My DIY Amp project

[chasw98]

That ones missing all kinds of knobs and stuff.

Ooops, sorry about that. Didn't look close enough.

[Hdale85]

The chassis is only going to be 6" high 19" wide and about 16 1/8" deep. So not to big for a Class A amp. I'm not sure about the copper plate. I wouldn't think it would be too terribly hard to sand it down real smooth and polish it so it matches up perfectly. I don't know though.

[Dennis H]

Copper in direct contact with aluminum will cause corrosion of the aluminum. When you use aluminum in house wiring, like for the big service entrance wires, you have to use a special grease where they join the panel.

[JonMarsh]

Metal to metal interfaces are a thermal interface problem- when you look at it under a microscope, "smooth" looks pretty rough. Thermal grease or interface sheets help, but only so much. Bose had a pro oriented power amp in the 70's that looked pretty brawny, but it's problem was the way the power transistors were mounted on relatively small aluminum pieces and bolted to the heatsink- the Rth from transistor through the plate to the heatsink was much higher than from the heatsink to ambient.

Ayre fought this with the V1x monoblock. That's why their new MX-R is milled from a single piece of aluminum- no thermal interfaces, and the whole chasis is a heatsink.

Image not available




52 lb each, 300W @ 8 ohm, 600W at 4 ohms, no loop feedback, balanced input to output, thermaltrak output devices with bias diodes integrated on the power transistor chips, bandwidth of DC-250 kHz.

I'm not familiar with the arrangements for the DIY alephs, but I'd think carefully about what they recommend, and what to use, because they are nearly full class A, if I recall correctly.

[Hdale85]

They are full Class A I believe. Others have built something similar to what I'm planning though.

[JonMarsh]

They are full Class A I believe. Others have built something similar to what I'm planning though.

If that's the case, and the transistor case temperatures are reasonable running in summer ambient temperatures, then go for it. How hot are the transistor cases after warming up an hour with the design you're going to use?

[Hdale85]

Should be around 60c I believe maybe 55. They can run up to 70c.

[relder]

Your picture implies 3 separate heatsink extrusions per side, so I can see why you might want to couple them together, but I'd just put an output transistor pair per sink, which is convenient since the A5 has 3 output pairs. But then your output section PCBs wouldn't fit. You could do what I did and use a PCB for the input section and point to point for the output. Those output section PCBs don't buy you much anyway. As you can see from your 1st picture they're just a few big fat traces. Something to consider anyway.

Here's the one I built a few years ago:
My aleph

Don't laugh at my PCB, it was the 1st one I ever designed and built.

Rob

[JonMarsh]

Nice looking work, Rob. I bet you enjoy your music on it.

~Jon

[Eric S]

Dougie,

I'm sure you'll enjoy your amps once they are finished. I'm working on a set of Pass Labs Aleph-X amps that will deliver about 150w of Class A power into a 4ohm load for the Avros that I also have in the works. I've been slowly working on these projects for years... Too many open projects...

I have a web page that documents much of the construction and parts for the Aleph-X amps here. It has parts lists, costs, and considerations for choosing transformer sizes, power supplies, heat sinks, matching components, etc.

To answer Jed's question, by building it yourself you can save a great deal of money over the price of even used equipment from Pass Labs. This may not be the case will other manufacturers though.

[TacoD]

I have a 50W Aleph-X, it sounds different than a Aleph5, but there is nothing wrong it just build the Aleph 5. You cannot go wrong with this one.

(Both the Aleph-X as Aleph designs have trouble to drive 4 ohm load).

[Eric S]

Both the Aleph-X as Aleph designs have trouble to drive 4 ohm load.

That's the first I've heard of the Alephs having trouble with 4 ohm loads. Could you elaborate?

Eric

[BobEllis]

I have a 50W Aleph-X, it sounds different than a Aleph5, but there is nothing wrong it just build the Aleph 5. You cannot go wrong with this one.

(Both the Aleph-X as Aleph designs have trouble to drive 4 ohm load).

Maybe as published it could be said they don't like 4 ohm loads because they don't double their power compared to 8 ohms. It's not a stability issue that I am aware of.

For 4 ohm use, just increase the bias (easy way: add more output devices), You can also reduce the rail voltage somewhat to reduce the heat dissipation.

[Hdale85]

I believe the Alephs actually lose output power going down to 4ohms Well some of them I've seen rated at something like 60 watts at 8 and then 45 watts at 4.

I got the boards today BTW! Oh and as far as mounting to the heatsinks I was thinking I could take the 2 output boards and mount them just right so that there are 2 transistors on each heatsink. Although they wouldn't be in the middle of the heatsinks I'm not sure this would matter too much. I may still try the copper thing and if I can't get it to work go P2P or something. These boards are gorgeous! Although they are black and was expecting blue. But they are extremely thick much better then any commercial PCB I've seen.

