don't use 4ohm nor 6ohm nor 4 to 8ohm speakers with the 25Vac transformer.
Only use 8ohm or higher @ this supply voltage.
You may need a bigger heatsink with the higher PSU voltage.
I use a variety of speakers but my favorites are Acoustic Energy AE1s.
They are tiny and roll off the bass @ ~ 60Hz and yet I can easily hear the difference in changing the input filter from 90mS to 10mS and by careful comparison the 90mS sounds better than 30mS.
Yet, these filter frequencies are way below what the speakers should be capable of reproducing. 10mS=16Hz, 30mS=5Hz, 90mS=1.8Hz.
Only use 8ohm or higher @ this supply voltage.
You may need a bigger heatsink with the higher PSU voltage.
I use a variety of speakers but my favorites are Acoustic Energy AE1s.
They are tiny and roll off the bass @ ~ 60Hz and yet I can easily hear the difference in changing the input filter from 90mS to 10mS and by careful comparison the 90mS sounds better than 30mS.
Yet, these filter frequencies are way below what the speakers should be capable of reproducing. 10mS=16Hz, 30mS=5Hz, 90mS=1.8Hz.
Cheers Andrew.
The stock trafo has 24v secondaries. Would I be better off then sticking to that, or slightly less if i cant get one with 24v? Like 23/22v?
Regards the feedback cap, I'll try the mod you suggest as I have a load of lytics in different values. If I like what it does then I'll replace the cap with a better quality one of the favoured value.
Thanks as always for your input. 🙂
The stock trafo has 24v secondaries. Would I be better off then sticking to that, or slightly less if i cant get one with 24v? Like 23/22v?
Regards the feedback cap, I'll try the mod you suggest as I have a load of lytics in different values. If I like what it does then I'll replace the cap with a better quality one of the favoured value.
Thanks as always for your input. 🙂
if the cambridge has 28Vdc at the PSU then it doesn't have a 24Vac transformer. More likely it's 20 to 22Vac.
That's what I thought... it's something like 1.4x AC, so that doesn't add up.
22VAC secondaries are looking good then Mike.
Simon
22VAC secondaries are looking good then Mike.
Simon
Hello. CA chasis is 60mm height, so neither 300VA (60*110) nor 500VA (60*136mm) Trafo would be suitable 🙁
BTW, I found i-shop with Panasonic FM,FC,FK Caps and LM4562, and they all have very pleasant price, so I think NE5532 should prepare to get out off the amp 🙂
Mike. Thanks for SM.
P.s. sory for delay with our deal. Have some little problems in university and have no free time to go at Bank.
BTW, I found i-shop with Panasonic FM,FC,FK Caps and LM4562, and they all have very pleasant price, so I think NE5532 should prepare to get out off the amp 🙂
Mike. Thanks for SM.
P.s. sory for delay with our deal. Have some little problems in university and have no free time to go at Bank.
The 225VA should just go in.
Airlink 225VA 2 x 22v secondary
Stream,
Did you measure the chassis internally? In the maunual it says the chassis is 70mm high. Thats good you found that shop, Panasonic FC are great caps and dont cost too much. Use them all over the Power supplies and Im sure the amp will rock. For the opamp its a really goos idea to fit a socket. Then you can try other opamps. The LM4562 like good decoupling caps. You could get a pair of 10uF 50V BG N's for about 10 Euro I think.
Im going to mausure the chassis now, back soon.....
Mike.
Airlink 225VA 2 x 22v secondary
Stream,
Did you measure the chassis internally? In the maunual it says the chassis is 70mm high. Thats good you found that shop, Panasonic FC are great caps and dont cost too much. Use them all over the Power supplies and Im sure the amp will rock. For the opamp its a really goos idea to fit a socket. Then you can try other opamps. The LM4562 like good decoupling caps. You could get a pair of 10uF 50V BG N's for about 10 Euro I think.
Im going to mausure the chassis now, back soon.....
Mike.
Hi Mike,
I'm just thinking about this rebuild you are doing now.
This chassis size does not allow for everything you would like to accomplish. Have you decided to go nuts on this one and forget your optimum amp kit build?
Just curious.
-Chris
I'm just thinking about this rebuild you are doing now.
