Point to point is so much fun

[00940]

I'm half-through a new amp, completly done P2P. The first channel is working; sadly it's the ground channel and I cannot hear it

Honnestly, P2P takes way more time than building on a PCB but it is far more interesting. As long as you don't have to troubleshoot I guess... (crossing fingers).

The little vertical protoboard is the diamond buffer (made of 2SC1815-2SA1015). Schematics (nothing new, most values come from the Pimeta/PPA) are here : http://www6.head-fi.org/forums/showthread.php?t=136814 . Only difference is that I added a 1K resistor before the buffer. All parts are coming from my junk box, which explains there's no boutique parts in there.

 

[setmenu]

I also enjoy p2p ,all of my amps/dacs were done this way .[with the exception of a pimeta]
And boy it can be time consuming, especially when ones trying to build a very tiny compact layout.
The thing that often takes me the most time is deciding on the best layout and routing of 'traces' as this can be very critical to the performance of the device.
P2p is a great way of learning about these things as it forces you to research things that would never need considering when using a ready made pcb.

Hope it sounds good

Cheers

Setmenu

 

[DaKi][er]

Everyone should start off with a schematic and have to learn how to p2p on a protoboard from scratch, it’s a great skill that everyone into DIY should know

Too many kids these days wanting everything to come on a pre-fabbed PCB and just stuff part in it, there’s no skill in that at all and my mother could probably do that :eek

 

[aerius]

I did a p2p cmoy once and figured it would take me 10 minutes at most to slap together. A chip, 6 resistors or somthing like that and a couple caps plus a pot and the jacks. How hard could it be? Took me well over an hour to lay it all out and get it soldered up. Swore I'd never do that again. Couple years later I built one channel of a Dynahi p2p because I wanted to hear how it sounded like and there were no PCBs out yet. That one took me several days to figure out. Never again.

 

[00940]

The little amp is done, just in need of a case. Up to now, it took me roughly six hours, among which 40 min for each buffer. Very clean sound, I'm really happy with it, especially with the Grado SR225 it's been made for. It will do more than hold its own against a dynalo, while dissipating a lot less heat.

Technical details : 8mA lets the buffers' transistors barely warm at stand by, a tad warmer when playing loud. It's still 24mA per channel of class A (about what's suggested by Tangent for a PPA). Offset is around 3ma per channel. Judging by the differential between the opamp output and the buffer output, the buffers would have around 30mV of offset open-loop.

 

[00940]

Hum, I spoke too quickly. I've got a little problem.

At startup, there's an heavy offset. About 180mV for each channel. It slowly goes to 3-5mV per channel, in about two minutes. Any ideas how to fix this ?

 

[Shosta]

I have made that way three Cmoy, a almost Pi meta and THE clone of a mahogany amp...
I spent a lot of time thinking how to put the things, specially difficult was the pimeta.
I'm not very good soldering but all of them worked almost from the beginning (multimeter it's a must).

 

[Blorton]

Looks nice, double-naught, but it looks like you're missing some parts there.

I don't see any tube sockets anywhere.

Cheers!
Dan

 

[jbloudg20]

Quote:

Originally Posted by Blorton I don't see any tube sockets anywhere.

 

[GLF]

Yes, where are the tube sockets?

Point to point rocks, it is tons of fun.

All you need now are some (read: a ton) of tube sockets and enough capacitance to kill a large farm animal and you will be set.

Andrew

 

[Tomo]

Hi,

If you wanna P2P something hard, you gotta start from breadboard (pin cushion type for the lack of better words). Then paste it onto the soldering breadboard.

As for doing relatively simple or Tubes, I like positioning parts (chasis work etc) first thing.

Why all this? because P2P gets messing fast if you got no plan. I often ended up soldering in positions nearly impossible (I haven't done soldering hand-standing ... but I would hate to try.) and I heck don't wanna repeat it.

But P2P's tweekability is so much greater than hard-printed boards. (Except for PSU's. I think we tweeked the crap out them in last few years. Plus I am comfy with a switcher.

)

T

 

[setmenu]

I would certainly agree with Tomo , you definitely need to know how everything
is going to go together before picking up a soldering iron.

With my little portable amps I first selected the case, then all the hardware
such as sockets pot etc and then decided on the battery to be used.
It was then a case of cutting a dummy board and populating it with parts
to find the best layout,taking into account the best routing for traces, best parts
layout did not often mean best circuit layout.
Constructing stuff this way does mean a deep intake of breath before contemplating a build,
by comparison populating a pcb is almost like placing it in a box
of components and shaking until they just fall into the correct holes!
P2P is more like making a one off piece of jewelery or sculpture,
I guess that's why I enjoy it.


These are my favorites to date, installed into the smallest clear hammond cases,
3 channel amps with interchangeable bass boost modules and 5 level batt monitor:

http://www6.head-fi.org/forums/attac...achmentid=4554

http://www6.head-fi.org/forums/attac...achmentid=4556

http://www6.head-fi.org/forums/attac...achmentid=4553
.

 

[amb]

Here's a battery-powered moving coil catridge pre-preamp I built some 20 years ago in P2P. It's basically a high-gain cmoy-like circuit using two NE5534 opamps. Not "high-end" by any means, but it did the job in a compact enclosure.

 

[Tomo]

Hi,

Since ya'll want it. ...

It's literally hybrid. Hybrid as in tube/solid ... well ... It's a really easy tube/solid. ... And it is P2P/Board.

Ciao!

T

P.S. The board is not screwed on. It is held by the ground lug of the Socket and a piece of insulator plastic piece. The board is P2P too!

P.P.S. And, that's my boxer shorts. I'm sorry; my shorts is not P2P.

 

[00940]

My amp is really an ugly duck compared to yours, and especially to Setmenu's very neat amp. It's not full p2p, there's a little dac in there I'm very happy to have done on pcb.

Really, you don't want to see the underside. Each buffer and each opamp has his own wires to bring V+ and V-, a real forest. Still, it sounds real good. I finally used a winding for the amp and a winding to power the dac.

The usb jack of my laptop is so crappy however that I get some faint noise with grado sr225. It goes away when using a desktop pc.