shelly_d
Not An Audiophool
Using about 800 to 1000 ohms in series with the led on 9V will keep you current between 7 and 9 mA. Should be bright enough.
Shelly_D
Another Super High End Phono Stage! No expense spared...
- Thread starter Fasterdamnit
- Start date
Using about 800 to 1000 ohms in series with the led on 9V will keep you current between 7 and 9 mA. Should be bright enough.
Shelly_D
ghazzer
Senior Member
dspear99ca:
Use dual batteries. (9v, 12v, or 4 6V). There are several layout drawings in this thread, but I don't remember if any show the LED. I know that the ones I posted don't. Seepost #537
I wired mine thru a relay controlled by B+ from my TT, so I don't need a LED to tell me when it is on. The CNC is on whenever my platter is turning.
.
Use dual batteries. (9v, 12v, or 4 6V). There are several layout drawings in this thread, but I don't remember if any show the LED. I know that the ones I posted don't. Seepost #537
I wired mine thru a relay controlled by B+ from my TT, so I don't need a LED to tell me when it is on. The CNC is on whenever my platter is turning.
.
bobrown14
Super Member
I use an 8.2k resistor across both batteries for 18v and this keeps the current draw at around 2ma and is plenty bright enough.
Two OPA2134 op amps draw 8ma's so having your led draw 8ma's you are halving your battery life and it's going to light up your room using a standard Red LED.
Two OPA2134 op amps draw 8ma's so having your led draw 8ma's you are halving your battery life and it's going to light up your room using a standard Red LED.
ghazzer
Senior Member
B+ in my TT is 20 vdc, so I could use a 24 vdc relay, ~$5. I put the batteries and the relay in a small plastic box right behind the TT and used a 4 conductor phone wire to run the 2 rails and ground over to the CNC and wrapped that with the RCA cables.
Points A & B could be used to connect the batteries to a charger, but that would require more switches and controls.
.
Renron
Active Member
Am I too late???
Wow, what a wonderful thread. It took me 3 days to read the entire story, so far.....
I just stumbled across this thread while searching for a DIY Phono Pre. It must be my lucky day! I have been a long time member of the other Diy forum. Man, you guys are a lot nicer to each other.........LOL
I there any way i can be added to the CNC buy list?
Whos arse do I have to kiss to be included?
This is such a wonderful pre I hope to be able to enjoy building and listening to it.
Thank you all,
Ron
Wow, what a wonderful thread. It took me 3 days to read the entire story, so far.....
I just stumbled across this thread while searching for a DIY Phono Pre. It must be my lucky day! I have been a long time member of the other Diy forum. Man, you guys are a lot nicer to each other.........LOL
I there any way i can be added to the CNC buy list?
Whos arse do I have to kiss to be included?
This is such a wonderful pre I hope to be able to enjoy building and listening to it.
Thank you all,
Ron
Ron, Thanks. I per my knowledge 'sach888' has ordered some PCBs. I am not sure if he has some more available or not. Please PM him for more details.
dspear99ca
Super Member
I see this mod in my imminent future... I already left it on overnight accidentally. Oh well, it'll help with burn-in.
My impressions so far are good. I've got a Shure M97xe cart with about 100 hours on it. People rave about the bass this cartridge delivers but I wasn't getting that at all with the phono stage in my Parasound preamp... thin weak bass. I added some capacitance to the pre phono input to get it up to 250pf which is the recommended value but it didn't really help. I was going to mod the input load to 63k as well when I stumbled on the CNC thread. While I waited for parts and free time, I started using the phono section of an old JVC receiver and was actually pretty happy (vs. the anemic Parasound). But the CNC is about 10 steps in the right direction. It's clear, it's definitely not lacking in bass, and it's pretty musical with the ADS823 opamps in it. I'm going to try a few others. My total cost to build was about $70, not too shabby considering I couldn't buy a better phono stage for 5 times that. One thing I did notice though is that it's far from "dead quiet" when the volume control is above say 11 o'clock. But it's quiet enough for me... may some different op-amps will lower the noise floor.
Thanks much to everybody that put the effort into making this happen, it allowed me (and many others) to upgrade their phono stage for not much $$.
I'll post some pics when I get around to it, not much to look at, black metal box with a switch and a red light. I used an 8K2 resistsor across 18V and it's plenty bright enough for me to notice it was on with sun streaming in the windows.
Dave
Fasterdamnit
Super Member
You are quite welcome! This was just a fast and dirty build that sounded awesome for the price that was then taken by Hypnotoad and others to a fantastic level. Power to the people!
