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Group order of non-inverted LM3875 pc boards? Anyone interested?

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#881
Status Update:

Over the past week, 51/63 of the US orders from the new batch have been fulfilled, consisting of 37 premium kits, 16 basic kits and 41 pcb sets.

As for the remaining US orders, there will be a couple more days delay on them, as I am waiting for my shipment of BlackGate capacitors to come in. I underestimated the number of BG 1000uF STD capacitors needed (ordered 100, and orders for 140 placed. I placed the order last week, so it should be here quite soon.

For the international/canadian orders, I shipped all the kit components up to Peter at the end of last week, and he should receive them soon, and start shipping out the kits. I shipped all needed components for all the current orders as of Friday for the international. The international orders included 84 - BG STD 1000uF capacitors, which took most of my initial order, which is why I have the extra delay on some of the US orders that included the BG 1000uF STD capacitors.

I also have shipped out 6 free pcb sets to previous people (from the new batch of pcbs) from the earlier gallery entries (first 20 entries got a free pcb set). I will work on getting the free pcb sets shipped out to the international entries soon. If you are in the US, and haven't received your free pcb set by the end of the week for your entry, drop me an e-mail. International people who submitted entries should also e-mail me with your address, and I will get the boards shipped out asap. I believe I have mailed out free pcbs to 12/20 entries thus far.

I am a few days backlogged on e-mail, but will try to catch up soon. Please don't think that I am ignoring your e-mail, and I will try to respond to it soon.

A new user's manual will be released soon on the website. I will post details here when I upload it.

--
Brian
 
#883
hey brian...i was curious if you knew your order site was down? i went to order a premium kit tonight, and the link is now dead. is this by design because you are swamped; server problems; or new to you?

i'll try it again tomorrow in case it is (indeed) unintentional. if it's not...could ya let me know so i don't keep trying to hit the site in my anxiousness to get a kit ;-)

thanks!!
 
#884
enochRoot said:
hey brian...i was curious if you knew your order site was down? i went to order a premium kit tonight, and the link is now dead. is this by design because you are swamped; server problems; or new to you?

i'll try it again tomorrow in case it is (indeed) unintentional. if it's not...could ya let me know so i don't keep trying to hit the site in my anxiousness to get a kit ;-)

thanks!!
Click to expand...

The server is having problems, and it is being worked on now.

--
Brian
 
#887
Transformer wiring

Hi All-

I know there have been MANY discussions about transformers and wiring for Brian's Gainclone Pwr boards but I never found what I was looking for so I drew this.

Hope it is helpful to some one.

Troy
 

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  • gc pwr xformer.gif
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#889
I put up a new version of the manual, in the same location:
http://www.briangt.com/nigc_kit-users_guide.pdf

It is about 1 meg in size, so I highly recommend on downloading it first, instead of just following the above link.

I had quite a bit of help from Sandy H. with the manual, and we based some of the new content on member suggestions.

I created a mail account dedicated to suggestions for the manual. Feel free to mail me with what you think the manual should contain, or if you spot any errors:
manual@chipamp.com

Note: this account will be only be checked periodically, so use this mail for only questions related to the manual.

I am still in the process of creating new material for the new revised pcbs, and the manual will be updated in the future.

--
Brian
 
#890
I just ordered the premium kit 😀 and a few questions aroused
(stupid questions 😱 I'm sure that the answers lie here somewhere but I'm new to this Forum and Gainclones so I think it's better to ask. I'm sure that you are all sick of these newbie questions so I won't be offended if I won't get any answers )

The PSU is designed for transformer with 2 secondary windings? Why?
Is it possible to use a transformer with only one secondary winding? Getting a 330 VA 2*18 V transformer would be very easy for me and it costs only 50 $ !
http://www.trafox.fi/rengassydan/rsmuuntajat.htm

If it is really worthwhile to get a different transformer I'm ready to invest more time and money for it.

Is it ok to use Dynaudio Audience Speakers with Gainclone (4 ohm, 86dB)?

I have a DACT CT2 10 kOhm stepped attenuator as a passive preamp. Is it a problem with Gainclone?

Thanks !!
 
#891
Toroid transformers usually have two separate windings but it will work also with a center tap. Note that you only can use one rectifier bridge. When you have two windings, you have choose to have one or two rectifier bridges.

If you plan to use a transformer with only one winding and no center tap, this requires more work. Look in the datasheet how you must do.
 
#893
In section 3.1 of the new manual it states:
"The original standard application of this kit uses the first, a transformer with dual secondaries. For this application, the primaries are attached to the mains, while V+ and 0+ are attached to PG- and V- and V- and 0- are attached to V- and PG-."

Is this what it is really supposed to say??

It's late here but this doesn't make any sense to me.
 
#896
moving_electron said:
In section 3.1 of the new manual it states:
"The original standard application of this kit uses the first, a transformer with dual secondaries. For this application, the primaries are attached to the mains, while V+ and 0+ are attached to PG- and V- and V- and 0- are attached to V- and PG-."

Is this what it is really supposed to say??

It's late here but this doesn't make any sense to me.
Click to expand...
Maybe so but the best you can do is to get the datasheet for LM3875 plus AN-1192 and just compare.

PG is Power Ground.

The rectifier baord is made for 4 wires and two separete windings.
 
#898
peranders said:

No need to worry. Lower value is better. The pot should be more than 2 kohms. Most preamps can drive 2 kohms.
Click to expand...

Hmm.. I'm not sure what you mean by that. I use the 10 kOhm attenuator as a preamp with my CD player:

http://kotiweb.kotiportti.fi/audiovideo/DIY/preamp1

Thanks for all your answers.

(by the way, it seems that there are people organizing a group order for BrianGT's Gainclone kits in a finnish hifi forum 😀. This gainclone fever spreads like grazy 😱 )
 
#900
Center tapped x-former

Hey variac-

I drew the diagram according to what I interpreted from Brian's email.

"Troy,

It looks to me like your power supply is wired up wrong. You need to wire the AC1H and AC2N to the center-tap on the transformer, which forms the PGND connection. I would recommend swapping this and checking your power supply voltages."

I have several transformers I bought from Steve @ Apex so I am going to evaluate the sound with each pwr option on the diagram.

I have NO DOUBT that the dual transformer version will sound best, but some people may be more inclined to try the GC if the cost could be minimized.


BTW, I can not believe the support we get from Brian. You don't get this level of support from Hi-end manufacturers much less a $35-75 kit!

Thanks again,

Troy
 
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