Tone controls for TDA2030 amplifier - UK Vintage Radio Repair and Restoration Discussion Forum

Neil Purling · 28th Aug 2015, 7:27 am

Having bought one of these cheap panels online I see it has only a volume control.

I have looked at a active tone control with a Baxandall network & op amp. The op amp type was not stated.
Has anyone made such a circut & can tell me what type of op-amp is used?

julie_m · 28th Aug 2015, 2:57 pm

Unless you are using the offset-null functionality (which is chip-specific), op-amps tend to be more or less interchangeable; they all aim at the same ideal, and the differences are in how they fall short of that ideal. Your choice is basically between a low-noise type such as the 5532, or a low-power type such as the 2904.

If you use a socket for the IC, it will be easy to compare a few different types.

Restoration73 · 29th Aug 2015, 4:23 am

At line level, any op-amp will do, e.g. 741, and assuming you only have a single dc
rail (+ and 0V) then needs to be biased, see fig 4.2.6 in this example
http://www.learnabout-electronics.or...plifiers42.php

Diabolical Artificer · 29th Aug 2015, 6:59 am

Mark Hennessy's site www.markhennessy.co.uk (interesting site BTW) has a schematic from an active speaker he built using a TDA2030 that has a buffer and tone control on it. See the second version, it has some changes made. The circuit is simple and easy to knock up.

I'm in the process of building it on breadboard but I'm using only the front end as I have some amplifier module's (TTC E1206 6 transistor Hi Fi audio amplifier) that use two 2SC793's for the OP transistors instead of the TDA2030.

Andy.

Neil Purling · 29th Aug 2015, 11:50 am

Re: Post #3 Figure 4.2.6 is what I was looking at making. DC supply will be +12V.

Restoration73 · 29th Aug 2015, 1:15 pm

741 op-amp (or TL071 or TL081) is ok at 12 volts, one further thing to note is if you are
using the same power supply as TDA2030, then the op amp +ve should connect to
the main 12 rail via a resistor say, 100 ohm, and connect a capacitor, say 100uF electrolytic, across the opamp +dc and ground ; this provides decoupling.

Tony

paulsherwin · 29th Aug 2015, 2:07 pm

Although pretty much all standard op-amps will work in a tone control module, some do produce better audio performance than others, so it's worth paying a pound or two more for a part specifically optimised for audio work. As has been said, there is a standardised pinout so you can experiment if you use an IC socket.

28th Aug 2015, 7:27 am	#1
Neil Purling Nonode Join Date: Jul 2005 Location: Hull, East Yorkshire, UK. Posts: 2,087	Tone controls for TDA2030 amplifier Having bought one of these cheap panels online I see it has only a volume control. I have looked at a active tone control with a Baxandall network & op amp. The op amp type was not stated. Has anyone made such a circut & can tell me what type of op-amp is used?

28th Aug 2015, 2:57 pm	#2
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Tone controls for TDA2030 amplifier Unless you are using the offset-null functionality (which is chip-specific), op-amps tend to be more or less interchangeable; they all aim at the same ideal, and the differences are in how they fall short of that ideal. Your choice is basically between a low-noise type such as the 5532, or a low-power type such as the 2904. If you use a socket for the IC, it will be easy to compare a few different types. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

29th Aug 2015, 6:59 am	#4
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,670	Re: Tone controls for TDA2030 amplifier Mark Hennessy's site www.markhennessy.co.uk (interesting site BTW) has a schematic from an active speaker he built using a TDA2030 that has a buffer and tone control on it. See the second version, it has some changes made. The circuit is simple and easy to knock up. I'm in the process of building it on breadboard but I'm using only the front end as I have some amplifier module's (TTC E1206 6 transistor Hi Fi audio amplifier) that use two 2SC793's for the OP transistors instead of the TDA2030. Andy. __________________ Curiosity hasn't killed this cat...so far. Last edited by Diabolical Artificer; 29th Aug 2015 at 7:05 am.

29th Aug 2015, 11:50 am	#5
Neil Purling Nonode Join Date: Jul 2005 Location: Hull, East Yorkshire, UK. Posts: 2,087	Re: Tone controls for TDA2030 amplifier Re: Post #3 Figure 4.2.6 is what I was looking at making. DC supply will be +12V.

29th Aug 2015, 1:15 pm	#6
Restoration73 Nonode Join Date: Jun 2013 Location: Surbiton, SW London, UK. Posts: 2,801	Re: Tone controls for TDA2030 amplifier 741 op-amp (or TL071 or TL081) is ok at 12 volts, one further thing to note is if you are using the same power supply as TDA2030, then the op amp +ve should connect to the main 12 rail via a resistor say, 100 ohm, and connect a capacitor, say 100uF electrolytic, across the opamp +dc and ground ; this provides decoupling. Tony

29th Aug 2015, 4:23 am	#3
Restoration73 Nonode Join Date: Jun 2013 Location: Surbiton, SW London, UK. Posts: 2,801	Re: Tone controls for TDA2030 amplifier At line level, any op-amp will do, e.g. 741, and assuming you only have a single dc rail (+ and 0V) then needs to be biased, see fig 4.2.6 in this example http://www.learnabout-electronics.or...plifiers42.php

29th Aug 2015, 2:07 pm	#7
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,970	Re: Tone controls for TDA2030 amplifier Although pretty much all standard op-amps will work in a tone control module, some do produce better audio performance than others, so it's worth paying a pound or two more for a part specifically optimised for audio work. As has been said, there is a standardised pinout so you can experiment if you use an IC socket.