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Paul Spencer

DIY audio: what are you building?

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Guest Muon N'
1 hour ago, misternavi said:

blast from the past

AMW acoustic labs - made in sydney on the 70’s - had it posted from NSW recently 

 

inductor with the thinest wire snapped off. looks like 33awg wire.

A19D2C55-02C3-4E6C-BA13-4E8246B53D99.jpeg

Wow! That's like tone arm wire.

 

If not just shunting to ground I have images of a watermelon being squeezed through a garden hose.

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34 minutes ago, RankStranger said:

 

I use the hardware volume control in my DAC, or else leave it all at 100% and adjust the volume further down the analogue chain.   I am not sure using an analogue control after the DAC will be of much benefit.

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4 minutes ago, aussievintage said:

 

I use the hardware volume control in my DAC, or else leave it all at 100% and adjust the volume further down the analogue chain.   I am not sure using an analogue control after the DAC will be of much benefit.

I have volume control in the moode interface or I could get off my butt and change the volume manually on the integrated amp but I have decades of muscle memory with IR remote controls and I have a good universal remote which is always to hand (notwithstanding kids losing it) so I thought this could work.

 

I’m currently using the moode volume but if I’m halfway through an album and the iPad has gone to sleep and all I want to do is tweak the volume up or down a bit without getting up, this is the simplest way I can think to do it.

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After 15 years of having this sitting in the shed and armed with the little audio knowledge I have (which makes me more dangerous) I thought I would have a go at this 1954 Ferris Super Seven car radio.

 

2144399945_DSC06334e.jpg.fbeddeb91e96a66691dcae32b3ca58e0.jpg

 

941732497_DSC06359e.jpg.4beb26fecc33841a97a16ed2e25a0ac0.jpg

 

988228326_DSC06358e.jpg.273a977e21fedb4c47d2ae8f1b9ee645.jpg

 

I cannot believe I found the schematic, parts list and valve specs on the net.

 

839112978_DSC06379e.jpg.5b6b7b8fb8ea40bac1fc0f8b73736c65.jpg

 

First power up brought on an undy change. No smoke but the vibrator was making a hell of a noise. Read up on these. Stripped, cleaned the points, reset the rubber cap and reinstalled. All good.

Second power up showed 6 and 12 volts where they should be but no high voltage. 

Finally followed the advice I had read on the net. Replace all paper caps.

A walk down to Jaycar (not sure if its a good or bad thing yet have a shop so close) and I had most replacements in hand.

 

1318227821_DSC06606e.jpg.c8afc9815fd5cf7a1c6a4da5ccbc7bc9.jpg

 

Not all are exact values but I can only go with what they had. So in they went.

Through good luck more than good management it actually works. I was stunned.

I replaced the screwdriver antenna with a slightly better one and I am getting 6 or so AM channels. There is still some background static and I don`t fully understand how to tune the IF transformers and some coils but for now its sounding pretty good.

 

On one of the car forums I visit a gentleman fitted a Bluetooth receiver to his 50`s valve radio so I followed his led and did the same.  

Like the caps in the radio there is some very suspect wiring and switching but I have it working.

 

21227922_DSC06601e.jpg.144847a2282f50ba8a7230f1fc8c8d47.jpg  

 

It probably took me longer to figure out how to get the Bluetooth on the phone to work than anything else. To me a phone is a phone.

So in the next couple of days its another walk to the shops for a box and a better switch and will tidy it all up a bit.

Apart from a Altronic`s valve pre amp kit I have had little to do with valves. 

It has been a steep learning curve with a lot of head (and a$$) scratching combined with the joy of listening to these old and new parts working together.

 

Tony

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I had one of those in my old FJ when when I first bought it, and it worked LOL. Then when I bought my EH, it had a clamshell rack for a Diamond Dot portable tranny, above the glove box, and my old man was able to get a brand new looking Diamond Dot radio to fit in it. Ah the good old days LOL. Good job mate. :)

 

Now in my old Troopy, I have a kenwood mechless, with dual USB inputs. The rear one has a 128GB thumb drive, via a lead and sitting in the glovebox, and the front one alternates between 2 X 64GB low profile drives... ah, better days LOL.

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On 30/01/2020 at 12:54 PM, RankStranger said:

I use a relay volume control. Biino volume attenuator. Zero noise. Easily better than any of the ldr attenuators, or potentiometer types  I've built.

 

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Thanks, Simon

 

I’ve had a bit of a google and could only find a link to a circuit board for sale with the name Biino. Is that the one?

 

how are you using it?

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1 hour ago, niss_man said:

I use a relay volume control. Biino volume attenuator. Zero noise. Easily better than any of the ldr attenuators, or potentiometer types  I've built.

 

Thanks, Simon

 

ive had a bit of a look and I could only find a pcb for sale under that name. Is that the one?

 

how are you using it?

