• The Vendor's Bazaar forum is for commercial offers and transactions. Only unmoderated members can post here.

    diyAudio provides this forum for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members. Use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

First One - mosFET amplifier module

Jump to Latest
#3,644
Erlend Sæterdal said:
TO USE FIRST ONE M with a Tube pre ( Lua Serenada MK II) I woul like to increase the input impedance to 47 kohm. Would this be ok?
Click to expand...
This topic was actually explained a long ago, nevertheless we can do it again. Input impedance of the First One module could be raised to 25 kOhm without serious degradation of noise, stability or DC offset performance, although an effect is linear, higher Zin value is not recommended. Anyway preamp connected will dictate much lower impedance, in a case of Lua that will be 600 Ohm (output impedance) across interconnect cable, so cable's influence on the sound will have much more important role here.
 
#3,651
maxlorenz said:
We are looking at great builds here!

Dear Zas,

Congratulations for a beautiful case.

IF you prefer passive volume control, please consider Transformer based Volume Control (TVC) as it works great with the FO. It has various advantages like BAL/unBAL in/outs possible configurations, galvanic isolation, possibility of wiring as autoformer for claimed optimal linearity (which I have not used, as it defeats the former), very dynamic sound with high Vout sources as the EMF is conserved.

Amicalement,
M.
Click to expand...

This is an interesting thought. The designer of the DACs I will be using strongly recommends use of the balanaced outputs. I happen to already own a TVC so I could use its RCA output to feed the FO. I wonder how this would compare to the That 1200 option? Thoughts welcomed.

Also I have an active set up and the other amps I'll be using have a gain of 26db. I could therefore use the TVC to attenuate the 27db gain of the FO with the volume control in a fixed position - overall system volume control would be done with the digital volume control of the DAC.
 
Last edited:
#3,654
Hi Studley,
the bankcaps are made with 2 AudioGrade mlytics 3300u/100V each having 41miliohm ESR, this is high quality caps so if you have other caps , make sure they desserve it.
More caps on the SMPS rail will bring better (smaller) impedance and therefore beter capability to deliver pike current, and they will also smooth the 100hz ripple, which will have good impact to reduce IMD and then better sound.

LC bankcap also includes a wima 220nf and a duelund bypass as an option. So this demonstrates that tuning the SMPS impedance is a complex task and not just pluging caps here and then 🙂

but be carreful their was a post (I think from fab) saying that the hypex PCB came to smoke with 15mf per rail (from my memory)
 
Last edited:
#3,655
Thanks maxidcx. You convinced me that I should use LC's cap banks. Do they have to be mounted on the heatsinks as LC has shown in his photos?

Also, I know you talked earlier about using the That 1200, so I'd be interested in your thoughts re my post number 3651.
 
#3,656
Well the bankcap will be more efficient as close to the FO as possible, this is the only guidance for placing it.
That1200 with proper +/-12v reg (like hypex HRx) will give you very highend results. But if you use 2 smps as recomended by LC and if you organise the cabling so that the 2 gnd converged as close as possible to the source gnd, then I foresee no benefit with differential
 
#3,657
Studley said:
Are you planning on offering a stereo or monoblock enclosures suitable for the L modules?
Click to expand...

Studley,

He doesn't have any more cases. I just got a private mail from him. Apparently, he is going to go into business selling a variety of FO components (e.g., PRE/DAC, AMP, SERVER) so he stopped offering them.

I asked him when this happen and am awaiting his reply. I'm curious what the pricing will be for the FO amps. I guess it will depend on his target market.

--Lenard
 
#3,658
lenard said:
Studley,

He doesn't have any more cases. I just got a private mail from him. Apparently, he is going to go into business selling a variety of FO components (e.g., PRE/DAC, AMP, SERVER) so he stopped offering them.

I asked him when this happen and am awaiting his reply. I'm curious what the pricing will be for the FO amps. I guess it will depend on his target market.

--Lenard
Click to expand...

Err, will the kits we know still be available at the similar prices? I am quite interested in the FO M modules, and why not a clever PRE/DAC à la Mytek but for DIYer at affordable money.

I hope LC's DIY bits stays as it is... why not aside finished products (as he offered) as these have for sure a market for non DIYer.

Claude

Claude
 
#3,659
ClaudeG said:
Err, will the kits we know still be available at the similar prices? I am quite interested in the FO M modules, and why not a clever PRE/DAC à la Mytek but for DIYer at affordable money.

I hope LC's DIY bits stays as it is... why not aside finished products (as he offered) as these have for sure a market for non DIYer.

Claude
Click to expand...

Claude,

It was just the cases that he wasn't going to sell anymore. At least that is how I understood it.

Who knows, maybe he figured that it would take away the incentive to purchase the finished product if he offered a full DIY kit.....maybe it is a sign that his FO products will be competitively priced compared to DIY! 🙂

--Lenard
Save
Save
Save
Save
Save
Save​
 
#3,660

Attachments

  • IMG_0267.JPG
    IMG_0267.JPG
    836.7 KB · Views: 493
You must log in or register to reply here.
Top Bottom