Banned
Joined 2002
Thanks
JasonL: not sure what you mean by isp.
mFinalHeaven: I used enamelled copper wire that were offcuts from the toroids and a little bit (20mm) of cat5 for the signal wiring.
aiwonsi: I used the Peter Daniel's minimalist IGC schematic. 2 filter caps, 1 input cap, 2 feedback resistors but I used a 100K resistor across the input instead of a pot. Both use the identical circuit.
JasonL: not sure what you mean by isp.
mFinalHeaven: I used enamelled copper wire that were offcuts from the toroids and a little bit (20mm) of cat5 for the signal wiring.
aiwonsi: I used the Peter Daniel's minimalist IGC schematic. 2 filter caps, 1 input cap, 2 feedback resistors but I used a 100K resistor across the input instead of a pot. Both use the identical circuit.
Banned
Joined 2002
Hi Raka,
I'm not using a GC type PSU yet so it is a little premature to judge the sound quality and to be honest I think I may have LEAD ears anyway.
I'm using my test PSU, which is a 2x12VAC 300VA, a bridge and 2x10,000uf filter caps. This gives about only 17-0-17VDC.
What I am suprised about is;
1. with only 17 volts these amps generates more than adequate volume on my inefficent speakers.
2. the difference between the LM1875 and LM3875TF is surprising small. I was expecting chalk and cheese. The LM3875TF may have a little more guts.
3. the LM1875 seems to heat up the heatsink quicker than LM3875.
I rotate between 3 GC amps at the moment and here is my preferences, although, the differences to my ears are minute and I am happy listening to all of them.
1. LM3875 IGC
2. LM1875 IGC
3. LM1875 non-inverted GC
Even in there present state these amps sound better than my old Yamaha, but that not surprising to us DIYers,
I'm not using a GC type PSU yet so it is a little premature to judge the sound quality and to be honest I think I may have LEAD ears anyway.
I'm using my test PSU, which is a 2x12VAC 300VA, a bridge and 2x10,000uf filter caps. This gives about only 17-0-17VDC.
What I am suprised about is;
1. with only 17 volts these amps generates more than adequate volume on my inefficent speakers.
2. the difference between the LM1875 and LM3875TF is surprising small. I was expecting chalk and cheese. The LM3875TF may have a little more guts.
3. the LM1875 seems to heat up the heatsink quicker than LM3875.
I rotate between 3 GC amps at the moment and here is my preferences, although, the differences to my ears are minute and I am happy listening to all of them.
1. LM3875 IGC
2. LM1875 IGC
3. LM1875 non-inverted GC
Even in there present state these amps sound better than my old Yamaha, but that not surprising to us DIYers,
The 1875 has higher idle current, so it's no surprise that the heatsink gets warmer.
You didn't read my thread about ABing GC, did you?
You have to take care when you say "it's better" to me, because I will ask you about how did you compare both.
I did some comparitions and my Denon 1801 sounds as good/bad as my IGC in my system. BTW, which is the rest of your system?
You didn't read my thread about ABing GC, did you?
You have to take care when you say "it's better" to me, because I will ask you about how did you compare both.I did some comparitions and my Denon 1801 sounds as good/bad as my IGC in my system. BTW, which is the rest of your system?
Hi Raka,
You caught me out
I didn't do a direct A/B comparison between my Yamaha and the GCs. About a year ago I build an AKSA 55 and that was definitely better than my Yamaha, so I haven't plugged to old Yamaha in for well over a year now.
From memory (failing), these GCs are closer to the AKSA than the Yamaha was, so there you go. Not very scientific I know. I'll get the Yamaha out over the weekend and have another listen.
If you noticed, I was trying to be non committal about judging the sound quality between the GCs as I don't believe there is that much difference and by the time I disconnect all the wiring and set up the next one a definite answer is difficult.
BTW, I have once done a "proper" A/B/X test with preamps and got 80% WRONG so that must prove something. Even by guessing I should have got 50% right. During this test one person, who happened to be the wife of one of the premaps owners, got it 90% right.
I consider the rest of my hifi equipment to be nothing special, quite ordinary actually. I have a leaning towards electronics rather than Hifi. I guess thats why I have 6 amps, a preamp and more under construction.
