Tape Project Forum

Tape Machines => Tape Project Machines => Topic started by: docb on March 03, 2010, 12:26:45 PM

Title: Studer A810 head rewire
Post by: docb 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.
Title: Re: Studer A810 head rewire pic 2
Post by: docb on March 03, 2010, 12:27:40 PM
Here is a detail of the headblock switch:
Title: Re: Studer A810 head rewire - jacks
Post by: docb on March 03, 2010, 12:28:16 PM
And here are the added jacks:
Title: Re: Studer A810 head rewire
Post by: Ki Choi 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
Title: Re: Studer A810 head rewire
Post by: High and Outside 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.
Title: Re: Studer A810 head rewire
Post by: docb 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.
Title: Re: Studer A810 head rewire
Post by: audioblazers 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
Title: Re: Studer A810 head rewire
Post by: docb 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.
Title: Re: Studer A810 head rewire
Post by: audioblazers 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
Title: Re: Studer A810 head rewire
Post by: Ki Choi 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
Title: Re: Studer A810 head rewire
Post by: audioblazers on March 10, 2010, 05:16:01 AM
Yes, tube repro has balanced input
Title: Re: Studer A810 head rewire
Post by: MylesAstor 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
Title: Re: Studer A810 head rewire
Post by: audioblazers on March 11, 2010, 12:51:05 AM
Raven AC 3 with schroeder 2fw and ortofon A90. Waiting for raven 10.5 tonearm
Title: Re: Studer A810 head rewire
Post by: audioblazers 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
Title: Re: Studer A810 head rewire
Post by: audioblazers 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
Title: Re: Studer A810 head rewire
Post by: ironbut on July 24, 2010, 12:35:43 PM
Hi Song,
Glad to hear that you've narrowed down the problem.
Unfortunately the nos tube market is getting pretty low for some of the more sought after items. When it comes to the really big money tubes (like the TFK EF806s) it really pays to buy from a good tube dealer. That gives you some return options.
One thing that you should try before tossing any "bad" big money tubes into the trash is to spend a little time and clean the pins. On premium tubes, the pin surface is usually very smooth so any bumps that you can feel with a swab is probably oxidation.
If they're steel pins (as with the TFK) a little contact cleaner and something like a piece cut off of a Scotchbrite pad works pretty well. Be very gentle and as always, use the minimum amount of contact cleaner. I use some generic stuff called "Super Contact Cleaner" from MG Chemicals that's stocked at my local electronics store.

As Doc had mentioned quite a while ago, it's worth cleaning the pins of all the tubes in your Repro since it does lower the noise floor a bit.
Title: Re: Studer A810 head rewire
Post by: audioblazers on July 26, 2010, 11:43:12 AM
I did try cleaning it with Progold but it didnt help much. I suppose I need something more abrasive. Well, at least I knw that the tube rush sound that I have been hearing is due to TFK ef 806s that I have been using. I suppose it better to buy from more reliable seller but it wouldnt be cheap.
Will be comparing my amperex 7308 PQ with telefunken e88cc and e188cc and lets see how it goes
Title: Re: Studer A810 head rewire
Post by: ironbut on July 26, 2010, 01:02:28 PM
Yeah, ProGold works better as a protective coating once the pins are clean.
You should clean the pins with something that removes oxidation before using ProGold or you're just sealing it in.
Title: Re: Studer A810 head rewire
Post by: jcmusic on July 26, 2010, 02:23:26 PM
I did try cleaning it with Progold but it didnt help much. I suppose I need something more abrasive. Well, at least I knw that the tube rush sound that I have been hearing is due to TFK ef 806s that I have been using. I suppose it better to buy from more reliable seller but it wouldnt be cheap.
Will be comparing my amperex 7308 PQ with telefunken e88cc and e188cc and lets see how it goes
Song,
If you are using these tubes with the Seduction in my system the Telefunken E88CC is the clear winner, closely followed by the Amperex JAN white labeled 7308 from the 1960's not the PQ version. The PQ version did not work in my application, all others were similar. Forgot to mention that I found the same results in my Tube Repro!!!

