AudioSector-chip amp kits, dacs, chassis

[lohk]

With chipamps it often seems to me that it is a question of too much bass, or too loose bass, here the right caps and the right speakers are essential. I never experienced not enough bass.
Did you doublecheck everything? Did you test your setup with different preamps or passive pot values? Maybe your source cannot "drive" your pot very well (in my experience the passive pre=pot must have at least 20k, 50k or 100k is even better).

[spacemen12]

Hi,
Sorry for the reduncy, but I'm not shure if I posted this a the right place, because nobody replied. Here is my message from the chip amp section:
Humm in a gainclone by a newbie

I've built my first gainclone (first electronic project as well) a few month ago. It made from a premium kit of audiosector withl dual mono power supply.

It works fine: it amplify the sound and plays the music! But when there is no sound getting in (like no track playing on the cd) there is noise in the sepaker. This noise is not strong but its audible.

This noise didn't get out after the burn-in period.

The noise is like the sound of giant speaker in a show when there is no music playing or when you crank up the volume of a guitar amplifier without a gitar plug in.

The noise don't vary in intensity when I change the volume (turn the volume pot on the preamp)

I use a cambridge 540A as a preamp (through the preamp output) and a cambridge 540c as a cd player.

I ran some tests, here the results (I'm not able to interpret them alone).

1. When the only thing plug in my "power bar" (AC) is the amp, and the speaker are connected to the amp, there is no noise.

2. When I connect 1rca wire to the input of the amp on configuration 1. (and the other end of the rca is not connected), then the noise come back.

3. When I touch with my finger on the unconnected side of the rca wire in 2. configuration:
a) the noise increase if I touch the hot (pin)
b) the noise reduce if I touch the ground (circle)


Here are some picture of my gainclone
http://geocities.com/spacemen12/gainclone/

If I'm not clear, tell me, I really want to learn.

Thanks

[Peter Daniel]

Originally posted by spacemen12

Here are some picture of my gainclone
http://geocities.com/spacemen12/gainclone/

From your layout schematic, can you remove completely the green chassis ground wire and see if it helps?

[Peter Daniel]

Originally posted by gaborbela
HI Peter
I dont know if is OK if I post here . I purchased from your GC premium kit .I put them together using 2x20V 160VA transformer for each chanel .
I used silver wire with teflon tubing for the signal and for the power I used Kimber 4TC Kable .
It works well but unfortunatly some how I miss the bass .Compare to another amplifiers it sound les dinamic and the bass..... less punch ..
I tought to increase the power supply voltage . I purchased two toroid from same commpany but 2x25V 225VA each .
I intaled the new toroids hope to do some positive , more power or more bass but it get worst .
Yes there is more power but somehow the sound get tinier , it just get lauder with less bass .
I tried to mounth diferent film capacitors or to use larger capacitors insted the 1500MF but did no impruvment .
Do you have some idea why the larger transformers has less bass than the smaller ones .
Both from same commpany .
If you know some good idea how I can get more bass or more punch please let me know .
Thanks Regards
Ya I'm using a Alps blue velvet pot ....

Silver is not always good for bass, you might try copper. Increasing PS voltage won't improve bass. Panasonic caps are not champions for bass either, you might try BG STD caps, they produce better bass. But, the most important question is, what are the speakers and the source?

[gaborbela]

HI
Thanks Peter for your reply . I tried diferent cd players like NAK. OMS-5 , Audio alchemy , Kenwood (top of the line) same problem .
I will replace the silver wire soone. My speakers are home made , Visaton drivers, another speakers made of Perless .
I have a Philips tube amp , single ended and only 4W but it is to loud if I turn on all the way and has a lot of bass . I know is not the best to comper with a tube amp , I just wrote these to let you know the speakers are sensitive enough.
I have a Nak recever and the speakers very good with it .
The amplifier works well , only that problem and sims to me a bit slow .
I tried to replace the 1500mf capacitors with Rifa caps but get worst .
It is worth to replace the caps with BG ?
The amp has very good vocal sound , top is nice only the bass .
Peter that why I asked you about that France gainclone , I saw that he use diferent circuit and big caps for the power supply .
Did you saw it , I sent second time ..
Thanks one more time ..
Regards

[-=Zepplock=-]

Originally posted by -=Zepplock=-
What if I add dedicated regulator for optical and connect it directly to 8V inputs?

So I made it work Pieter.
The trick was is to take +5V not from the U1 but from U2.
That 5V is more stable ;-)

Thank you Peter again for wonderful job!

[spacemen12]

Originally posted by Peter Daniel


From your layout schematic, can you remove completely the green chassis ground wire and see if it helps?

Hi,
I've removed both ground from the amp pcb, but it didn't solve the problem. There is still a humm.

The strongest humm occurs when all the rca are connected (cd - preamp - gainclone), but only the gainclone is connected to the AC (the power cord of the preamp and cd are not plug). Then it sound like a strong ground loop. When I plug back the the power cord the noise is a lot weaker, but audible.

Thanks

[planet10]

Originally posted by gaborbela
I used silver wire with teflon tubing for the signal ....it sound les dinamic and the bass..... less punch ..

How many hours on the silver wire? This is the kind of thing i've heard with the addition of fresh silver to a system.

dave

[dake13]

Hi Peter and all-

I'm trying to build my first gainclone using Peter's premium kit and I have a couple questions. I have some electronics experience from doing other kits, mods, etc., but I wouldn't say I'm an expert or anything. This gainclone is for a friend in Italy - maybe I'll build one for myself if it works out.

My friend's asked that I build separate mono power supplies (in two separate boxes) with the amp/volume in one chassis. I think this is more or less what the 47 Labs looks like.

Questions:

1) Can I build it with a switch for 110v/230V mains lines? My friend wants to be able to use it both in the US and Italy. Not sure if there's anything to watch out for with this.

2) What's a good value for a passive volume control?

3) My friend also wants Plitron trannies. It looks like I need either 067016201 (225VA, 25V output) or 077016201 (300VA, 25V output), marginal price difference. Would anyone mind confirming these parts nos. for me?

Thanks for any assistance.

[Destroyer OS.]

Those are the right transformers. Those or 24v will give you good power at the rail. That should work with either 4 Ohm or 8 Ohm speakers from how I understand it... You could also use 400va version as well if you wanted.

The Plitron is capable of working with 120/230 vac so yes actually you can, so long as the 230 is at 50hz. You will have to figure out the switching.... I have no idea how many wires off of the transformer have to be switched in the process.

The prices from Plitron are higher than on their website... I payed $96 for a 400 VA 24vx2 transformer.