Gainclone Cool/Cheap Parts Treasure hunt

[planet10]

Id really like 2 pieces of this PLEASEE!!! maybe when i come there for the audio meet.

bring a big hacksaw... it is still just one 250 pound chunk.

dave

 

[widman]

I needed to replace the 100K RS pot I used to get my amp going, so I went on a spree at Electronics goldmine. I ended up getting 12 pots for about $10 (inc. shipping).

The best find was from an assortment:

Goldmine

I settled on a black Noble 10K stereo pot, which tracked fairly well between channels (<100 ohms). My BrianGT amp sounds much better now, significantly louder and more presence. Now all I need is a Zobel .

widman

 

[Variac]

Here are some knobs that seem to be a reasonable deal:

http://www.diycable.com/main/product_info.php?products_id=525

I like that they have a flattened area to make stepped switches easier to turn, but also have a round area for fine adjustments.

Keep in mind that 30mm is almost 1 1/4" inch so is pretty big.

 

[planet10]

Apple ImageWriter IIs have an 80 VA 0-28 VAC transformer. It is very low profile and quite a chunk of iron. I'm going to try a virtual ground to get 14-0-14 VAC rails -- and if i can scare up another pair i'll try stacking the trafos in series for a true 14-0-0-14 output.

dave

 

[carlmart]

Apple ImageWriter IIs have an 80 VA 0-28 VAC transformer. It is very low profile and quite a chunk of iron. I'm going to try a virtual ground to get 14-0-14 VAC rails -- and if i can scare up another pair i'll try stacking the trafos in series for a true 14-0-0-14 output.

A virtual ground circuit is good for low level signals. If you have a single supply and want to do a GC from it you should use the single supply version suggested in the datasheet, with the large output capacitor. Don't know about the sound quality, though.


Carlos

 

[planet10]

A virtual ground circuit is good for low level signals. If you have a single supply and want to do a GC from it you should use the single supply version suggested in the datasheet, with the large output capacitor. Don't know about the sound quality, though.

That was my original thot, but a guru friend suggested i try it anyway, i do want to avoid the cap.

If i have to i'll just have to double up (but will have to figure out how to fit 2 in each chassis)

dave

 

[planet10]

Here is a pic... it weighs 1.8 kilos but is only 43 mm high.

dave

 

[jleaman]

now the real question is.. DId he remember to bring up the PCMCIA network card for me. : O )



i stli have 3 chips here with your name on them dave..

 

[jackinnj]

A virtual ground circuit is good for low level signals. If you have a single supply and want to do a GC from it you should use the single supply version suggested in the datasheet, with the large output capacitor. Don't know about the sound quality, though.

Carlos

The reason that a "virtual ground" may not be satisfactory is that the supply has a somewhat higher impedance than "zero" --

The single supply version should be "ok" -- but if you could lay your hands on two transformers you could connect the primaries in series -- in this way the line voltage would be split between them, and the output would also be halved.

 

[carlmart]

if you could lay your hands on two transformers you could connect the primaries in series -- in this way the line voltage would be split between them, and the output would also be halved.

That would be much better, also having then a 160VA transformer.


Carlos

 

[planet10]

That would be much better, also having then a 160VA transformer.

Actually because the pimaries are running at 55V it would be a very understressed 80 VA. I've scored 2 more (at least i have the IW to dissassemble). Will have to see if i can get 2 trafos in the boxes i was going to use for chassis (really nice 1st gen SuperMac SCSI cases)

dave

 

[bzdang]

Low profile transformers

Don't know anything about them but a friend has been looking for single-rackspace toroids so....

http://www.powertronix.com/html/low_profile_transformers.html

 

[troystg]

Hi-

Now those are neat and funny.

Looks like a regular torid that was squashed.

I bet they cost a pretty penny though.


Thanks,

Troy

 

[DaKi][er]

i'll share my experience in finding cheap toroidal transformers

from an electronics store over here which deals in 'junk', in their barigain corner here they have 250va dual 9v secondary toroidals for $25 aus (~17usd) each which is a real bargain seeing that the next best thing here is 300va things for nearly $80 from the local electronics stores

An externally hosted image should be here but it was not working when we last tested it.

i picked up 3 of these, and run 3 secondaries in series for 2*27v @750va thats going to run my 8ch gainclone im working on at the moment and im sure they could handle more than the 250va they are rated for

now only to find some big caps (+100mf) to go before the voltage regulators

 

[Chris8sirhC]

Out in the garage today, i came up with another cheap, solid metal enclosure. Just find a used pot, like you cook with. The lid comes off easily too.