The No.1 Website for Pro Audio
 Search This Thread  Search This Forum  Search Reviews  Search Gear Database  Search Gear for sale  Search Gearslutz Go Advanced
Studer B30 tube tape recorder
Old 24th August 2012
  #31
Quote:
Originally Posted by artmanjam View Post
Hi Anghello, some misunderstanding here, Studerfreak was talking about test tapes I guess, not tapes...

BTW RMG tapes are produced by Pyral in France now. I would like to think it's a good news...
Yeah.. first time it was misunderstanding and i did edit my post that its about usual tapes only. But then I made a research and found out that they produce test tapes also!
Old 24th August 2012
  #32
Lives for gear
 
Studerfreak's Avatar
 

Quote:
Originally Posted by artmanjam View Post
Hi Anghello, some misunderstanding here, Studerfreak was talking about test tapes I guess, not tapes...
You guessed perfectly right: I was talking about TEST tapes and these are not made anymore.
Old 26th August 2012
  #33
Gear Nut
 

Quote:
Originally Posted by Studerfreak View Post
If you take the head cover plate off, you will notice a adjustable capacitor C61 (trimmer) which controls the amount of HF bias.
Hi,
Here's an update about my machine: tape path is ok, relapped heads are set up, here is the frequency response (Rec 15ips):



Hi frequencies are still increasing more than they should but global sound is ok, even with this extra high end... I'm really intrigated by the fact I can't set up hi freqs, I mean Rec Eq pot is fully counterclockwise but still too much highs. I already encounter this on my J-37. That's why I'm wondering about SM900...

I've been unable to set up the Bias with hi freq, there are 2 successive peaks. So I went to your 30Hz method and everything was totally clear then, I choosed the second peak to overbias then :-)

After 250nWb alignment, I tried a 355nWb one (15ips). Seems to work!

Unfortunately, one issue's remaining, some bad 50Hz buzz and tons of harmonics: noise is @-41dBu at powering up, I mean without playing/recording on tape... Not happy with that as I don't know how to figure it out :-(
Old 26th August 2012
  #34
Lives for gear
 
Studerfreak's Avatar
 

Recording alignment is done with first setting the record level by sending a line level 1 KHz tone and adjust the recording level to get the same level back from the playback output.
Then turn the output of the oscillator down with 20 dB and then see what you get as playback frequency levels going from 20Hz to 20 KHz.
Assuming that the bias level has been set correctly.
In your frequency respons I notice that you keep sending 0 VU levels from 30Hz to 12 KHz and then you switch to -10 at 16KHz.
I hope that you did that by mistake.

So: set bias level
If you use the -10 dB at 10 KHz use the largest peak and adjust for overbias of 3 dB.
Set record level
Go down 20 dB and set record frequency response.

You may get quit different results...

50Hz buzz etc: Are youmin a 50Hz country ?
Is your wiring OK ? Grounded properly ?
Maybe a power supply issue ?
Old 26th August 2012
  #35
Gear Nut
 

Thank you for your advice, here's the frequency response while recording a -20dB signal. What do you think about?



About the buzz, I didn't notice that before all the work which has been done. The machine is properly grounded I guess, I just tried another power cable just in case, no change... I recorded the buzz to check the frequencies so I guess it's some AC frequency, out of my knowledge unforftunately :-))

I'm running the machine quite everyday to check anything faulty feature. All transport functions work ok. The only thing which still has to be done is to change the flywheel roller bearings which are press mounted. I won't do it by myself and have to find some competent guy to take the bearings off...

BTW, after one hour running, the deck is really hot, is it usual?
Old 29th August 2012
  #36
Gear Nut
 

Some hidden things on this machine: the roller guide located behind the head block can be used for an endless tape loop. The roller can be just pulled off, nothing to unscrew. But...

Surprise, there's a 3-pin DIN connector on bottom of roller location hole ! What is it for?
Old 29th August 2012
  #37
Lives for gear
 
Studerfreak's Avatar
 

Quote:
Originally Posted by artmanjam View Post
Some hidden things on this machine: the roller guide located behind the head block can be used for an endless tape loop. The roller can be just pulled off, nothing to unscrew. But...