Jay
Title: Re: Studer A810 head rewire
Post by: audioblazers on July 27, 2010, 09:22:09 AM
I m using tube repro. I got both tfk e188c and e88cc. Lets see how it goes. I m curious whether we can use tfk 804s in place of tfk ef 86 or 806s? saw a posting in whatsbestforum and was told its good
Title: Re: Studer A810 head rewire
Post by: microstrip on August 17, 2010, 05:48:09 PM
Yeah, ProGold works better as a protective coating once the pins are clean.
You should clean the pins with something that removes oxidation before using ProGold or you're just sealing it in.
If the tube pins look dirty or oxide I clean them with a Dremel felt polishing tip at 12000 rpm. Only in desperate cases I use se a bit of polishing cream. After that I wash with water and soap using a tooth brush, rinse with plenty of water and a give a final wash to the pins using ethanol. Progold is just the final touch to protect them.
Title: Re: Studer A810 head rewire
Post by: audioblazers on September 01, 2010, 10:17:27 AM
Correction- I have always thought that my hum issue was due to bad tfk ef 806s. Purchase 4 pairs and still experienced hum problem. After some trouble shooting with Doc, and connecting ground wire fr Studer to Repro, my hum virtually vanished. Credit to Doc for his excellence customer service for taking the trouble to guide me thru my problem- even sent me drawing to make sure I understand his instruction.
Title: Re: Studer A810 head rewire
Post by: ironbut on September 01, 2010, 11:31:06 AM
Great news Song!
So, now that that's straightened out, how is the Studer/Repro sounding?
Title: Re: Studer A810 head rewire
Post by: xcortes on September 01, 2010, 05:29:14 PM
Quote
I have always thought that my hum issue was due to bad tfk ef 806s. Purchase 4 pairs

They were scarce before. Now I'm pretty sure you purchased the remaining stock!
Title: Re: Studer A810 head rewire
Post by: audioblazers on September 03, 2010, 11:22:37 AM
Xavier , not too scarce , just got to be patience. For 6922 tube, I have tfk e88cc, e188c and amperex 7308 PQ Holland, any idea which is better. A little lazy now. Just got myself a raven 10.5 (on raven ac3) as my 2nd tonearm with zyx omega gold, love it

Steve, on studer A810 stock electronic I don't find tape that exciting but with tube repro, it's out of the world and To my ears way better than my LP set up particular TP016, Rock with me baby , such quiet background and when Hatch sings it's as though he is In my room. To me , reel to reel is the source if you want the best music reproduction. If I m from USA, I will probably hunt for A820 but in Malaysia without tech support it's tough. Reel to reel is definitely a much cheaper entry to enjoy quality music production compared to most high end analog set up. With cables, phonostage, tonearms , cartridges , turntable which cost a couple of times the cost of studer/tube repro set up, I still prefer studer/repro and that sum up how I feels about studer/repro. Only set back is that we abt 26 tapes, 16 tapeproject tapes and 10 aaanalog tapes, listening to limited tapes can be boring. Wish I have at least 100 15 ips tapes 
Title: Re: Studer A810 head rewire
Post by: jcmusic on November 07, 2010, 08:51:15 AM
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.
Here are some pic's of my Studer's headblock mod.

Jay
Title: Re: Studer A810 head rewire
Post by: jcmusic on November 07, 2010, 08:53:15 AM
A couple more of the Studer and Otari.

Jay
Title: Re: Studer A810 head rewire
Post by: xcortes on November 07, 2010, 10:26:43 AM
Is there a tenth AAA tape? I only have nine.
Title: Re: Studer A810 head rewire
Post by: audioblazers on December 24, 2010, 12:49:16 AM
Xcortes. Somehow I missed your question. There is only 9 AAA tapes not 10. My mistake
Title: Re: Studer A810 head rewire - photos not "working"
Post by: stellavox on May 15, 2015, 07:54:15 AM
Hey guys,

I'm trying to view the photos (in Windows Photo Shop) and nothing is working - links OK?

Charles