AudioSector-chip amp kits, dacs, chassis

[Peter Daniel]

Hi Mike, you will find more info here: http://en.wikipedia.org/wiki/Unknown_Pleasures

 

[DeanP]

ground loop problem

Peter,
I was wondering if you could look at my thread here.

I would like your thoughts on my problem...ground loop

 

[Colin]

Hi Peter - How did the buffer work out for preamp use?

 

[joshuajoshua]

transformer brand

Hi all! I'm a newbie here....
Don't mean to interrupt the ongoing subject, but hopefully here is the correct thread to post my question...

Peter,

I'm planning to built dual mono gainclone LM3875. I read from your previous thread that Plitron brand is highly recommended toroidal transformer. Then Avel. Do you have any opinion about Hammond in comparison to the previous ones?

Thanks,

Joshua

 

[jleaman]

Re: transformer brand

Hi all! I'm a newbie here....
Don't mean to interrupt the ongoing subject, but hopefully here is the correct thread to post my question...

Peter,

I'm planning to built dual mono gainclone LM3875. I read from your previous thread that Plitron brand is highly recommended toroidal transformer. Then Avel. Do you have any opinion about Hammond in comparison to the previous ones?

Thanks,

Joshua

If you try a Hammond, you will have alot of problems moving the secondary wires around, they are EXTREMELY stiff, the Plitrons are very soft. You could also purchase it from Avel, i use them and i like them alot.

Jase

 

[Peter Daniel]

Re: transformer brand

Hi Peter - How did the buffer work out for preamp use?

The buffer was mainly intended to use at the output of the DAC. It can be still used in a preamp, but I can't say how well it will perform. I tried it briefly with the 10k relay volume attenuator: http://www.diyaudio.com/forums/showthread.php?postid=1175938#post1175938 but I wasn't happy with the results (one reason could be that the impedances were not the best match)

I'm planning to built dual mono gainclone LM3875. I read from your previous thread that Plitron brand is highly recommended toroidal transformer. Then Avel. Do you have any opinion about Hammond in comparison to the previous ones?

I never used high power Hammond toroids, so I can't really comment. I used a lot of smaller Hammonds and I like them. I actually built a power supply for Shigaraki transport using 70VA 266 Series Hammond and in direct comparison it was better than the original Dumpty.

As to the secondary leads stiffnes, I wouldn't make my choice depending on that. It may be an advantage if it's the same wire as used in a transformer.

 

[joshuajoshua]

Re: Re: transformer brand

If you try a Hammond, you will have alot of problems moving the secondary wires around, they are EXTREMELY stiff, the Plitrons are very soft. You could also purchase it from Avel, i use them and i like them alot.

Jase

Thanks for the info.

May I know your Avel transformer setup (power & secondary voltage rating)?

Joshua

 

[joshuajoshua]

Re: Re: transformer brand

I never used high power Hammond toroids, so I can't really comment. I used a lot of smaller Hammonds and I like them. I actually built a power supply for Shigaraki transport using 70VA 266 Series Hammond and in direct comparison it was better than the original Dumpty.

As to the secondary leads stiffnes, I wouldn't make my choice depending on that. It may be an advantage if it's the same wire as used in a transformer.

Encouraging result of that comparison to use Hammond..

Do you mean that the stiffnes as one of a sign of a bigger wire gauge? And if it is used as a coil itself in the transformer, it will have less resistive loss in that coil?

Joshua

 

[AndrewT]

If the transformer's wire leads are solid core , then it's worth changing them to stranded for the extra flexibility and resistance to fatigue.

 

[joshuajoshua]

If the transformer's wire leads are solid core , then it's worth changing them to stranded for the extra flexibility and resistance to fatigue.

Personally I prefer to connect it directly to the board/rectifier as long as it has enough length to route the wire in ‘relax’ position. Probably full solid core connection (it the transformer does have it) to the bridge will give a little bit better regulation?

But I can see your point, the trade off of mechanical stress to the leads especially in solder joint if it is not done properly.

Joshua

 

[AndrewT]

hi,
and the flexible leadouts allow rotation of the transformer to orient the hum field for minimum noise.

 

[joshuajoshua]

hi,
and the flexible leadouts allow rotation of the transformer to orient the hum field for minimum noise.

Ah, good point

Can you explain it in detail how to achieve the optimum transformer orientation? Is it just simply trying to orient the transformer and listen for the resulted hum?

Joshua

 

[jleaman]

Ah, good point

Can you explain it in detail how to achieve the optimum transformer orientation? Is it just simply trying to orient the transformer and listen for the resulted hum?

Joshua

Correct, also mounting it above the chassis, ie on a block of wood or rubber helps.

 

[lordvader]

In regards to rotating transformers, is there are way to be sure to get the orientation right the first time ?

If not, what are the maximum degrees of rotation necessary ? Once these things are wired up, it'll be a major pain of you need to rotate 180 degrees, only to find the wires aren't long enough !!!

 

[jleaman]

In regards to rotating transformers, is there are way to be sure to get the orientation right the first time ?

If not, what are the maximum degrees of rotation necessary ? Once these things are wired up, it'll be a major pain of you need to rotate 180 degrees, only to find the wires aren't long enough !!!

Its not a HUGE issue, your best bet is to make sure the wires are short and cleanly soldered to the board, another good thing ( noted above ) isolate it from the chassis.

The less hum you can create the beter, gain clones are very prone to hum You can look at it and recieve hum LOL, im sure you'll be fine tho.

 

[joshuajoshua]

Correct, also mounting it above the chassis, ie on a block of wood or rubber helps.

Thanks for the tips!

Joshua

 

[joshuajoshua]

magnet wire

Does anybody have any experience of using magnet wire for interconnection for gainclone amp in particular ...or for any amp in general?

Is it a benefit or vice versa?

Let me hear your comment please.....
Thanks in advance!

Joshua

 

[jleaman]

Re: magnet wire

Does anybody have any experience of using magnet wire for interconnection for gainclone amp in particular ...or for any amp in general?

Is it a benefit or vice versa?

Let me hear your comment please.....
Thanks in advance!

Joshua

pin in the BUT to use, plus strip the coating off of. Just stick to some decent silver/decent wire make life simple not harder, once amp is up and ruining then do it, if yuo think you can hear the difference then go for it, but i doubt you will

 

[joshuajoshua]

Re: Re: magnet wire

pin in the BUT to use, plus strip the coating off of. Just stick to some decent silver/decent wire make life simple not harder, once amp is up and ruining then do it, if yuo think you can hear the difference then go for it, but i doubt you will

Right, i might give a try but later.....

Thanks for the prompt response.

Joshua

 

[joshuajoshua]

grounding scheme

Peter,

I notice in your Patek Amp design, you put a chassis connection from the star point ground thru a small value resistor. I believe this is for safety reason in which it gets connected to the earth ground connection at separated power supply module...cmiiw..

That brings me to another different question, does the 0 volt point at secondary side of the transformer has always to be connected to the earth ground? Can we just leave it floating?

Thanks,

Joshua