Some New 500 series projects coming up....

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Yes!!! I've been waiting for this post  ;D

If you'll post to Australia put me down for 4 of these 4 channel boards. Will this design still use a rotary switch for gain?

Kris

Hi Kris

Yes, the gain is still done with a rotary switch.

Peter

Moog LFO   Very cool!!!

500 series green pre would be awesome. If you don't have time to do the design I'm sure there will be someone willing to do the pcbs with your blessing

peterc said:

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Fourth, a Moog style Lowpass filter with Resonance & LFO, wee-aaah
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500 series??

    ...
    Fourth, a Moog style Lowpass filter with Resonance & LFO, wee-aaah
    ...


500 series??

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Yes it is

Hipo Lopo! Sounds awesome 8) Hi pass and lowpass are some of my favorite eqs!

Two Tria´s this way, for shure.

Tria looks cool, I'd be in for a pair. The Moog filter looks cool also but I've got a modular eurorack system so I'll pass on that.

I really like the TriA! Great!

Can you provide/publish more details? (schematics)

Theo

interest expressed ... What other types of input/output transformers can be used?

peterc said:

Hi Kris

Yes, the gain is still done with a rotary switch.

Peter

Click to expand...

Awesome! One thing I love about the green pre is that there are no esoteric parts. What do you mean by minimal metering? One green, one yellow and one red? Or are we talking just one red clip led? TBH, I think we should be using our ears anyway and if it would save on components/PCB size I would be all for leaving the metering section out.

Kris

Sounds great!

One thing I'm curious about regarding the TriA: I've read on another board that the Trident A-Range really requires a 48V supply to achieve its proper sound. I'm only a novice when it comes to this stuff so I can't say whether that's true or not, but I was wondering if you could give your thoughts on the subject. Is there something you're doing to get around that issue, or is it not really even a problem in the first place?

I've got to say, too, that the TriA looks like a pretty easy build. Would you say that is the case? If so I could definitely see myself with at least a couple of those.

Updated first post with pics & sound file.

Tim:

The only section that runs on 48v is the output driver, so I scaled some parts to keep the figures similar. I have been using it as my inline pre for about 6 weeks now, sounds great

Peter

Cool, I'm definitely looking forward to building some myself. And the High/Low Pass filter thing is a great idea - not only is that an area that has for the most part been absent in 500 land (the only truly versatile HPF/LPF module I can think of is the CAPI Missing Link), but the simple circuit looks like it would be an ideal first build for beginners. You can put me down for a couple of those as well (depending on price of course).

peterc said:

Updated first post with pics & sound file.

Tim:

The only section that runs on 48v is the output driver, so I scaled some parts to keep the figures similar. I have been using it as my inline pre for about 6 weeks now, sounds great

Peter

Click to expand...

The first stage is running on 30V in the original design, I expect you are running this on +24V?
I would be most interested in the design you created.

grT

I am using the -16v rail a the 0V rail & running the whole thing on +32v, I have not done a 51x version, only 500 series.

Sounds big and fat...

Great, excellent swing! (I was hoping you did it this way)
I also like your 'single-sided' PCB design.

What transistors are you using?
Did you modify/tune your first-stage input to the different input transformer? (Zobel network etc..)

grT

What transistors are you using?
Did you modify/tune your first-stage input to the different input transformer? (Zobel network etc..)

Click to expand...

I did not like the OEP much, cant remember what Zobel values I used (probably the wrong ones, hence the sound) even though I have liked their transformer in other designs, the Lundahl sounds fantastic with no Zobel network, I will experiment further when I have the Sowter version done.

peter