[pinkfloyd4ever]

Ok so I'm putting together my first real speaker setup, and it's gotta be on a budget since I'm a college student. I bought some Insignia bookshelfs and I have an Alien I plan to use for a source. I think I'm going to get the Amp 10, if I'm reading things correctly it's just an updated version of the 5? Are there any reasons one might get the 5 instead? Why doesn't the regular 10 have a relay? Is it that big of a deal? I can simply hook up a 2-channel pot to the input and I won't need a preamp, correct? I know the Amp10 has an onboard PS, just have to add a transformer. Does that mean it's ok to put AC into it? The 41Hz site says the max DC supply voltage for the Amp10 is +/-35V. Other than noticing that most people use a toroidal for 41Hz builds, I'm clueless about transformers. Could someone direct me to a good one? Hammonds don't seem like they would make good heatsinks; what kind of enclosures out there do?

Arrrghh, part of me still wants to check out a chipamp / gainclone too. Btw, where does dual mono lie between stereo and balanced?

And what about speaker wire? What gauge, etc? Are partsexpress' or markertek's house brands good? What about monoprice? I had never heard of monoprice before but I saw somebody on the diyaudio.com forums recommend their speaker wire. It is ALOT cheaper than Markertek's & partsexpress'

 

[m0b1liz3]

I was going to build the amp 10 at first myself but decided to go with the amp6 basic instead. There are a lot of small parts to work with on those kits and the instructions for a lot of the builds are not the greatest. Jan had revised some of the boards to a newer version and hadn't changed the instructions (not sure if this has been remedied yet). There is a table on his site that show which of the amps are suitable for an SMPS or need a transformer. Support from 41hz is minimal at best but there are some nice guys on the 41hz forum that will answer questions.

The gainclone kit looks much more simple to work with. There are fewer parts and the chips only have about 5 pins instead of 20+.

Don't think you need to worry about the case acting as a heatsink since these amps tend not to run that hot.

 

[error401]

I built an AMP5 and m0b1liz3 is right, the instructions were really pretty crap. I ended up having to work out a few things myself, which wasn't that hard, but it was kind of annoying that they were never mentioned (like bypassing the space for the DS1802).

I think I'd still go with the AMP5, there seems to be very little difference between it and the AMP10 and it's got the protection relay. Probably doesn't really matter which you choose though, they're both good.

Also check the gainclone kits at audiosector.

 

[m0b1liz3]

My amp6 took forever to build because of the poor support. The amp sat on the desk partially done because I was being cautious in proceeding on a few steps before I had a few questions answered. Those questions eventually got answered in the forum but not by anyone at 41hz itself. Keep in mind that the amp6 basic is supposed to be the best supported.

I bought an audiosector gainclone kit and so far my questions have been answered right away. (Haven't asked any in a long while though) I keep planning on building it but my amp6 is doing the job as a desktop amp fine.

I had an idea about building a guitar amp with a tube pre amp driving either a gainclone mono or a class d amp. I somehow doubt it will ever happen though. I may consider selling the gainclone kit if you are interested.

 

[Heady]

I have built an Amp5 and Amp6 Basic. I agree about the instructions. I think the Amp6 Basic was very easy to built though and was extremely gratifying. Especially for a little pair of bookshelf type speakers.

 

[rjad]

I built an amp32, the only trouble I recall having was something with the led and the associated resistor. Since others had had the same problem the answer was on the forums (seems to be pretty essential reading to build these). I run this amp from a 12volt SLA, and I think it is great. This would be a pretty good set up if you weren't too sure about what you wanted--it is cool just because it is so small (though the battery obviously isn't small!).

I would build another one, in fact I probably will try an amp32ps for my brother and will see how it goes with a wall-wart power supply.

 

[pinkfloyd4ever]

hmmm thanks for all the responses guys. A high parts count doesn't really bother me, as long as I can tell what things are, which actually may be a problem with 41Hz kits as you guys suggest. I'm still trying to decide between a 41Hz kit or a gainclone kit. I've just found out that audiosector.com and chipamp.com are run by the same guy, which didn't surprise me cause they seemed eerily similar to me. Anyway, anyone know about differences between the LM3875 and the LM3886? Also, what's dual mono?

And what about transformers? would this Avel 250VA 18V+18V or this Avel 250VA 25V+25V work for either a gainclone or a 41Hz Amp5 or Amp10? According to the 41Hz site, a 300VA 24V+24V like this Plitron would be ideal, but it also costs almost twice as much as the Avels, and I've read that Plitron takes FOREVVERRRR to ship cause you usually hafta wait for them to do a manufacturing run. BTW, does anyone know how you order from SumR? Do you have to wait for them to manufacture the damn thing too?

 

[error401]

Quote:

Originally Posted by pinkfloyd4ever /img/forum/go_quote.gif Also, what's dual mono?

Two completely separate amplifiers, one for each channel. Sometimes they might share a trafo, but at least you have two separate rectifiers and amps. With the dual chips (like LM4780), it usually implies that each chip is used in a parallel/BTL config per channel instead of splitting it and using it as a stereo chip.

Quote:

And what about transformers? would this Avel 250VA 18V+18V or this Avel 250VA 25V+25V work for either a gainclone or a 41Hz Amp5 or Amp10?