[Hdale85]

relder, Are those few holes in the top adequate for ventilation. Been trying to think of how to add ventilation to the top of my chassis as I don't have access to many tools. Can't seem to figure a place I could order one from with slots in it or something.

[relder]

relder, Are those few holes in the top adequate for ventilation. Been trying to think of how to add ventilation to the top of my chassis as I don't have access to many tools. Can't seem to figure a place I could order one from with slots in it or something.

I haven't melted anything yet :#. Running it for a few hours at a time here and there it seems adequate. It gets pretty toasty though, but that's not from lack of holes, but the overall amount of heat it's pumping out for those heatsinks and still air where it sits in my house. The slightest of breezes helps things greatly.

The temp as built was at the upper level of acceptable. For casual listening I was a little uncomfortable with running it that hot, so I later added switchable inductors between the rectifier and the caps in the power supply to lower the rails to a stock aleph 30 voltage, while providing a bit extra power supply filtering. With those switched in it's comfortably warm 8). I can crank it up on demand.

Rob

[Eric S]

Rob: Great idea for switchable cap-input vs. choke-input power supply. I might have to give that a try with my Aleph-Xs. That would allow me to switch between 22v rails and 16v rails, maybe an interesting way to deal with heat... I will be building 3 high-powered monoblocks and a smaller stereo chassis (5 channels all together) for my basement theater.

Bob: No, they don't double their power into 4 ohms, but I plan to run with 22v rails and about 7A bias, so they should be fine. This will deliver about 100w into 8ohms and about 150-160w into 4 ohms.

Dougie: Go to Mcmaster.com and search on "Metal Perforated Sheets". Something here might work well for the "lid" of the chassis and provide some extra cooling.

[Hdale85]

Thanks Eric, although I'm not sure any of that would really work with what I want. I was hoping to find aluminum with slits cut in it like normal audio gear has. Like this




This is where my front and rear panels are coming from http://www.frontpanelexpress.com/home/index.htm
Maybe I can get them to do something for the top.

[JonMarsh]

Have you ever checked out Par Metal? I use them for electronics enclosures, they make a lot of different things in aluminum.

[kvardas]

I am glad to see someone post their DIY amp project on this forum. I've been looking at building a UCD180HG amp project, but welcome other alternatives.

Thanks

[Hdale85]

I didn't like the UCD because its pretty much already built. I also was not sure about Class D. So I started looking for Class A designs and the Aleph 5 seemed to fit my needs.

You know Jon I didn't think of trying to find a top panel from par metal. Thats a very good idea indeed.

[Ecir38]

Would Cardas Quad Eutectic be alright for a job like this?

Lansing b-style are some nice enclosures too.

http://www.lansing-enclosures.com/main/graybox/b-style/index.html

Hammond makes enclosures on the cheap but you get what you pay for.

http://www.hammondmfg.com/dwg21.htm

[Hdale85]

Yeah but I just want a panel for the top. Not an entire enclosure. And yeah that cardas stuff would probably be good although overpriced. You can get any silver solder to use. Although needs to be high temp. Most will say silver solder is over kill but.....thats why we are DIY'ers I'll be using solid core silver wire for the internals as well.

[itsparks]

Thanks Eric, although I'm not sure any of that would really work with what I want. I was hoping to find aluminum with slits cut in it like normal audio gear has. Like this




This is where my front and rear panels are coming from http://www.frontpanelexpress.com/home/index.htm
Maybe I can get them to do something for the top.

You know, i do have some spare parts. Useing the copper with alumium and some heat compound between the 2 pieces of metal will work perfectly.. If need help let me know, i helped Briangt do the boards.

[Hdale85]

You know, i do have some spare parts. Useing the copper with alumium and some heat compound between the 2 pieces of metal will work perfectly.. If need help let me know, i helped Briangt do the boards.

Thanks I'm sure I will be asking you lots of questions

[Hdale85]

This is about what I was thinking I would do if the copper thing didn't work



The boards are about the right size although the components (transistors) are nowhere near right. That tranny is probably too big as well but gives an idea of layout. I didn't feel like getting all detailed drawing all the components :B

relder, Where did you get your heatsinks? They are quite nice looking....

[Amphiprion]

You know, sometimes I regret having an electronics job. I have all the tools necessary to do anything right at hand - but come 5 o'clock, screwing around in PADS or using the board mill is the last thing I want to do. I could whip out some awesome stuff though with what I've learned. Unfortunately most of what I do at work now is pulsed high voltage power supplies for plasma research. I can get you 20kV at 20 amps for 40 nanoseconds at 10kHz rep rates, but I can't find the motivation to tinker with audio stuff after 5. Kind of depressing...

