The idea was to measure both versions of the PS (labelled 60V and 64V) under no load to figure out wether these are technically identical but just wear different stickers.
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Melba59
Member
Hello everyone,
I measured a 64v power supply, JLY64004001 of one of my LA90/LA90D, at no load.
It delivers 63.9V like the 60v measured previously.
They are therefore identical.
Only the characteristics of the stickers have changed : the regulated voltage under load instead of the regulated voltage at no load, which is more conventional.
Small note:
64v x 3.75A* (LA90D) = 60v x 4A (B200) = 240VA.
* This is the amperage indicated in the commercial topping specifications, the JLY64004001 sticker gives 4A
In any case on a class AB transistor, it seems to me that the amplification is more efficient with low voltages at the terminals of the transistors.
For 200W and 4A which would be drawn constantly, the voltage would be around 50V assuming that the COS PHI is 1.
At 200W, 60 or 64V regulated, the amps will not draw more than 3.5A in practice (or else you have to like odd order H3's distortion, all tastes are in nature
)
I measured a 64v power supply, JLY64004001 of one of my LA90/LA90D, at no load.
It delivers 63.9V like the 60v measured previously.
They are therefore identical.
Only the characteristics of the stickers have changed : the regulated voltage under load instead of the regulated voltage at no load, which is more conventional.
Small note:
64v x 3.75A* (LA90D) = 60v x 4A (B200) = 240VA.
* This is the amperage indicated in the commercial topping specifications, the JLY64004001 sticker gives 4A
In any case on a class AB transistor, it seems to me that the amplification is more efficient with low voltages at the terminals of the transistors.
For 200W and 4A which would be drawn constantly, the voltage would be around 50V assuming that the COS PHI is 1.
At 200W, 60 or 64V regulated, the amps will not draw more than 3.5A in practice (or else you have to like odd order H3's distortion, all tastes are in nature
)
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I don't know where you got the value of 3.75A from? Both the 64V and 60V power supply stickers always show 4A. I'll tell you more, in the LA90 review there's a photo of the sticker and it also says 64V*4A. Could it be that you have a third version of the power supply with yet another sticker?Hello everyone,
I measured a 64v power supply, JLY64004001 of one of my LA90/LA90D, at no load.
It delivers 63.9V like the 60v measured previously.
They are therefore identical.
Only the characteristics of the stickers have changed : the regulated voltage under load instead of the regulated voltage at no load, which is more conventional.
Small note:
64v x 3.75A* (LA90D) = 60v x 4A (B200) = 240VA.
* This is the amperage indicated in the commercial topping specifications, the JLY64004001 sticker gives 4A
In any case on a class AB transistor, it seems to me that the amplification is more efficient with low voltages at the terminals of the transistors.
For 200W and 4A which would be drawn constantly, the voltage would be around 50V assuming that the COS PHI is 1.
At 200W, 60 or 64V regulated, the amps will not draw more than 3.5A in practice (or else you have to like odd order H3's distortion, all tastes are in nature
Next question. I assume you have both the LA90D and the B200. Do you use the LA90D in power amp mode, i.e. with the bridge and volume control turned off? If so, do you notice any audible differences and the way it plays? I assume you can't feel it. Because if not, there's no point in paying extra for the LA90D, which costs much more. I understand that the LA90D came out much earlier and Topping didn't have an idea for the B200 yet. The B200 shoots the LA90D in the foot in power amp single, mono mode.
2xLA90D vs 2xB200=2x more expensive for a set of two LA90D
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Melba59
Member
Hi, Burns,
As the note referenced by the asterix (*) indicated on my previous message, I found the information on a commercial doc from shenzenaudio or an authorized reseller, but it was indeed the specifications given by Topping. It was on a table, identical to the B200 which indicated 60v/4A, hence my confidence in the information collected. Yes the sticker indicates 4A, it is also specified in the note on my previous message.
I had found the information in less than 2 minutes; it is what made me calculate the power for comparison. Unfortunately, impossible to find the link again! I have been looking for 1 hour! And since the initial search dates back more than 24 hours, my browser history is deleted. I intend to find it and post it.
