Average cost of a Pass F5

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So, you are looking to build an F5 for around $150? It is not impossible, but will be a tough challenge unless you have a lot of the more expensive items (heatsinks, power transformer, large filter capacitors) already on hand. You can maybe find the more expensive items at surplus electronics stores for some savings.

For my F5, I bought surplus heatsinks at $20 each. The power transformer was around $60, and the parts were probably around $100 from Mouser (don't remember the exact amount since I bought parts for multiple projects at the time). Miscellaneous metal for building the rest of the case (and tools to do so) costs extra.

EDIT: Forgot the input JFETs. They are a bit pricey these days and add abut $50 to the parts total above.
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Official Court Jester
Joined 2003
Paid Member
if you need to ask , no , that's not possible

you can build any amplifier for cheap ......... strictly meaning cheap in fresh money, only if you already have plenty of parts on your shelves .... or if you are capable/able/have opportunity to find/buy/trade parts from surplus places , but that way is impossible without necessary mileage

count that value of parts needed (case with heatsinks , xformer(s) , capacitors for PSU , terminals are in neighborhood of 450E , in EU money and usual circumstances

rest is peanuts (pcbs , small parts ) except input JFets , and these two pairs (matched 2SJ to 2SK) are in vicinity of 50E , shipped

however , for proper choice- which amp to make - maybe is wise to share with us - what size of room you have , your SPL habits , speakers you're using or intend to use

of course - it could help if you write in your profile your exact location
Official Court Jester
Joined 2003
Paid Member
My budget it's around the 200€, try to make less.

My room it's about 40 square meters and the speakers that i intend to use are a pair of acoustic energy aegis two.

I'm sorry but i don't know what you mean by "SPL habits"

SPL , meaning Sound Pressure Level ...... in other words - how loud you like your music

40sqm , nice task ...... usual First Watt amp will have plenty to fill , and for that you'll need more efficient speakers , than 88.5db/W/m ones , equipped with tiny 8" bass drivers

to be precise - I can't see those spks filling your space well enough , no matter how potent amp you point at them

Your completely right, it's very inpolite of me to not make the proper presentation. I have corrected it.

inpolite , no - not at all

just harder to help with possible location related tips and tricks
Aegis 2 is a 88db/8 ohm speaker. Should be fine with an f5 in that room provided 85db at the listening position is enough for you, volume wise. Which is actually pretty loud.

If you can find a transformer and heat sinks cheaply or salvaged from something else you might be able to make the budget work. If you have to buy these things at retail you are probably looking at $500 or so minimum to complete an f5.
I think I don't hear my music very loud, my neighbors didn't complain :)

So, do you recommend any other amp that's cheaper? I was thinking also in the gainclones.

Also, for the amp camp, the shipping cost to my country is very expensive (about 100$) is there any place in Europe that sell them?
if memory serves me right, i did spend around $1000 on my F5 build. but it was not build on a tight Budget.

that's crazy! ..perhaps with bejeweled chassis, dual mono and caddocks. To the original poster, the big expenses here are aluminum, iron and capacitance. Figure out how to get a transformer without breaking the bank. Surely there are EU folks who know how to get some decent iron on the cheap who can chime in. Caps are also cheaper if you want to string several (or a bunch of) smaller ones together, particularly if they were purchased from a 'surplus' outfit. I believe a few folks say this is better even, btw..

Then figure out how to get some aluminum. From my experience, a pound of Al is good for ~10W, so go industrial if it's simply about the sound. For example, I'm attempting to recycle my old 12 ft. satellite dish into an amp.. (hey, it's aluminum and it's free). There's 460 watts there by my estimation. Might take some propane brazing and my imagination, but there it is.. diy

and to "gild the lily", as they say... build it point-to-point or on a perfboard.. there's nothing cheaper than that.
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Simple answer, it's pretty much impossible to build an f5 or similar amp for 200€, unless you have a way of finding ultra cheap case and heatsinks. Going with cheap components and a very simple case should be around the 250-300€.

Take a look at the swap meet, sometimes pass amps parts and components are sold their at nice prices.
Founder of XSA-Labs
Joined 2012
Paid Member
You can save on heatsinks using a PC CPU heatsink with a small quiet fan. They can evacuate watts like no tomorrow for maybe $20. You will have sound of a small fan but that may or may not bother you.

There is no getting around the necessary transformer with big VA rating. At least $50 to $100 unless salvaged from somewhere. Possible to use cheaper SMPS with dual rail 32v. But that is sort of anathema to class A folks.

The most expensive part is the case. If you don't mind having a bare amp on a plywood board - it works just doesn't look pretty you get music but not looks. :)

Try buying the miscellaneous parts and electronics and caps from Aliexpress. A lot less money than big name suppliers like Mouser, Digikey, Farnell etc but you will wait for 1 month for parts. When you get the parts you will have enough to build 10 amps for the price you would have paid with regular store. I have had good luck - parts are as described and measure well. No fakes so far. For input Jfets you have to buy genuine.
Joined 2002
Paid Member
Unfortunately a class A amp means big hardware and its associated cost.
That said, being patient and keeping an eye out for sales, obtaining
surplus parts (especially the heavy ones) locally will help.

If you can procure some heatsinks and machine the case yourself, that can
be a source of saving.

I recommend looking at some builds by members, getting an understanding
of what's needed, and see what you can find locally. Don't rush into buying
things when you're unsure; buying things that turn out to be inappropriate is
an easy way to blow a budget.
Don't rush into buying
things when you're unsure; buying things that turn out to be inappropriate is
an easy way to blow a budget.

Been there, done that. :(

I didn't keep close tabs, but I think my son's F5, which we built together, ran about $300 - $350. That was with heat sinks and chassis aluminum from the local scrap metal yard and transformers from an online surplus store (BG Micro). Bunch of smaller components from local electronics surplus. For input jfets first tried ebay, then tried substitutes, then did what we should have done first and ordered the real deals from Spencer...

I don't see how you could build an F5 (dual mono or stereo) for less than $200.
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