Getting Started With a Decent Background

[wardour]

Hello, ive been a long time lurker. I curently am more of a home theater person but recently I have been doing a lot more music listening. I currently run a pair of PSB Image 5T's, a 9C, a pair of Acouistic Energy evo3's, and a Velodyne VLF1012 all off of a Sony DA4ES.

I have an electric engineering background (computer engineering / hobby stuff). I have looked at a lot of schematics and designs and am fairly comfortable with all of it.

My goals are to eventually build a solid stereo system, using at the least a DIY amp design, and very possibly a DIY preamp.

For the speakers I have and the room I have, a [email protected] amp should be sufficent. I just feel with so many designs and opinions floating around, I havent really found a thread that fits my situation.

I would like some examples of cost. Also I am interested in something that, has the potential to be a marked improvement over my current reciever (which has line level output).

Am I going to need to etch the board myself? Do people go the DIY route for reasons other than "its fun". Because honesty thats mostly why im here. I know I would love a project like this.

I also know that with components, you can pay whatever you want. What id like to hear are some ballpark figures for some amps that fit what im looking for.

Admittedly I have very little idea, what makes a good amp. I have read all of the articles at Pass Labs, and that only gave me the faintist of hints. Currently im looking for something just beyond the packaged kit, as I want quality, not just a learning project.

Thank You for anything you can tell me.

::Stuart

 

[Nelson Pass]

If you look at the parts lists in some of the projects here and
elsewhere, you can cost quite a few of the ordinary parts at
Digikey. After that at a minimum you have a power transformer
and heat sinks. Power transformers and heat sinks you can
scrounge, and if you elect to buy a new transformer, take a look
at stock pieces by Plitron and Avel Lindberg. Depending on the
details, you can get a decent transformer from 30 to 40 dollars.

Too bad you don't live in Foresthill, where there's a company
with dumpster loads of slightly noisy or off-spec transformers.

How low can you go? I can build an amp for about $100, if I
make part of it from plywood.

 

[ingrast]

Choices choices ....

Stuart:

I suggest you first make up your mind about with which camp comes closer to your heart.

- There is the tube vs. solid state.
- There is the all out class A vs. class AB.
- There is the gainclone vs. discrete.
- You can go passive vs. active crossover.

Just to name some possibilities.

If you do not feel a particular sympathy, then my recommendation as for cost-effectiveness is a gainclone. An LM3886 will give 68W on 4 ohms or the dual chip LM4780 will provide over 120W on 8 ohms with state of the art monolithic performance and a fair immunity to assembly blunders. You can also get into ready made PCB's and parts group buys.

If you want to tweak and experiment, there are fully discrete or hybrid approaches, but the choices are so many I cannot suggest a particular one.

Rodolfo

 

[metalman]

A lot of the answer also lies in your own inclinations. For example regarding your question on pcbs, to date I have built two headphone amplifiers, a preamplifier, and I am 90% through building a pair of 50W Aleph-X monoblocks. I have built all but one of the headphone amps using perfboard. The circuits might not look as pretty, but as far as I can tell they sound just as good, and no-one sees them unless I open up the chassis.

Some reference to costs:

I took a no-compromises approach to building my preamp, bought top quality parts (Holco resistors, Solen film caps, Panasonic FC electrolytics, a CRC plus regulation power supply big enough for the average power amp, Cardas and Neutrik connnectors, DH Labs wiring, prefabricated chassis, blanced stepped attenuator) and I built the whole thing for just under $500US.

My Aleph-X monoblocks I am also going for top performance approach, but I have scounged heatsinks and chassis materials from surplus stores to save some costs, and I figure in the end I'll have spent around $600US. Again, I am using premium parts throughout.

I think I can also say confidently that many here will find my costs to be high. I am a busy guy so I don't put a lot of effort into scrounging to keep costs down. That being said, in my mind at least, my projects stack up sonically against components costing thousands of dollars each. In short, save a bunch of money and have a boatload of fun, what's not to like!

Cheers, Terry

 

[SY]

I'm moving this over to Introductions, just to keep things neat and tidy.

From one Stuart to another, welcome to the forum!

 

[GRollins]

"...dumpster loads of slightly noisy or off-spec transformers."

Sigh.

All I've got around here are dumpster loads of rusty mufflers and bald tires. High tech in this neck of the woods consists of fuel injection--still called 'fool injection' by some who think it's funny, in spite of the joke having gotten old thirty years ago.
Man, what I wouldn't give to have access to such useful castoffs. I must have been really, really bad in a previous incarnation.
wardour,
I'm not clear on whether you're looking forward to doing PC boards or dreading it. On one hand, you can sometimes find a pre-made board ready for a project that you want to do. There are frequently group buys for such things here. On the other hand, you can do your own if you want. I've done scads of boards on my own. I like the layout process, but am less enthusiastic about some of the nonsense I have to go through to get that pattern onto the board prior to etching it. Etching is trivial--a fifth-grader could do it with one hand tied behind his back.
Go for it.

Grey

 

[Variac]

Is that company Passlabs?

