[b0bb]

180uF local bypass electrolytics.
Brown caps under board, improves power availability to amp stage.

Bass tightness and speed improved with this change.

 

[NoNameNPC]

180uF local bypass electrolytics.
Brown caps under board, improves power availability to amp stage.

Bass tightness and speed improved with this change.

Can you send link on this brown caps and white caps?

 

[slex]

180uF local bypass electrolytics.
Brown caps under board, improves power availability to amp stage.

Bass tightness and speed improved with this change.

I like wat you did to your Frankenamped H20, after covid and travel free, will experienced it.

 

[b0bb]

Can you send link on this brown caps and white caps?

https://www.mouser.com/ProductDetai...500ell181mh20d/?qs=48xh8PjiJp58S/ljQWdc%2bQ==

 

[NoNameNPC]

Replace diodes on preamp bridge rectifiers, swap regular silicon diodes with schottky diodes.

Schottky diodes have very low switching noise, removing this source of noise takes off the graininess in the midrange.

Before. (D70, D68 etc)



After

Can you send link on diodes? Thx.

 

[b0bb]

Can you send link on diodes? Thx.

https://www.mouser.com/ProductDetail/vishay/v8pa22-m3-h/?qs=BJlw7L4Cy78sySmQZ%2biykA==

 

[ezduzit2500]

Hi all, just checking in. My opinion of the H20 is still pretty good with the short time I've owned it. With that said, I feel the bass could be a little tighter and more defined sometimes. I've got Sparkos ss3602 opamps installed, maybe will try Sonic Imagery 994's, are they tighter in the bass. I'm not equipped nor do I have the on-hand recent experience to do all of the mods of the last few pages. Any thoughts on the opamps, Sparkos vs Sonic Imagery?

 

[migo]

Hi, I've got used H20 and are experiencing hum coming from transformers, it resonates the chassis, but can't be heard in headphones itself. But it is annoying at night, it is loud to hear it from 2m away. Is anybody experiencing it too?

Thank you!

 

[ProLoL]

Hi, I've got used H20 and are experiencing hum coming from transformers, it resonates the chassis, but can't be heard in headphones itself. But it is annoying at night, it is loud to hear it from 2m away. Is anybody experiencing it too?

Thank you!

I've heard the transformers on the A20H does the same, it's their modified transformer.

 

[migo]

I've heard the transformers on the A20H does the same, it's their modified transformer.

Interesting that no one in this thread had complained about it. I only want to know if it is "normal" with Gustard H20, I don't want to give bad reputation to the seller if it is common manufacturer flaw. Thank you!

 

[ezduzit2500]

Interesting that no one in this thread had complained about it. I only want to know if it is "normal" with Gustard H20, I don't want to give bad reputation to the seller if it is common manufacturer flaw. Thank you!

If possible, contact Gustard....or search for a replacement XFMR from Parts Express, Mouser, etc. There could also be an easy fix, though you'd have to search around the internet. Hope you are able to fix it or get it fixed, it's really a very decent HP amp. Maybe try plugging it into a different outlet or by itself. May help.

 

[b0bb]

Hi, I've got used H20 and are experiencing hum coming from transformers, it resonates the chassis, but can't be heard in headphones itself. But it is annoying at night, it is loud to hear it from 2m away. Is anybody experiencing it too?

Thank you!

Buzzing in a toroidal transformer can be caused by DC in the power line.
This does not include the buzzing at turn on.

Powerlines can sometimes can unbalanced, homes use 1 phase of a 3 phase powerline, if the power draw on the 3 phases is not equal the unbalance can happen.
DC and powerline harmonics are the result.

I have my H20 conneced via isolation transformers.
My isolation transformers can buzz because of this, most of it stopped when I put in a line filter that takes out the harmonics.

If it is a DC issue there are boxes to eliminate DC from the power going to your audio equipment.

 

[ezduzit2500]

Buzzing in a toroidal transformer can be caused by DC in the power line.
This does not include the buzzing at turn on.

Powerlines can sometimes can unbalanced, homes use 1 phase of a 3 phase powerline, if the power draw on the 3 phases is not equal the unbalance can happen.
DC and powerline harmonics are the result.

I have my H20 conneced via isolation transformers.
My isolation transformers can buzz because of this, most of it stopped when I put in a line filter that takes out the harmonics.

If it is a DC issue there are boxes to eliminate DC fr

Good post B. I looked it up after my earlier post. Went to Emotiva's website and others. Glad that there's a simple solution if I ever need it. Thnx.

 

[migo]

Buzzing in a toroidal transformer can be caused by DC in the power line.
This does not include the buzzing at turn on.

Hi @b0bb, thank you for your answer! It starts buzzing immediately after turning my unit on. I've tried to connect it to another phase in house (I have all 3 phases connected) with the same result.

 

[b0bb]

Hi @b0bb, thank you for your answer! It starts buzzing immediately after turning my unit on. I've tried to connect it to another phase in house (I have all 3 phases connected) with the same result.

This is powerconditioner I use, it is just a large toroidal isolation transformer.

https://www.powervar.com/products/power-conditioners/gpi-series-1-power-conditioners.
If it is problem is from the powerline then this will start buzzing instead of your H20.

It stops DC and reduces the harmonics going to the H20.
Buzzing is the transformer's way of dealing with the powerline harmonics.

If you have other connected audio equipment with toroidal transformers in them and they do not buzz, the transformer in your H20 may be defective.