drive and are not very picky. nothing new really, just basic stuff common circuit, used all the time back in the day.
the grid resistors used will determine the input impedance. your unit uses a 6SN7 as the input amp stage, in this case 470k resistors are used from grid to ground. so... a safe bet is to say the input impedance is 500k, half a meg.
now if I used a 12AU7 or 6CG7 the impedance will be 220k.
output impedance is 8 ohm for best match, no problems to go down to 1 ohm loads either with that great output iron on that bad boy.
hey Greg,
the one thing about my units is they are very, very easy to drive and are not very picky. nothing new really, just basic stuff common circuit, used all the time back in the day.
the grid resistors used will determine the input impedance. your unit uses a 6SN7 as the input amp stage, in this case 470k resistors are used from grid to ground. so... a safe bet is to say the input impedance is 500k, half a meg.
now if I used a 12AU7 or 6CG7 the impedance will be 220k.
output impedance is 8 ohm for best match, no problems to go down to 1 ohm loads either with that great output iron on that bad boy.
Also, here's a review of Jim's work, so you can get a better idea where he's coming from. BTW, he has told me that the "monster beast", as we refer to it, is his best work to date. Lance estimates output at above 100w per channel--8 EL 34 tubes and hammond organ amp trannies, weighing in at 85 lbs.
Master Builders: Lance Cochrane And Jim Nicholls Review By Dick Olsher
Master Builders: Lance Cochrane And Jim Nicholls Review By Dick Olsher
sabocat,
Run! Run far away! Go quickly before it is too late!
Once you begin reading the interesting forum posts and start getting ideas in your head, you will start one project, then plan another with a different topology, and then start another with a different circuit, and plan another. And then plan "just one more..." I planned one project and am already up to 3.5 planned projects.
It doesn't end...
Well, enjoy and have fun!
He's in too deep already!
Take it from this newbie the information pipeline from this place is quite remarkable.
Ironically while the specific info saves me time the exposure to the underlying theoretical
underpinnings has tripled my related reading requirements.
I am a tube guy transitioning to SS at least in some areas. It's like the first day of school!
Take it from this newbie the information pipeline from this place is quite remarkable.
Ironically while the specific info saves me time the exposure to the underlying theoretical
underpinnings has tripled my related reading requirements.
I am a tube guy transitioning to SS at least in some areas. It's like the first day of school!
Sooo, after doing a bit more reading it has become clear that the skill and expertise necessary to build a kickass preamp is currently beyond me. Perhaps a simple headphone amp build for starters. Any thoughts?
The Cavalli-Kan Kumisa III from AMB.org is the one I'm looking at. Does everything I want in a headphone amp, and has fantastic documentation and support. (Everything from AMB does...)
The Cavalli-Kan Kumisa III Stereo Headphone Amplifier
The other cool thing is the sheer amount of information on the site, for every project.
The Cavalli-Kan Kumisa III Stereo Headphone Amplifier
The other cool thing is the sheer amount of information on the site, for every project.
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