I second the $500 price for a 2 channel Aleph of some sort, and the quality is top tier. Of course scrounging helps a LOT. Those class A amps are always going to require big power supplies and lotsa heatsinks. There are lots of new, surplus stores on the web and e-Bay. Tracking down the parts at a good price is a big part of the process

A 2 channel chip amp can easily be under $200 with all new parts including case.

 

[Cal Weldon]

Regardless of what you choose, welcome to the forums Stuart. I hope you find all you need and more.

Cal

 

[leadbelly]

Am I going to need to etch the board myself? Do people go the DIY route for reasons other than "its fun". Because honesty thats mostly why im here. I know I would love a project like this.

Well, you've gotten a lot of advice from heavyweights, so there is little I can add, except maybe on this very topic of "fun". I do it almost solely for the fun aspect, I'm actually barely into the audiophile enjoyment side of the hobby, but enjoy the woodworking and soldering side of things more. And so you question about etching boards is very pertinent. Sure you can do what some do here and just go whole hog on everything, and I totally respect that and one day I might do it that way. But if you find something that is difficult to do the hardcore audiophile way, don't worry about it, worry about moving forward having fun. Use perfboard. Use thin gauge stranded wire on hand. Make your driver cutouts with a jigsaw. Use regular plywood for an enclosure. Just have fun foremost.

 

[Eclipse911t]

Getting started with no background...

The costs estimates I have been hearing in these posts seem a bit low to me...

I am brand new to all of this and am only a short way into my first project. All materials have been purchased however. Maybe I've just made some poor purchasing decisions, or haven't scrounged enough, but My amplifiers are costs way more than $500. I have logged my expenses throughout my project and don't mind sharing them if you are interested.

Keep in mind that I am brand new to all of this and have a DMM and Soldering Iron included in my figures. I had a second cheaper fluke meter on hand as well as a 12v regulated power supply used for matching.

I got some random parts cheap. The cans and power resistors were used along with the expensive heatsinks off of ebay. I got my toroids from partsexpress.com

I'm building a large pair of ALeph-X monoblocks at 25volts and 12 amps of bias. Pretty much they are way more than it sounds like you need, but it required 2 625VA toroids each and I went with 208,000uf of capacitance per channel. Like I said kinda over-kill. I also went with some expensive connectors.

Here have a look. Kinda makes you consider your desired output power...

 

[wardour]

Thank you all

This may be the best responce ive ever recieved in a forum. I have been looking mostly at the pass designs. I have never heard a class A amp in person. I am not interested in tubes, I think ill be staying in the realm of solid state.

Currently im interested in purchasing a ready made board. I dont have my etching setup anymore. I do have all the tools I would need to do this (DMM, weller iron, and just about anything else) I even have a scope at my disposal.

im currently looking to spend about 300-500 on my first pair of amps / or stereo amp. I have looked at the high heat class A's mostly. What are their benefits over the chip amps?

I hve done my fair share of TSOP soldering, so that isnt a restriction. I am a pretty pationt person, but I would like a semi fool-proof first run.

Thanks for all the input

 

[ingrast]

Re: Thank you all

...but I would like a semi fool-proof first run.

Thanks for all the input

Then it looks you have narrowed your interest in the direction I previously hinted, gainclones. You will have good performance, ease of construction, good built-in protection from assembly goofs and low cost. Check the group buy threads.

Come back with your impressions once "first sound" is achieved !!!

Rodolfo

 

[wardour]

Any specific units I should look at?

 

[Variac]

Eclipse's list IS very educational. And it shows the decisions and tradeoffs when making a project. First lesson is that when you keep a careful list, you can't fool yourself- maybe a good reason not to make a list

Second, his costs aren't foolish, they are a very possible cost for a certain level of finish, power, convenience and luck finding stuff. Also time plays into how much stuff you can find. ( I spent 2 years accumulating parts for an amp!)

My costs are less first of all, because I don't count my equipment as part of the project - this is MY post, I can do it as I wish!! heh heh

So, I saved $430 already! An inbetween philosophy would amortize the cost of tools over various projects.But I am using a DMM I got on sale for $25 - I was alerted to the sale on this forum. I got my Hakko Digital soldering station in the Trading Post for $40. Don't have a 'scope yet.

That Aleph X he is making is a big one! And big power Class A costs a big power supply and a lot of surprisingly expensive heat sinks. I agree with Eclipse- Consider carefully the power you need, I wasn't thinking of such a big amp in my estimate.

I did find some over 1000 VA toroids for $30 each, but had to do some tricks to make them work- you gotta be a bit lucky to find the right voltage. And you gotta be the kind of guy that enjoys spending hours browsing for parts, and doesn't count that as a cost! My heatsinks were a lot cheaper but probably not as pretty.

Finally- does it make sense to spend hundreds of dollars on a case? I'd say sure, for a fine quality amp it is well worth it, and worth it for the pride in showing it off. However Par metals makes a painted sheet metal rack mount case with an anodized alu front panel for about $100 if you don't mind a more utilitarian look. Might need some beefing up to handle the weight... or have the power supply in a different box.

All and all this hobby can be expensive and fun or you can keep power down and choose efficient speaker designs, and it can be pretty reasonable and fun.