Siemens V276 MicPre

[Fishsound]

I am building the Mic PreAmp Siemens v276 (schematic on www.bloemsma.tk) and ran into some trubble concerning the gain-knobs (connection for fine-adjustment-knob) and certain elements called "dr2" "dr3" etc..(what´s that?) on the schematic. Anyone having some v276 building experience?

 

[CJ]

those look like inductors but I do not know the values.
Maybe Ollover at Tab would know, but he is kind of a tube head.
cj

 

[NewYorkDave]

Drossel (inductor).

 

[Fishsound]

thanx. Drossel, that makes sense...the values seem to be secret, though :?

 

[soundguy]

its a hipass filter that is ALWAYS in the circuit. I have originals, IMO I would leave them out altogether if I was cloning one. This ciruit I bet would be nice with lundahls I bet. Still cheaper to buy one than make one considering what you have to spend on a three position switch for the gain.

dave

 

[gyraf]

[quote author="soundguy"] Still cheaper to buy one than make one considering what you have to spend on a three position switch for the gain.[/quote]

It's a 6-position switch! Very, very expensive thing....

 

[mig27]

Original V276 preamps can be had dirt cheap at eBay.de
They hardly fetch more than $250.00.

I know this is against DIY spirit but you can still mod and recap them :roll:


michael


p.s.:

here are two current auctions (not my gear - not affiliated...)
http://cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&category=22048&item=3847682840&rd=1&ssPageName=WDVW
http://cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&category=22048&item=3847693929&rd=1&ssPageName=WDVW

there's also a V272 up for grabs:
http://cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&category=21776&item=3757559302&rd=1&ssPageName=WDVW

 

[soundguy]

the gain switch in mine is a three tier switch that must be at least 15 positions if not more, I dont think you'd have many alternatives outside of an Elma. The gain switch is an expenseive one.

dave

 

[volki]

[quote author="soundguy"]its a hipass filter that is ALWAYS in the circuit. I have originals, IMO I would leave them out altogether if I was cloning one. This ciruit I bet would be nice with lundahls I bet. Still cheaper to buy one than make one considering what you have to spend on a three position switch for the gain.[/quote]

D2 is part of a HPF for sure, but what about D1 and D3 in those feedback loops? if they're left out, mighn't the phase response of the loops get altered and introduce the danger of instability...?

as for the gain switch, there's this guy in the u.s. who's selling those 10pos. 4wafer grayhill's for 20 or 30$ a pair on ebay. you could get those, leave out one of the 11 original positions, and use another proprietary switch for the input pad in front of the xformer. maybe even just a dip switch with only one pad arrangement. at least myself hardly ever uses the lowest gain settings...