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-   -   Arjen Helder Buffer V2 (http://www.diyaudio.com/forums/class-d/164635-arjen-helder-buffer-v2.html)

Zero One 6th April 2010 11:16 PM

Arjen Helder Buffer V2
 
I though a few D amp fans might be intersted in this.

I received the new Helder version 2 Buffer yesterday and have hooked this up to my Helder 2020 mk 3 amp. In my case I used a NOS Phillips Miniwatt 12AU7 that I had on hand. So how does it sound.

In my system, wonderful, it gives a sweetness and smoothness to the sound that is quite obvious and especially so if the amp is being fed from an iPod. For the money it seems like an excellent addition.

In my case it is being fed by a separate 12V battery, I am not sure how it would go on an SMPS, but I don't feel that would be an ideal marriage , experience tells me SMPS and pre amps don't work that well together.

The board quality is pretty good, but not as good as the 2020 amps. In terms of mods I would likely tap off the signal before the output caps as it is going through the inputs on the 2020 anyway, so getting rid of one set of caps makes sense to me. Secondly the volume control is pretty basic and would be best replaced with say a 23 step type one and maybe the opamp could be changed for something better though in essence its fine.

Hope it helps.

rhing 7th April 2010 12:57 AM

Quote:

Originally Posted by Zero One (Post 2144662)
In my case it is being fed by a separate 12V battery, I am not sure how it would go on an SMPS, but I don't feel that would be an ideal marriage , experience tells me SMPS and pre amps don't work that well together.

Bummer, because I am planning to use a multi-output SMPS with the TA2020 amp I just purchased from Arjen. I was also considering the mk2 buffer to run off the SMPS.

Zero One 7th April 2010 01:15 AM

Rhing the SMPS from Helder may well be fine for the buffer, I think it operates at a higher switching frequency than most, there are a lot of differences between SMPS units.

Overall I have just found that SMPSs tend to introduce a bit too much noise into pre amp stages and batteries have always sounded better, but I would certainly give the SPMS a try and see how it sounds.

The SMPS should be very good for the power amp.

onis_uk 7th April 2010 04:02 PM

hi im thinking of getting the buffer for my 2020 mk3 but i dont want to end up with 2 volume controls !!!
can i just bypass the volume on the buffer ? or will this cause my 2020 to clip all the time ??????

thanks for any help ;)

Zero One 7th April 2010 10:54 PM

onis you need to control the volume from the buffer, you may indeed get clipping otherwise with std 2V sources, and in any case the idea of a buffer is to buffer just before the amp, with nothing in between.

The vol control on the buffer is 100k, its a pretty average one, can you simply replace it with the other vol control you have, I assume it is a better quality pot.

You could of course simply use the amps vol on full and control from the buffer, but this seems like a bit of a dodge and of course puts one extra part in the signal path.

onis_uk 8th April 2010 05:10 PM

yeah i'll just take the alps pot off my 2020 board !

onis_uk 8th April 2010 06:51 PM

Quote:

Originally Posted by Zero One (Post 2144759)
Rhing the SMPS from Helder may well be fine for the buffer, I think it operates at a higher switching frequency than most, there are a lot of differences between SMPS units.

Overall I have just found that SMPSs tend to introduce a bit too much noise into pre amp stages and batteries have always sounded better, but I would certainly give the SPMS a try and see how it sounds.

The SMPS should be very good for the power amp.

the switching frequency is very high, well above 50 KHZ, so that noise is not an issue !!:D

Zero One 13th April 2010 01:57 PM

I have now had some time to listen to the buffer and amp combined and must say it is a sweet combination.

One thing worth doing is to bypass the output caps on the buffer if it is only going to feed the standard amp module. Having done this I found the bass was improved and the whole set-up gained a little more detail.

A second thing which I will do is replace the vol pot, I have found it does not track perfectly on both channels and this leads to minor imbalances in stereo imaging, not surprising, it is just a basic pot and most of this type are not great. I will put a stepped 100k Dact style pot on instead in the next week.

I notice the price on the buffer has gone way up, but still a good buy I would say.

onis_uk 13th April 2010 09:47 PM

it has gone up but now has free p&p ...so basically the shipping has been added to the price lol

tubesteve 15th April 2010 10:48 AM

the volume pot in the buffer amp is for best adjustment of both amplifiers combined. with this pot, the buffer amp can control distortion, when the connected audio source which delivers higher audio voltages. so, both volume controls are able to select a certain of wanted or unwanted kind of THD or soft clipping.


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