Measure it and compare to similar size on the Antek site. Will get you close. If you weigh it and compare both, will get you even closer.
I doubt it is a 750w, the Dayton is a total 150w amp (75w / c), I think it's more of a 250w. As mentioned by bullittstang, compared the size with those on Antek.
Do you have a photo of the transformer label?
Yeah doesn’t sound right. Got that info from this review: [Review] Dayton Audio APA-150 - Class AB integrated amp/power amp - [English]
The label doesn’t mention VA or watts unfortunately but I’ll check later.
The label doesn’t mention VA or watts unfortunately but I’ll check later.
This is an error on the review of the link.
From what I see and to the eye, it is a transformer of 250va with 25v. For your needs, with 6 ohms speakers and a "normal" volume of a living room, the power will be very correct
HI, I have some remarks regarding L12-2 in my thread, the link is below:
https://www.diyaudio.com/forums/sol...v8100-v303-upgrade-l12-2-a-3.html#post6564255
https://www.diyaudio.com/forums/sol...v8100-v303-upgrade-l12-2-a-3.html#post6564255
Hi, I've been reading your thread, it's very interesting the changes to the Grundig.
I will order Wima 0.33uf to bypass all the condos feeding the outputs, as advisor by Calvin's. For the addition of the bias adjustment potentiometer, I will wait.
You changed the C8 by a Nichicon Muse, why a lower value than the original one, you had this value in hand ???
About the tone of the L12.2 in your Grundig. For me the L12.2 is very transparent, and I'm convinced that the preamp degrades the tone of the L12.2 a lot.
I tested mine directly at the output of my DAC, and now I use a DCB1 active buffer preamp.
Denbret, my observation is that for bias adjustment potentiometer it is better to be put from solder side, vertically. The access to it is much easier that from the front side.
I will order Wima 0.33uf to bypass all the condos feeding the outputs, as advisor by Calvin's. On Calvin's pages additional capacitors are 1uf and 100nF - where do you want to put those 0,33uF ?
On Calvin's pages C8 value is 220uF therefore I put my Nichicon Muse there, I have also Nichicon Muse 470uF/50V but they are big and don't fit there. Other bipolars are either non audio or non available.
Don't know if Grundig's preamp degrades the tone of L12-2, despite of an equalizer I am turning on basses and treble potentiometers in my Grundig. What makes me nervous is that small hum which appears already when I connect just a volume petentiometer plate - in Grundig there is seprate plate for peramplifier with power supply, defeat and mono switch, treble, bass and balance potentiometer and a separate plate with double volume potentiometer ( one for imput other for output), loudness switch and the motor. When I connect that plate without a connection to the main preamplifier one the hum appears. I should experiment with a different potentiometer etc. But that Grundig is in my cupboard and it's a lot of work to access to it. So when I listen music from loudspeakers it's OK and for headphones I have a separate amplifier.
I will order Wima 0.33uf to bypass all the condos feeding the outputs, as advisor by Calvin's. On Calvin's pages additional capacitors are 1uf and 100nF - where do you want to put those 0,33uF ?
On Calvin's pages C8 value is 220uF therefore I put my Nichicon Muse there, I have also Nichicon Muse 470uF/50V but they are big and don't fit there. Other bipolars are either non audio or non available.
Don't know if Grundig's preamp degrades the tone of L12-2, despite of an equalizer I am turning on basses and treble potentiometers in my Grundig. What makes me nervous is that small hum which appears already when I connect just a volume petentiometer plate - in Grundig there is seprate plate for peramplifier with power supply, defeat and mono switch, treble, bass and balance potentiometer and a separate plate with double volume potentiometer ( one for imput other for output), loudness switch and the motor. When I connect that plate without a connection to the main preamplifier one the hum appears. I should experiment with a different potentiometer etc. But that Grundig is in my cupboard and it's a lot of work to access to it. So when I listen music from loudspeakers it's OK and for headphones I have a separate amplifier.
