Need some help (Philips 7871, Audiocontrol C101, BGW 410

[StephenNJ]

Good Morning, I am brand new here today, and a hobbyist, hooking up a stereo rig for my home office with some nice equipment I have assembled.

Here is the core gear.
#1. My lovely Philps Receiver 7871 (basically in New Condition) just a cool unit
#2. AudioControl C101 Equalizer
#3. A really nice BGW 410 amplifier.

There is no preamp out on the 7871, I have photos for front and back of the receiver, below.

My speakers, are an old set of EMI's, NEAR, and Warfdales

So what is the best way to set this up, I would like (if possible) that I could adjust volume from the receiver, now I can only adjust volume with the controls on the front of the BGW Amp for right and left channel. I'd rather not adjust the volume to listen to the unit through the BGW Left and right levels.

There has to be some better way to do this, and I'm sure you are laughing at me for setting this up more. Thanks to Reverb and US AudioMart for the hosted images, but my gear is much cleaner

 

[StephenNJ]

This is the gear as it is installed now...

 

[StephenNJ]

Thanks, any suggestion about how to hook it up better such that the volume control on the Tuner would act as the Preamp?

 

[StephenNJ]

Nice

I appreciate the "nice" comment.. .it sounds better than it looks... but it looks cool.... I love the BGW amp, and the EQ looks like the whopper from WarGames...

 

[StephenNJ]

I appreciate the "nice" comment.. .it sounds better than it looks... but it looks cool.... I love the BGW amp, and the EQ looks like the whopper from WarGames...

 

[StephenNJ]

https://www.youtube.com/watch?v=iRsycWRQrc8

 

[jheu02]

You really can't do what you want UNLESS you add your own Preamp Out Main In jacks to the rear panel. Someone else would have to check fully, but looks like you should be able to tap either before or after R301/302. I'm not sure which side of the resistor though as I'm not sure if it's part of a filter network in combination with C301/302. The fact that both cap and resistor are in the "300" series on the schematic (as well as the rest of the power amp portions) lead me to believe that you would run wires from the junction of R301/R247 and R302/R248 to RCA jacks you install and label Pre Out. Then, from the other set of jacks you instal that are labeled Main In, run wires to the legs of the resistors you desoldered (R301/302). Don't know whether this is at your skill level or not, nor whether it would be better to run them on the trace side or component side of the board. It will all depend on where you can find room on the chassis to mount the RCA jacks. Alternatively, if you want to remove the low and high cut filters and the switches the signal runs through, you could tap off just after the balance pot out to the pre-outs, and then bring the main in wires as above to the legs of R301/302.

Personally, I'd just see how the 7871 sounds. I have a 7851 I rebuilt and it sounds great. Not sure you need 200wpc of the BGW for a home office, but to each his own.

 

[Catmanboo]

The amp not needed with that receiver, since receivers are basically all-in-one-package units. A tuner, however, is just a tuner, no preamp (usually) or amp in the package. As you noted, no pre-out/main amp-in capability on your receiver (no, it ain't just a tuner), so I'd just use that. I'm listening to my 7961 right now, it's perfectly adequate for the task, but I added outboard heatsinks , since Philips saw fit to use the back panel for a sink, nothing with fins in that thing. It gets WAY hot when I run it hard, but ymmv. Keep an eye on that.
Well, pics aren't the clearest, but the only thing on back of this thing that belongs there is the black plastic cover on the transistors. Everything else is added on by me to radiate heat from the back panel.

 

[StephenNJ]

You really can't do what you want UNLESS you add your own Preamp Out Main In jacks to the rear panel. Someone else would have to check fully, but looks like you should be able to tap either before or after R301/302. I'm not sure which side of the resistor though as I'm not sure if it's part of a filter network in combination with C301/302. The fact that both cap and resistor are in the "300" series on the schematic (as well as the rest of the power amp portions) lead me to believe that you would run wires from the junction of R301/R247 and R302/R248 to RCA jacks you install and label Pre Out. Then, from the other set of jacks you instal that are labeled Main In, run wires to the legs of the resistors you desoldered (R301/302). Don't know whether this is at your skill level or not, nor whether it would be better to run them on the trace side or component side of the board. It will all depend on where you can find room on the chassis to mount the RCA jacks. Alternatively, if you want to remove the low and high cut filters and the switches the signal runs through, you could tap off just after the balance pot out to the pre-outs, and then bring the main in wires as above to the legs of R301/302.

Personally, I'd just see how the 7871 sounds. I have a 7851 I rebuilt and it sounds great. Not sure you need 200wpc of the BGW for a home office, but to each his own.

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Thanks.. it does sound ok, but it sounds much better with the amp, not for being "loud" but the whole sound is better. The room is bigger than most home offices 14 by 24......

The amp not needed with that receiver, since receivers are basically all-in-one-package units. A tuner, however, is just a tuner, no preamp (usually) or amp in the package. As you noted, no pre-out/main amp-in capability on your receiver (no, it ain't just a tuner), so I'd just use that. I'm listening to my 7961 right now, it's perfectly adequate for the task, but I added outboard heatsinks , since Philips saw fit to use the back panel for a sink, nothing with fins in that thing. It gets WAY hot when I run it hard, but ymmv. Keep an eye on that.

My 7871 has a big heat sink on the back of it? between the speaker connects see photo I borrowed below, it shows it clearly. Where did you put and get the outboard sinks... or maybe I did not understand you.

 

[Catmanboo]

Thanks.. it does sound ok, but it sounds much better with the amp, not for being "loud" but the whole sound is better. The room is bigger than most home offices 14 by 24......


My 7871 has a big heat sink on the back of it? between the speaker connects see photo I borrowed below, it shows it clearly. Where did you put and get the outboard sinks... or maybe I did not understand you.

never mind, yours has proper finnage back there. Must be that Philips got wise after mine was made. I'll post a pic soon after I "make it presentable". Btw, these came out of the Fort Wayne, Indiana Magnavox TV plant, if I recall. Pop the lid off that, you'll see a lot of domestically-made componentry reminiscent of tv guts.

 

[Rama C]

You really can't do what you want UNLESS you add your own Preamp Out Main In jacks to the rear panel. Someone else would have to check fully, but looks like you should be able to tap either before or after R301/302. I'm not sure which side of the resistor though as I'm not sure if it's part of a filter network in combination with C301/302. The fact that both cap and resistor are in the "300" series on the schematic (as well as the rest of the power amp portions) lead me to believe that you would run wires from the junction of R301/R247 and R302/R248 to RCA jacks you install and label Pre Out. Then, from the other set of jacks you instal that are labeled Main In, run wires to the legs of the resistors you desoldered (R301/302). Don't know whether this is at your skill level or not, nor whether it would be better to run them on the trace side or component side of the board. It will all depend on where you can find room on the chassis to mount the RCA jacks. Alternatively, if you want to remove the low and high cut filters and the switches the signal runs through, you could tap off just after the balance pot out to the pre-outs, and then bring the main in wires as above to the legs of R301/302.

Personally, I'd just see how the 7871 sounds. I have a 7851 I rebuilt and it sounds great. Not sure you need 200wpc of the BGW for a home office, but to each his own.

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Hi, I have the same receiver that is totally dead. It blows fuse. Looks like you have the schematic for 7871. Can you please share the schematic?

 

[jheu02]

I have a 7851 not 7871.

 

[Rama C]

I have a 7851 not 7871.

Thank you. I found the same at Hifiengine.