To move forward in the exchange: Those who would like to use another power supply to push these amps. This is in my opinion a heresy: 240VA or Watts: corresponds to 10% of THD on the B200. More than 3% of THD is unlistenable in my opinion (it is 3% cumulated to the 2 to 4% of THD of a good speaker).
I do not have a B200, no 60v/4A power supply to compare but the measurements were posted previously.
I have 2xLA90 and 4xLA90D purchased well before the release of the B200.
All are bridged, with their volume bypassed.
The 2xLA90 are used on focal OD8 v1, for lack of being able to buy 4 others at the time (problem of supply of the AOP; Topping thus released the LA90D, barely 1 year after the smash release of the LA90).
The 4xLA90D are reserved for the channels of a 3-way DIY speaker of 98db/1W/1m, still in prototype state. Same for the DIY digital filtering, 3 to 4 channels based on miniDSP shark/DAC R2R/Interface USB Xmos316 and an ADC for the analog. The filtering at the mid/high level is passive for now (it's for evaluations).
This DIY project without compromise dates back more than 25 years, even the auditorium is still to be finalized.
The low midrange (4x15" Davis Acoustics 31TCA12W, often used for large studio monitors) was supposed to be driven by an Audiophonics PURIFI 1ET400A (4-channel version) but I'm not satisfied: the impedance matching at the amp's input ruins everything, so it's in the closet and on sale to finance the purchase of 4 other LA90D or B200 for their price.
I also have to sell 2 Nuprimes STA-9, which are in the closet, also barely used: Power supply too sensitive to mains interference. The problem is that I'm too honest and therefore a very bad reseller LOL.
To procrastinate and share my choices, the advantage on high-sensitivity speakers is not having to push the amplification to its limits. The mono block: Zero crosstalk.
Finally, the use of identical amplification is, from experience, essential for the coherence of the registers reproduced in active filtering. This especially avoids headaches.
Topping B200 Monoblock Amplifier Review
This is a review and detailed measurements of the Topping B200 "monoblock" (single channel) audio amplifier. It was sent to me by the company and costs US $599. I don't think it is possible to make the unit more solid and high-quality feeling in this form factor. The amp is heavy for its size...
www.audiosciencereview.com
JeremyFife
Major Contributor
This thread may help, it's very thorough: https://audiosciencereview.com/foru...distortion-propagate-through-my-system.33358/
More pragmatically, you have very well measuring gear: low noise and distortion and you can set it the way that seems good to you without worrying that there any real negative impact on the sound. Your 'Hi/Lo' option seems safest and also satisfying.
Melba59
Member
Hello
Thank you, for Amir's review
From a quick first reading,
I'm surprised that the B200 couldn't be pushed as much as the LA90D bridged in 4Ohms?
LA90D:
B200 :
On the other hand, I didn't find the initial link that mentioned the 64v/3.75A power supply for LA90D. But I found the info on another site with the specs of the B200 power supply:
"1x AC-DC power adapter (DC 64V / 3.75A (3-Pin))"
Thank you, for Amir's review
From a quick first reading,
I'm surprised that the B200 couldn't be pushed as much as the LA90D bridged in 4Ohms?
LA90D:
B200 :
On the other hand, I didn't find the initial link that mentioned the 64v/3.75A power supply for LA90D. But I found the info on another site with the specs of the B200 power supply:
"1x AC-DC power adapter (DC 64V / 3.75A (3-Pin))"
Thank you for your answer, this is exactly the kind of thread I needed where it is illustrated with numbers and graphs. I will probably read it ten times to understand everything thoroughly.
Two things in this article surprise me:
- probably the right and true assumption: "Also note the power amplifier has the worst performance and so will usually determine the performance of the entire chain"
and the final result of his, I emphasize, his system:
- "For this system, output SNR is better when amplifier volume (G4) is adjusted rather than preamp volume (G2), at least for this setting (-10 dB). Output THD is essentially the same for either choice since it is limited by the power amplifier. The result is that overall output SINAD follows the SNR curves and again best performance is obtained by adjusting the amp rather than preamp volume control – for this system and at this volume level." So I should set something completely different than what logic and imagination suggest, i.e.