I'm using an Avel 160VA 22+22V for my AMP5 and it works fine. It's borderline enough, a 250VA would be better. Unless you're driving a 4 ohm load it's certainly sufficient. With a chip amp you're going to want a bit more power, but 250VA is more than sufficient for driving 8 ohms with 2x60WPC (LM4780). For dual mono, you really should have a separate trafo per amp, but I'd go with 160VA transformers in that case for the budget-conscious.

You might also look at AnTek Inc. for inexpensive transformers, though I e-mailed them a few days ago about one and haven't got a response. Unfortunate since I just forgot to order the Avel I actually wanted on my PE order and now it's going to cost me almost $20 to ship another parcel with just the trafo. Arrgh.

 

[Heady]

Quote:

Originally Posted by pinkfloyd4ever /img/forum/go_quote.gif And what about transformers? would this Avel 250VA 18V+18V or this Avel 250VA 25V+25V work for either a gainclone or a 41Hz Amp5 or Amp10? According to the 41Hz site, a 300VA 24V+24V like this Plitron would be ideal

I am quite sure 41hz spec for amp5 is 300VA 22V+22V. I believe the spec said higher voltage may cause the internal relay to trip due to over-voltage protection.

Gave me a hard time searching for a 22V transformer in this part of the world.

 

[pinkfloyd4ever]

http://www.41hz.com/main.aspx?pageID=120 It actually says to use tansformers of +/-18VAC to +/-24VAC, but it sucks because Avel's product line has nothing near a 300VA 22+22 which would be ideal, and Plitron and Hammond toroids are way more expensive. From the Amp5 page: Quote:

With the supplied components, rail voltages between +/-22V and +/-35V can be used. Under voltage threshold is nominally +/-20V and over-voltage threshold nominally +/-36V. Transformers of +/-18VAC to +/-24VAC are suitable. VA rating depends on speaker impedance and supply voltage. With a +/-24VAC transformer and 4 ohm speakers, a 300VA transformer is recommended. Lower voltage and higher speaker impedance reduces the required power/VA rating.

So 25*1.414 = 35.35. Would it be unwise to count on there being enough loss in the rectifiers to keep it down below +/-35?

EDIT: Ahhh, you just led me to what I was already going to ask next..you said it may trip the internal relay, I assume you mean inside the Tripath chip...is that how the Amp10 (not 10-Basic) and the other 41Hz amps without output relays have over/under voltage protection, as well as over current and temp protection? If so, what's the advantage of the output relay on the Amp5 and Amp10-Basic?

 

[error401]

Quote:

Originally Posted by pinkfloyd4ever /img/forum/go_quote.gif http://www.41hz.com/main.aspx?pageID=120 It actually says to use tansformers of +/-18VAC to +/-24VAC, but it sucks because Avel's product line has nothing near a 300VA 22+22 which would be ideal, and Plitron and Hammond toroids are way more expensive. From the Amp5 page: So 25*1.414 = 35.35. Would it be unwise to count on there being enough loss in the rectifiers to keep it down below +/-35?

You'll lose about 1.4V in the rectifiers. But since you're planning on buying such an overrated transformer, your output voltage is going to be higher than that. Transformers are rated based on their voltage at full load, and the voltage climbs when they are lightly loaded. I'd expect you to see up to 40V across the rails with a 25V toroid. The chip is rated for +/-40V rails, so it'd probably be fine, but it's skating pretty close to the published spec.

If you must go with Avel, I'd get the 230VA 25+25. Antek is probably your best bet, other than Avel, toroids are a bit tricky to source in small quantities (for a reasonable price).

 

[pinkfloyd4ever]

ARRRGGGHHH that's what I was afraid of. I don't mind going with someone other than Avel. You said you hadn't heard back from Antek yet, right? What VA and V transformer are you getting? Oh and on Antek's site, does 22V mean 11V+11V? Has anyone used Plitron before? Maybe if I order now I'll get it in the month or so it'll take me to get everything else ordered and built. And obviously PartsExpress doesn't have Avel's full line, anyone know who else sells Avel?

Oh wow, I hadn't looked at Antek's prices before, those are a steal!!..If we can get a hold of them...

 

[error401]

I checked my e-mail history and it looks like I actually sent the e-mail late Monday night, so it hasn't been that long. They did respond to me in the past when I asked them for a shipping quote. I'm ordering a couple 0215s (15V, 20VA) and one 2225 (25V, 200VA). The voltages are for each secondary, all their toroids have dual secondaries.

 

[pinkfloyd4ever]

hmmm well sweet, I think I may shoot them an email myself, or better yet, just call them tomorrow. I'm glad you brought them up or I never would've found them, and they are definitely cheaper and have a better selection than Avel...hopefully the quality is up to par with others. Have you used them before (or been involved in any projects that did)?

Damn, in fact, they're so cheap that I may be able to entertain the idea of a dual mono gainclone again... AWESOOMMMEE

 

[error401]

Quote:

Originally Posted by pinkfloyd4ever /img/forum/go_quote.gif Have you used them before (or been involved in any projects that did)?

I haven't, no. I can't remember who recommended them to me, but it was definitely someone from here or DIYAudio. Other than being slightly over-rated on voltage, I expect that they're okay.