sr1200
Well-known member
Ive got pots on all of mine. Dont really notice any noise per se but my guess would be it depends on the quality of the pot. And ps, being able to push that gain stage is awesome and well worth any noise trade off.
8 Channel, 3U NEVE 1073 completed
- Thread starter madriaanse
- Start date
Help Support GroupDIY Audio Forum:
critterkllr
Well-known member
sr1200 said:
Thanks. I have a bunch of PEC 5K log pots and it would be easy to just hook one up I guess. I'm just getting nit picky in the planning stage before actually hearing it
FWIW I also put pots on all 8 of mine. They wouldn't be the same without them. Highly Highly recommend the trimmers, like sr1200 says being able to push the gain and pull the trim back brings out something, how do we say like Mr Neve, 'Sweet' 8)
The trimmers really make them more versatile for me.
Chose some high quality conductive plastic pots linked earlier in the thread or similar. I think they cost me some ~$8/ea and feel smooth. I cannot comment on added noise, I would assume this comment is relating to the distortion which I concur. Again they really sound something sweet when driving the front end with full ~full gain and the trimmer pulling the output level back.
The trimmers really make them more versatile for me.
Chose some high quality conductive plastic pots linked earlier in the thread or similar. I think they cost me some ~$8/ea and feel smooth. I cannot comment on added noise, I would assume this comment is relating to the distortion which I concur. Again they really sound something sweet when driving the front end with full ~full gain and the trimmer pulling the output level back.
tomas1808
Well-known member
Any reason not to use a rotary switch instead of a trim pot?
critterkllr
Well-known member
Can anybody recommend a suitable transformer alternative to the 62085-P2S02 listed in the bom? I've had 2 on backorder from Digi-Key for a month and just finally received an estimated lead time of December 19th. I have 2 x EZ1290s (plan on having 4 eventually) and have the JLM ACDC. Everything is ready to go waiting on the transformer. I'm a bit of a noob when it comes to PSUs.
Should this do the trick? http://www.digikey.com/product-detail/en/70085K/TE70085-ND/251503
Should this do the trick? http://www.digikey.com/product-detail/en/70085K/TE70085-ND/251503
Chrome Heart
Well-known member
http://www.hammondmfg.com/182.htmcritterkllr said:
critterkllr
Well-known member
Chrome Heart said:
Maybe I should have mentioned this is my first time building a power supply and have no idea how to calculate/design around a transformer. None of the hammond transformers I've found have the same specs as the transformer listed in the bom 62085-P2S02. Specifically, the Hammond's are all at 24V and the Amveco is 22V. Also, the Hammond's have dual secondaries, would I just wire it up with one of the secondaries disconnected? Is it a better choice than the pcb mount Amveco in my link?
Chrome Heart
Well-known member
I thought the Amveco had dual secondaries. I see a couple of 22V torroids on the Hammond list that look like they would work. Maybe Im wrong. It wouldnt be the first time.critterkllr said:
http://www.hammondmfg.com/pdf/182%20Insert.pdf
Awesome! Thanks for pointing out the hammond options. I think I've narrowed it down to this model... http://www.mouser.com/ProductDetail/Hammond/182L12/?qs=%2fha2pyFaduhkZsoALO1xLH8m%2fA88eyezwSWKx62QmIo%3d
There's also a 30 VA option
Can anyone confirm this will work for one or two channels? I'm a noob when it comes to power transformers, and just want to be extra sure... Thanks
There's also a 30 VA option
Can anyone confirm this will work for one or two channels? I'm a noob when it comes to power transformers, and just want to be extra sure... Thanks
critterkllr
Well-known member
wimmy7986 said:
For one or two channels, Digi-Key has this in stock: http://www.digikey.com/product-detail/en/62075-P2S02/TE62075-ND/299875
Not sure if it will work, but it seems like it should.
Chrome Heart
Well-known member
795mA seems a bit on the light side to me. The 62085 in the BOM is 1.13A. I would opt to go higher than lower.critterkllr said:
critterkllr
Well-known member
Chrome Heart said:
I know it's been discussed before, but I talked to Joe at JLM and he said one should power 4 with phantom power. I picked one up and am powering 2 with it.
Harpo
Well-known member
Seems a lot over the top. A 1290 will draw 125mA of DC current. 250mA for two. Add current draw of enabled +48VDC phantom rail 2 Ch.* worst case 14mA * form factor 4 from voltage doubler circuit, current draw of voltage regulators network and some status LEDs on top, the 795mA AC current of the Amveco 62075 with paralleled secondary windings seems sufficient for two channels, delivering up to 795mA AC/form factor 2.3 from halfwave rectifcation=345mA DC. As always YMMV.desol said:
I can't recall exactly the value, but I want to say the inrush was quite a bit higher.
desol
Well-known member
- Joined
- Jun 20, 2005
- Messages
- 2,168
It was a while ago, but I remember blowing a 2.5 amp fuse upon powering up my 8 channels. I decided
to measure the inrush current...and it clipped about 3.2 amps dc....then settled at around 800 mA.
Threw in a 3 amp fuse...no more problems.
to measure the inrush current...and it clipped about 3.2 amps dc....then settled at around 800 mA.
Threw in a 3 amp fuse...no more problems.
critterkllr
Well-known member
It seems like a lot of guys don't have access to an oscope and signal generator. Did anybody do a before and after to test the difference between biasing correctly and the ballpark voltage listed? I hooked mine up before because I let somebody borrow my oscope. It sounded good before, but after biasing seemed to sound wider with more of the signature pronounced chunky low mids. Sound went from very Neve inspired to Neve.
Just wondering if others could share their experience so people without a scope could potentially make some adjustments using their ears.
Just wondering if others could share their experience so people without a scope could potentially make some adjustments using their ears.
Chrome Heart
Well-known member
Page 84 of the thread had a discussion on that topic recently.critterkllr said:
critterkllr
Well-known member
Chrome Heart said:
Checked the thread a few times for the audio difference between biased and under/over biased and can't find anything.
One more question. What are the different specs on using a 5k or 10k pot for trim? -20db, +/-10db, etc? Is it passive with unity turned fully clockwise, or active like some Neves where unity is at the center?
