Hafler DH101

[teknobeam]

Hi. I hope that this question is in the right forum.
I am rebuilding a Hafler DH101 and upgrading the capacitors and replacing the resistors with metal films, etc.
I am also replacing all of the transistors and rebuilding the power supply with all new parts..

What I noticed is that there are some tantalum capacitors (2 in series at each location) that feed the base legs of push pull transistors at the Phono input section.
There are also the same tantalums in line between the volume control and the high level gain stage of the preamp.

I know that you can swap out tantalums for electrolytics or even mica's, but I read somewhere that tanatalums can be vital and inherent to the sonics of an audio circuit in certain situations. This issue was discussed regarding Neve recording console input strips that are jam packed with tantalums, etc.
I'm not an electronics engineer so I am unable to determine whether or not swapping out the tantalums for something else will degrade the fidelity of the preamp?
Thanks in advance for any advice on this.

 

[Alrainbow]

Hi. I hope that this question is in the right forum.
I am rebuilding a Hafler DH101 and upgrading the capacitors and replacing the resistors with metal films, etc.
I am also replacing all of the transistors and rebuilding the power supply with all new parts..

What I noticed is that there are some tantalum capacitors (2 in series at each location) that feed the base legs of push pull transistors at the Phono input section.
There are also the same tantalums in line between the volume control and the high level gain stage of the preamp.

I know that you can swap out tantalums for electrolytics or even mica's, but I read somewhere that tanatalums can be vital and inherent to the sonics of an audio circuit in certain situations. This issue was discussed regarding Neve recording console input strips that are jam packed with tantalums, etc.
I'm not an electronics engineer so I am unable to determine whether or not swapping out the tantalums for something else will degrade the fidelity of the preamp?
Thanks in advance for any advice on this.

Try DIY website. may I ask why are you changing the transistors ?

 

[teknobeam]

Try DIY website. may I ask why are you changing the transistors ?

Thanks for your reply Alrainbow. I will check that site out.
Hafler offered an upgrade following the release of the DH102 (not sure how long after). It involved some transistor changes as well as some resistor value changes in a few spots. The upgrade called for both the transistors and the resistors to be changed together.
The version was referred to as the 'D106".

 

[Alrainbow]

enjoy the ride , i too played with haflers and other well known past products . share how it changes and DIY is loaded with info some really smart folk there . not to redirect but have you tried any old ps audio preamps they too were the bomb at one time .

 

[dgale]

Hi. I hope that this question is in the right forum.
I am rebuilding a Hafler DH101 and upgrading the capacitors and replacing the resistors with metal films, etc.
I am also replacing all of the transistors and rebuilding the power supply with all new parts..

What I noticed is that there are some tantalum capacitors (2 in series at each location) that feed the base legs of push pull transistors at the Phono input section.
There are also the same tantalums in line between the volume control and the high level gain stage of the preamp.

I know that you can swap out tantalums for electrolytics or even mica's, but I read somewhere that tanatalums can be vital and inherent to the sonics of an audio circuit in certain situations. This issue was discussed regarding Neve recording console input strips that are jam packed with tantalums, etc.
I'm not an electronics engineer so I am unable to determine whether or not swapping out the tantalums for something else will degrade the fidelity of the preamp?
Thanks in advance for any advice on this.

John Hillig at Musical Concepts may be of some help.