The hum usually has to do with grounding. What kind of PSU are you using? The one from the Pearl article? Is it in a seperate enclosure put at a reasonable distance from the amp enclosure? Is the ground wire from the turntable connected?
In my case it is wired as follows: the Pearl is connected to the chassis in one point. Only the ground wire from the centre of the boards is connected to this point, as is the ground wire from the connected turntable. Signal ground at the inputs is isolated from the chassis, as is power ground on the input.
In my case it is wired as follows: the Pearl is connected to the chassis in one point. Only the ground wire from the centre of the boards is connected to this point, as is the ground wire from the connected turntable. Signal ground at the inputs is isolated from the chassis, as is power ground on the input.
That was it! the dam ground cable.
Sound is quite amazing. Very clear and stereo field has improved. Amp output is very powerful I have to set my converters to lo gain.
Quite amazing!
Sound is quite amazing. Very clear and stereo field has improved. Amp output is very powerful I have to set my converters to lo gain.
Quite amazing!
Right channel is clipping bit
I'm very impressed. It does sound as good as advertised =).
I'm very impressed. It does sound as good as advertised =).
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Almost done. Need to buy the heat sinks.
I would like to thank you all for your help! Specially Jim who has had a lot of patience with me. Showed me how to create the PSU and basically walking me all the way through.
This forum and community is the best. Love this stuff!
Next project, upgrading my 1200mk2.
I would like to thank you all for your help! Specially Jim who has had a lot of patience with me. Showed me how to create the PSU and basically walking me all the way through.
This forum and community is the best. Love this stuff!
Next project, upgrading my 1200mk2.
Attachments
What cartridge are you using? I guess MM if a channel is clipping. You could try to lower the gain a bit.
Hi, I'm using an Ortofon Arkiv. Not sure if its MC or MM. I know the cabling on my 1200 is not good. Ever since I bought it one channel sounds louder than the other. I'm looking into changing PCB and cabling.
What resistor do I need to change to lower output?
-Thanks
What resistor do I need to change to lower output?
-Thanks
yes, that's an MM with 6mV output. Which is high for the gain of the Pearl 2.
In the pdf Wayne says the following about gain:
The overall gain of the circuit as shown is 55 dB @ 1K Hz. Decreasing R14 from 1K to 300 Ohms gives 10 dB more gain when desired for lower output cartridges. R15 which normally would be shorted to 0 ohms can be replaced by a resistor to provide more gain as an alternative to reducing the value of R14
So you could experiment with increasing R14 (1k5, 2k2), or lowering R16. There might be limits to this beyond which the circuit becomes unstable.
An alternative (although pricier) would be to get a cartridge with lower output which would make your Pearl sound even better (the Arkiv looks like a DJ cartridge to me). Denon DL110 for instance
In the pdf Wayne says the following about gain:
The overall gain of the circuit as shown is 55 dB @ 1K Hz. Decreasing R14 from 1K to 300 Ohms gives 10 dB more gain when desired for lower output cartridges. R15 which normally would be shorted to 0 ohms can be replaced by a resistor to provide more gain as an alternative to reducing the value of R14
So you could experiment with increasing R14 (1k5, 2k2), or lowering R16. There might be limits to this beyond which the circuit becomes unstable.
An alternative (although pricier) would be to get a cartridge with lower output which would make your Pearl sound even better (the Arkiv looks like a DJ cartridge to me). Denon DL110 for instance
Does the denon color the output? I would like to get a cartridge to record all my vinyl as true as possible.
How you perceive sound quality is highly personal of course. Some find the Denon boring sounding, others praise it for neutral sound.
I would try to lower the gain for now and then consider an upgrade of the cartridge later on. Your turntable can handle a nice mc and the Pearl is definitely worth one! The possibilities depend on how much you want to spend of course.
Some of the more affordable mc's are: Benz mc gold, Ortofon Quintet red, Goldring Eroica LX, Denon DL110, Dynavector 10x5, Goldring Eroica H, Benz mc silver.
I would try to lower the gain for now and then consider an upgrade of the cartridge later on. Your turntable can handle a nice mc and the Pearl is definitely worth one! The possibilities depend on how much you want to spend of course.
Some of the more affordable mc's are: Benz mc gold, Ortofon Quintet red, Goldring Eroica LX, Denon DL110, Dynavector 10x5, Goldring Eroica H, Benz mc silver.
I'm gonna keep the arkiv until I get everything working right. Then I'll look into upgrading the cartridge.
I'm wanting to get home and start testing the amp. I think one of the boards might have some problems. I will switch around the turntable inputs and see if it's consistant.
In case I need to buy just one board where can I find them?
-Thanks!
I'm wanting to get home and start testing the amp. I think one of the boards might have some problems. I will switch around the turntable inputs and see if it's consistant.
In case I need to buy just one board where can I find them?
-Thanks!
I don't know, I built mine on perfboard ;-) Some people have designed their own boards and had them made in China.
Just re-tied the grounding cable coming from the 1200 and I have basically 0 noise, except some minor click/pops from the record. Only problem is the slight volume difference which i know for sure its the 1200 (I placed the order from KAB for the tonearm cables and PCB RCA kit).
Really awesome sounding. Not sure how much improvement I can get with a better cartridge. Which I had one to compare =)
My current setup is: Technics 1200 -> Pearl 2 -> RME ADI-8 DS (AD/DA Converter) -> RME RayDat (ADAT/TosLink) -> PC
Which would be a recommended cartridge?
-Thanks!
Really awesome sounding. Not sure how much improvement I can get with a better cartridge. Which I had one to compare =)
My current setup is: Technics 1200 -> Pearl 2 -> RME ADI-8 DS (AD/DA Converter) -> RME RayDat (ADAT/TosLink) -> PC
Which would be a recommended cartridge?
-Thanks!
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There might also be a small difference in gain between the two boards. I solved that in mine by finetuning R14 in both channels. To do that you need a test record and you must be sure the turntable wiring is not the cause of the difference.
Cartridge? I named a few, but it really depends on how much you want to spend. It also depends on the match with your tone arm. I would start reading up on the net and then try to audition a few you think that might suit you.
Cartridge? I named a few, but it really depends on how much you want to spend. It also depends on the match with your tone arm. I would start reading up on the net and then try to audition a few you think that might suit you.
The cartridge overloading, MM, occurs in the high frequency range, prior to the comp network. Lowering the gain of the first stage defeats the purpose of using 4 JFETs in parallel.
You can mitigate the problem by changing the cartridge loading, i.e. lowering the value of R19 from 47k5 to put the T5 compensation ahead of the rest of the passive network. To do this, you have to know the inductance of the cartridge.