Outstanding work, Dave! Look forward to the pics. I also look forward to some more direct comparisons with commercial phono stages. :yes:
Renron
Active Member
Thank you Omishra,
Sachu888 contacted my via PM last night and I am included in the latest GB.
Very happy I made it in time. I would have cried if I had missed such an excellent opportunity to build the CNC.
In case anyone was wondering about 9 Volt battery types, I've done some research and have come up with some interesting information.
Depending upon what type of usage (how often) you actually listen to the preamp, different battery compositions may be better a choice than others for you.
I'll explain.
Alkaline type(non-rechargeable)
The standard ones you can buy just about anywhere hold a higher voltage than most of the rechargeable ones.
Their power drain curve is more like a stair step than a curve. Rather gradually. See Alkaline graph. They are able to hold a charge for a long time between usage. Generally cheapest, once dead they must be replaced.
Alkaline type(rechargeable)
All the same long shelf life features as non-rechargeable but able to be recharged. (duh!) The disadvantage is that they loose their ability to fully charge each time they are re-charged. May start out as an example as 1000mAh then drop to 900mAh the next charge then 800mAh and so on.
Old technology and they are prone to leakage.
NiCad type
Rechargeable but are said to have a "memory" of their last charge from which they never recover completely. If not fully discharged they will decrease their performance until worthless. Lower capacity than Alkaline or NiMH. Power drain curve is similar to NiMH, slight drop when new then very flat until almost dead, quick drop near the end of their lifespan. Old technology and outdated. Contain toxic metals----->should be recycled.
NiMH type
Next evolution in battery technology. Does not have a "memory" when re-charged. Good performance over the power drain curve, slight drop then flat until near-death experience then sharp drop off. Does not hold a charge over time. Self discharges when not recharged frequently. Does not contain toxic metals. Higher capacities than NiCad but lower than Alkaline. Available in multiple mAh ratings. May not charge properly in some battery charges designed for NiCad batteries.
Lithium Ion type
Rechargeable and Photo Cell. Photo Cell type are NOT rechargeable. Expensive! Excellent long term storage device,(up to 10 years!) ie; smoke detector, flash lights. Does not self discharge rapidly. Power drain curve similar to MiHM. Excellent for infrequent usage. Contain toxins and should be recycled.
Graphs stolen from: http://www.churchtecharts.org/home/2010/3/9/battery-shootoutthe-results-show.html
Ron
Sachu888 contacted my via PM last night and I am included in the latest GB.
Very happy I made it in time. I would have cried if I had missed such an excellent opportunity to build the CNC.
In case anyone was wondering about 9 Volt battery types, I've done some research and have come up with some interesting information.
Depending upon what type of usage (how often) you actually listen to the preamp, different battery compositions may be better a choice than others for you.
I'll explain.
Alkaline type(non-rechargeable)
The standard ones you can buy just about anywhere hold a higher voltage than most of the rechargeable ones.
Their power drain curve is more like a stair step than a curve. Rather gradually. See Alkaline graph. They are able to hold a charge for a long time between usage. Generally cheapest, once dead they must be replaced.
Alkaline type(rechargeable)
All the same long shelf life features as non-rechargeable but able to be recharged. (duh!) The disadvantage is that they loose their ability to fully charge each time they are re-charged. May start out as an example as 1000mAh then drop to 900mAh the next charge then 800mAh and so on.
Old technology and they are prone to leakage.
NiCad type
Rechargeable but are said to have a "memory" of their last charge from which they never recover completely. If not fully discharged they will decrease their performance until worthless. Lower capacity than Alkaline or NiMH. Power drain curve is similar to NiMH, slight drop when new then very flat until almost dead, quick drop near the end of their lifespan. Old technology and outdated. Contain toxic metals----->should be recycled.
NiMH type
Next evolution in battery technology. Does not have a "memory" when re-charged. Good performance over the power drain curve, slight drop then flat until near-death experience then sharp drop off. Does not hold a charge over time. Self discharges when not recharged frequently. Does not contain toxic metals. Higher capacities than NiCad but lower than Alkaline. Available in multiple mAh ratings. May not charge properly in some battery charges designed for NiCad batteries.
Lithium Ion type
Rechargeable and Photo Cell. Photo Cell type are NOT rechargeable. Expensive! Excellent long term storage device,(up to 10 years!) ie; smoke detector, flash lights. Does not self discharge rapidly. Power drain curve similar to MiHM. Excellent for infrequent usage. Contain toxins and should be recycled.
Graphs stolen from: http://www.churchtecharts.org/home/2010/3/9/battery-shootoutthe-results-show.html
Ron
Attachments
ghazzer
Senior Member
Good info Ron!
