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wim 15th September 2004 05:40 AM

Pre-amp with Gainclone
I am going to build the Gainclone with Brian's boards (i already ordered them).

I want to use this gainclone in combination with the pre-amp MK II from Rod Elliot (project 88).

Will that give good results you think, or do i need to change anything on the gainclone or the pre?

Hope to hear from you.

dine1967 15th September 2004 12:35 PM

Iam using brian's GC with P88 and they seem to be fine. Just lower the gain on P88 and you should be ok.

wim 15th September 2004 01:16 PM

Thanks a lot Dinesh.

wim 15th September 2004 01:40 PM

By the way Dinesh, to what value do you advise me to change wich components?

dine1967 15th September 2004 07:12 PM

In P88, there are switches to adjust gain. You can play around with them to get the right amount of gain. No components to change ( if you are using Rode's PCB). Hope this helps.

wim 15th September 2004 07:22 PM

Thanks again!

moving_electron 18th September 2004 05:03 AM

I just completed a BrianGT Premium amp with my son and am listening to it with a project 88 preamp and am very happy with the combination.

I find that the preamp should be set for some gain to sound the best (at least switch 1 and 4 closed). For some reason it seems less detailed to me if switch 1, 2 and 3 are open.

I am currently using OPA2134 as the first op amp and OPA2604 as the second after trying some combinations. I added extra bypassing extra close to the opamps.

If you want to play around with bypassing very close to the op amps it is pretty easy to do this on the P88 board. Put 100nF caps between the V+ and V- on the opamps themselves, and put electrolytics and 100nf ceramic caps under the board from the supply pins to ground. It is a little nicer to do if you have the capability to drill small holes but I expect that they can be soldered to the copper without holes.

Even if you don't experiment with this extra close bypassing you should expect the P88 to sound very good to you with OPA2134 and your Gainclone. I have one preamp built this way and always enjoy listening to it.

I had to put 220pF caps in parallel with R8L and R8R as I was getting oscillation in one P88 I built. For good measure I put them at R3L and R3R also. Others do not seem to report a similar problem so perhaps it is the high RF in my local.

wim 18th September 2004 06:28 AM

Thanks for your detailed information. I am building a P88 at the moment.

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