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elizard 29th March 2003 05:56 AM

New pre-amp kit just arrived in mail
Well, my new preamp kit just arrived in mail couple days ago from, and i've been gathering stuff that i need to build it. Now i just need time :)

The preamp stuff can be found at

This is my first project .. gotta take it slow, and hopefully not screw anything up :)

now .. I just have a couple questions
of all the components, which ones do i need to heatsink (i.e. its a good idea to even though i can get away w/o doing it) while soldering ..
i know IC's (there's a bunch) and diodes perhaps?
capacitors i know i don't have to .. anything else on the parts list that i might need to heatsink (i.e. LED's, caps, anything you guys can see?)
Also, the kit comes with a 50k ALPS pot .. my question is what sort of quality the pot is generally? also what sort of a difference would i see if i ever put in a 100k pot in there instead of a 50k pot? (sorry, but not too sure on what the difference would be between a 50/100k pot .. and if i can do it .. beginner at most electronics stuff!)

thank you .. i'll try to get some pics up when i'm finished it :)

elizard 29th March 2003 06:51 PM

wow .. 60 views and no comments for me?
not even some to answer my newbie questions??? :(

Nuuk 29th March 2003 07:14 PM

Hi Elizard, I'll give you a few pointers ;)

The instructions with Velleman kits are usually very specific and if they tell you to use a heatsink on something then do so. Otherwise don't worry about it. Preamps, as a rule, don't use a great deal of power and nothing should get very hot.

The Alps pot is a good one. Use it, get used to it and then if you want to upgrade think about getting a stepped attenuator (or making your own). A 100K pot will only sound better than a 50K if the preceding circuitry needs to feed in to a higher impedance. But if you are just starting out don't worry too much about this sort of thing - you will only get more confused.

If you need more advice on basics, try my web site which is dedicated to helping people like you. (Just click on the www below).

BTW - practise your soldering on something that doesn't matter before doing it for real on your kit!

Audiofanatic 29th March 2003 07:17 PM


Originally posted by elizard
wow .. 60 views and no comments for me?
not even some to answer my newbie questions??? :(

Hi elizard,

First of all, please take you'r time and do it right!!
Remember,... you better check it 10 times then just one time and afterwards blame yourself for not checking it thoroughly.
And folow the steps in the manual. Personaly, I don't like Velleman products; but it is a realy good beginners choice!

Don't change anything (e.g. ALPS)build it first, and aftrewards learn frome the forum members and try a few modifications.

All the best and let us know how it sounds!

Best regards,

Audiofanatic ;)

daxy 29th March 2003 07:18 PM

I don't really think anything would need a heatsink, seeing that it only consumes about 6W, and i don't really see anything needing a heatsink on the pic (it's only a preamp after all).

ALPS pots are pretty good as far as i know, and a 50K should be ok. A 100K pot would just provide a bigger resistance, which isn't really needed for a volume control.

Good luck with building it!

elizard 29th March 2003 07:19 PM

awesome, thank you :)

yeah .. i haven't soldered in a few years .. i'm gonna do a little bit for practice first :)

now .. are you sure i don't have to solder the diodes/transistors while i am soldering them? i seem to remember frying quite a number of parts back in my electronics class because i didn't heat sink them while soldering ..

Nuuk 29th March 2003 07:45 PM

If you are worried about over-heating something while soldering it you could get a clip on heatsink but this is only really needed for transistors and then only if you are really taking too long to solder the joint.

If you practise your soldering first, you shouldn't really have any problems. And like Audiofanatic said, check everything 10 times and then once more.

Cradle22 29th March 2003 08:08 PM


The first thing I did when I got into DIY audio last year was buying a good soldering station (a digital 60W station from Conrad, I dislike COnrad generally, but their own gear like multimeters, scopes or soldering stations are very good & comparatively cheap).

The advantage of such a station is that you can chose what temperature you want to use in accordance to what you want to solder. For example, for printed circuits I always use 350 C, while for heavy duty work (soldering thick cables, soldering stuff directly on metal cases :) ) I use 400 - 450C...

The soldering times decrease with a good iron / station, so less stress on parts...



paulb 29th March 2003 10:02 PM

Semiconductors are much less sensitive to soldering-type heat than they were years ago. The recommendations you see in old books about putting a clip on a transistor or diode lead while soldering are not necessary.
Recommend you practice. Also, start with the less heat-sensitive parts like resistors (I'm sure the kit manual leads you through it this way).
Regarding temperature: one mistake many people make is they get a relatively cool iron temperature for soldering semiconductors. My approach is to keep the tip temperature fairly high (350C sounds okay), and get it over with quickly.
Looks like a nifty preamp, I'm sure you'll be very happy with it. I wouldn't modify it - just build another one!

jleaman 29th March 2003 10:46 PM

it took me 4 days to put mine together the instructions are verry well layed out i liked them alot. The only thing i got stuck on was the transormer wireing. when i wired mine up i got 220 insted of 110 witch didnt alow the unit to turn on. but from then in it works AWSOME i used it every day.

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