Amp Building question

[mcrracer]

Answer to #1 $100 amps are the simple two tube amps. One preamp and one power tube.Volume control ( maybe a tone control) , SS rectifier, point to point or make your own eyelet board. Make your own chassis or buy an inexpensive one and drill it yourself. Don't buy onesies and twosies in resistors, caps and diodes. I buy mine 100 to 1,000 at a time at wholesale prices.
You can make an eyelet board for a 5 watt or an 18 watt for less than $5.00. You should be able to buy a chassis for around $20 or so.
Do your research and find out how to acquire parts on the cheap.
High prices don't necessarily equate to high quality!

Dumble clone...many more tubes, more sockets, more parts, more complicated tone stack, switching circuits , more expensive iron.
Have you done any research and read up on Dumble clones and simple amp designs?

#2 Yes to a point certain tubes are interchangeable. More reading needed.
Try searching preamp tubes for example.

#3 Yes certain parts. But as inexpensive as most parts are for me it is not worth the effort.

[TheGimp]

#3 In addition, most old parts may have drifted in value (carbon comp resistors especially), and some will have dried out (alumimum Electrolytics).

The tubes can be pulled and tested. If they are still good, they are still good.

Transformers may still be good if they have not been abused (not cooked).

Sockets might be good if of high initial quality (I pulled a bunch of sockets from a Tektronix 545 Oscilloscope and even used they are better quality than some new sockets I've purchased.)

[Cliff Schecht]

Okay, since you have all been so patient with me (which is very much appreciated.) I have a some other questions:

1. some say I can build an amp on the cheap -$100-200 +/-
What makes an Amp like a Dumble clone so expensive? Is it Components? I'm sure there are more, but $1000 more? -I'm perplexed.

(warning: this next one is going to be really dumb.)

2. are tubes interchangeable? eq. If I have an amp with an "X" tube in it, can I replace that with a "Y" for a different sound or effect? Is this part of the craft that keeps your head spinning at night in search of perfect tone?

3. Can you cannibalize old tv's radio's ect for parts?
Where is good place to get parts?

1. Three of the last four amps I built were essentially free for me. I can build pretty much anything I want for $100-$200. How? I have a two bedroom house that I share with my girlfriend. One of the bedrooms is my lab which is stocked floor to ceiling with parts, equipment, scraps, tools, etc. Granted I also do a lot of research and don't just use my equipment for one thing, so I can easily justify having a ridiculous amount of crap. Heck, it all comes in handy when it comes time to prototype or build pretty much anything I can dream up.

But if you don't have a full room full of parts and have to buy every single little last detail, all of those little purchases add up quickly, especially with shipping charges and tax and such. Your $200 dream amp just cost you $120 in extra accessories, and that's not including the wooden housing most of you guys like to shove your metal masterpieces in.

2. This is a dangerous question with a simple answer, once you get what to look for. It's never safe to assume that tube X fits into slot Y without checking the datasheet and understanding how to tell the difference between different types. It's not hard, you check the pinout to make sure it's the same, the maximum ratings and make sure you aren't exceeding those and then look at the amplification factor (mu). Here is a nice table showing what will fit into your standard 12AX7 slot: http://en.wikipedia.org/wiki/12AX7#Simi ... de_designs

And yes, playing with different types will change how things sound. Lower gain tubes means less gain in the amp.

Don't be ashamed to ask questions like this, not everyone has old experts around to answer their dumb questions. I promise you more than one person will learn from your questions which is always a plus in my book.

3. Yes but it's good to know how to check the parts you cannibalize for correct operation. This means having the tools and the time to do so as well. I won't trust most used carbon composition resistors or older capacitor styles without testing them for, at minimum, value and leakage. ESR is also a good thing to measure in electrolytics but not everyone has the ability to generate Bode plots. Is it really worth the time it takes to remove a part, clean it, check it for operation and try to somehow extend the leads to fit into your circuit? For me, the answer is typically no and so I keep a decent sized collection of parts necessary for tube amp building around. This way I can figure out what I want, collect up what I have, spend a bit of money to get what I need and have a working amp for cheap or (usually) free.

[dcribbs1412]

My 2 cents
kits I would recommend to get started

http://www.triodeelectronics.com/deluxerebuild.html

http://www.triodeelectronics.com/18wtmbkit.html

good quality parts,fairly simple designs and relatively cheap...both can be platforms for many mods

[mcrracer]

My 2 cents
kits I would recommend to get started

http://www.triodeelectronics.com/deluxerebuild.html

http://www.triodeelectronics.com/18wtmbkit.html

good quality parts,fairly simple designs and relatively cheap...both can be platforms for many mods

He still needs to buy a chassis and tubes. More sourcing and more shipping charges. IF you are going to buy a kit buy a complete one.