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A Very Compact Hybrid Amp - Page 57

post #841 of 2213
Quote:
Originally Posted by holland View Post
tacitapproval. My 2nd build is having some issues as well, and I'll be looking at it. Can you measure the DC offset, and keep an eye on it. What I mean is power it on, measure the DC offset (before the e12 if you can). Watch both channels or find the one that is tripping the e12.

What I am finding with mine is that the DC offset climbs with time, on the right channel. It bounces around, albeit slowly, but it is significantly higher than the left. The left is at a few mv at most.

I was just wondering if your problem is similar.
Once I get it back to the state it was in, assuming I can, I will measure the offset.
post #842 of 2213
Thread Starter 
There is no heater voltage from the heater supply.

My first guess would be to check all of the connections in the supply and the continuity of the chokes. They should have very low resistance across their leads.

If the chokes are good the switching reg has probably burnt out. Why I don't know. Did you initially put your diodes in backwards or was that someone else? I'm losing track.
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #843 of 2213
Quote:
Originally Posted by runeight View Post
If the chokes are good the switching reg has probably burnt out. Why I don't know. Did you initially put your diodes in backwards or was that someone else? I'm losing track.
heh..that was me Alex..had D4P in wrongly..Q1P is burning up, making R7S burn like an LED into ash..


Also having problems with the E12 on my other board. getting OR->SG, OL->SG as 2.5volts and OG-> SG at 1.5volts.

All other voltages on this board checks out though. The E12 trips within 2 seconds but the voltages are off at the output.
post #844 of 2213
The chokes are good. I guess I need a new ICH.

I am losing track of all the problems I have had as well... But, no, I didn't put the diodes in wrong. I guess the ICH got shorted somehow, in all the taking apart and poking and prodding I have done. Could it take out a wallwart with it?
post #845 of 2213
Thread Starter 
Oh yeah, I remember now. You may have had some fine wires on the top of the board.

The switching reg could possibly take out the wall wart if it is causing too much current draw. There may be other components that are bad too, but given the design of this supply, I would say that they are ok.

You might want to check all of the diodes in the heater rectifier just to be sure.
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #846 of 2213
Ok, I will check the diodes and replace the regulator.
post #847 of 2213
I would also check all the solder pads on the bottom of the board. Some of the pads are very close together and may touch, especially near Q4E/Q5E.

And do all testing before casing it. I mounted the fuse holder in the back panel and soldered that to the two switch points, and tested the board before wiring the front I/O and pot for HT+ and OG and offsets.

I can say however that all 5 of my builds worked first time, so the design definitely works! Just have 2 left to fully case up now.
post #848 of 2213
Alex, On my board, I removed the regulator, replaced Q1P and Q2P and turned on the amp.

Q1P is not burning out. So the problem is not with the power supply it seems.

R7S has burnt out twice now along with Q1P. Perhaps something is up in the splitter circuit.
What do you make of R7S burning up?
post #849 of 2213
Quote:
Originally Posted by TimJo View Post
What kind of time frame are you seeing typically?
about 5 mins. I've replaced all my transistors in the right buffer and haven't timed it, but it does still go up in a small bouncy way and after a certain point of time it starts to bounce in larger steps. feel free to PM me as I figure it'll take me another week before I can get back onto this. I think I need to get this on my scope. I'm still away and I've completely lost all sense of time (vacation mode).
post #850 of 2213
Got my kit from wiatrob and looking to spend some time building it this week, however before I start welding parts on the board do I need any heads up?

I know nux had already built like 20 of them but just wanted to make sure
post #851 of 2213
Quick update:

I have my production board running now...turns out it was a stupid mistake of me forgetting to install R9S...popped that in and its making music.

Now the last of the proto boards remains.going to take quite a bit of surgery..gonna get to it tomorrow.
post #852 of 2213
Quote:
Originally Posted by nux View Post
< snip >
I can say however that all 5 of my builds worked first time, so the design definitely works! Just have 2 left to fully case up now.
That's great... This would support Alex amending the line In every instance during the prototype phase where the builder has put the right parts in the right places with the correct orientation the amp has come alive on first power up to include production PCBs

And its great we have another helper... Five CTHs... Wondering if some are gifts or may we see a couple up for sale? I know there are a few that want a CTH but are not builders...
post #853 of 2213
Quote:
Originally Posted by cfcubed View Post
And its great we have another helper... Five CTHs... Wondering if some are gifts or may we see a couple up for sale? I know there are a few that want a CTH but are not builders...
Three are for friends, two for myself. May possibly sell one of mine when I'm done trying tubes out to cover some costs, as it was going to be for another person but they pulled out.
post #854 of 2213
All- I'm out of town for a week so if anyone needs spares it'll take a bit of time. The first set of custom panels showed up in The mail minutes before I left. Thy look great.

I'll get some pics posted when I return. Good luck with your builds...
post #855 of 2213
Thread Starter 
Quote:
Originally Posted by nux View Post
Three are for friends, two for myself. May possibly sell one of mine when I'm done trying tubes out to cover some costs, as it was going to be for another person but they pulled out.
nux, I am amazed that you built five of these. You must have a steady hand and a great deal of patience.

So, how do your friends like them?
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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