[kdaq]

I'm afraid that some 'upgraded' electrolytic caps made a change for the worst in my amp..


I soldered up a Dynalo awhile back, starting with the parts BOM @ dgardner's site, with as many parts from Digikey as I could get.

With the PCB populated and measuring nicely, I threw on jacks without a volume control. Using my Zen Micro DAP as source and volume control, the dynalo sounded absolutely fantastic! The added detail, bass impact, and just general sense of fine-grained control over the transducers really impressed me. Seemed that this amp didn't color the sound so much as it set it free.

Later, I partially cased the amp with a volume control. I also removed the pansy ~200 uF Pana FC caps and threw in a set of Cerafine 470uFs. My first impression was 'what the hell...I sucked the life out of my Dynalo'!

After a bunch of hours, I perceived that the sound warmed up and revived, though not quite to the level it was before. Just told myself that the caps needed to 'burn in'.


Well here I am, probably 100 hours of listening later, and it sounds the same. Did the different caps do this?! I realize I'm making a crutial error here, blaming the caps solely. There's actually three important variables that changed - an added pot in the sound path, the changed caps, and now the amp isn't running full gain all the time. Also, I might be suffering from a case of over-zealous and overly excited initial impressions, but I don't think so.

So what do you think?

 

[robzy]

Quote:

Originally Posted by kdaq Also, I might be suffering from a case of over-zealous and overly excited initial impressions, but I don't think so.

Im sorry, im siding with this. But thats from an audio standpoint, not an electronics one.

If someone comes with electronic reasons why it isnt- go with them

Rob.

 

[n_maher]

Quote:

Originally Posted by kdaq Later, I partially cased the amp with a volume control.

What did you use for a pot, I can't remember from Boston?

Quote:

Also, I might be suffering from a case of over-zealous and overly excited initial impressions, but I don't think so.

There's probably a degree of this going on as well.

Nate

 

[dgardner]

Quote:

Originally Posted by kdaq ...I threw on jacks without a volume control. Using my Zen Micro DAP as source and volume control, the dynalo sounded absolutely fantastic!

Sometimes two volume controls (source+amp) at half mast can have a small effect. Try turning up the amp all the way and using the source's volume control. Then, turn up your source all the way and use the amp's volume control. You may discover something. Tough to say for sure.

 

[kdaq]

@ Boston, the amp wasn't even working in the original state yet.

The pot I'm using is a blue velvet.

And look, I just listed the overzealous option cause I'm an engineer and I have to be exhaustive

I'm not imagining this!

On the other hand, I should note that the difference I hear is more subtle than it is huge. It's the difference between a SR325 and an MS2. Might not seem like much, but on some music the added 'passion' of the 325 is missed when listening on the MS2.

 

[kdaq]

Quote:

Originally Posted by dgardner Sometimes two volume controls (source+amp) at half mast can have a small effect. Try turning up the amp all the way and using the source's volume control. Then, turn up your source all the way and use the amp's volume control. You may discover something. Tough to say for sure.

*Smacks self* of course, why didn't I try this?? Thanks Dan!

 

[n_maher]

Quote:

Originally Posted by kdaq *Smacks self* of course, why didn't I try this?? Thanks Dan!

So your avatar is prophetic, eh?

 

[kdaq]

Quote:

Originally Posted by n_maher So your avatar is prophetic, eh?

I like avys that are a reflection of one's self

 

[MisterX]

Quote:

Originally Posted by kdaq I like avys that are a reflection of one's self

If that is the case I should prolly change mine to this------->

 

[n_maher]

Quote:

Originally Posted by MisterX If that is the case I should prolly change mine to this------->

When I first started out at work that was my desktop, classic! Got too many weird looks from clients so I changed it to something more benign...

Quote:

Originally Posted by kdaq I like avys that are a reflection of one's self

Yeah, mine works in this way as well. It's probably when I should have stopped building amps

...

Nate

 

[kdaq]

Quote:

Originally Posted by dgardner Sometimes two volume controls (source+amp) at half mast can have a small effect. Try turning up the amp all the way and using the source's volume control. Then, turn up your source all the way and use the amp's volume control. You may discover something. Tough to say for sure.

Sooo...today I hooked my zen micro up to the dynalo and tried a variety of musica in these two situations:

a) Zen micro @ 90% volume, dynalo volume adjusted to a comfy listening level
b) Dynalo @ 100%, Zen micro volume adjusted to same comfy listening level

And guess what - I heard precisely the difference I was complaining about! God help me if I remember what the original Dynalo configuration sounded like way back when, but the difference I just heard between these two configs is clear as day.

With the Dynalo volume cranked, the sound is simultaneously more tightly controlled, and more 'full'. It makes me feel like I'm perceiving more detail, but I think it's really just a more lively and fun sound.

I would babble on with more impressions, but halfway into testing I got irrevokably drawn into the music, so screw that

The HF-1/Zeta Flats is AWESOME.

 

[kdaq]

Quick follow-up. I tried the same experiment with my Overture DAC fed via my computer. Man, that was terrifying with the Dynalo volume maxed. There's this evil hiss that comes from the very tiniest bit of noise out of the DAC that's being juiced up from the Dynalo, and it just reminds me that if my computer volume accidentally jumps up to 100%, my eardrums will be shot straight to Peru.

In any case, I heard the same thing happen again (tho I might not explain it the same way, due to the inherent differences between the zen and overture sound).

Man, if the improvement between a Dynalo and a Dynahi is along these same lines, except more pronounced, I'm psyched.

 

[AtomBoy]

kdaq,

What are you using for a power supply?

I've tried to reproduce your symptoms with my Dyanlo and the volume on the source and the pot on the input don't seem to do what you describe on my set up.

I'll defer to the experts here, but I wonder if all the extra capacitance is making your PS unhappy?

 

[kdaq]

I use a Headroom power brick. It's an external +15/-15 supply with 240mA current capability per rail.

 

[AtomBoy]

See, if I knew what I was talking about here I'd start expounding on the nature of capacitive load vs resistive and such. Since I don't, I won't.

If I get a chance, I'll stuff a couple of 2200uF in my Dyanlo and see what that does, but since we don't have the same supply the experiment might have limited value.