@Peterpl
Thanks for your return. I take note for the potentiometer.
Here is what Calvin's wrote for capacitors:
Parallel to the Lytics C1/C2/C12/C13, that decouple the supply rails, small film or ceramic X7R caps may be soldered, e.g. MKS2 of Wima from 100nF to 1µF, with a lead pitch of 5mm throughole or 1812 in SMD style.
Regarding your grundig I can't help you. I have tested and I am currently listening to my L12.2 with a preamp and it is really good.
The L12.2 is very analytical and needs such a transparent preamp that can calm things down if I may say so. I will soon do a little review, I will test with other preamps as an entry.
Thanks for your return. I take note for the potentiometer.
Here is what Calvin's wrote for capacitors:
Parallel to the Lytics C1/C2/C12/C13, that decouple the supply rails, small film or ceramic X7R caps may be soldered, e.g. MKS2 of Wima from 100nF to 1µF, with a lead pitch of 5mm throughole or 1812 in SMD style.
Regarding your grundig I can't help you. I have tested and I am currently listening to my L12.2 with a preamp and it is really good.
The L12.2 is very analytical and needs such a transparent preamp that can calm things down if I may say so. I will soon do a little review, I will test with other preamps as an entry.
Hi everyone,
I'm still waiting for my parts for additions.
So far I have advanced in my preamp comparisons with the L12.2. Unlike other amps I own, the L12.2 plugged directly into the DAC output doesn't sound quite right.
This amplifier is very analytical and moreover it needs a good preamp to calm it down a bit and add a bit of warm tone. I started with the DCB1 Hotroad active buffer preamp from Salas. The sound is more balanced with a soundstage which is growing especially in depth. The bass as always with the DBC1 is powerful and dynamic.
But the L12.2 is not at its maximum, for having compared the DCB1 with my other Diamond buffer preamp, which has more definition and opening in the top, but oddly it sounds worse than with my other amplifiers .
I decided to replace the Diamond Buffer with an OP. So I installed a support for OP, so I took the opportunity to change the PSU by another which has a regulator.
In addition I changed the capacitors, the fake Elna by Nover HI-Ripple of higher capacity at the AC input, and Nichicon at the DC output.
Currently I put an OP Muses 8920, then I will test an ADA4898. I have several OPs like OPA16, 32, but not the 1656.
With the Muses 8920, the sound is very balanced and really musical. I have some pictures of the preamp.
I will then compare with the OP ADA4898, which is excellent and come back to you with a little review, when the PCBs have the bypasses. My speakers are very detailed and dynamic, the slightest change in the system is easily heard. So far the L12.2 is for me the current best offer for a low price.
I'm still waiting for my parts for additions.
So far I have advanced in my preamp comparisons with the L12.2. Unlike other amps I own, the L12.2 plugged directly into the DAC output doesn't sound quite right.
This amplifier is very analytical and moreover it needs a good preamp to calm it down a bit and add a bit of warm tone. I started with the DCB1 Hotroad active buffer preamp from Salas. The sound is more balanced with a soundstage which is growing especially in depth. The bass as always with the DBC1 is powerful and dynamic.
But the L12.2 is not at its maximum, for having compared the DCB1 with my other Diamond buffer preamp, which has more definition and opening in the top, but oddly it sounds worse than with my other amplifiers .
I decided to replace the Diamond Buffer with an OP. So I installed a support for OP, so I took the opportunity to change the PSU by another which has a regulator.
In addition I changed the capacitors, the fake Elna by Nover HI-Ripple of higher capacity at the AC input, and Nichicon at the DC output.
Currently I put an OP Muses 8920, then I will test an ADA4898. I have several OPs like OPA16, 32, but not the 1656.
With the Muses 8920, the sound is very balanced and really musical. I have some pictures of the preamp.
I will then compare with the OP ADA4898, which is excellent and come back to you with a little review, when the PCBs have the bypasses. My speakers are very detailed and dynamic, the slightest change in the system is easily heard. So far the L12.2 is for me the current best offer for a low price.