Lo (L70 - PreAmp) / Hi (B200 - Amp)
It's good that I have such a large reserve, even setting Hi /Hi, SINAD should not drop more than 110dB
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Melba59
Member
I understand this sentence differently:
Power amp volume lowered to -10dB
Preamp volume at 0db (or -1 to -3dB to have a safeguard for compressed recordings limited)
If the input/output impedance matching is ok, this is generally the optimal setting (output: 0dB, input adjusted). Be careful with the preamp outputs of headphone amps, these preamps sometimes have non-zero amplification ratios (they amplify). It is rarer on hifi preamps (where the 1:1 ratio is common, except the PRE90 which allows +6dB amplification or a tube SRPP assembly, for exemple)
For memory :
If the source is too weak => loss of dynamics (Finally, most recordings rarely exceed 40dB of dynamics
It is all relative)If the source is too strong for the input => distortion by clipping
I think it is better to set your L70 in HI, B200 in Low
To broaden the debate, here is an article in French/Belgian quite explicit on impedance adaptation and the problems of non-standard hifi devices
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Melba59
Member
It was just to "contribute my stone to the building" (French expression for a contribution). I didn't take a picture, I would have needed 2 more hands
I am careful about this,I understand this sentence differently:
Power amp volume lowered to -10dB
Preamp volume at 0db (or -1 to -3dB to have a safeguard for compressed recordings limited)
If the input/output impedance matching is ok, this is generally the optimal setting (output: 0dB, input adjusted). Be careful with the preamp outputs of headphone amps, these preamps sometimes have non-zero amplification ratios (they amplify). It is rarer on hifi preamps (where the 1:1 ratio is common, except the PRE90 which allows +6dB amplification or a tube SRPP assembly, for exemple)
For memory :
If the source is too weak => loss of dynamics (Finally, most recordings rarely exceed 40dB of dynamics
If the source is too strong for the input => distortion by clipping
I think it is better to set your L70 in HI, B200 in Low
To broaden the debate, here is an article in French/Belgian quite explicit on impedance adaptation and the problems of non-standard hifi devices
that's why I'm asking and posting tables
Pre90 looks quite similar with the numerical values, but maybe I'm making a mistake somewhere and I don't want to waste money on Pre90 (I don't really have money for another device) if E70 does the same.
I'm asking if it's good?
On my reasoning it is as you warn me. E70 amplifies the same as Pre 90 provided that we are in low mode and that is by +6dB. high mode is as much as 19.8dB. I just don't understand why Vrms decreases from 9.6 to 1.9?
Attachments
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Melba59
Member
This is going to be quite complicated in translation, I'm French education
This is the input gain setting of the L70, which does not exist on the PRE90.
In low, the source can emit a signal up to 9.6Vrms without the preamp saturating, the gain between the incoming signal and the outgoing signal of the preamp is zero in unbalanced, and +6dB in balanced
The "standard value" for pro equipment between an unbalanced and balanced connection is often +10dB corresponding +/- to a voltage of 4.5Vrms, 0dB to +/-2.2Vrms. But +6dB becomes common with hifi equipment. This varies because of the third factor in correlation: the input/output impedances.
In balanced, the voltage is doubled: in fact, it goes from about -2.2Vrms to +2.2Vrms, the GND no longer corresponds to the negative pole but to 0Vrms and therefore to the ground (this is to avoid a floating voltage for example +1V to +5.5V and to allow the cancellation of parasitic currents with long distance cables)
In fact, in Low on the L70, we can consider that there is no gain unless we use an unbalanced source and a balanced output or that the volume can be pushed to +16dB like the PRE90 (there is a real gain of +10dB)
In high, the gain between the incoming signal and the outgoing signal of the preamp goes to +19.8dB (real gain13,8dB), therefore the source cannot emit a signal of more than 1.9Vrms otherwise the preamp saturates at the output.