Surprise, there's a 3-pin DIN connector on bottom of roller location hole ! What is it for?
Yes, indeed ! The roller guide is for endless tape loops.
In the original documentation this is specified as a special feature.
The tape loop should be approx. 109 cm and you then have 5,5 seconds at 19,05 cm/s (7,5") or 2,75 seconds at 38 cm/s (15")

You also found the cleverly hidden three pole Tuchel T3268 connector ! Well done !
That connector is for measuring erase current, bias current and LF record current.
You must use a vacuum tube volt meter for that.
Erase current: In series with the erase head is a 10 ohm resistor (R92). To adjust the erase current of 45-60 mA you must measure a voltage of 450-600mV between pin 2 and 3 of the three pole connector.
Bias current: In series with the record head is a 100 ohm resistor (R91).
to adjust the HF bias current of 3,5-8 mA you must measure 350-800mV between pins 1 and 2 of the three pole connector.
LF current: Can be measured following the same procedure as with Bias current, but you have to pull the oscillator tube (V6) first.
Which makes perfect sense, because at the record head you normally have the combination of LF and Bias when in record mode, so if you want to measure the LF current you have to take the HF away - simply done by just pulling the tube out of the socket.
Old 3rd September 2012
  #38
Gear Nut
 

Thank you for the great infos, looks like the machine has no secret for you! You're talking about 3-p Tuchel, do you mean it's different from a 3-p DIN?

I'm checking the machine several days a week, it works great. I'm still surprised the recorder to be so hot after one hour working, it's a compact device and there's no fan so that's the way it is I guess...

The flywheel bearings are still to be replaced and the only last issue is the 50Hz buzz @-41dB. Once this fixed, the machine should be fully operational. I can't stand having some tests for voice recording. I feel like the nice high end should be exciting to check with different voices and mics...
Old 3rd September 2012
  #39
Lives for gear
 
Studerfreak's Avatar
 

Quote:
Originally Posted by artmanjam View Post
Thank you for the great infos, looks like the machine has no secret for you! You're talking about 3-p Tuchel, do you mean it's different from a 3-p DIN?
The original documentation says Tuchel, but 3-p DIN will fit as well.
"If it fits -you can use it..."

Warm: No fan, but 8 tubes producing heat and heating the thick, heavy, metal top plate.

Buzz: Try to change V1 with one of the other tubes, or a new one.

I will try to find my B30 documentation, because I remember that the alignment of the record side had something special.
How is your German language ? Could save me translation work
"I'll be back....
Old 3rd September 2012
  #40
Gear Nut
 

Quote:
Originally Posted by Studerfreak View Post
Warm: No fan, but 8 tubes producing heat and heating the thick, heavy, metal top plate.
That's what I thought...

Quote:
Buzz: Try to change V1 with one of the other tubes, or a new one.
I think I did it already, not sure, I'll check it again.

Quote:
How is your German language ? Could save me translation work
"I'll be back....
Deutsch kann ich lesen, dafür brauche ich nur mein Wörterbuch ;-) I know hi freq is special, recording 10kHz, notice the level difference, do nothing, record 1kHz and adjust Entzerrung by the relevant value. But it looks like it decreases (or increases) the general gain value so it looks quite obscure to me...
Old 16th February 2013
  #41
Gear Nut
 

I've been back to some setup on the machine. I tried SM911 instead of SM900 and went back to 250nWb/m.

It works but the high freqs setup problem is still there. I've been told it has to see with modern tapes which feature better hi freqs repro performances than tapes from the old days...

Even with Rec & PB Entzerrung at lowest setup, fully counterclockwise, I get a rise in high freqs. So I guess some mod in the electronics could improve that. I tracked some acoustic instruments (guitar, mandola) and the result is really interesting. Very nice high freqs compression :-)

The only real issue is still the 50Hz noise (-41dBu). I tried to swap the V1 tube with no effect. It's there at powering up, no matter if the machine is in play/rec or stopped mode.
Old 30th July 2013
  #42
Gear Nut
 

So, the machine has been checked by the tech. Unfortunately, the 50Hz buzz (-41 dB) couldn't be solved. Still a mystery. Looking for any advice!
Old 30th July 2013
  #43
Lives for gear
 