You caught me out
I didn't do a direct A/B comparison between my Yamaha and the GCs. About a year ago I build an AKSA 55 and that was definitely better than my Yamaha, so I haven't plugged to old Yamaha in for well over a year now.From memory (failing), these GCs are closer to the AKSA than the Yamaha was, so there you go. Not very scientific I know. I'll get the Yamaha out over the weekend and have another listen.
If you noticed, I was trying to be non committal about judging the sound quality between the GCs as I don't believe there is that much difference and by the time I disconnect all the wiring and set up the next one a definite answer is difficult.
BTW, I have once done a "proper" A/B/X test with preamps and got 80% WRONG so that must prove something. Even by guessing I should have got 50% right. During this test one person, who happened to be the wife of one of the premaps owners, got it 90% right.
I consider the rest of my hifi equipment to be nothing special, quite ordinary actually. I have a leaning towards electronics rather than Hifi. I guess thats why I have 6 amps, a preamp and more under construction.
Hi Bricolo,
Thanks. I have been trying to make these things really compact because......I don't really know why.
Anyway, I got the RCA and speakers sockets here at a local electronics store.
http://www1.jaycar.com.au/
Sorry I couldn't get the direct URLs to the parts so here are the part numbers, use them in the search field.
PS0276
PS0277
PT0430
PT0431
PP0434*
PP0435*
The speaker posts marked with an * have fragile insultators. In the first picture you'll notice one of the black insulators is not centralised because it is broken.
Thanks. I have been trying to make these things really compact because......I don't really know why.
Anyway, I got the RCA and speakers sockets here at a local electronics store.
http://www1.jaycar.com.au/
Sorry I couldn't get the direct URLs to the parts so here are the part numbers, use them in the search field.
PS0276
PS0277
PT0430
PT0431
PP0434*
PP0435*
The speaker posts marked with an * have fragile insultators. In the first picture you'll notice one of the black insulators is not centralised because it is broken.
grege said:
Hi Greg
Whereabout in Sydney are you? Sounds like we ought to get together. I am near Liverpool, head out the M5, and it just a bit of it.
I just love to show my JLTi (tubed gainclone) amp off, even better playing it.
Check out the link below, "The Tube Gainclone for DIY Buffs".
Joe R.
Hi Joe,
Thanks for the invite, I'd love to have a look and listen to the JLTi. I live at Mt Kuring-gai but I do go to Parramatta regularly and I do venture to Warwick Farm on the odd occassion.
BTW, I think we may have already crossed paths at the AKSAfest, I did a lot of listening to your CD player on Malcolm Fear's system if I'm not mistaken. Can't remember talking to you though.
Also, I was wondering if those yellow caps on your production JLTi are from Jaycar. They do look similiar and I have a set but haven't tried them yet.
Thanks for the invite, I'd love to have a look and listen to the JLTi. I live at Mt Kuring-gai but I do go to Parramatta regularly and I do venture to Warwick Farm on the odd occassion.
BTW, I think we may have already crossed paths at the AKSAfest, I did a lot of listening to your CD player on Malcolm Fear's system if I'm not mistaken. Can't remember talking to you though.
Also, I was wondering if those yellow caps on your production JLTi are from Jaycar. They do look similiar and I have a set but haven't tried them yet.
These things are nothing special. They are just no name bits and I wouldn't be suprised if someone in Europe sells exactly the same things.
You could try buying from JayCar, I believe them to be trustworthy and I think postage through Australia Post is fairly cheap. Don't forget one Australian dollars equals about 0.6 of a euro so they are cheap.
Nice 3875 layout. I like the idea of the chipscrew/ground star.
It is so small, would be tough for an amateur to get good pix. If you slip me an r/t plane ticket (and ones for the wife and kids, of course) I'll pop over to Australia and make some really nice photos for you. I am a professional, you know...
Nice job.
GnD
It is so small, would be tough for an amateur to get good pix. If you slip me an r/t plane ticket (and ones for the wife and kids, of course) I'll pop over to Australia and make some really nice photos for you. I am a professional, you know...
Nice job.
GnD
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