vinyl dragon
Member
Hi Sachu & Omishra, are the boards available still? Can't find any references anywhere :-(
All the best
All the best
DIrect coupled(DCB1) buffer build
- Thread starter sachu888
- Start date
I'm not sure what the point of an LDR volume control is. Two resistors make a potential divider. If one resistor is light dependent, you can make a potential divider that is light sensitive. But what's the advantage for a volume control? LDRs have higher distortion than metal film resistors.
Grainger49
Old Fart
I have no first hand knowledge of them. They are popular here but are said to be very noisy. It is a novelty. But, I agree, there are much better options for volume control.
temaadaudio
New Member
Hi What is the max +/- VDC that can be applied to this DCB1, I would like to run it off of batteries. Is two 14.5 SLA batteries to much voltage Cheers?
temaadaudio
New Member
Hi, Thanks for reply, being a newbe, DC offest? Does that mean the difference between to +DC voltage and the -DC voltage. If so what is the max allowable Cheers
imdocjas
Well-Known Member
resurrecting this thread as i'm on the cusp of building one of these myself. curious as to whether it can be powered by two 12VDC SLA batteries. also, after doing some cursory reading i would infer that an audio/log 20K potentiometer is what omishra is referring to in post #25 above. is that correct?
thanks in advance
thanks in advance
sachu888
Spare the tigers, kill me
Few members from Lencoheaven are using DCB1 as phonostage for Ceramic carts, read post #113 by williamsunique here http://www.lencoheaven.net/forum/index.php?topic=12092.105
Regards
Sachin
Regards
Sachin
williamsuniq
New Member
I am using a DCB1 as a phonostage for ceramic cartridges. It works very well. A ceramic cartridge likes to see a high input impedance, fets are ideal. I changed the two resistors across the inputs R2andR6 to 5M ohm. I did have problems with a hum, which wasn't present when using a moving magnet cartridge into it's phono stage. The same tonearm and turntable. Conversely one would have expected the ceramic cartridge to have been quieter with regard to mains 50Hz hum compared to a MM cartridge.
I eventually sorted the problematic hum by changing the cable from the tone-arm. I used balanced cable in a Pseudo balanced configuration. No hum.
I am really enjoying the music quality I am hearing from these underrated ceramic cartridges, especially my Sonotone 9TAHC into the DCB1.
Paul
I eventually sorted the problematic hum by changing the cable from the tone-arm. I used balanced cable in a Pseudo balanced configuration. No hum.
I am really enjoying the music quality I am hearing from these underrated ceramic cartridges, especially my Sonotone 9TAHC into the DCB1.
Paul
Grainger49
Old Fart
Now I have to ask, can you link some information about good ceramic cartridges? I am aware of the Panasonic Strain Gauge cartridge but no Hi-Fi ceramics.
Thanks.
Thanks.
williamsuniq
New Member
In order of my preference. Sonotone 9TAHC, Sony VX23-P, Decca Deram, Sonotone 9TA. The Decca Deram will only work with an original Decca stylus, all after market ones are useless.
There is also a Phillips GP390, which is meant to be very good, but this is connected straight into a moving magnet RIAA phono, therefore the DCB1 would not be required.
Paul
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sachu888
Spare the tigers, kill me
You can power it by two 12v batteries, bit a dedicated power supply with +/-10v is better. 20k or 25k log or stepped attenuator is preferred.
Regards
Sachin
williamsuniq
New Member
Improving the sound of the DCB1 as a ceramic cartridge pre-amp was not so easy. I had noticed that the bass was too high, it may suit others, but not me. Originally I had just changed the resistor in R2 and R6 position from 1M ohm to 5M ohm, but after doing some listening and comparisons, I felt it needed an improvement. The more than adequate bass was masking the sound. I think we have all been to a function where there is a disco and the bass is drowning everything else out. Well this was similar, though not as bad.
I played about with different values of R2 and R6. This gave me an idea of what did what. Eventually I settled on a 20M ohm resistor, but with a 1M ohm resistor and a 600pF capacitor in series across the 20M ohm resistor. This bought everything into focus, the vocals were now up front, where they should be. It wasn't an enormous change in the sound, but a subtle one. I for one am very pleased with the out come.
Paul
I played about with different values of R2 and R6. This gave me an idea of what did what. Eventually I settled on a 20M ohm resistor, but with a 1M ohm resistor and a 600pF capacitor in series across the 20M ohm resistor. This bought everything into focus, the vocals were now up front, where they should be. It wasn't an enormous change in the sound, but a subtle one. I for one am very pleased with the out come.
Paul
Got this together today well knowing I wouldn't get it finished but low and behold I had this cannibalized CNC case with rca's in place. Took my time with all the connections and it fired right up. Only a couple of hours run time and it's sounding sweet on my open baffles. @ CNC's, 2 AD797 and now 2 of these. What's next sachin. Thank's, MKane 
SQ, if sonically less intrusive. In my experience, pots can affect the result depending on quality. Stepper pots with silverplate contact points should have less effect compared to carbon track types, Penny and Giles conductive plastic track pots are highly regarded but not cheap.
