avis ampli t.amp s150 mk2

[nightwish_daisuki]

Je publierai la cause du bourdonnement et l'une des solutions.

Cause of Hum. (S-150mk2)
https://youtu.be/SYG2WYpisY0

Resolve Hum. (S-150mk2)
https://youtu.be/saIzovDrFtw

Ham may be a concern with high-efficiency speakers.
The cause was the structure that transmits 24V DC from [CN14] to the power saving board.
Humming can be reduced by modifying the power saving board so that it can operate without this 24V DC supply.

In the power saving board, this 24V is used to turn on the delay relay to suppress the inrush current.
The power saving function of the power saving board is realized by the 12V relay,
but this is removed and this 12V relay is transplanted as a delay relay to suppress the inrush current.
Add one resistor to the delay relay drive circuit and modify it so that the delay function is realized even with a 12V power supply.

In Japan, there were cases where the relay did not turn on because the power supply voltage was low. This was solved by using low VF Schottky diodes and increasing the voltage after rectification.

[nightwish_daisuki]

One speaker cable inside the amplifier is omitted (it is P3).
The sound quality improved when I added one and remodeled it to four.

[Picture of P3]


https://youtu.be/WGUzWLhWx2A
https://youtu.be/qziREmb0PCs

[alfachris]

Je publierai la cause du bourdonnement et l'une des solutions.

Cause of Hum. (S-150mk2)
https://youtu.be/SYG2WYpisY0

Resolve Hum. (S-150mk2)
https://youtu.be/saIzovDrFtw

Ham may be a concern with high-efficiency speakers.
The cause was the structure that transmits 24V DC from [CN14] to the power saving board.
Humming can be reduced by modifying the power saving board so that it can operate without this 24V DC supply.

In the power saving board, this 24V is used to turn on the delay relay to suppress the inrush current.
The power saving function of the power saving board is realized by the 12V relay,
but this is removed and this 12V relay is transplanted as a delay relay to suppress the inrush current.
Add one resistor to the delay relay drive circuit and modify it so that the delay function is realized even with a 12V power supply.

In Japan, there were cases where the relay did not turn on because the power supply voltage was low. This was solved by using low VF Schottky diodes and increasing the voltage after rectification.

Whaouhhh...Ca c'est de l'info ! Merci nightwish_daisuki !
Dommage que j'ai 2 bras gauches, et que j'ai peur de faire une bêtise.....mais je vais bien trouver une "âme charitable" qui pourra me faire la modif

[alfachris]

One speaker cable inside the amplifier is omitted (it is P3).
The sound quality improved when I added one and remodeled it to four.

[Picture of P3]


https://youtu.be/WGUzWLhWx2A
https://youtu.be/qziREmb0PCs

Là aussi...merci!

[nightwish_daisuki]

Thomann cachait la banane.

Only the plastic parts can be drilled.
Be careful not to perforate metal parts.

https://youtu.be/vAtJlVwUc2Y

[Gug42]

Hello,

Thank you for thoses informations !

Well, It seems that the "hum mod" is not quite easy ... at least needs some real modifications. I was hopping a easy, and straight forward, one

About the P3 cable : same thing with xlr output or not ?

Thx

[nightwish_daisuki]

Hello,

Thank you for thoses informations !

Well, It seems that the "hum mod" is not quite easy ... at least needs some real modifications. I was hopping a easy, and straight forward, one

About the P3 cable : same thing with xlr output or not ?

Thx

Hi, Gug42

'P3' is Just 'Ground'. (GND)
It is the best place to path the return current from the loudspeakers in a 'Single ended' amplifier.
However, when used with a monaural amplifier in 'bridged' (BTL) mode, it does not become the current path from the loudspeaker.
So in 'bridged' mode (BTL) it can be said to be the same as XLR's GND.

References:
https://en.wikipedia.org/wiki/Push%E2%80%93pull_output
https://en.wikipedia.org/wiki/Bridged_a ... al_circuit
https://www.thomann.de/gb/tamp_s75.htm

[damdam95]

Je publierai la cause du bourdonnement et l'une des solutions.

