SS and tube pre's in the same rack cage?

gerard

gerard

Member
Hi all, planning on putting 8 mic pre's in a rack cage. 2 of the pre's use 2 tubes each and I'm not sure of the plate voltsge (didn't get the tube specs yet) but the high voltage tranny close to the the other solid state pre's shouldn't cause any noise problems if I'm carefull with the mechanical and wiring layout, right?

Not sure of the tube pre's origin but it uses 1 6072 and 1 6414 each. The other pre's are 2 API 990C based, 2 API(?) 2520 based and 2 Shpere pre's. Got all the PCB/turret boards, some amps, tranny's (Jensen) and "fiddily bits". I just hope there isn't any "interaction" between the tube and SS pre's with the HV tranny in there. Thanks in advance!

Jerry
 
gerard said:
... high voltage tranny close to the the other solid state pre's shouldn't cause any noise problems if I'm carefull with the mechanical and wiring layout, right?
Click to expand...
Jerry, based on my miserable "experience", that's a tough question. I'd say you'll know the answer when you try and then if you get problem(s) you'd have to play around and see what can be done. If I was you, I'd make some "model-version" (so you can still move parts, transformers and boards around the chassis and test. Good luck.
 
The case of the tube pre should adequately shield it from any adjacent units (assuming it's steel or aluminium).

API opamps and Jensen trannies eh? I reckon those pres should sound pretty nice!
 
Thanks gents!

Yep, I'm gonna use an aluminum chassie/rack. Found 2 Paia Frack Rack units that I forgot about so I'll try to "stuff" them in. My friend gave me a stack of PCB's, some tranny's, amps, and a tri-output power supply "kit" for Chrismass so I'm taking the plunge to build them. (my kinda friend!) I would like to get all the parts at one time but I think my wife would shoot me since I'm putting a small project studio together and started to turn into a gear slut! Didn't know what I was getting into with the pre's till I priced the op amps. $70 just for the 990C! Yikes!

Can do a step by step of the project when the chips and solder start flying if anybody's interested.

Thanks again for the reply's gents!

Jerry
 
John Hardy sells his 990c for $50.

http://www.johnhardyco.com/prices.html

I might be teaching granny to suck eggs here but in terms of reducing the likelihood of noise within the box I’d recommend using toroidal power transformers. I’ve built several units (mic pres, EQs, comps) with internal power supplies using toroidals and with a decent star grounding scheme I never have any problems with noise.

Yeah it would be interesting to see how you get on.
 
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