Oh, if anyone has a need for a circuit board plating machine or a multilayer board press (both LPKF), my company is looking to get rid of our in-house fab capabilities. Advanced Circuits is just too damn good these days.

Oh, and if you ever buy a multimeter, don't bother with anything other than Fluke. And if you need tweezers for electronics, get something from Erem. I like the AASA model. The right tweezers are as important as a good scope or multimeter, anything less will annoy the hell out of you when you start doing SMT work. Make sure you have a flux pen. Use Kester 245 core 50 or 58 for circuit board work if your boards are plated. If you're doing bare copper boards use Kester 44 with core 66. If you use bare copper boards spray them with Solder-Lac from LPKF, worth its weight in gold if you etch your own. Like it a lot better than tin. Does it's own fluxing thing when you hit it with the iron and stops the copper from oxidizing (its main purpose). Buy a good set of probes for your meter, don't stick with the cheapy probes you get with it. Get a set of alligator clip leads and some pin gripper types. Fluke makes a test probe set that has several of what you'll want. As for scopes, Tektronix is fine, get at least 100MHz bandwidth and at least two channels, and color. Also we have a Fluke 199C at work that is very very handy and nice to use. It's spectrum analyzer is sort of an afterthought it seems though, not that accurate - told me a 16MHz crystal was 16.7Mhz or something. Using the normal frequency measurement in scope mode showed the crystal was 16.00MHz so it's just the analyzer portion. Crystal had harmonics on it though which were neat to see. Autoranging on the Fluke scope is quite good and useful. Never ever ever use 60/40, always use eutectic blends, I have found no need for anything fancier than Kester 245. It's pretty clean and fine to use on tinned boards and new parts. For copper get Kester 44 core 66. I like .015 for SMT work and .031 for anything else. Soldering stations - for the love of god don't cheap out here. Pace and Hakko are the two brands I would go with. We just got the MBT350 at work and it's worth it's price twice over. Not a DIY'er kind of product though. Too pricey. But still, don't spend 1-200 on a soldering station, they don't get much better than the 50 buck irons until you get to the 300+ range. Wanting the Hakko FX-951 to get stateside (will it ever?!?!) so I can try it out, we;re replacing our old wellers at work and will probably go with that or the smaller Pace stations. So stick with the 'self regulating' 50 buck ones unless you intend to spend real cash. The only solder sucker worth anything is the blue and yellow one that I think was once sold as a Solda-Pult but is now sold by OkI (Metcal), I think you can get it at Allied. The vacuum pump desoldering tool on the MBT350 smokes it though. Hmm what other tips to pass along. Unless you are getting a solder mask on your board, don't to anything closer than 15, pref 20, mil spacing. Splitting pins on a DIP is about as close as I'll cut it with a track on a board without a mask. Don't cut through a 12/3 Romex line with a pair of strippers unless you're sure it's off, and the 45kV ignition coil can reach out and get you. Your company starts to think of you as a liability when they have to invest >4k in portable defibrillators for your location because of you. Oh, don't do anything stupid or you might end up needing a defib. No rings, no watches, no nada. Isolation transformers are a good idea, and variacs can be good before cranking things all the way to line voltage. Cheap switching supplies suck terribly. Building your own is waaaay better than using a cheap switcher. Not sure it really matters in audio but I had real problems in some of my higher speed stuff with noisy switching supplies.

Ah crap. I'm rambling. Tired. Didn't sleep last night. Maybe there was something in there of some use. And seriously. Buy the Erem's. AASA model. $15 at Allied, pick up the solder pump at the same time. Oh, and I can't remember which brand of wick I like but it's the one that doesn't get a lot of nasty brown flux crap on your board. Oh, and get flux remover spray. But put on your electrolytics last, after using the spray. Eats the plastic around the casing.

I think I'm gonna go have a beer now. Man I feel tired. Tomorrow I get to figure out how to get a lithium polymer battery in close proximity to a 90C heater module without having things explode. Those things get hot really quick when you accidentally short them. Amazing current though. An amp out of something not much larger than a coin battery. If anyone is wondering battery technology is what your car of the future will be running on. No H2, no ethanol, no biodiesel. Invest in batteries. One word: batteries. It's like 'plastics' in The Graduate, except I'm telling it to you, and the word is batteries.

[Amphiprion]

Nice project btw The CAD work looks very good.

[Martyn]

I didn't feel competent to build a design from scratch, so I built one of Hugh Dean's AKSA 100N+ kits. Relatively straightforward. The heatsinks came with the kit. I had the front panel made out of 10 mm aluminum bar stock and the chassis out of 2 mm pre-anodised sheet.