This chassis size does not allow for everything you would like to accomplish. Have you decided to go nuts on this one and forget your optimum amp kit build?
Just curious.
-Chris
OK.
Chassis 63mm high internally, the 300Va can just about go in if its potted in the middle and the potting allows space for the nut to sit blow the top of it.
A potted trafo like this would be necessary:
Measurements:
Roughly 115mm across.
63mm height
Its likeley that there is a tolerance in the size of the Airlink trafos so If I ask I might be able to find one @ 59mm high.
Airlink 300VA 2 x 22v secondaries.
Chassis 63mm high internally, the 300Va can just about go in if its potted in the middle and the potting allows space for the nut to sit blow the top of it.
A potted trafo like this would be necessary:
An externally hosted image should be here but it was not working when we last tested it.
Measurements:
Roughly 115mm across.
63mm height
Its likeley that there is a tolerance in the size of the Airlink trafos so If I ask I might be able to find one @ 59mm high.
Airlink 300VA 2 x 22v secondaries.
Hi Chris.
I still want to build a killer amp from scratch. Im looking at the 3 x LM3886 pcb at the moment with dual mono LM4562 preamp. I'd like to do an intergrated with relay input switching and LDR volume control.
Maybe I'm getting carried away. But since discovering the earlier metioned mod - using the channel LED's to control relays - Im optomistic that really good sounsd can be acheived. Having the switching ic out of the way would make other mods worthwile. Adding the new trafo isnt really difficult, but the relay thing will takle a lot more thought and planning.
Mike.
Hi Mike,
Should be interesting.
The power transformer change will not change anything unless you are causing the supplies to collapse right now. I have confirmed this myself, but the popular notion is that these changes miraculously improve the bass. I've even run amps from larger regulated power supplies. All that changed was the noise level, because all ripple was removed.
Just trying to save you some $$. At least enjoy yourself.
-Chris
Should be interesting.
The power transformer change will not change anything unless you are causing the supplies to collapse right now. I have confirmed this myself, but the popular notion is that these changes miraculously improve the bass. I've even run amps from larger regulated power supplies. All that changed was the noise level, because all ripple was removed.
Just trying to save you some $$. At least enjoy yourself.
-Chris
I have no considerations on cash. 😀
And this had no effect on the sound?
Has anyone else changed to a bigger trafo and not had a difference?
Sorry Chris, I just need more opinions to get a better idea. We all percieve differently....
Mike
Hi Mike,
No problem.
No, no difference in sound quality. Also, no difference in measured power output (except a tiny fraction higher with the reg supply that didn't droop under load).
The case is very simple. If you make a change that is supposed to improve the sound, you will hear a difference! Especially if the change was difficult and / or expensive. You want to know the truth about your work? Ask a child or some women that have no stake in keeping you happy. Those are the only unbiased opinions you will get.
This is also why you will get varying opinions and many positive ones. Even people who have never tried this will sit in their armchair and insist they heard a difference!
Most people are completely unreliable when it comes to judging these kinds of issues. Too much comes from suggestion and expectation. One thing is for sure though, those who believe in this are in fact convinced this is true. They are not lying.
Anyway, just have fun. Enjoy.
-Chris
No problem.
No, no difference in sound quality. Also, no difference in measured power output (except a tiny fraction higher with the reg supply that didn't droop under load).
The case is very simple. If you make a change that is supposed to improve the sound, you will hear a difference! Especially if the change was difficult and / or expensive. You want to know the truth about your work? Ask a child or some women that have no stake in keeping you happy. Those are the only unbiased opinions you will get.
This is also why you will get varying opinions and many positive ones. Even people who have never tried this will sit in their armchair and insist they heard a difference!
Most people are completely unreliable when it comes to judging these kinds of issues. Too much comes from suggestion and expectation. One thing is for sure though, those who believe in this are in fact convinced this is true. They are not lying.
Anyway, just have fun. Enjoy.
-Chris
I got moderated 
Sig was too long... clogging up threads... 2-3 lines max they say!!! "The man" took me down!
So now I've gone to a statement about my religious beliefs.
Sig was too long... clogging up threads... 2-3 lines max they say!!! "The man" took me down!
So now I've gone to a statement about my religious beliefs.
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