Which amplifier kit to build

[Xerxes75]

I know that the answers to this question are numerous so I will try to narrow it down a bit.

I have build a TA2020 a LM3886 amp and a LM4780 and the ultimate goal in the future is to build a big Class A monster.

But for now I am looking for:

Class a/ab
+/- 70 Watts at 8 Ohm
Capable to drive 4 Ohm
Compact size
Good bass
No SMD soldering…
Well documented/build guide
Good quality (for a nice price)
Amp that does not heat up to extreme temperature because of the enclosure I have and want to use
And maybe I want to build two (or four channels) so I drive my bass units separate.

What do I have: (to save some cash)

2 toroids 2*25V 225VA
Two Naim shoecase cabinets
Dact CT-2 attentuator 50K

On the following amps I did some reading

Akitika GT101
VSSA
The wire LME49830
First One mosfet amp
Naim NAP140 clone
A lot of eBay amps
Group buy threads

And some threads with the similar question

I do like a challenge but I rather avoid problems so I would appreciate your idea on what to build.

 

[Ranchu32]

Hi Xerxes, you'll fall slightly short of your power target with those transformers. Expect ~55W from 25VAC secondaries.

I wholeheartedly recommend the VSSA (or one of the through-hole derivatives).

 

[jkuetemann]

You mention looking for a kit. That means different things to different people. Are you looking for pre built modules, full kit of boards with all components, boards with some components or finally just bare boards?

I'll add my recommendation for a VSSA or derivative.

 

[Bixbacon]

P3A

This is a very popular amp that I plan to build one day soon. I think your toroidals will be suitable for Rods recommend psu design. Hope this helps. Good luck

High Quality 60 Watt Power Amplifier

 

[lanchile]

My favorite! 2sk1058 2sk2221 irfp9240 mosfet amplifier schematic

 

[esgigt]

Hi Xerxes, you'll fall slightly short of your power target with those transformers. Expect ~55W from 25VAC secondaries.

I wholeheartedly recommend the VSSA (or one of the through-hole derivatives).

@Xerxes: Since a well designed PSU has more effect on soundquality than a hand-full of watts more, I would not worry about the ~55W. Search this website for ideas on PSU's. Since you have two toroids, I'd go for a double mono configuration. Pay attention to proper suppression of all the garbage that is also supplied with your 230V mains.

 

[Xerxes75]

Thank you for the input.

To answer the question about a kit: I would like a pcb with at least some parts and some recommendations.

today I will do some reading about the proposed amps, they look very nice.

I will settle for ~55W

The reason why I like some sort of short guide is that I find it difficult to filter all the opinions and solutions out of the (mostly) long threads.

 

[crispycircuit]

For low cost fun. Check out the MX50-se on Ebay. Under $20 get you a stereo kit delivered to your door.A few DIY members have built and enjoyed these. Then mean while slowly build your dream amp. My MX50 se is assembled but not up and running yet.

 

[Xerxes75]

I was just the MX50 thread...are you a mind reader?...

The thread you replied in started with a question about the different versions, which did you choose?
And there are also posts about tweaking the board are you or have you implied these?

And I agree that it is a low-cost option

 

[crispycircuit]

I bought the MX50 se. IT took 2 weeks to get. Nicely packed. All the parts are there and they look decent. The actual board is tiny. You can fit 2 on 1 heat sink. My only surprise was the outputs were not marked PNP orNPN. I work slow & it took me several hrs to stuff the boards. You need good eyes and a skinny soldering tip (no dogs or cats, kids, because the parts scatter easy). I use a flux touch up pen to get the solder to flow good. Then take a tooth brush and generic paint thinner to remove the flux. I have the boards mounted on the heat sink. Now I'm working on input/output jacks & wiring the power supply. I couldn't resist the price. I have VASS amp boards on the way for some real fun.

 

[Ranchu32]

Xerxes, a new "group buy" for VSSA clone boards has popped up:

http://www.diyaudio.com/forums/group-buys/251782-vssa-through-hole-version-jason.html#post3831506

I would jump on it if I were you.

 

[Xerxes75]

I am curious of how the MX50 sounds.

And thanks for the tip on the group buy, I just ordered a set of boards....And throw myself a bit in the deep. But I think it will be fun...

 

[jkuetemann]

I don't think you will find the VSSA difficult to build at all, it is the Very Simple Symmetrical Amplifier.

 

[Xerxes75]

Ah thanks! I am in the proces of ordering the parts, and that's a bit of a job....there is to much choice....
And I am trying to understand the CCS thing so I can order the right items..For these spots

 

[jkuetemann]

I will suggest making use of the LED biased CCS option. Standard red LEDs, order the two CCS trimmers as 1kΩ units and instead of the 22KΩ resistors use 3.9KΩ.

 

[Xerxes75]

Mabye a stupid question but do i understand correctly that 1Q + led means 1k trimmer + led. Or Does a ccs trimmer means something else?

In the articles I read Q is mentioned but it does not say what it is...

 

[jkuetemann]

We often use Q to denote the use of a transistor, a sort of shorthand if you will. In this case the 1Q is the transistor that is the active element in the constant current source, the LED is used to provide a reference voltage and the trimmer is adjusted to set the current.

To confuse things, in electronics Q also represents a quality of reactive components like inductors and capacitors. It is about context.

 

[Xerxes75]

Thanks a lot. Now I know a bit more of what the parts are and more important what they actually do.. Tomorrow I will do some more reading on the subject.

...can't wait to build.