[Hdale85]

Where do you guys get those heatsinks with the platform to mount fets to? And that looks very nice Martyn. I was thinking about doing something like that getting a parmetal chassis and just modding it. But to do that much work I would probably be better off going from scratch in the end.

[relder]

Where do you guys get those heatsinks with the platform to mount fets to?

Conrad Heatsinks

I got mine in a group by to avoid excess shipping costs from Australia.

Rob

[JonMarsh]

I didn't feel competent to build a design from scratch, so I built one of Hugh Dean's AKSA 100N+ kits. Relatively straightforward. The heatsinks came with the kit. I had the front panel made out of 10 mm aluminum bar stock and the chassis out of 2 mm pre-anodised sheet.

Nice looking work, Martyn. Hugh does good designs; he spends a lot of time listening to them, not just a bench designer. Nice guy, too.


Aspen Amplifiers

[Hdale85]

Well the Conrad heatsinks are nice but only 11" long was hoping for 16". And at 90 bucks for 2 of them before shipping I think I'll stick with what I picked before. But they are nice. As soon as I get a BOM for the Aleph 5 and another paycheck (next friday) I'll be ordering components and a new soldering station or iron at least and making some smoke.

[itsparks]

Here is my stereo block, i have 2 of these so 4 channels.

Image not available

[Martyn]

Where do you guys get those heatsinks with the platform to mount fets to? And that looks very nice Martyn. I was thinking about doing something like that getting a parmetal chassis and just modding it. But to do that much work I would probably be better off going from scratch in the end.

Hugh supplies the heatsinks as part of the kit. Don't know whether he'd be interested in selling you a pair separately.

I kept the cost down on the sheet metal by just buying the pieces cut to size and bent. I then did the simple but time-consuming marking out and drilling of holes myself. From memory, I think the sheet metal cost me C$100 and about C$45 for the front panel.

Now I need a quality pre-amp to match (Hugh's are rather expensive for me). A passive or active with stereo volume control and selector switch would do - any recommendations?

[JoshK]

Martyn, You can build an Aikido rather inexpensively if you like tubes or you can take a look at twistedpair audio and they have some kits which look interesting.

[Hdale85]

Yeah I've been debating the Aikido for a while. Still not sure I want to build a tube preamp. We'll see. I was originally going to build an Aikido preamp first but that didn't work out. Martyn if you want a nice kit there is the Basie+ kit that comes with everything including a very nice chassis. It's like 595 bucks shipping is kind of high as they are shipped from Hong Kong. It's based on the Aikido PCB though and has a remote and everything. Here is a link to it http://www.diyhifisupply.com/diyhs_basie.htm It's very nice looking thats for sure.

[Hdale85]

I just won a Weller EC2002M On ebay for 125.49 It's in pretty good condition I'd say here's the pic from the auction. Do you think this is a good price?



The places that I can find that actually have them are like 375-450 new. Not sure if this is acurate though?

[Johnloudb]

Weller

I just won a Weller EC2002M On ebay for 125.49 It's in pretty good condition I'd say here's the pic from the auction. Do you think this is a good price?



The places that I can find that actually have them are like 375-450 new. Not sure if this is acurate though?

I own a Weller, very happy with it!

[TacoD]

Weller is oke, but you don't need a solder station, a 15W (pcb) and 25W (big wires) soldering iron will do for your project.

The new price for Weller is steep, so I think the price is accurate.

[Hdale85]

Well I have lots of projects coming up. Not to mention I like owning a nice soldering station. It will be used for a very long time and quite often.

[chasw98]

Well I have lots of projects coming up. Not to mention I like owning a nice soldering station. It will be used for a very long time and quite often.

Dougie:
I have had my Weller iron since before 1980. It still works perfectly and replacement tips and parts are available for it. You made a good decision. If you take care of it, it will last a lifetime.

Chuck

[Hdale85]

What are decent quality capacitors rather then panasonic? Most of my parts are going to come from Mouser so something they carry would be nice? I'm not sure which are the input caps and what not but??? I'm going to be posting up my BOMS in a bit here and getting them all together.

[Hdale85]

Well with no reply to my previous post this is my current BOM. By the way I'm building the Aleph-30 now as it seems everyone is in consensus that 30 watts of class A power is quite a lot and the heat of the Aleph-5 is just not worth it. Here is the BOM

[Johnloudb]

caps

What are decent quality capacitors rather then panasonic? Most of my parts are going to come from Mouser so something they carry would be nice? I'm not sure which are the input caps and what not but??? I'm going to be posting up my BOMS in a bit here and getting them all together.

I would just buy all your caps from Digikey.

What speakers are you using? If you plan on building a 30 watt amp, just be sure your speakers have a +90dB sensitivity.