Commercial Gainclone kit- building instructions

[AndrewT]

I think it is water in the joint that becomes the corrosion problem.

Other fluids may allow this electric effect. But I doubt the greases/oils and other non-conducting organics allow this corrosion. It may even inhibit corrosion.

 

[Joerytech]

After some search on the net I've put paste between the copper and aluminum

 

[lanchile]

To improve the bass you have to use a big power supply like the one Peter showed.😉

 

[Joerytech]

To improve the bass you have to use a big power supply like the one Peter showed.😉

I guess this is not to me because I'm very pleased with the overall performance of the amp

 

[Joerytech]

I've got a question.

At the moment I use Mission M52 speakers.
Some time ago I build different speakers:
Jack's Place - Vifa Basis 95 2.0

At that time I used hafler mono amps and it sounded great.

My friend that bought my speakers at that time but wants to sell them back to me.

I wonder if the amp I build now (LM4780 parallel) will be able to drive them with satisfaction.

 

[pbertino]

I'm interested in adding the optional snubber components to my 3875 classic.

But I'm pretty new to this stuff so my questions are dumb. Can someone who has done the snubberizing suggest the brand/type of ps caps? I see reference to a lot of 10,000uF and Peter Daniel shows a pic of 2 4,700uF. What "type" of caps are those? Is that a standard size?

Any suggestions would be welcome. And what other parts are required to snubber?

 

[Xerxes75]

Maybe this is a silly question.... but it is said that bigger caps can be put in parallel off the 1500uf ones (photo gallery thread). But i see a lot of builds with bigger caps on the rectifier board (with or without the snubber components) or is this just the same?

 

[AndrewT]

All amplifiers need High Frequency decoupling very near the main output devices.
They all need Medium Frequency decoupling somewhere close enough on the amplifier PCB.

The capacitors fitted by Peter Daniel fit the above requirements.
Don't change them. The amplifier NEEDs both HF and MF decoupling.

What you can experiment with is, adding main smoothing capacitance at the PSU rectifier.
This is ADDITIONAL capacitance.

 

[Joerytech]

With only 1500uf caps on the amp of P. Daniels amp I build the sound is really great, I know that according to many its impossible but even with the heavy reggae i like it still sounds great. I for sure support P. Daniels idea of how to build the perfect amp.

 

[Joerytech]

I've got a question.

At the moment I use Mission M52 speakers.
Some time ago I build different speakers:
Jack's Place - Vifa Basis 95 2.0

At that time I used hafler mono amps and it sounded great.

My friend that bought my speakers at that time but wants to sell them back to me.

I wonder if the amp I build now (LM4780 parallel) will be able to drive them with satisfaction.

Anybody any idea?

 

[Peter Daniel]

Take the amp to his place and check how well it drives those speakers.

 

[MagnumOpus]

Take the amp to his place and check how well it drives those speakers.

This amp is awesome. I have a pair of PSB Image B6 and they effing rock with this amp 🙂 It leaves nothing to be desired.

 

[Joerytech]

Take the amp to his place and check how well it drives those speakers.

Did you ever try the LM4780 parallel amp on those kind of speakers? And if yes, what was your opinion?

My idea is that with those quiet heavy to drive speakers the capacitance of your amp design might have trouble.

 

[Peter Daniel]

Never tried on such speakers. If I see speakers like those, I always recommend bi-amping

 

[MrOfficer]

Dear All,

I've a center tapped EI core transformer with 18 0 18 secondaries.

Also, have rectifier PCB from audiosector - I searched on the forum and added 4 diodes and 3 jumpers to use with CT trafo.

The issues I've are that I'm getting a lot of variance in DC voltages.

 

[Mark Whitney]

Where is the CT connected to the board? you need to connect + 0 -

 

[Skwiddy]

Welp...I just finished my temporary wire-up of my amp kit and I'm experiencing an odd issue. But let me take one step back first. When I first powered her up the wire coming out of V- over-heated and went up in smoke immediately. I believe the culprit was a stray ground wire touching the V- tab on the amp-board. I rectified this issue and haven't experienced the problem since. The problem I am experiencing is that the power output from the amplifier is definitely low. If I had to estimate I would guess it's sounds about half as powerful as it should be. I've tried it on several pairs of speakers and at full volume the sound is still about as loud as a normal conversation (there is no distortion)

Some measurements

(Oddly) Led tabs are outputting 33 volts dc
Pg - v - 33 volts dc
Pg + v + 33 DC
Speaker Terminals .013 DC


Thoughts? I'm stumped. Did I miss something while assembling? Did the shorted wires damage something?

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

 

[barry.childs]

Did it work OK between faults. Sounds to me like the short has blown the ICs.

 

[Skwiddy]

Did it work OK between faults. Sounds to me like the short has blown the ICs.

It was playing music (at the same low volume) when it shorted out. If the IC's are blown would they still be capable of playing music distortion free?

 

[barry.childs]

It was playing music (at the same low volume) when it shorted out. If the IC's are blown would they still be capable of playing music distortion free?

Unless the IC's are Chinese! or you have a wrong value resistor somewhere.