I decided to build a Gainclone after I had read this froum for a few days. However, I had trouble on gathering parts in US, but I found an answer in a thread.
Originally posted by rammsteinme
The real question was in the transformer part.
What transformer should I use?
Did the shape of the transformer affect (Square, circle ?_?I hope to make it as thin and as small as possible)
What value of Dual potentiometer ( where to connect? input or output )and Power Port should I use?
How can I build this amp with gain control?
How can I build a Gainclone with stereo in (I mean something like
headphone pot.)and RCA in, RCA out and stereo out?
My budget : $100
My Sources: Toshiba 5205-S505 Laptop / a Deatop / even a
system I don't know (My Laptop will be my first
concern.)
My Speaker: Aiwa Speaker System SC-51
Music Power 35W
Normal Power 25W
Impedance 8 Ohm
P.s Feel free correcting my English.
Code:
Qty Description Part # Supplier Cost (US$) Total
2 Cond 4.7uF, 50V BlackGate N BLKGATE- 60186 partsconnexion.com $2.50 $5.00
4 1000uF, 50V Panasonic FC P10333-ND (or P11263-ND) digikey.com 2.37 $9.48
2 10K Ohm .75W Caddock:MK132 CADDOCK- 51201 partsconnexion.com 3.95 $7.90
2 220K Ohm .75W Caddock:MK132 CADDOCK- 62290 partsconnexion.com 4.5 $9.00
8 MUR860 Diodes MUR860-ND digikey.com 0.76 $6.08
2 LM3875 Op-Amp LM3875TF-ND digikey.com 5.81 $11.62
total $49.08
1 Transformer (range 20-40) Surplus? $0.00
1 50K Stereo pot Radio shack? Radio shack? $0.00The real question was in the transformer part.
What transformer should I use?
Did the shape of the transformer affect (Square, circle ?_?I hope to make it as thin and as small as possible)
What value of Dual potentiometer ( where to connect? input or output )and Power Port should I use?
How can I build this amp with gain control?
How can I build a Gainclone with stereo in (I mean something like
headphone pot.)and RCA in, RCA out and stereo out?
My budget : $100
My Sources: Toshiba 5205-S505 Laptop / a Deatop / even a
system I don't know (My Laptop will be my first
concern.)
My Speaker: Aiwa Speaker System SC-51
Music Power 35W
Normal Power 25W
Impedance 8 Ohm
P.s Feel free correcting my English.
I decided to build a Gainclone under the following part list by rammsteinme
My questions are:
What kind of transformer should I use? (I want to make it as thin & small as possible.)
What value of resistance Dual potentiometer do I use?
( Volume Control ) ( where do I connect it ? On the input or output )
How can I build this amp with gain control?
How can I build a Gainclone with two kind of input and output (headphone kind of pot, and RCA pot or I/O pot
My budget : $100
My Sources: Toshiba 5205-S505 Laptop / a Deatop / even a
system I don't know (My Laptop will be my first
concern.)
My Speaker: Aiwa Speaker System SC-51
Music Power 35W
Normal Power 25W
Impedance 8 Ohm
P.s Feel free to correct my English. [/B][/QUOTE]
Code:
Qty Description Part # Supplier Cost (US$) Total
2 Cond 4.7uF, 50V BlackGate N BLKGATE- 60186 partsconnexion.com $2.50 $5.00
4 1000uF, 50V Panasonic FC P10333-ND (or P11263-ND) digikey.com 2.37 $9.48
2 10K Ohm .75W Caddock:MK132 CADDOCK- 51201 partsconnexion.com 3.95 $7.90
2 220K Ohm .75W Caddock:MK132 CADDOCK- 62290 partsconnexion.com 4.5 $9.00
8 MUR860 Diodes MUR860-ND digikey.com 0.76 $6.08
2 LM3875 Op-Amp LM3875TF-ND digikey.com 5.81 $11.62
total $49.08
1 Transformer (range 20-40) Surplus? $0.00
1 50K Stereo pot Radio shack? Radio shack? $0.00My questions are:
What kind of transformer should I use? (I want to make it as thin & small as possible.)
What value of resistance Dual potentiometer do I use?
( Volume Control ) ( where do I connect it ? On the input or output )
How can I build this amp with gain control?
How can I build a Gainclone with two kind of input and output (headphone kind of pot, and RCA pot or I/O pot
My budget : $100
My Sources: Toshiba 5205-S505 Laptop / a Deatop / even a
system I don't know (My Laptop will be my first
concern.)
My Speaker: Aiwa Speaker System SC-51
Music Power 35W
Normal Power 25W
Impedance 8 Ohm
P.s Feel free to correct my English.
[/B][/QUOTE]
Hi S.C, I'll try and answer some of your questions.
A torroidal type if transformer is probably your best bet. Unfortunately, if miniturisation is the goal, the transfomrer will be the limiting factor, ie they just don't make very small ones capable of powering a power amplifier.
You will need a transformer with 110 volt primary windings and secondaries of 18-0-18 and rated at 120VA or higher (if you use just one).
If you are building the basic inverted version of the GC, I suggest using the stepped attenuator described on my
FAQ page
The volume control is connected on the input of the GC as shown in many of the schematics posted on this and other chip amp forums.
Why do you want to control the gain? There is no need if you are controlling the volume with a pot of attenuator.