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Notes about l12
aliexpress web site some comments about l12-2;
Features:
L12-2 Amplifier Post Kit. The rigorously tested high-performance amplifier designed by LJM himself.
L12-2 is mainly based on monitoring, ultra-low distortion amplifier.
The first thing to note is that the lowest distortion does not mean that it may be the best speaker to listen to.
The L12-2 is more suitable for professional users who have a very high level of accuracy and detail.
It's not suitable to listen music??
aliexpress web site some comments about l12-2;
Features:
L12-2 Amplifier Post Kit. The rigorously tested high-performance amplifier designed by LJM himself.
L12-2 is mainly based on monitoring, ultra-low distortion amplifier.
The first thing to note is that the lowest distortion does not mean that it may be the best speaker to listen to.
The L12-2 is more suitable for professional users who have a very high level of accuracy and detail.
It's not suitable to listen music??
Not at all, it's the most musical amp I own.
If you connect the L12.2 direct to the output of a dac, for example, the sound is very detailed and lacks a bit of coloring ... that's what they want to explain in the description. It's very analytical and each instrument is placed precisely in the soundstage.
For this reason, adding an excellent preamp is essential.
Sometimes I plug in another amplifier that I have, and I quickly come back to the L12.2.
I love the musicality of this amplifier. I have a friend who ordered it too.
Idle current on my L12-2 bought from Aliexpress/Aiyima is about 1 Amp. That current is estimated from the power drawn from the wall; approx 55w for +/- 25v power supply. I bought two assembled boards and both are showing the same behavior. Input terminals are shorted for testing.
Aiyima title says that it is a Class A amplifier, and the description says that the quiescent current should be about 80mA.
Has anyone else experienced this issue?
Thanks!
Aiyima title says that it is a Class A amplifier, and the description says that the quiescent current should be about 80mA.
Has anyone else experienced this issue?
Thanks!
Are there two different versions of L12-2 (Class-A and Class-B)? Can they be switched between Class-A and Class-B by changing bias resistor?
I found these two items from the same seller:
Class-A (PCB Ver 4):
TZT 30W Class A Amplifier Board 2 Channel Power Amplifier Class A Amp Board A30 L12|Amplifier| - AliExpress
Class-AB (PCB Ver 3)
LJM Class AB L12 2 55V 120W Dual Channel Finished Audio Power Amplifier Board Amp|Amplifier| - AliExpress
This is the first time I am trying Class-A! I loved my Class-AB based on 2N3055 from Elektor and that had overall idle current of about 100mA per channel (IIRC).
I just connected this amplifier to my main speakers in my room, and they sound really good (for the time I could play this).
After removing the second transformer that I had in this setup for speaker protection, the power consumption from the wall for one channel is about 42W. Compare that with 4 channels of MyRef-C(LM3886) that draw about 30W total in my listening levels! Second channel keeps tripping the speaker protection (uPC1237). Looks like the DC offset on that board takes a little while to settle.
@OldDIY: Vbe is about 613mV for Q7 and about 632mV between collector and base.
I was using the following schematic also for reference:
L12-2 - modifcations - calvins-audio-pages
@denbret: Do you know the differences between various versions of the PCB?
I just connected this amplifier to my main speakers in my room, and they sound really good (for the time I could play this).
After removing the second transformer that I had in this setup for speaker protection, the power consumption from the wall for one channel is about 42W. Compare that with 4 channels of MyRef-C(LM3886) that draw about 30W total in my listening levels! Second channel keeps tripping the speaker protection (uPC1237). Looks like the DC offset on that board takes a little while to settle.
@OldDIY: Vbe is about 613mV for Q7 and about 632mV between collector and base.
I was using the following schematic also for reference:
L12-2 - modifcations - calvins-audio-pages
@denbret: Do you know the differences between various versions of the PCB?