DIY Projects

Crafty

As per bottledtone's suggestion...

bottledtone wrote: How bout a DIY amp gallery. So we can see what guys have put together themselves.
It has probably been asked for, but would be cool to scan over peoples builds.
Can be inspiring for those wanting to venture.

DIY FX stompies too!?

Blessings.

Here is mine:

These are not for guitar... One day though. Still need to develop my taste in what I want before I build something. Perhaps a very crisp tone as is used on the 3rd track of the wall cd1, Happiest days of or lives. (I think that is the track...)
This is for my stereo setup.
a bit of background...
I started to listen music on my NAD T748, and was simply not happy. Music should Never be played on a movie amp. This made me decide to investigate building my own.
Purely for music. Criteria, It should play cd as well as turn table, and it should play it well.
This is what came out.

Power amp:
NAIM NAP 150 clone.
It is the Avondale upgrade, with some more modifications, and a few mods by myself as well.
Already built and planning the case layout... As you can see, it is a dual mono design for optimum channel separation.

After anodizing...

The Pre-Amp
-------------------

I wanted a preamp with inputs for 1.) PC, 2.) Harmoni/Kardon cd player, 3.) turn table, and 4.) FM Tuner for Tuks FM
Gain is manually controlled for each input device so the headroom is right when the signal gets to the power amp.
Mounting boards to ground plate:

Getting ready for 1st test:

After about 2 years, and about R25K spent on project, this is the end result.

And then of course I had to share AC/DC - Highway to hell on Vinyl with my 4 year old.

The cases was not made by me. I had them CNC'ed by a friend in return for a favour. The favour, I had to build another NAIM Clone power amp for him. He is simply a wizzard when it comes to machining of solid aluminium.

It may not look like much, but every single component was hand selected for best sound. In some cases I bought like 100 transistors, then matched them by hand for best sound, when I only needed 2. (variance and all that crap)
The sound.... well to put it mildly, its bloody awesome!
I can put it on max volume, with cdp on pause, and not hear a sound.
Due to my modifications on the input of the power amp, the sound is punchy and VERY dynamic and fast.

The valve stage on the pre-amp gives it a warmth that only valves can give. Of course, I do not need to tell guitar players about the greatness of valves. It's always been around in guitar amps. I'ts only making it's way back to high end hifi amps now.
Not much... but it is mine
?

Tamago

Hi there

I was doing some R&D today about whether to do a local electronics magazine or not, and I saw this post of yours come up.

While the build is commendable, I can offer you a few pointers.

Some of the capacitors you used there are really low-grade. Those HITANO caps are really cheap and should not be used in audio equipment.

Those screw terminal blocks are also a big no-no for audio equipment. They have resistance issues as I have experienced using them in many designs of security equipment over the years.

Crafty

Tamago wrote: Hi there

I was doing some R&D today about whether to do a local electronics magazine or not, and I saw this post of yours come up.

While the build is commendable, I can offer you a few pointers.

Some of the capacitors you used there are really low-grade. Those HITANO caps are really cheap and should not be used in audio equipment.

Those screw terminal blocks are also a big no-no for audio equipment. They have resistance issues as I have experienced using them in many designs of security equipment over the years.

Thanks for the advice. I always appreciate helpful criticism. Helps with future builds.
The wires on the terminal blocks has been tinned. Then using pliers I held down the block and let the screw "bite" into the lead to try and counter scratchy, high resistance joins. Not ideal, and going to redo the pre-amp any ways.
This pre-amp is based on the SRPP design. I want to do a srpp+ at some stage. SRPP+. so that I can hopefuly drive some 300 ohm headphones directly from the pre-out. the + version is said to be strong enough to do that.
I bought the hitanos because I had experience with the Hitano low ESR caps. They are quite fantastic where low ESR is needed. sounded better than the Panasonic low ESR caps. Used them in the power amp.
Currently I'm not happy with the phono stage. These caps might be a good starting point. It is an op amp based phono stage, so by design far from the best. I might be doing a solid state, or valve phono stage at some stage. Just need to get the finances to stabilise a little 1st.
thanks again for the pointers.

Gearhead

If I wanted to build a phono pre I would not doubt and go straight for the Aikikdo range. What you want in such an amp is very high gain and very low distortion and transient intermodulation distortion - not feasible with opamp technology. Aikido is rediculously good at the gain vs. distortion thing as well as high PSRR because of the topology, although you do still want good tubes and a stable power supply. Plus, minimal caps in the signal path means you don't worry about what caps to buy.

Tamago

Thanks

Currently I'm not happy with the phono stage.

Due to the risk of hum and microphony I would not do this with tubes. I also find lately that, in hifi, tubes are generally much over muchness and an unnecessary challenge.

I know how to design a phono preamp with discrete components, however, the question is, are you prepared to pay for the matched transistor sets at R173.00 per each?
If that is no issue then we can talk about it, the math will be quite fun but ja, I did it looong ago, back in '95 so it will be old hat.