Some of you will probably think this after seeing the picture of my new amplifier. I just wanted to show it off a little. Below are a couple pictures of it. I have yet to build the walnut volume know, but you can see the shaft sticking out. Also note that the brightness is adjusted way up, the case body is a gloss black and i could not get a decent picture without doing it this way. The circle is basically the original thor-amp with the following:
220k holco + 0.1uf from 7 to gnd
220k holco feedback
4.7uf bg n input
10k riken ri
crappy bridges (going to soon replace with some mur860 bridges i built)
300va plitron tf
As for the sound. There is a slight hum at around 1m, but disappears for the most part beyond that. Other than the hum, which is hardly noticable with the source on even with the lowest volume, the sound is far better than any other combination i have tried ... (which is several of the main permutations i have seen on here).
220k holco + 0.1uf from 7 to gnd
220k holco feedback
4.7uf bg n input
10k riken ri
crappy bridges (going to soon replace with some mur860 bridges i built)
300va plitron tf
As for the sound. There is a slight hum at around 1m, but disappears for the most part beyond that. Other than the hum, which is hardly noticable with the source on even with the lowest volume, the sound is far better than any other combination i have tried ... (which is several of the main permutations i have seen on here).
Banned
Joined 2002
towers were my own design. i know i shouldve put woofer and tweet closer (dont scold, these were my first serious pair). i think they sound great though. its a vifa p17 with vifa d25. i just went to the dark side and bought some speakers. i was incredibly impressed by them and found a great price on some acoustic energy 309's, so they will probably take the spot in my main setup.
and the receiver is actually a kenwood vr6070 (which i must say is far more impressive than most would give credit) and the cd/dvd player is a sony ns715p (awesome if you are on a college budget like myself!!!)
and the receiver is actually a kenwood vr6070 (which i must say is far more impressive than most would give credit) and the cd/dvd player is a sony ns715p (awesome if you are on a college budget like myself!!!)
Attachments
Banned
Joined 2002
hum
... about the hum. it is audible at 1 meter, but not very audible at about 2.5-3 which is where i sit. this is with the source connected, but off and the volume all the way up. there is no ac filter on this amp (yet, i have yet to tinker with that, the ol cap and two diodes helped on last gc but i think affected the sound) and the dc offset is 11 mv on one side and 10.2mv on the other.
i haven't played with shielding the transformer at all (especially since my last gc had a separate ps a la peter daniel) which may help we'll see here in a week or so. the bg 1000 uf std on the ps are the most significant gain in sound for me. i now take the power supply much more seriously than i did on my first implementation.
so.... overall review is that the sound is great. i have no complaints about bass (granted i'm -3 db at ~50hz) and the mids and highs blow away my last gc and of course my kenwood (this is with a blind test which (believe it or not) my girlfriend (EDIT!!! she's my fiance! i better not forget that, cause i'm still waiting for my wedding presents from all of you!) assisted with!!
... about the hum. it is audible at 1 meter, but not very audible at about 2.5-3 which is where i sit. this is with the source connected, but off and the volume all the way up. there is no ac filter on this amp (yet, i have yet to tinker with that, the ol cap and two diodes helped on last gc but i think affected the sound) and the dc offset is 11 mv on one side and 10.2mv on the other.
i haven't played with shielding the transformer at all (especially since my last gc had a separate ps a la peter daniel) which may help we'll see here in a week or so. the bg 1000 uf std on the ps are the most significant gain in sound for me. i now take the power supply much more seriously than i did on my first implementation.
so.... overall review is that the sound is great. i have no complaints about bass (granted i'm -3 db at ~50hz) and the mids and highs blow away my last gc and of course my kenwood (this is with a blind test which (believe it or not) my girlfriend (EDIT!!! she's my fiance! i better not forget that, cause i'm still waiting for my wedding presents from all of you!) assisted with!!
cabling
I have also toyed a lot with different cables with the gainclone. After several much more complicated topologies (twisted pair, braids, etc.) i have found my favorite to be just a plain belden 89259. and while i have some eichmann bullet plugs, in the picture im using a set with daytons $10 locking rca's.
as for speaker cable that is ribbon laid on top of one another and spaced.
power cable is partsexpress formula that they explain on their site. cheap and good.
I have also toyed a lot with different cables with the gainclone. After several much more complicated topologies (twisted pair, braids, etc.) i have found my favorite to be just a plain belden 89259. and while i have some eichmann bullet plugs, in the picture im using a set with daytons $10 locking rca's.
as for speaker cable that is ribbon laid on top of one another and spaced.
power cable is partsexpress formula that they explain on their site. cheap and good.
breguetphile,
Have you tested a 18k resistor instead of the 220k/0.1uf combo on the non-inv. input?
Anyway, the hum may be a question of joining the two channels together and run a thick wire from the star ground of one channel to the other. The mid point of that wire goes to the star ground of the case.
This is what you should do when you have only one transformer for the two channels.
In my experience, connecting each star ground of each channel to the case ground means hum.
You have to join them toguether and use the smallest length of wire you can.
You don't show internal pictures of your amp, so these are general suggestions.
Let me say that your amp is beautiful.
Have you tested a 18k resistor instead of the 220k/0.1uf combo on the non-inv. input?
Anyway, the hum may be a question of joining the two channels together and run a thick wire from the star ground of one channel to the other. The mid point of that wire goes to the star ground of the case.
This is what you should do when you have only one transformer for the two channels.
In my experience, connecting each star ground of each channel to the case ground means hum.
You have to join them toguether and use the smallest length of wire you can.
You don't show internal pictures of your amp, so these are general suggestions.
Let me say that your amp is beautiful.
i'm hiding...
i'm hiding the internals for a reason! its ugly in there. i have everything as close as i could possibly get it but its kind of a rats nest, i plan on doing some rewiring once i get some decent wire. currently i was using radio shack's wrapping wire which is tinned 30 gauge copper, but its very hard to control and breaks easily. the star grounds are close so this will be easy to do (they are about 2 inches apart. and the chassis ground is about 3 inches from their midpoint.
i'm hiding the internals for a reason! its ugly in there. i have everything as close as i could possibly get it but its kind of a rats nest, i plan on doing some rewiring once i get some decent wire. currently i was using radio shack's wrapping wire which is tinned 30 gauge copper, but its very hard to control and breaks easily. the star grounds are close so this will be easy to do (they are about 2 inches apart. and the chassis ground is about 3 inches from their midpoint.
Re: i'm hiding...
It may be ugly on the inside, but no problem for us.
On the outside it's prettier than my "PC Gainclone".
But looks aside, when I put it playing I'm in heaven.
Some people got out of my house needing medical assistance.
And some of them are used to high-end.
breguetphile said:
It may be ugly on the inside, but no problem for us.
On the outside it's prettier than my "PC Gainclone".
But looks aside, when I put it playing I'm in heaven.
Some people got out of my house needing medical assistance.
And some of them are used to high-end.
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