Edited by RankStranger

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1 hour ago, niss_man said:

I use a relay volume control. Biino volume attenuator. Zero noise. Easily better than any of the ldr attenuators, or potentiometer types  I've built.

 

You have my attention too.

I've tried lots of LDRs, TVAs and passives and still am a long way from Nirvana.

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7 minutes ago, Red MacKay said:

You have my attention too.

I've tried lots of LDRs, TVAs and passives and still am a long way from Nirvana.

 

i believe nirvana are on spotify

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4 hours ago, RankStranger said:

Thanks, Simon

 

I’ve had a bit of a google and could only find a link to a circuit board for sale with the name Biino. Is that the one?

 

how are you using it?

https://www.audiopcb.de/boards/biino-volume-control/

Yep thats the one. He sells the pcb boards, relay, display and power supply boards unpopulated. You have to then buy the components and solder them yourself and then put them in a box. 

 

I use it as a volume/input control and then send the signal to my power amplifier. It is controlled by an arduino which also needs to be bought as well.

 

Simon

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15 minutes ago, niss_man said:

https://www.audiopcb.de/boards/biino-volume-control/

Yep thats the one. He sells the pcb boards, relay, display and power supply boards unpopulated. You have to then buy the components and solder them yourself and then put them in a box. 

 

I use it as a volume/input control and then send the signal to my power amplifier. It is controlled by an arduino which also needs to be bought as well.

 

Simon

Thanks. It looks really cool but probably a bit more than what I’m looking for. I did find some stuff about putting a volume relay on the Pi itself but I think it needs code which is currently above my pay grade. 

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5 hours ago, scruffy1 said:

 

i believe nirvana are on spotify

But Spotify is rubbish - no audio nirvana there.

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21 minutes ago, Red MacKay said:

But Spotify is rubbish - no audio nirvana there.

 

that's why i said nirvana are on spotify, not nirvana is on spotify

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Would the member who bought my chip (LM3886) amp please PM me. 

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Are these Class D amp modules getting smaller or am I imaging things.

 

This 100W stereo module (about 70+ into 8ohms).is to going into a 1U enclosure with PS. This is a repurposed enclosure where the last two attempts to make a low profile amp have failed. Not sure where to go if this doesn’t work. 
 

The modules are certainly cheap enough. This one supposedly uses latest technology to make it smaller, cheaper and better performing. 

A991557A-645B-44AF-AE58-956348C4A779.jpeg

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26 minutes ago, mwhouston said:

Are these Class D amp modules getting smaller or am I imaging things.

 

This 100W stereo module (about 70+ into 8ohms).is to going into a 1U enclosure with PS. This is a repurposed enclosure where the last two attempts to make a low profile amp have failed. Not sure where to go if this doesn’t work. 
 

The modules are certainly cheap enough. This one supposedly uses latest technology to make it smaller, cheaper and better performing. 

A991557A-645B-44AF-AE58-956348C4A779.jpeg

 

Yep, very tiny.  Which chip is that using?  I have a similarly rated one based on the older TPA3116 and I didn't think it sounded as good as my older TK2050 amp.  Still, that's being picky, it still sounds alright.

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13 minutes ago, aussievintage said:

 

Yep, very tiny.  Which chip is that using?  I have a similarly rated one based on the older TPA3116 and I didn't think it sounded as good as my older TK2050 amp.  Still, that's being picky, it still sounds alright.

This one. Cheap enough.

 

https://www.ebay.com.au/itm/400738354081?ViewItem=&item=400738354081

 

https://www.st.com/resource/en/datasheet/tda7498.pdf

 

 

Edited by mwhouston

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Good start. It will fit in a 1U. Here is the vision.

FBB74243-7421-4B53-B7F8-91AB4B54C82D.jpeg

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1 minute ago, mwhouston said:

Good start. It will fit in a 1U. Here is the vision.

FBB74243-7421-4B53-B7F8-91AB4B54C82D.jpeg

 

You have room to whack in a phono preamp and some switching and make it into a nice integrated.

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Quick question,  have you ever had one of those stick-on standoffs let go?  Looks like a nice easy way to go, instead of measuring and drilling.

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43 minutes ago, aussievintage said:

 

You have room to whack in a phono preamp and some switching and make it into a nice integrated.

Absolutely agree but there is only  one pair of inout RCAs and to make a true integrated (I feel) you would require at least one other input connection and a selector switch.  At this point it remains a power amp with an attenuator to set overall volume against the gain of a preamp.

Edited by mwhouston

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1 hour ago, aussievintage said:

Quick question,  have you ever had one of those stick-on standoffs let go?  Looks like a nice easy way to go, instead of measuring and drilling.

Yes all of the time at work. It is due to the fact that the adhesive dries out over time.

I would not recommend using them for any thing that has a substantial current flowing through it and definitely not on mains devices or in the vicinity there of. 

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