Studerfreak's Avatar
 

The filaments of the V1 and V2 tubes are supplied with a DC voltage from bridge rectifier GL3 (B30C600) and C32a-b-c (3x 400 uF).
Did you replace that C32 ?
I am not sure, but I think C32 is one aluminium housing that contains three capacitors.
V3-4-5-6 and V8 are fed with AC, directly from the power transformer.
Also V7 is powered with AC, but from a different winding of the transformer.
If you have an oscilloscope check the ripple of the DC voltage on V1 and V2.
If the ripple is quite high, check the capacitors and bridge rectifier.
Do you "close" the reproduce head with the greenish handle in front of the head block ?
That handle puts a screen before the reproduce head and needs to be used.

Oh: I have sent you a P.M.


Keep up the good work !

Last edited by Studerfreak; 30th July 2013 at 07:38 PM.. Reason: Add info
Old 24th October 2015
  #44
Gear Nut
 

Ok, the B30 has been left aside for a while so I'm back to it. I didn't make it work for more than one year, that's bad. The idler didn't work smoothly, it was hard to have it go back to rest position. I just had to clean the piston, the grease was dry, everything's ok then. Good news, the hum is gone :-)

So I made a new alignment tour, adjusting heads, playback, bias and record. I had to manage something in between as with regular setup I had a boost beyond 7/8kHz and a 1dB loss from 2 to 6 kHz. Result was recorded material was nice but darker than original one.

Changing bias a bit and adjusting hi freqs was the right thing. The machine sounds amazing now, particularly on voice, delightful! It sounds warm and creamy, I intend to use it with the Clasp to record voice soon.

Apart from that, the 7.5ips light bulb is dead. Nothing serious indeed but I just wonder how I could find any replacement bulb. It's a bulb inserted in a bakelite support with a flat metal contact to be inserted in the connector. Didn't find anything accurate on the web. I tried with a standard new bulb, it works but the bulb is too long, no space enough for it...
Attached Thumbnails
Studer B30 tube tape recorder-6v-lightbulb-2.jpg  

Last edited by artmanjam; 24th October 2015 at 04:31 PM..
Old 24th October 2015
  #45
Lives for gear
 
Studerfreak's Avatar
 

The original lamps for this Studer B30 (and a lot of other equipment from that period) were made by the company RAFI in Germany.
In German they were called "Steckmesserlampe" and the type was ML26.
I think it may be possible to use the old socket to solder a new lamp on it.
Old 26th October 2015
  #46
Gear Nut
 

Thank you so much for the accurate infos, Studerfreak ! They let me find something, I ordered a few lamps, they're 4mm longer, don't know if they will fit, I'll tell about as soon as I get them... I wonder if they're the same on C/J37 to light the transport buttons.

Soldering a new bulb could be the solution but modern lamps have a squared base which won't match with the old socket unfortunately, old ones were sharp and I don't know if one can find such bulbs anywhere...
Attached Thumbnails
Studer B30 tube tape recorder-elektronik-lavprisdotdk.jpg  
Old 26th October 2015
  #47
Lives for gear
 
Studerfreak's Avatar
 

The lamp on your photograph may fit.
The lamp base seems to be the same as the old one.
What I meant with "solder a new lamp" is that there are small wire ended lamps available and it could be possible to solder such a lamp to the old socket.
Make sure, if you try that, to cool the old socket as the heat of the soldering iron may melt the plastic socket.

The old B30 lamps most likely are the same as the C/J37's as these RAFI lamps were widely used in a lot of old broadcast equipment.
Old 8th February 2016
  #48
Gear Nut
 

Ok, I finally got the lamps... Finding 6V ones has been a mess actually but here they are. They fit, I just had to slightly cut the plastic end as there's no extra-space for...
About the bulbs themselves I couldn't find single bulbs which could fit and be soldered in the original socket. Old ones are conical but modern ones are rather squared.
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Similar Threads
Thread
Thread Starter / Forum
Replies
Mark1353 / So Much Gear, So Little Time
16
andychamp / High End
4
niteflite / High End
40
Dr Funk / So Much Gear, So Little Time
7

Forum Jump
Forum Jump