That's a big clue. Check the speaker continuity and wiring. With the speaker connected (and the amp OFF) you should read something in the 4 to 10 ohm region (speaker dependent) if you read across R14 (the 1k on the output of the amp)
ACA pre amp selector switch
Hi, I'm building the stereo basic amp and haven't decided whether to build a preamp or build the bare amp but install an alps pot and selector switch (to change between two different RCA inputs) and make it into an integrated amp rather than just a power amp.
So, what selector switch would people recommend? either of above scenarios require a selector switch.
I'll need a 6mm shaft and a minimumof two inputs.
The last one I bought for a T Class amp had three or four inputs and I just needed two, but I'm not bothered about having too many.
The important thing is that it's good quality, so what are your preferences please?
Hi, I'm building the stereo basic amp and haven't decided whether to build a preamp or build the bare amp but install an alps pot and selector switch (to change between two different RCA inputs) and make it into an integrated amp rather than just a power amp.
So, what selector switch would people recommend? either of above scenarios require a selector switch.
I'll need a 6mm shaft and a minimumof two inputs.
The last one I bought for a T Class amp had three or four inputs and I just needed two, but I'm not bothered about having too many.
The important thing is that it's good quality, so what are your preferences please?
Make sure the binding posts are isolated from the chassis when not wired to the ACA's
I've read this on an audio blog, don't know how relevant it is to switch ground for something that's not really high end, but if you think it's really worth it...
[FONT=arial,][FONT=Arial, Helvetica][SIZE=-1]"Whatever types you consider as selector switches it must be break before make type, otherwise you will have two sources simultaneously connected while changing selection which would probably damage at least one of the sources as its output impedance will be much lower than the pre-amp input impedance. Maplin sell a series of 12 pole switches, the one suitable for stereo is configured as 4-pole 3-way. This limits builders to 3 sources, so you might be tempted to use the 2-pole 6-way version and simply common the negative connections as is common practice (groan)"[/SIZE][/FONT][/FONT]
[FONT=arial,][FONT=Arial, Helvetica][SIZE=-1]"Whatever types you consider as selector switches it must be break before make type, otherwise you will have two sources simultaneously connected while changing selection which would probably damage at least one of the sources as its output impedance will be much lower than the pre-amp input impedance. Maplin sell a series of 12 pole switches, the one suitable for stereo is configured as 4-pole 3-way. This limits builders to 3 sources, so you might be tempted to use the 2-pole 6-way version and simply common the negative connections as is common practice (groan)"[/SIZE][/FONT][/FONT]
Thanks for that insight Zen Mod, so I need a BBM I get that, but what about switching out the ground? And can you recommend a switch?
Many thanks
no , what I meant ( and probably wasn't clear enough ) is that you actually need MBB (shorting ) switch
if you can have enough sections to switch GNDs too , to fully isolate unused inputs , even better
if not , do not loose your sleep about that
best switches ......... use cheap Lorlin rotary switch or clone (still needing MBB ..... Lorlin is having letters S and NS to differentiate) , to actuate small Takamisawa relays for actual signal switching
RY-12W-K FUJITSU-TAKAMISAWA - Relay: electromagnetic | TME - Electronic components
if you can have enough sections to switch GNDs too , to fully isolate unused inputs , even better
if not , do not loose your sleep about that
best switches ......... use cheap Lorlin rotary switch or clone (still needing MBB ..... Lorlin is having letters S and NS to differentiate) , to actuate small Takamisawa relays for actual signal switching
RY-12W-K FUJITSU-TAKAMISAWA - Relay: electromagnetic | TME - Electronic components
Eagle eyes. Thanks KS for all the suggestions. I reflowed and added solder to all the connections and it worked. If I pull the board aain, I could double check the resistors. I added to the C1 connection.
Now to build the next one.
Thanks for the help everyone.
Now to build the next one.
Thanks for the help everyone.
Far from pretending to know more than you but, for instance, the DCB1 BOM in the store specifies a non shorting type for switching inputs. Is it a typo there then? Or maybe is there something else that drives the choice?
I'm just saying what's my experience ..... somebody else is certainly having opposite stance
I had pops and clicks while using nonshorting switch , directly or for relays control;
when I realized that switch is culprit , mounted shorting one and pops and clicks were gone
all that with preamp input absolutely DC free
I had pops and clicks while using nonshorting switch , directly or for relays control;
when I realized that switch is culprit , mounted shorting one and pops and clicks were gone
all that with preamp input absolutely DC free
In all the years I have been building audio equipment ,the conseces has been , you need a make before break switch on the input of an amplifier or you will have clicks and pops. I have never seen a failure due to using a make before break switch. I personally use the Glassware input selector Stereo selector switch
For the ACA 1.6 kit, a 200 mm x 80 mm x 40 mm heatsink is used for each board which amounts to 0.67 deg C/W. I would recommend at LEAST that, and preferably 0.5 deg C/watt. Even lower is fine too. Remember this is a single ended design, ie it is constantly biased at 1.45 A per board.
With 0.67 deg C/watt, I am measuring roughly 50- 55 deg C (average) on various areas of the enclosure with a room temp of 22 deg C.
Best,
Anand.
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) and was pretty similar in dissipation.It looks like it's a case of horses for courses, I have previously used BBM on my chipamp and "T" class amp, these switches being both with in circuit and no pops at all.
I merely wanted to get a view on preferences in general on what is considered to be the route forward, and that clearly seems to be in favour of MBB.
Zen Mod, I would like to select best route but my abilities don't stretch to adding relays or even know
what a veroboard is for that matter.