You can build a simple device with resitors to enable you to connect headphones through the speaker terminals. A design was mentioned in another thread but I can't remember where. Try a search.
To use the amp with different inputs, you will need to build a preamp with a selector switch and multiple input sockets. Again, refer to the relevant sections of Decibel Dungeon for more information.
Realistically, your budget of $100 is a bit tight but it depends how much you can pick up at surplus prices and whether you buy, or build your case.
Good luck, it may all seem a bit confusing at first but if you study all the information available and then take things in easy steps, it is possible to build a good sounding GC!
A torroidal type if transformer is probably your best bet. Unfortunately, if miniturisation is the goal, the transfomrer will be the limiting factor, ie they just don't make very small ones capable of powering a power amplifier.
You will need a transformer with 110 volt primary windings and secondaries of 18-0-18 and rated at 120VA or higher (if you use just one).
If you are building the basic inverted version of the GC, I suggest using the stepped attenuator described on my
FAQ page
The volume control is connected on the input of the GC as shown in many of the schematics posted on this and other chip amp forums.
Why do you want to control the gain? There is no need if you are controlling the volume with a pot of attenuator.
You can build a simple device with resitors to enable you to connect headphones through the speaker terminals. A design was mentioned in another thread but I can't remember where. Try a search.
To use the amp with different inputs, you will need to build a preamp with a selector switch and multiple input sockets. Again, refer to the relevant sections of Decibel Dungeon for more information.
Realistically, your budget of $100 is a bit tight but it depends how much you can pick up at surplus prices and whether you buy, or build your case.
Good luck, it may all seem a bit confusing at first but if you study all the information available and then take things in easy steps, it is possible to build a good sounding GC!
Good info, thx !
I currently had a Panasonic EVJY10 Series Dual potentiometer, is it connect it like the following picture is ok for this amp?
I currently had a Panasonic EVJY10 Series Dual potentiometer, is it connect it like the following picture is ok for this amp?
An externally hosted image should be here but it was not working when we last tested it.
from Headwize
After I read some of the transformer suggestion, I had a question.
How come ppl in USA can use transformer input up to 2xx VAC, isn't US Wall supply only have 120VAC?
I'm confused by these transformer stuff now, and what else do I need if I had LM3875 from samples, that make the digikey parts total around $18. Then I need to pay for the $5 handling, unless I make the total cost at $25. In the partsconnexion side also had the same problem.
How come ppl in USA can use transformer input up to 2xx VAC, isn't US Wall supply only have 120VAC?
I'm confused by these transformer stuff now, and what else do I need if I had LM3875 from samples, that make the digikey parts total around $18. Then I need to pay for the $5 handling, unless I make the total cost at $25. In the partsconnexion side also had the same problem.
SC - I wouldn't get yourself too confused worrying about such matters but a quick answer is that a transformer designed for use at 230 volts can be used with 115 volts but the output will be half what it is when used with 230 volts. So if that transformer puts out twice as much power as is needed, at 115 volts it will be the right amount.
Yes, it's always a good idea to make up an order so that you don't pay a minimum order charge or postage. Check my complete parts list to see if you have got everything and if you have, just order a few spare plugs or sockets as they always come in useful.
So far this is my conclusion.http://us.f1f.yahoofs.com/users/bda2f635/bc/GC/My+Gainclone+Part+List.txt?bfGgjB_AhOiR7sAr
Do you think this will be ok for th pre amp section?
from headwize
An externally hosted image should be here but it was not working when we last tested it.
from headwize
Yes, at least to get you going but I would later replace that pot with the stepped attenuator recommended by TL (on my FAQ page) and I presume that the headphone out socket goes to a dedicated headphone amp!
Also there are just two inputs!
Your link isn't working at present so I can't pass comment.
I think this one will work
http://hk.geocities.com/solomon_choi/gcpartlist.txt
I didn't know that cheap yahoo free e-mail can't share file to public, unless you pay for your account.
http://hk.geocities.com/solomon_choi/gcpartlist.txt
I didn't know that cheap yahoo free e-mail can't share file to public, unless you pay for your account.
God ! New Problem !!!!!!!!!!!!!!!
My good uncle hided a lot of old transformers at the garuge ( can't spell ), the square sharped one. There are more then 10 of them. However, they are not marked anything. How can I test thoses?
Second, he gave me a nice Aluminum Case. But I don't know how to mesure the already build in power supply. He kept it well, and it looks pretty good. http://hk.geocities.com/solomon_choi/GC.html
P.S The photos won't avaluable (can't spell again ) under an hour. It is what GeoCities told me.
My good uncle hided a lot of old transformers at the garuge ( can't spell ), the square sharped one. There are more then 10 of them. However, they are not marked anything. How can I test thoses?
Second, he gave me a nice Aluminum Case. But I don't know how to mesure the already build in power supply. He kept it well, and it looks pretty good. http://hk.geocities.com/solomon_choi/GC.html
P.S The photos won't avaluable (can't spell again
) under an hour. It is what GeoCities told me.
the aluminium box looks good...you can try using that...but it's transformer in side is likely to be too puny to be used for your GC...from the looks of it...it has 110-220V primaries and split or tapped secondaries...I guess the box was used for motor control...as for the "uncle kept some trafos" pproblem...you can get those that look BIG and HEAVY. Inject your mains into it's secondary and measure the output...try to find one that is near to your target range...(18-25V)...
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