Check out the new Tape Project website at tapeproject.com, now with online ordering. Inventory is updated every week, so stop by often to see what we have in stock.

Author Topic: Studer A810 head rewire  (Read 17974 times)

Offline docb

  • Administrator
  • leader in spreading disinformation
  • *****
  • Posts: 1345
    • View Profile
    • Bottlehead Corp.
Studer A810 head rewire
« on: March 03, 2010, 12:26:45 PM »
Here are the pics I promised of the finished playback head output modification we performed on a Studer A810. The small black pushbutton in the hole in the headblock cover allows switching the playback head from its normal connection to the internal playback electronics to a pair of XLR outputs that have been added to a blank plate on the top rear next to the existing XLR jacks. The only caveat with this setup is that you don't want to throw the switch with the machine turned on, as connecting it to the "hot" internal preamp will magnetize the head. So the procedure for switching is: power down the Studer and the external preamp, wait 60 seconds and then push the button.

It's quiet, there is plenty of output for a Tube Repro, frequency response is quite flat, all in all it's a nice combo.
« Last Edit: March 04, 2010, 06:20:51 PM by ironbut »
Dan "Doc B." Schmalle
President for Life, Bottlehead Corp.
Managing Director - retired, The Tape Project

Offline docb

  • Administrator
  • leader in spreading disinformation
  • *****
  • Posts: 1345
    • View Profile
    • Bottlehead Corp.
Re: Studer A810 head rewire pic 2
« Reply #1 on: March 03, 2010, 12:27:40 PM »
Here is a detail of the headblock switch:
« Last Edit: March 03, 2010, 12:33:31 PM by docb »
Dan "Doc B." Schmalle
President for Life, Bottlehead Corp.
Managing Director - retired, The Tape Project

Offline docb

  • Administrator
  • leader in spreading disinformation
  • *****
  • Posts: 1345
    • View Profile
    • Bottlehead Corp.
Re: Studer A810 head rewire - jacks
« Reply #2 on: March 03, 2010, 12:28:16 PM »
And here are the added jacks:
Dan "Doc B." Schmalle
President for Life, Bottlehead Corp.
Managing Director - retired, The Tape Project

Offline Ki Choi

  • Sr. Member
  • ****
  • Posts: 313
    • View Profile
Re: Studer A810 head rewire
« Reply #3 on: March 03, 2010, 04:06:14 PM »
Hi Doc:

Very nice work.  Is there a reason why you used the XLR connectors for direct head output than female RCAs?

Did you use twisted pair wires with additional shield (like the factory head wires with spring shield) or single shielded coax cable for each channel with shield carrying the common signal (like the Nagra factory head wiring)?

Hope you will still have the deck at your place when I can come visit for a listen!

Thanks,
Ki
Ki Choi

Offline High and Outside

  • Administrator
  • Sr. Member
  • *****
  • Posts: 344
    • View Profile
Re: Studer A810 head rewire
« Reply #4 on: March 03, 2010, 04:42:09 PM »
Very clean looking. But it seems a lot of trouble for a switch that will be used precisely one time.
Paul Stubblebine
Managing Director, The TapeProject

Offline docb

  • Administrator
  • leader in spreading disinformation
  • *****
  • Posts: 1345
    • View Profile
    • Bottlehead Corp.
Re: Studer A810 head rewire
« Reply #5 on: March 03, 2010, 04:56:51 PM »
Quote
But it seems a lot of trouble for a switch that will be used precisely one time.

I agree, but we had to try it. We get asked all the time for this kind of switching mod on Technics, Otaris, all of 'em. It worked well but it was a royal pain in the ass. The customer got this extra work for free since it was the first one and we were figuring out how to do it. The next guy will have to pay maybe $500 or so for the work. IMO that is money far better spent on premium tubes for one's Tube Repro.

In answer to Ki, the customer requested XLR connectors. We can do either on the Tube Repro input, and he asked for XLRs there, so it only made sense to do them on the machine as well. We used shielded twisted pair for the internal wiring. Achieving continuity with the spring shield on the head leads is a challenge.

