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 Post subject: Heathkit wa-p2 mono pre amp use
PostPosted: Dec Sat 02, 2017 4:46 pm 
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Joined: Jan Sun 06, 2013 2:14 am
Posts: 179
Location: Butler, PA
Hi all
If I have a stereo CD player can I use two of the above amps one for each channel to hear stereo?
Thsnks

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Dan W3DKY
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 Post subject: Re: Heathkit wa-p2 mono pre amp use
PostPosted: Dec Sun 03, 2017 1:27 am 
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Joined: Jun Wed 08, 2011 2:33 am
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Location: Ohio 45177
Of course, if they are working properly. And you don't mind handling two volume controls. Of course you need a power amp of some sort, or two Heathkit mono power amps, maybe! Or build a combiner containing a stereo volume control pot to avoid the PITA of adjusting the two channels.


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 Post subject: Re: Heathkit wa-p2 mono pre amp use
PostPosted: Dec Sun 03, 2017 4:18 am 
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Joined: Jan Sun 06, 2013 2:14 am
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Location: Butler, PA
Thanks but I don't understand why j would need a power amp? What wattage do the pre amps put out?

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Dan W3DKY
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 Post subject: Re: Heathkit wa-p2 mono pre amp use
PostPosted: Dec Sun 03, 2017 4:45 am 
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Joined: Feb Sat 12, 2011 2:29 pm
Posts: 425
Location: Fayette County, Pa
Preamps don't put out "Wattage", they boost the signal voltage but it is a high impedance not intended to drive a speaker. You could put a matching transformer on one and connect a speaker but the sound level would be slightly above a whisper. The power amplifier is intended to put some current behind it and drive a low impedance.


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 Post subject: Re: Heathkit wa-p2 mono pre amp use
PostPosted: Dec Sun 03, 2017 12:00 pm 
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Joined: Jan Sun 06, 2013 2:14 am
Posts: 179
Location: Butler, PA
Thanks that is really good to know. I always thought that it was a low wattages sent to a higher gain amplifier. What would be the cheapest mono power amps or a stereo power amp? Or would it be cheaper to buy another aa-181 I already have one.

If I want to use a CD player input which can I use?
Microphone
Phono magnetic
Phono ceramic
Tape

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Dan W3DKY
Butler, PA


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 Post subject: Re: Heathkit wa-p2 mono pre amp use
PostPosted: Dec Sun 03, 2017 6:06 pm 
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Joined: Feb Sat 12, 2011 2:29 pm
Posts: 425
Location: Fayette County, Pa
Without knowing the type output from the player it is hard to say. If the player is intended to directly drive a headphone or speaker you will probably need to run it through an attenuator first.

But assuming it has a line level output (most CD decks do) you would most likely have the best results with using the Tape Play input on the preamp. If that was to low (insufficient gain) possibly the ceramic phono input would work however equalization may be a concern. Both magnetic phono and microphone probably have too much gain and would be overdriven by the CD player


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 Post subject: Re: Heathkit wa-p2 mono pre amp use
PostPosted: Dec Sun 03, 2017 7:10 pm 
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Joined: Jan Sun 06, 2013 2:14 am
Posts: 179
Location: Butler, PA
The cd player is a Sony cdp-397 and the amp I just bought is a realistic sa-101
Could I tuner two wa-p2 through to the sa-101

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Dan W3DKY
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 Post subject: Re: Heathkit wa-p2 mono pre amp use
PostPosted: Dec Sun 03, 2017 8:31 pm 
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Joined: Feb Mon 04, 2013 6:55 pm
Posts: 545
Those are preamps, they cant drive a speaker or headphone. they are for amplifying tiny signals liek from a phono cartridge, and provising switchable imputs and tone controls, they are designed to be plugged into a power amp. These Heathkit preamps get power from the power amp, and dont even have thier own power supply.


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 Post subject: Re: Heathkit wa-p2 mono pre amp use
PostPosted: Dec Mon 04, 2017 1:54 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2054
Location: New Port Richey, FL, USA
The Realistic amp you have does not need a pre-amp, nor does the AA-181. So the WA-P2's you have would be of no use either way.

If you go with the Realistic, then you should be set to just plug in the CD player and you're off and running. If you want to go with tubes, then get another AA-181. I'd think the microphone input would work just fine.

Here's the thing with the WA-P2's. All amps are going to have a pre-amp and a power amp section. Most amps such as the two you have (the Realistic and the AA-181) have their pre-amps built in. The WA-P2 was a bit earlier on (1957), and Heathkit gave you a couple choices of the power amp side of things, but none were stereo. Having a stereo system didn't really get big until later. But that's why the WA-P2's have all the switches and controls, but no power cord. It does have an cord with an 8 pin plug on it (Octal plug). The power amp you would get to go with it, has the power cord, but no controls. You plug that octal plug into a socket on the back of the power amp, and that feeds the voltage supply from power amp to pre-amp. You also have to run an RCA cable between the two for the audio feed.

A good power amp to go with the WA-P2 is the Heathkit W-5M, though there are others as well. But no matter what power amp you choose, you will need two of them, and they aren't going to be cheap.

Here's a website that has manuals to lots of Healthkit items, which you might find useful. https://www.vintage-radio.info/heathkit/

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Michael


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 Post subject: Re: Heathkit wa-p2 mono pre amp use
PostPosted: Dec Mon 04, 2017 2:05 pm 
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Joined: Jan Sun 06, 2013 2:14 am
Posts: 179
Location: Butler, PA
Thanks Mike
I have both wa-p2 on eBay and I have the aa-181 on a variac at 70% no smoke all tubes lite.
I will put it on eBay today. What is a good stereo integrated amp vintage tube around 25 watts

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Dan W3DKY
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