The LOW or High setting of the preamp depends mainly on your sources. For example:
- with a D90SE set to 5V at the output and balanced connection => L70 in Low, if balanced connection to the B200 => B200 in Low, if unbalanced connection to B200 => B200 in high
- With a phono preamp and a very low voltage MC cell in unbalanced connection, Output voltage of about 1.2Vrms => L70 in high, if balanced connection to the B200 => B200 in Low, if unbalanced connection to B200 => B200 in high
There is a trick to connect an unbalanced input to a balanced input: connect the negative voltage to GND. In this case the signal is not amplified at all, and we get 0 to 2.2Vrms.
The B200 and LA90 are not equipped with an unbalanced input, this is the reason for the high gain
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You describe it very nicely, but I still lack information to understand everything.This is going to be quite complicated in translation, I'm French education
This is the input gain setting of the L70, which does not exist on the PRE90.
In low, the source can emit a signal up to 9.6Vrms without the preamp saturating, the gain between the incoming signal and the outgoing signal of the preamp is zero in unbalanced, and +6dB in balanced
The "standard value" for pro equipment between an unbalanced and balanced connection is often +10dB corresponding +/- to a voltage of 4.5Vrms, 0dB to +/-2.2Vrms. But +6dB becomes common with hifi equipment. This varies because of the third factor in correlation: the input/output impedances.
In balanced, the voltage is doubled: in fact, it goes from about -2.2Vrms to +2.2Vrms, the GND no longer corresponds to the negative pole but to 0Vrms and therefore to the ground (this is to avoid a floating voltage for example +1V to +5.5V and to allow the cancellation of parasitic currents with long distance cables)
In fact, in Low on the L70, we can consider that there is no gain unless we use an unbalanced source and a balanced output or that the volume can be pushed to +16dB like the PRE90 (there is a real gain of +10dB)
In high, the gain between the incoming signal and the outgoing signal of the preamp goes to +19.8dB (real gain13,8dB), therefore the source cannot emit a signal of more than 1.9Vrms otherwise the preamp saturates at the output.
The LOW or High setting of the preamp depends mainly on your sources. For example:
- with a D90SE set to 5V at the output and balanced connection => L70 in Low, if balanced connection to the B200 => B200 in Low, if unbalanced connection to B200 => B200 in high
- With a phono preamp and a very low voltage MC cell in unbalanced connection, Output voltage of about 1.2Vrms => L70 in high, if balanced connection to the B200 => B200 in Low, if unbalanced connection to B200 => B200 in high
There is a trick to connect an unbalanced input to a balanced input: connect the negative voltage to GND. In this case the signal is not amplified at all, and we get 0 to 2.2Vrms.
The B200 and LA90 are not equipped with an unbalanced input, this is the reason for the high gain
The source is E70 set in 5/2.5V mode. I have both XLR and RCA cables connected to the L70 preamplifier. All I have to do is switch the input with the remote control. I can also lower the voltage to 4/2V if necessary.
I would like to avoid clipping.
In the B200 review it was measured that the B200 needs 6.6V to play at full power.
Will you spend some more time and calculate it for me and then write how I should set this E70>L70>B200 chain correctly? I will not buy Pre90, I have no money and someone rightly noticed that Pre90 does not have a trigger
Melba59
Member
I can't find any information on the input impedances of the L70 and B200.
Anyway, it's not that important to calculate.
Given the "standard" output impedance of the E70, I'll leave it in 5V/2.5V configuration and the L70 in Low gain.
The High or Low gain configuration of the B200 input will depend on the limitations in volume adjustment on the L70:
Even if you have to push the volume almost to the maximum but it already plays beyond listening in full physical shape, leave the gain of the B200 in low.
If the volume at max remains too low, set the B200 to High.
Yes, for the price of around 1200 I'd rather get the new Audiophonics instead (especially if living in Europe)
AUDIOPHONICS LPA-S450ET Power Amplifier Stereo Purifi 1ET6525SA
We're proud to present the Audiophonics LPA-S450ET, a Class D stereo power amplifier based on two Purifi 1ET6525SA modules. Electronically similar to the HPA-S450ET, this version is housed in a more compact case...www.audiophonics.fr
Power 2x230W @ 8Ω, 1%THD
2x450W @ 4Ω, 1%THD
2x510W @ 2Ω, 1%THD
Agree. Or BoXem for a more thought-through design, both inside and outside. Apollon makes also very nice looking and well built amps.
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