Our customer has been waiting since before Xmas for this setup, which was held up while we waited for a 240V mains transformer to be made for the Tube Repro. It's now all packed and will probably ship in the next day or two.
Dan "Doc B." Schmalle
President for Life, Bottlehead Corp.
Managing Director - retired, The Tape Project

Offline audioblazers

  • Full Member
  • ***
  • Posts: 30
    • View Profile
Re: Studer A810 head rewire
« Reply #6 on: March 05, 2010, 10:16:16 AM »
I believe that would be my studer I sent to Doc for modification. I requested Xlr connector because I did not read Doc email carefully assuming that since the original connector is XLR, modified head output must be XLR as well. Would have use RCA, cheaper and easier to source for rca interconnect. However since there is a switch to playback original electronic, its a pleasant bonus with xlr connector.
Doc , neat work thanks a bunch
Happy Listening

Song Soon Onn

Offline docb

  • Administrator
  • leader in spreading disinformation
  • *****
  • Posts: 1345
    • View Profile
    • Bottlehead Corp.
Re: Studer A810 head rewire
« Reply #7 on: March 05, 2010, 10:53:36 AM »
Actually the XLR cable has the potential to be more resistant to hum pickup, so it's a pretty good choice.
Dan "Doc B." Schmalle
President for Life, Bottlehead Corp.
Managing Director - retired, The Tape Project

Offline audioblazers

  • Full Member
  • ***
  • Posts: 30
    • View Profile
Re: Studer A810 head rewire
« Reply #8 on: March 05, 2010, 11:07:28 AM »
That would be good news.
Eagerly waiting for Waltz for debby tape and the Studer and Repro so that I can compare it my original riverside LP
Happy Listening

Song Soon Onn

Offline Ki Choi

  • Sr. Member
  • ****
  • Posts: 313
    • View Profile
Re: Studer A810 head rewire
« Reply #9 on: March 05, 2010, 09:00:12 PM »
Hi Doc;

Since the A810 has XLR direct head outputs, do the Tube Repro also has XLR head input connections?

Thanks,
Ki
Ki Choi

Offline audioblazers

  • Full Member
  • ***
  • Posts: 30
    • View Profile
Re: Studer A810 head rewire
« Reply #10 on: March 10, 2010, 05:16:01 AM »
Yes, tube repro has balanced input
Happy Listening

Song Soon Onn

Offline MylesAstor

  • Full Member
  • ***
  • Posts: 218
    • View Profile
    • Positive-Feedback Online
Re: Studer A810 head rewire
« Reply #11 on: March 10, 2010, 06:35:04 PM »
That would be good news.
Eagerly waiting for Waltz for debby tape and the Studer and Repro so that I can compare it my original riverside LP

Song:

What are you using for an analog front end?

Myles
Myles B. Astor
Magico S5 Mk. 2/cj ART>cj GAT Series 2 preamp>Doshi 3.0 phono>VPI Vanquish/3D arm/Atlas SL/Ortofon A95 cartridges/SRA Ohio Class XL+2 base>Technics 1506/low ind. FM heads/balanced out/Doshi V3.0 tape stage>Kubala-Sosna Emotion/ Transparent Audio Gen. 5; Viero speaker cables

Offline audioblazers

  • Full Member
  • ***
  • Posts: 30
    • View Profile
Re: Studer A810 head rewire
« Reply #12 on: March 11, 2010, 12:51:05 AM »
Raven AC 3 with schroeder 2fw and ortofon A90. Waiting for raven 10.5 tonearm
Happy Listening

Song Soon Onn

Offline audioblazers

  • Full Member
  • ***
  • Posts: 30
    • View Profile
Re: Studer A810 head rewire
« Reply #13 on: May 15, 2010, 02:08:55 AM »
Finally I got my Tube Repro and my cable is too short (0.6m) for my Repro which is sharing the same shelf as my Studer. Temporarily holding it up with a storage box. Not ideal at all until I find a better solution
Have my Studer A810 for abt a 1 1/2mths, while it doesnt have the annoying ticking sounds due to dirty vinyl and sounding pretty natural, I find it lacking in bass and not so dynamics. It certainly doesnt float my boat with the stock electronic. With the Tube Repro hooked up, its so much more dynamics and exciting. It has been burnt in for abt 150 hrs by Paul, with another 50 hrs , I believe it should be better. Only grouse I have so far is the presence of a very audible hum when its on standby and in between song. Not very acceptable hum. Both stock and NOS telefunken ef 806s I used is noisy. To be fair I have only 2-3 hrs on it. According to Dan, hopefully after 50 hrs the telefunken ef 806s will quieten down. Anybody with Tube Repro has such experience ?
Other than the noise, it sounded superb. Despite such brief listening I dare said its probably better than my Raven AC3, schroeder fw tonearm, Ensemble phonostage and Ortofon A90 catridge costing more than 3-4x reel to reel set up
Happy Listening

Song Soon Onn

Offline audioblazers

  • Full Member
  • ***
  • Posts: 30
    • View Profile
Re: Studer A810 head rewire
« Reply #14 on: July 24, 2010, 10:39:02 AM »
Feedback

The hum that I posted in the previous thread is due to noisy telefunken ef 806s. When I replaced it with a newly purchase pair of ef 806s , it was very quiet and without hum/. Unfortunately 1 of the tube is defective. What a frustrating experience. Looks like I will replace it with GEC CV 4085 and see how it perform
Happy Listening

Song Soon Onn