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fubar II dac - op amp rolling - Page 3

post #31 of 45
10/4/07 at 11:40pm
wait 'til you try opa627!
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post #32 of 45
10/5/07 at 7:41pm
would you have a spare pair? lol
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post #33 of 45
6/27/08 at 11:36pm
I bought a Fubar and Big Joe for my new k1000 system and I noticed that compared to my Entech 205.2 with the Big Joe, the bass seems way too light, almost K501 light! I plan on switching the OP amps around. I've just purchased the OPA627, AD827AQ and OPA2107. Is there any other OP amps any of you guys recommend?
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post #34 of 45
4/5/09 at 3:54am
sorry to bump an old thread

but there isn't a point to starting a new fubar II thread.

I need help with this because I have no idea how to perform any of this.

I'm going to get dual 627s, is there anything I should know?

is this an easy process?

Anyone else made any other adjustments?
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post #35 of 45
5/9/09 at 3:28pm
Thread Starter 
Hi roker,

You need a brown dog adapter to mount the 627s on. These OP amps are single channel chips, where as the stock 2604 is dual (thus, the 2 in front of the p/n).

You can buy one of these from here:

Single-to-dual Op-AMP Adapter - DIP version (p/n 021001)

I recommend picking up a couple just in case one gets messed up or something.

You'll need to solder the 627s into this adapter with no more than a 25W iron and be mindful of the orientation of the chip into the mounting socket. If you get them backwards, they will certainly fry as well as possibly doing damage to the Fubar. When soldering, do not allow the iron to remain at the solder joint for any longer than 3 seconds at a time. Longer durations will cause permanent damage to the chip. If you don't get it right the first time, let it cool (the chip), and then move on to a different pin. You can come back to it later.

It might sound a little scary at first, but it's actually rather straight forward and good results can be achieved with a little patience.

If you have doubts about your soldering skills, pick up a perf board with copper solder rings from Radioshack and practice soldering .22 gauge solid core wire into the vias (holes).

Good through hole solder joints should look like these:

http://curiousinventor.com/images/ho...mples_good.jpg

If you have more questions I'll try to answer them.

Z
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post #36 of 45
5/9/09 at 3:45pm
thanks for the bump
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post #37 of 45
5/9/09 at 4:03pm
can I just buy them premounted to avoid soldering anything?

Cimarron Technology, Inc. - Pre-Mounted Components
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post #38 of 45
5/9/09 at 4:23pm
Thread Starter 
Not that I'm aware of.

I saw some dual to mono socketed brown dogs on ebay, but I'm unsure of the pin configuration. It may not be what you're looking for.

Anybody else care to chime in?

Otherwise, I imagine one of us DIYers would happily perform the work free of charge for you.
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post #39 of 45
5/9/09 at 5:05pm
You had them in your link roker:
Two Pre-Mounted OPA627AU Op-amps on 020302 Adapter (p/n OPA627AU-020302S)
2 x OPA627 soldered on a 2 x single to dual browndog. I didn't read the entire thread, but that seems to be what you are looking for (replace a stock dual opamp with single opa627s in a DIP 8 format)?
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post #40 of 45
5/9/09 at 5:16pm
Thread Starter 
I missed the link for some reason =P

Edit: Hmm, that does not appear to be what he needs.

The op amp in the Fubar is a dual channel 8 pin part. Two separate op amps will do him no good.

Yes, there are two op amps in the Fubar, but only one is useful for tweaking purposes. The DC servo should be left alone.
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post #41 of 45
5/9/09 at 11:21pm
The part I linked replaces a single dual DIP-8 opamp with a pair of single OPA627s, so it appears to be exactly what he needs. Assuming the opamp form factor in the Fubar is a DIP-8 package.
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post #42 of 45
5/9/09 at 11:50pm
Thread Starter 
So it does. I just skimmed over the details.

Sorry for the confusion roker!

You can purchase the whole assembly and replace OPA2604 in your Fubar.

Just make sure pin one of the adapter goes to the notch and you're good.

Z
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post #43 of 45
8/19/09 at 10:30pm
so how does the current fubar 2 sound? Has anyone heard it? It says they come with the National Semiconductor LM4562
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post #44 of 45
8/19/09 at 11:19pm
The OPA627 have been used with great success for audio for a long time and many consider them one of the best audio opamps available. There are others you may also like, look around and ask questions. Opamp rolling gets to be a hobby all by itself before you know it.
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post #45 of 45
11/14/11 at 5:00pm

Sorry to dig up an old thread... but I'm trying to figure out what sockets are what on the Fubar II. The socket designations on my board are U4 and U6. Can someone tell which is the DC servo and which is the LPF? Thanks for any help!

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