Cause of Hum. (S-150mk2)
https://youtu.be/SYG2WYpisY0

Resolve Hum. (S-150mk2)
https://youtu.be/saIzovDrFtw

Ham may be a concern with high-efficiency speakers.
The cause was the structure that transmits 24V DC from [CN14] to the power saving board.
Humming can be reduced by modifying the power saving board so that it can operate without this 24V DC supply.

In the power saving board, this 24V is used to turn on the delay relay to suppress the inrush current.
The power saving function of the power saving board is realized by the 12V relay,
but this is removed and this 12V relay is transplanted as a delay relay to suppress the inrush current.


Add one resistor to the delay relay drive circuit and modify it so that the delay function is realized even with a 12V power supply.

In Japan, there were cases where the relay did not turn on because the power supply voltage was low. This was solved by using low VF Schottky diodes and increasing the voltage after rectification.

Whaouhhh...Ca c'est de l'info ! Merci nightwish_daisuki !
Dommage que j'ai 2 bras gauches, et que j'ai peur de faire une bêtise.....mais je vais bien trouver une "âme charitable" qui pourra me faire la modif

Salut Alfa, je suis preneur d’un tir groupé si jamais tu trouves quelqu’un pour faire la modif, le miens ronronne aussi et comme je suis également ds 95, fais moi signe

[alfachris]

Je vais attendre de recevoir mes nouveaux amplis, avant de faire modifier les T.Amp... mais c'est ok je te fais signe dès que je trouve quelqu'un

[will3230]

bonsoir a tous j ai fais la modif pour inserer les fiches bananes,ça marche mais allez-y tout doux car l epaisseur de plastique est fine pour ne pas abimée la partie metalique de la fiche ,méche de 5mn suffisante,bonne soirée.

[guyome]

Pour le hum, s'il s'agit du softstart qui fout le bordel, autant le changer plutôt que de modifier celui d'origine - la modif m'a l'air tout de même hasardeuse

Si quelqu'un veut m'envoyer son modèle, je regarderai ce que je peux proposer en plus "simple" pour tout le monde.

[alfachris]

Pour le hum, s'il s'agit du softstart qui fout le bordel, autant le changer plutôt que de modifier celui d'origine - la modif m'a l'air tout de même hasardeuse

Si quelqu'un veut m'envoyer son modèle, je regarderai ce que je peux proposer en plus "simple" pour tout le monde.

Je peux t'envoyer l'un des miens, maintenant que j'ai mes amplis ....appelle-moi

[Did77]

Content de voir que tu as récupéré tes amplis.

[nightwish_daisuki]

Did not work!!

In fact, the modifications shown in "Resolve Hum.(S-150mk2)" Did not work.
It may be solved by slowing down the charging current to the bulk capacitor. By "small-L".
https://youtu.be/q9jedS8ukUw

Je publierai la cause du bourdonnement et l'une des solutions.

Cause of Hum. (S-150mk2)
https://youtu.be/SYG2WYpisY0

Resolve Hum. (S-150mk2)
https://youtu.be/saIzovDrFtw


The following is omitted.

Postscript1：Good News.

When I inserted the choke coil between the diode and the bulk capacitor, the hum disappeared.
The resistor is inserted for the purpose of absorbing the transient high voltage generated by the coil.
Without this resistor there is a risk of damaging the diode.
These value should be considered in the future as it is a parameter that affects sound quality.
Due to the effect of this choke coil, the hum is as small as the "S-75mk2".

Postscript2：
I think I didn't need a resistor connected in parallel with the choke.
For example, the choke of a tube amp does not have a resistor attached.

[guyome]

Autant enlever le softstart puisque c'est lui qui fait engendre le bruit - le transfo est trop petit pour que cela soit vraiment nécessaire...

Christian, si tu veux m'envoyer un de tes exemplaires ?