Search found 699 matches

by Gold
Mon Jul 26, 2021 1:28 pm
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 249
Views: 6531922

Re: Phono Transfer System Construction Information

I have the low impedance heads on my 1/2" machine. I have high impedance heads on the 1/4". I can scan that one too. It has a 1:10 step up transformer that is terminated on the secondary with a 180K resistor in parallel with a 33p capacitor. After the front end it's exactly the same as the...
by Gold
Mon Jul 26, 2021 12:03 pm
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 249
Views: 6531922

Re: Phono Transfer System Construction Information

i think the schematic you're looking for is in the A80 VU Mk II … IV file. That's correct. I have three A80VU Pre. They are not strictly any vintage. My 1/4" machine has the MkI frames with the Weston meters but the electronics are MKII. I'm not sure about all the differences between models me...
by Gold
Fri Jul 23, 2021 11:51 am
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 249
Views: 6531922

Re: Phono Transfer System Construction Information

For both 15 and 30 IPS? Anything will do. Just one setting will work. This would just be for 'proof of concept'. As long as I can hook it up and play a tape it will give me enough information to know whether I want to pursue this further. I know there won't be adjustable Hi and Lo frequency adjustm...
by Gold
Thu Jul 22, 2021 2:53 pm
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 249
Views: 6531922

Re: Phono Transfer System Construction Information

Cool. What would it take to convert the RIAA EQ to an NAB or AES EQ?
by Gold
Wed Jul 21, 2021 12:06 pm
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 249
Views: 6531922

Re: Phono Transfer System Construction Information

Wayne, I didn't want to make the scans so big you couldn't see the whole circuit. I can see the component values aren't readable that way. I could post the full size version for download if that would be better. Anyway R20 is 56K. That's the first resistor at the input between each end of the coil i...
by Gold
Tue Jul 20, 2021 5:42 pm
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 249
Views: 6531922

Re: Phono Transfer System Construction Information

Here is a scan of the transformer less preamp that is used with 1/2" heads. I'll scan the 1/4" preamp soon.


Image

Image
by Gold
Wed Jun 30, 2021 12:10 pm
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 249
Views: 6531922

Re: Phono Transfer System Construction Information

I didn’t think the Telefunken M10 had a standard set of electronics. I had one in a Neumann SP66 console. The playback electronics were manufactured by an RFT company that wasn’t Neumann. I forget which one. That setup didn't sound as good as the M15 which sounds fabulous. I’ll have a chance to scan...
by Gold
Wed Jun 30, 2021 12:06 pm
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 249
Views: 6531922

Re: Phono Transfer System Construction Information

My machines all have the correct heads for the given electronics. The machines have been completely restored and gone over by Dan Zellman and Bob Shuster. Both are factory trained Studer technicians with decades of experience servicing them.Nothing is broken. The machines work like new. I’m looking ...
by Gold
Tue Jun 29, 2021 10:53 am
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 249
Views: 6531922

Re: Phono Transfer System Construction Information

I have a sheet with the impedance of the heads in Henries. The heads on each machine are a different impedance IIRC. I'll scan both preamp versions. I'm thinking of this more as 'proof of concept' than trying to get a finished build.
by Gold
Tue Jun 29, 2021 10:18 am
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 249
Views: 6531922

Re: Phono Transfer System Construction Information

I thought the main determining factor would be the impedance of the head. I realize the EQ section doesn’t have provision for adjustable low frequency and hight frequency adjust but that can probably be worked around. The 1/4” machine uses a preamp with a step up transformer. The 1/2” and 1” use tra...