[Earwax]

Over 40 people bought boards in the first group buy, but I didn't see that many post in the build questions thread.

How many have built an amp already? How hard was it to build?

 

[TrevorNetwork]

I finished mine quite some time ago. I'm in the process of building a second, completely maxed out one.

 

[zbuddah]

I bought the board from the first group buy but i haven't found the time to source/shop out the parts for it yet... I haven't even started on my subsonic mini gilmore board.

I have so little time and when I do have time I have no money!

 

[strohmie]

I have the boards 80% complete, the power supply about 50% complete, and will hopefully have it bench-test-ready by Thanksgiving.

 

[MisterX]

I had a pair of amps from the first group buy built within a week of receiving the boards.

Sourcing the parts before the boards shipped made it very easy to find them.

As far as how hard it was to build it goes:
It was nothing compared to matching the transitors....verifing the servo worked correctly and building the stepped ladders for the volume controls.

 

[rsaavedra]

I am 95% finished with my Dynahi. Just have to receive a power supply, wire it, do the DC-adjustment, and voila! The one power supply went bad and is still going through warranty repair at Condor. Incidentally I sent Condor an email today inquiring about the status, but haven't received a reply yet.

 

[Earwax]

Quote:

Originally Posted by MisterX I had a pair of amps from the first group buy built within a week of receiving the boards. Sourcing the parts before the boards shipped made it very easy to find them. As far as how hard it was to build it goes: It was nothing compared to matching the transitors....verifing the servo worked correctly and building the stepped ladders for the volume controls.

Which transistors need matching? How many extras would you suggest buying?

 

[amb]

Quote:

Originally Posted by Earwax Which transistors need matching? How many extras would you suggest buying?

As you know the Gilmore SS amps are all fully complementary designs. Ideally all transistors on the top half should match their counterparts on the bottom half. In addition, even though the dual-JFETs should be perfectly matched from the factory, in reality they are not. So picking from a batch would be good. Unfortunately, those 2SK389/2SJ109s are fairly expensive so that kind of limits how many one would buy...

 

[chillysalsa]

And how exactly would one go about matching the transistors?

Also, was there something I read about cutting a lead off one of them?

 

[amb]

Quote:

Originally Posted by chillysalsa And how exactly would one go about matching the transistors?

For the JFETs, you want to measure the Idss and try to find the best match between the two within the dual package, as well as between the N-channel and P-channel units. For the BJTs, you want to find the best match of the DC current gain (hfe) as well as the Vbe voltage drop, both while the transistor is operating near the intended collector current. It's a bit much to go into detail here but there are plenty of web resources that you could find just by searching.

Quote:

Also, was there something I read about cutting a lead off one of them?

I don't think so...

 

[MisterX]

Quote:

Originally Posted by Earwax Which transistors need matching? How many extras would you suggest buying?

For a single amp at least four extras.... they matched reasonably well from the factory but I had a couple that were way out in left Field and sent them back.

 

[chillysalsa]

So, to measure Idss of the JFETS, would this make sense:
Quote:

To measure IDss, just short the gate and source, connect the drain to ~9V, and measure the current from source to the supply return.

 

[PeterR]

Have finished populating four boards for weeks now, but haven't found any time to get on with it since...

 

[amb]

Quote:

Originally Posted by chillysalsa So, to measure Idss of the JFETS, would this make sense:

Yes, or you can bridge a resistor across where you have the ammeter, and measure the voltage drop across it instead. Compute the current using ohms law: I = V / R.

For P-channel, reverse the power supply polarity and do the same.