[Chiliman]

I will soon be building a speaker based around the Fostex FE-103, (zigmahornet) and am looking into building a amp to go along with it. Also, I would like to build one that isn't too expensive (bear with me, I don't know what 'expensive' is in the diy amp world)

I have looked into the Firstwatt F2 (hugz) but that is about it.

 

[sheya]

Inexpensive and first amp, sounds like you should check out building a gainclone. chipamp.com offers kits, and you could check the forum at diyaudio.com.

good luck-
aaron.

 

[dBel84]

my vote goes for one of the 41hz.com amps. Amp5 or Amp6..dB

 

[Pars]

I'd take a look at the SKA (here). Not sure how much power, etc. you are looking for.

 

[star882]

How much power are you dealing with? At high powers, digital amps are cheaper because the heatsinks and power supplies are much smaller.
BTW, for the very first project, I recommend something based on some high power opamps powered by a wall wart. Later on, you can DIY a digital amp but the SMD chips typically used with digital amps are not that easy to work with. At that point, you might as well just buy a complete digital amp and mod it...

 

[Uncle Erik]

How about some tubes? Check this out:

http://boozhoundlabs.com/howto/

It's about $200. But even if you don't build, read the article anyway. It's an excellent intro to tubes. One of the best I've seen.

Also, think about some kits:

http://www.bottlehead.com/

http://www.transcendentsound.com/

At Transcendent, you can also buy books with schematics in them. I'm working on his preamp and gathering parts for one of his OTLs. I've got the iron, but need the rest. Soon.

 

[cotdt]

Quote:

Originally Posted by dBel84 /img/forum/go_quote.gif my vote goes for one of the 41hz.com amps. Amp5 or Amp6..dB

x2!

 

[Joshatdot]

wow cool stuff over at www.41Hz.com ! I wonder if one could mod the AMP32 to work on a 9V batt, a minijack in & out, and fit in a Altiods can.

 

[Chiliman]

those 41hz kits are awesome! I will almost definitely be ordering one of those, maybe not even the kit

Edit: Where could i get a power supple for one of these? would tangents tread work?

Edit 2.0: Or I could just get the amp5 that has the psu built in, what would you guys recommend

Edit 3.0: Sorry for all the edits, but if I am eventually planning on getting the mmg's from magnepan, should i get the 100w amp or the 300w amp?

 

[dBel84]

I built 2 Amp6's - psu onboard and it went together very easily. Not all that powerfull but I only use it as a pc amp with an alien dac and it works very well. The Amp5 was not available when I built mine but that is the one I would go for now. Another plus, Jan is great to deal with and support is excellent on the forum. well worth it regardless of the option you choose. My brother is putting an amp3 together for his car ..... very tempting too

..dB

 

[Chiliman]

@dbel84 - what do you mean not all that powerful? isn't 100w pretty powerful?

Edit: NM, amp6...

Also, Assume I would need a preamp for this if i bought either the amp5 or amp1

 

[dBel84]

I would have to look at the Amp5 chip again , Amp6 has enough gain and can be set high / low via simple resistor selection. I prefer the sound with a tube front end , the reason I built the buffer but I had it running from a SOHA before that and it sounded very good..dB

 

[hugz]

Quote:

Originally Posted by Chiliman /img/forum/go_quote.gif I have looked into the Firstwatt F2 (hugz) but that is about it.

gee way to preempt me

Quote:

Originally Posted by Chiliman /img/forum/go_quote.gif Also, Assume I would need a preamp for this if i bought either the amp5 or amp1

They look like power amps, so you'll need some kind of preamp. Either you can get an active preamp (a normal preamp) which will boost the volume and then reduce the volume as needed, or you can get a passive preamp which will only reduce the volume. I wouldn't imagine you'd need to increase the volume on a 100w amp with fostexs, so passive would work if you go with that amp. With the lower power amp you may want an active preamp though.

My fe206e have a sensitivity of 96db/w. with my 5w amp it's probably getting close to the minimium power i could use with them, with a passive preamp. Fe103e puts out 89db/w (7db less efficient) so you'd need a 25w amp to get the same volume level that I get with my 5w and passive. The amp6 seems to be 25w at 4 ohm (12 at ohm?) and the amp5 seems to be 60w at 8 ohm. amp6 probably needs an active preamp whereas amp5 is probably fine with a passive preamp

Advantage of passive if that it's generally cheaper and it doesn't alter the sound signature (its more pure) which is good if you like your power amp. Advantage of active is that it can alter the sound signature in a good way (eg tube preamp) and can provide more volume if needed

I use this for my passive-pre. If you want one, get it preassembled. it seems pretty good value
http://www.diyfidelity.com.au/produc...products_id=32

The website for the amp5 says
Quote:

You need to add / not included in the kit Transformer with mains fuse and power switch Enclosure with connectors for speakers and line input if required Heat sink. For many applications, screwing the components to a metal enclosure is sufficient as a heat sink. However, for high power applications like bridged mono 8 ohms or high power 4 ohms, a heat sink is recommended. Mounting screws Volume control or pot if required

Make sure you do a little research into this, because for my amp the case, heatsinks, transformer and volume control are definitely all the biggest costs. The rest of the parts are penuts. So you'd definitly be mistaken to think that the amp is cheap just because the parts costs are cheap if it requires you to spend lots on those other parts. Exclusing transformer, heatsinkage, volume control and case, my f2 cost less than $200

 

[Chiliman]

Well, I was considering a horn just as a fun project until this summer, when i plan to by some Magnepan MMGs, I don't know if the horn's will happen given my current housing situation (college dorms)

Quote:

Originally Posted by hugz Make sure you do a little research into this, because for my amp the case, heatsinks, transformer and volume control are definitely all the biggest costs.

well, volume control would be the preamp (i think i want to go active) and that leads me to my next question, do any of you know of a cheap and beginner level active preamps that I could build?

Forgive me for not knowing much about electronics, but I am a little confused as far as the psu goes, if i were to build the amp5, there is a psu built in, but if i get the amp1, could i use the tread or steps?

 

[dBel84]

I think the amp1 may be a little ambitious for you (based on an earlier comment of being new to electronics), unless you are skilled with surface mount components, I would start off with the through hole options, like amp5. In which case the psu is not an issue. Tread / Steps do not have enough current for these amps, the idea is fine but a vreg with greater current capabilities would be needed. There is a section on psu design and requirements on the 41hz web page. I would also recommend browsing their forums if this is the amp you have settled on.

IMHO a preamp is going to add considerably to cost, the electronics are small in relation to psu / selector / attenuator / chassis etc. If funds are not an option then decide on tubed or ss, there are many choices out there.

To start, you may just want to use a good quality attenuator? -
http://glass-ware.stores.yahoo.net/aikampstepat.html

..dB