circuit requiring hitting to work

[FiveseveN]

Before you try doing something silly, could you tell us what is this store that sells various transistors but not op amps?

[mac]

I bet this circuit is for Germs, leakage bias.

mac

[antonis]

Maybe some high gain BJTs like 2N5089 or MPSA18, also..

[antonis]

On which particular circuit you refer on, Marcelo..??

[11-90-an]

Before you try doing something silly, could you tell us what is this store that sells various transistors but not op amps?

online store that sells random things... i mean like, at least i have somewhere to buy parts

BTW, its called Shopee, and ... i can't describe it hehe

[duck_arse]

https://shopee.ph/SUPER-200pcs10-Values-TO-92-BC327-BC558-Transistor-Assortment-Kit-i.93948225.1718680348

try something like this, wherever you are. there is a good assortment, a darlington, and none of the odd high voltage stuff those others have. AND - they'll have the BCxxx pinout, the one we all want! [the included parts will sub for many of the 2Nxxxx types you will likely find.]

[11-90-an]

https://shopee.ph/SUPER-200pcs10-Values-TO-92-BC327-BC558-Transistor-Assortment-Kit-i.93948225.1718680348

try something like this, wherever you are. there is a good assortment, a darlington, and none of the odd high voltage stuff those others have. AND - they'll have the BCxxx pinout, the one we all want! [the included parts will sub for many of the 2Nxxxx types you will likely find.]

Thanks @duck_arse! This seller sells a lot of kits that i could save money on by just buying all the parts i actually wanted to buy haha (saves me a lot of money since each seller has its own shipping fee...)

Which do you think are better? Carbon film or Metal Film ? i find the carbon films easier to read but the metal films are cheaper...

[FiveseveN]

I don't get it, there's a whole page of search results for TL072 and three pages for LM358. Was there some other reason besides availability that would drive you to use transistors in place of op amps?
PS: plenty of MOSFETs as well: https://shopee.ph/search?keyword=2n7000

[duck_arse]

for starting out - spend the extra, take it easy on your eyes, get the carbon. how much cheaper?

[11-90-an]

I don't get it, there's a whole page of search results for TL072 and three pages for LM358. Was there some other reason besides availability that would drive you to use transistors in place of op amps?
PS: plenty of MOSFETs as well: https://shopee.ph/search?keyword=2n7000

umm... sorry for the confusion, this website has multiple 'stores'. Each store is has its own shipping fee of like $2-4 (which is expensive-ish for my country). when i say that there are no MOSFETs, i mean in that specific 'store', because sometimes the products are as expensive as the shipping. also, I find that I don't really need op-amps with the pedals that I intend to build...

for starting out - spend the extra, take it easy on your eyes, get the carbon. how much cheaper?

the metal film are $4 for 1280pcs (assorted)
the carbon film are $8 for 1000pcs (assorted)

[mac]

On which particular circuit you refer on, Marcelo..??

The first one,



PNP Germs might work fine, but in&out&interstage caps needed.

mac

[antonis]

PNP Germs might work fine, but in&out&interstage caps needed.

Maybe, hitting wiring for circuit working (as OP stated..) was some form of interstage capacitance simulation..

[11-90-an]

is it possible to replace a 2n5088 with a bc549 in a Highway 89?  (just so i would know if buying bc549s would be useful or not...)

also, would it be ok to swap the 100k pots for 50k?

(sorry if this is drifting off topic, buying parts can present many options...)

[antonis]

BCs are always useful..

Just make clear for its C classification (both 2N5088s & BC549Cs fall into the same h_FE & V_CEO range..)

Swapping pots values is strongly depended on particular circuit use..
If you refer on 100k Bass & Treble pots of Highway 89, you can swap them for 50k ones but you'll also have to alter side resistors values for Bass pot (the ones connected to its outer lugs) to keep respective capacitors values and Q1 Collector loading the same, in the cost of tighten bandwidth margins..

But, in general, yes.. You can try it..
After all, you will not blow anything..

[duck_arse]

the metal film are $4 for 1280pcs (assorted)
the carbon film are $8 for 1000pcs (assorted)

hmm, well. are they both types 1/4W? it's up to you - can you read the colour codes without refering to a page/sheet, or do you need practise? I'd suggest practise on carbon till you get the numbers, cause they usually don't make easy sense on the blue metal films, and you'll need to meter measure every time.

BCs are always useful.. 
Just make clear for its C classification (both 2N5088s & BC549Cs fall into the same hFE & VCEO range..)

more important than the C suffix, the BCxxx pinout is nearly always 180^o rotated to the 2Nxxxx, which is something you have to catch every single time.

I like the idea of hitting as capacitance simulation, but how do you control the value?


probably worth pointing out that this thread has now degenerated somewhat, as they nearly all do, and as you started it yourself, you can take it any which direction you like.

[antonis]

this thread has now degenerated somewhat..

Like most Emitters of CE amps do..

[11-90-an]

BCs are always useful..

Just make clear for its C classification (both 2N5088s & BC549Cs fall into the same h_FE & V_CEO range..)

Swapping pots values is strongly depended on particular circuit use..
If you refer on 100k Bass & Treble pots of Highway 89, you can swap them for 50k ones but you'll also have to alter side resistors values for Bass pot (the ones connected to its outer lugs) to keep respective capacitors values and Q1 Collector loading the same, in the cost of tighten bandwidth margins..

But, in general, yes.. You can try it..
After all, you will not blow anything..

I was able to find some 100k pots

the metal film are $4 for 1280pcs (assorted)
the carbon film are $8 for 1000pcs (assorted)

hmm, well. are they both types 1/4W? it's up to you - can you read the colour codes without refering to a page/sheet, or do you need practise? I'd suggest practise on carbon till you get the numbers, cause they usually don't make easy sense on the blue metal films, and you'll need to meter measure every time.

Yes, both of them are 1/4 W. I continued to search and I found a cheaper carbon film set! It even was cheaper than the first metal film that I saw and had 1500pcs!

.

BCs are always useful.. 
Just make clear for its C classification (both 2N5088s & BC549Cs fall into the same hFE & VCEO range..)

more important than the C suffix, the BCxxx pinout is nearly always 180^o rotated to the 2Nxxxx, which is something you have to catch every single time.

Noted!

So I was thinking about a spring/plate/idk reverb unit, and i researched and realized that after the signal passes through the spring/plate, it loses about 0.4db. Some people solve this problem by placing a Lm386 as input booster(so the signal will have enough strength to pass through the spring/reverb) and another Lm386 at the other end, to boost the signal again. Would it be practical to just use 1 TL072, since that is basically 2 op-amps in a single package? (Just wanted to know if I should also be buying LM386s hehe )

[PRR]

> after the signal passes through the spring/plate, it loses about 0.4db.

More like 40dB.

Which is why you need gain both before and after.

[11-90-an]

> after the signal passes through the spring/plate, it loses about 0.4db.

More like 40dB.

Which is why you need gain both before and after.

ok, thanks!

[11-90-an]

There are 2 types of bc549's right? bc549B and bc549C? Is there basically no such thing as a bc549 (no suffix)?