Bridging an amplifier

Korppi

Member
2018-08-01 12:02 pm
Hello,

I have Genelec 1028a old power amplifier.

It uses two separate channels with Philips bdv66d and bdv67d transistor pair in each channel. It has two separate input level/ volume control for both channels.

Its rated also for 4 oHms. Only one toroidal transformer for both channels. Balanced inputs. Woofers i want to drive are 8 Ohms.

Its really really basic design, no bridging mentioned in the back of amp.

Sound is excellent, but i want more power.

Is this amp suitable bridging and what is the best way?

Balanced xlr connection is coming in from Rme dac.

I am newbie with this stuff
 
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Bridging (if possible - it is not always so) will give you theoretically double the power, but not in stereo - only mono. So for stereo you would need two of the amplifiers. Do you have two amps?

But, doubling the power may not do as much as you think - a doubling of power only allows a very few db extra volume - and chances are that you are not using all the volume available anyway - if you were you would be blowing your ears apart.
 
But, doubling the power may not do as much as you think - a doubling of power only allows a very few db extra volume

Yep, 3db, barely audible.

To get twice as loud you need to go up 10db which is 10 times the power.

I did a search for the amplifier ... Genelec 1028A

It's specified as 120 watts per channel... which with any reasonable speaker should be more than enough power.

I noticed there are RCA jacks on the back so you could bridge it with a simple one transistor phase splitter.

Or if you are driving a pair of woofers, just use an RCA Y connector and run one woofer on each channel.
 

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Korppi

Member
2018-08-01 12:02 pm
The system is 3 way active computer based crossover/ dsp with jriver, rephase,rew ..

I quess i could run the phase splitter with the convolution file in jriver?

System: computer --》 rew/jriver -- 》rme ufx six out -- 》 amps 6 channels-- 》3 way stereo

Rme has enough outputs, for example
- 4 outs for two bass woofers
- equals 2 outs per one bass woofer,
- one of those two is phase turned

Is it possible?
 
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Shouldn't it deliver twice the voltage and 4 times the power (assuming the power supply can deliver the current)?

That's a 6db gain.


When you bridge the load impedance may have to double - each amp sees half the impedance. Thus two 4-ohm capable amps bridge to drive an 8 ohm load. If you tried to drive 4 ohms bridged then each amp sees 2 ohms and is overloaded. Two amps can only give twice the max power of one of them.