AD797 Phono Stage Build and Help Desk Thread
- Thread starter HypnoToad
- Start date
weverb
Active Member
They started within .1 volts of each other. Just didn't stay there.
weverb
Active Member
Mine are within .1v also, whether charged or not, maybe a bad battery.
Try charging them again, if possible use a 12v charger to get them both at the same voltage.
If you know someone with one.
Will do. Ordering the smart 12v charger mentioned previously on Amazon. Is it still ok to use until charger shows up on Saturday?
weverb
Active Member
Ok. Just got back from Walmart and picked up a smart 12v charger for $20. Working so far. Will keep an eye on it.
It may be a good idea to try the suspect battery in the opposite position of the wire harness, or set up your VOM between the preamp and the battery to see if your current draw is different on one side than the other.
dodog
Addicted Member
The best op amps for the output stage (OA 3/4) IMO are the LME49990's, the LME 49710 will work as will the AD797, you need to have them both the same though as they have different specs and sound signatures.
dodog
Addicted Member
After all my problems (laid out here: http://www.audiokarma.org/forums/showpost.php?p=6581846&postcount=94), Phillip set me straight and was VERY kind to send me the correct PCB boards to mount the LME49990 on. Mouser has the slowest processing and ship time of any company every and I FINALLY got some replacement opamps the other day. I took my time this afternoon, soldered the opamps (pre-tinning the legs and using some flux makes this extremely easy), installed them, fired it up, turned on the power and, once again, ZERO noise. Well, damn, I must have screwed something else up. Oh yeah, I didn't have any vinyl spinning. Put on some Chet Atkins and immediately got some of the sweetest sounds I've ever heard. This thing is fully operational and damn fine sounding.
I know that a few have tried power supplies and not had good results. Some have been adamant that you have to use batteries. Rechargable SLA batteries seem to be all the rage with this new build. However, I had previously built Omishra's power supply (OPS), with it set at 10V to run my SSP/Lightspeed preamp, and a +/G/- supply for (previously) my MM CNC build. I opened up the power supply, set the trimmers with a multimeter to +13/-13V and I'm using an XLR cable as my umbilical. This thing ROCKS. Zero noise (I had to turn the volume to near 5 o'clock to hear even a hint of hiss). I'll repeat that. ZERO NOISE. Sachin and Omishra will be proud. I have zero desire to recharge or monitor batteries and this supply is as quiet as any battery supply I've ever used. OK, enough preaching.
Thanks to HypnoToad for the boards and support. Thanks to BillyK for the twisted/shielded hookup wire for this build. Another project completed. :yes:
I know that a few have tried power supplies and not had good results. Some have been adamant that you have to use batteries. Rechargable SLA batteries seem to be all the rage with this new build. However, I had previously built Omishra's power supply (OPS), with it set at 10V to run my SSP/Lightspeed preamp, and a +/G/- supply for (previously) my MM CNC build. I opened up the power supply, set the trimmers with a multimeter to +13/-13V and I'm using an XLR cable as my umbilical. This thing ROCKS. Zero noise (I had to turn the volume to near 5 o'clock to hear even a hint of hiss). I'll repeat that. ZERO NOISE. Sachin and Omishra will be proud. I have zero desire to recharge or monitor batteries and this supply is as quiet as any battery supply I've ever used. OK, enough preaching.
Thanks to HypnoToad for the boards and support. Thanks to BillyK for the twisted/shielded hookup wire for this build. Another project completed. :yes:
