Ipod drive for turntables

[netcastle]

I would assume I have both windings connected. There are four wires going into the motor and I have all four connected.

It's a 15v. I don't know too much more than that other than that it spins at the correct speed when I run it off my DIY control.

[netcastle]

Is there a better amp for this than the t-amp. I need 15v on the output, and I would rather not use my trafo's if I don't have to (around 40 bucks a piece). Something cheap and simple. It doesn't have to sound good.

[Nanook]

a nice 300B amplifier (pure class A)....

I defer comments to Mark...somewhere I think it was suggested to not use a class AB type, but can't remember who made that statement.

[kn]

I'm slightly embarrassed to have taken so long but I just finished and tested a phonoclone version 16a (i.e. I bypassed the on board LM79XX/LM78XX and used separate LM317/LM337 power supply boards). What took me time was deciding on this modification (vs getting newer boards), as well as deciding exactly how to implement Richard's suggestion of "using shunts" in order to be able to change R2 to be able to have the preamp work for different cartridges.

Anyway, I am very pleased with the results with an AT-F3II cartridge. Previously I was using a head am feeding a NAD 7220PE phono section. The improvement is astonishing. I am very grateful to you Richard for all your efforts. You have made available working plans for a wonderful mc phono preamp, have regularly ordered boards for people (like me) without the knowledge to do it themselves and have answered lots of questions.

For those who are curious here are some of the parts I used:

AVEL 160VA transformer (it seemed a bargain at US$36)
Panasonic ECQ-PZ series 50V 1% polypropylene caps for RIAA
Vishay/Dale 0.5W 1% metal film resistors for RIAA
Yageo 0.5W 5% carbon film resistors non-RIAA
Analog devices OP27GPZ (I made the lower gain version).

You don't need to spend a lot on parts for this project. I bought duplicates (at most 10) to match left and right and to get the RIAA values as close as possible to Richard's recommendations. It was still very inexpensive.

Anyway, I want to express again my deepest thanks to Richard.

kn

[Nanook]

a nice 300B amplifier (pure class A)....

I defer comments to Mark...somewhere I think it was suggested to not use a class AB type, but can't remember who made that statement.

er, .Cana Kit have some inexpensive amplifier kits...

[netcastle]

a 300b...60 hz never sounded sooooo good

Found a 25 watter on ebay for a reasonable price. I will drive it at or above 15v. Hopefully this will enable me to get the tranny's out of the system (so I can use them for something else). So, in the end, I had to pay about $30 so far for this project. It never ends.

[Nanook]

but the results are always rewarding...

[Nanook]

Mark,
I have decided to give this a go using a class AB amp as a voltage amplifier. I can use an AC synchronous (Hurst 3001-001 or Airpax/Premotec) or an induction motor. I do kind of like the idea of an induction motor. What are your thoughts and/or experiences?

The same could be done as per Altmann and use DC stepper motors of a suitable voltage, using essentially the same scheme.

any comments are appreciated.

[edd9000]

Sorry to dig this up.

I have experimented with this using a stepper motor and t-amp, much like the altmann setup.

Im interested in being able to use a higher quality motor like the hurst, but when you say you need to be carefull on transformer selection can you possibly suggest one? or what to actually look for when buying one.

Thanks,

edd