Pioneer PL-990: You can add a PreAmp bypass Switch

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danm5000
Posts: 4
Joined: 15 Jul 2010 13:58
Location: Vermont, USA

Pioneer PL-990: You can add a PreAmp bypass Switch

Post by danm5000 » 14 Feb 2016 23:39

You can add a PreAmp bypass switch to the Pioneer PL-990.

Whether you want to or need to is an entirely different question.

A colleague gave me a Pioneer PL-990. Its internal amplifier is based on TI-DRV602.

I thought that this Pioneer PL-990 would be perfect to satisfy the out of the blue recent request from my 16-yo wanna-be hipster daughter: "Dad do you have an extra turntable that I can have in my bedroom?" Sure I do have one, and even more so now! Believe me, there is a LOT more to that story.

Anyway, while doing basic research on this model online I came across some recurring themes:

1. This model has a built-in preamplifier.
2. This model does NOT have a switch to bypass the built-in preamplier.
3. This model CANNOT be fitted with a switch to bypass the built-in preamplier.
4. This model isn't a particularly good turntable, but it isn't a spectacularly bad one either.

All of the above came with various side-discussions about all kinds of things, as you can imagine.

I was then quite surprised to discover upon opening up my new PL-990 what appeared to be all of the provisions for a PreAmp bypass switch except the actual switch itself.

So... to prove the internet wrong, I added a PreAmp bypass switch to this unit, and took some photos to document the process. In addition to the switch, I had to remove 2 jumpers from the PCB and add 2 jumpers to the PCB.

I can't use this site to share a pdf of the project, but if anybody is curious you can contact me and I will tell you where to find the file.

The attached photo is before/after my switch was installed, it can be done fairly easily if that is what you want.
2016_02_yy1-001.jpg
Some photos of the project, ask for more details.
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avelec
Posts: 1
Joined: 19 Jan 2018 05:58

Re: Pioneer PL-990: You can add a PreAmp bypass Switch

Post by avelec » 19 Jan 2018 21:40

Hi danm5000, can you please point me to the howto pdf for bypassing the preamp on this PL-990. Thanks in advanced! Sam

Woodywood
member
member
Posts: 77
Joined: 06 May 2018 20:53

Re: Pioneer PL-990: You can add a PreAmp bypass Switch

Post by Woodywood » 06 May 2018 21:03

Hope your are still here!
Was wondering if it would be easier to simply disable the amp on the board ; or could you send me the PDFs or link ?
Thank you
Newbie

Yohonis
Posts: 2
Joined: 18 Jun 2018 22:41

Re: Pioneer PL-990: You can add a PreAmp bypass Switch

Post by Yohonis » 18 Jun 2018 22:51

This is awesome! Thanks for making this thread danm5000! I hope I can get my hands on the pdf so I can do this mode.
Cheers,
Yohonis

danm5000
Posts: 4
Joined: 15 Jul 2010 13:58
Location: Vermont, USA

Re: Pioneer PL-990: You can add a PreAmp bypass Switch

Post by danm5000 » 11 Jul 2018 00:00


Yohonis
Posts: 2
Joined: 18 Jun 2018 22:41

Re: Pioneer PL-990: You can add a PreAmp bypass Switch

Post by Yohonis » 11 Jul 2018 00:12

Your instructions worked like a charm. The board on my PL990 was a bit different but with your instructions I was able to get the bypass switched installed. Cheers!

Bohlja84
United States of America
Posts: 1
Joined: 12 Feb 2019 01:53

Re: Pioneer PL-990: You can add a PreAmp bypass Switch

Post by Bohlja84 » 12 Feb 2019 02:01

Can you upload the pdf again. I'm new to this site and would really like to upgrade my pl990 but says the pdf is out of date. Thanks.

rvcasa
Australia
Posts: 2
Joined: 09 Mar 2019 14:47

Re: Pioneer PL-990: You can add a PreAmp bypass Switch

Post by rvcasa » 23 Mar 2019 10:31

danm5000: I'm lost for words, you're a genius! A big thank you for sharing!

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