Does anyone have any similar info on the SLA batteries? These are most often found in a UPS, so I guess they have great longevity. They could be wired in so that they are connected to the charging circuit whenever the CNC is turned off. I think it was HT who previously pointed out that the batteries need to be completely isolated from the CNC when off, or there is some small current drain.
.
Does anyone have any similar info on the SLA batteries? These are most often found in a UPS, so I guess they have great longevity. They could be wired in so that they are connected to the charging circuit whenever the CNC is turned off. I think it was HT who previously pointed out that the batteries need to be completely isolated from the CNC when off, or there is some small current drain.
.
Both the positive and negative current sources need to be isolated to stop current drain. I think a switch with a center off position would be good for a battery charger, you can then have On, Off and Charging as charging won't be needed very often.
dspear99ca
Super Member
Hah! yes, true. Maybe I'll have to wire up a flasher or strobe circuit...
'Twas left on over night after I finished the enclosure and hooked everything up about 1am, then sat down and listened to music. By the time I was turning everything off I'm sure I probably wouldn't have noticed if it poked me in the eye with a pencil...
I have a pair of them in my Ack! dAck! I plan on a pair that will rotate from my fasterdamnit LO/HO/MC/PP and the CNC. Both will be set up to charge when off.
Look at post #140:
http://www.audiokarma.org/forums/showthread.php?t=387121&page=10
Sorry about the line width. I should have increased the line width before printing and scanning.
This shows a 4PDT toggle switch which I paid about $10 for. It completely removes the charging circuit and the nasty AC associated with it when the preamp is on.
I plan on buying new SLA batteries from Batteries Plus (no affiliation). They have a store about 4 miles from me and they are also on line.
Are they rugged, yes! I left the DAC on for 4 days totally draining the SLA batteries. They are fine now. It took a week plus for the green light on the charger to come on but a good "deep cycle" is a healthy thing.
Renron
Active Member
Dspear99ca,
Thank you for taking that in the spirit in which it was meant. (a joke) I can take a pun too.
SLA Batteries are made with many lead plates in the cells, the thicker the lead the better the battery (more drains and charges it will accept). All things being equal (there not) the heaviest battery will last longer.
Gel batteries would also be a great way to go as they are sealed. However more expensive.
I think the idea of rechargeable batteries and a 4PDT a winner!
Ron
Thank you for taking that in the spirit in which it was meant. (a joke) I can take a pun too.
SLA Batteries are made with many lead plates in the cells, the thicker the lead the better the battery (more drains and charges it will accept). All things being equal (there not) the heaviest battery will last longer.
Gel batteries would also be a great way to go as they are sealed. However more expensive.
I think the idea of rechargeable batteries and a 4PDT a winner!
Ron
sachu888
Spare the tigers, kill me
I am going to try this well filtered regulated powersupply for CNC.We have planned it for CNC,B1,and Lightspeed attenuator.
[URL=http://imageshack.us/photo/my-images/266/preamppsbrd.png/]
Uploaded with ImageShack.us[/URL]
Regards,
Sachin
[URL=http://imageshack.us/photo/my-images/266/preamppsbrd.png/]
Uploaded with ImageShack.us[/URL]Regards,
Sachin
I am also interested with this. This is based on LM317, 337 linear regulators.I am going to try this well filtered regulated powersupply for CNC.We have planned it for CNC,B1,and Lightspeed attenuator.
[URL=http://imageshack.us/photo/my-images/266/preamppsbrd.png/]
Regards,
Sachin
Reference: Application notes of those regulators and project-5b.
I am planning to provide 22-0-22 R-core transformer and CNC with up to +15, 0 , -15. ( But my preference will be (+/-) 9V.
Rectifier is D1-D4, MUR8xx diodes, though not warranted here for 50Hz/60Hz operation, I added for sake for low noise operation of CNC. Those C-R-C at input of regulator are placed to remove mains ripple. This is regulated but variable PS. You can see those trimmers near regulator ICs which will set output voltage.
Those output coils L1-L6 are 100mH, 20mA 10% inductors with ~270 ohm DCR. So for 20mA those two are dropping 2 X 5V (in series). No load voltage will be 10V higher than 20mA loaded PS. I tested for 10 minutes, those inductors are not getting heated at 20mA. Lower the DCR will be good but size increases. So I settled for 20mA inductors. These can be replaced by wire jumper if higher currents are sought.
I will be building it in next couple of days. I will show picture of the build.
by looking at feedback resistances of (3.32K, 100) and (3.32K, 150); total 3.03V max for 4mV input. Please correct me if I am wrong.
So what is the advantage for more supply voltage?
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