PPA builders' thread

[Barradio 0]

Me one of them and I think jason may one it too.

[jtfoo 0]

really? yeah I am. where do I put in my "student" status?

 

 

I was told by the receptionist girl that a student card will do.. That's if you're buying over the counter at Ubi...

[ablaze 0]

actually, I haven't ordered anything from farnell before. Do I submit the order online and go down to ubi to collect or what?

[jtfoo 0]

actually, I haven't ordered anything from farnell before. Do I submit the order online and go down to ubi to collect or what?

Just called the sales at farnell. Student got 10% upon showing student card in person. That means no discount if ordered via phone or internet.

 

I've been ordering over the counter from Farnell most of the time. If you need directions, I can meet up with you and go together..

[ablaze 0]

hmm..ok $7.11 for quantities >10 minus 10%=S$6.40 per buffer

so for 12 = $77 (save $8)

petrol down to ubi and back=???

 

whats farnell's delivery policy like for online/phone orders, jt? any idea?

[WatCult 0]

I am also interested in making one but have to wait until i come back to singapore in dec.

Farnell also got an office in tampines isn't it?

[ckng 0]

trying to figure out where to get all the parts for now. Farnell seems to have most of the stuff. I'm still wondering if I should go for it

 

btw, the HA5002 buffer's $10 a piece at farnell, but if you buy more than 10 its $7.

ie. 6 buffers will cost $60, but 12 buffers will only cost only $85

That doesn't sound very expensive.... RS sells the EL2001CN used by META42 for S$13+, and the 2002 for S$15+.

 

Are these HA5002s pin-compatible with the EL2001CNs? Have not checked their datasheets.

 

Regards

CK

[jtfoo 0]

hmm..ok $7.11 for quantities >10 minus 10%=S$6.40 per buffer

so for 12 = $77 (save $8)

petrol down to ubi and back=???

 

whats farnell's delivery policy like for online/phone orders, jt? any idea?

I've never order online or phone. You can call the sales up to check. They are rather friendly on the phone..

[jtfoo 0]

That doesn't sound very expensive.... RS sells the EL2001CN used by META42 for S$13+, and the 2002 for S$15+.

 

Are these HA5002s pin-compatible with the EL2001CNs? Have not checked their datasheets.

 

Regards

CK

No they're not pin compatible.

[jasonhanjk 0]

I am interest in the power buy. See classified section...

Will start a thread...

 

I am NUS student...

Edited August 26, 2003 by jasonhanjk

[ablaze 0]

hey guys, which of the parts in the "optional parts" list on tangent's page is actually necessary for a working amp?

 

any progress so far, jt?

[jtfoo 0]

For a basic working amp, no need all the optional parts. But if you want to built to the PPA team's spec as in the schematics,implement all.

 

Here's my initial plans for the optional parts. Feel free to comment and they are subjected to changes along the way.

 

LED circuit- Adopting KISS, will only use RLED and LED. So don't need the FET, RFET & ZNR . Will be using two pin socket for RLED, so I can swapped resistor to adjust the brightness of the LED.

 

Not going to use audiophile caps for C1/C4 to save cost. Probably settle for Panny FC.

 

1uF for C2/C5& 0.1uF for C3 - I've extra of these so will implement them, since they're not on signal path, can use polyester caps which are small enough for the PCB. You guys can try these polyester caps with tight tolerance from Farnell, order code 568211 (1uF) & 567450 (0.1uF).

 

Will put in DIL IC socket for all OPamps and Buffer, except ground channel opamp. This is to facilitate opamps rolling, and changing burnt buffers easily.

 

Still thinking whether to put in the bass boost C7 & R7.. Value of 82nF polypropylene and better caps are hard to find. Might just settle for 0.1uF.

 

Implement C6 to stabilise opamp at unity gain. I've some extra silver mica caps, though not the same value.

 

Implement class A biasing as per schematics. 2N5484 get from the Meta Cascode set from Tangent and 2N5486 from Farnell.

 

Power supply will be direct from my SLA battery, 24V.

[ablaze 0]

I'm aiming for a basic working amp too. after all, this IS my first attempt at amp building

 

I'll need to read what you posted jt, and probably follow what you're doing, hehe.

 

one question for now, where to get sockets for the soic-8 opamps?

 

wait, make that 2: how many buffers will you be using?

[jtfoo 0]

one question for now, where to get sockets for the soic-8 opamps?

 

wait, make that 2: how many buffers will you be using?

What I'm doing is get the browndog SOIC ot DIL adapter from Tangent to convert the AD8610 to DIL. Then I can use them on the DIL socket. Planning to compare them with the OPA637...

 

Plan to build the PPA as close to the team's spec as possible, so it'll be 12 buffers.

[ablaze 0]

thanks jt. just realised the hammond enclosures are NOT in stock