Reel to Reel Head Wire out and associated topics
- Thread starter tony ky ma
- Start date
Yea although what Tang is describing is an even greater sensitivity. Feeding the Doshi with the Studer preamp output would result in a crazy high output level.
Yes he said when he play Ed's he connected A820's out put to his pre amp (line stage ) not Doshi, and he has a switch selector for head to Doshi or back to A820, and I don't know what type head in his A820, in A80 RC and A80VU has different impedance head, RC type's head has higher impedance than VU type so the repro amp in VU has a in put transformer in the first stage for more gain
tony ma
tony ma
When I used Doshi, I connected it to the Headout not the Studer repro output. Exactly like Tony said.
Tang
Doshi in Mike's A820 and Steve's A810 both working OK for Ed's tape, I checked with the Studer A810 service instructions the transport is no change but different year made in different electronic circuit design some with transformer but some is transformerless because of different impedance head in used some of them is butterfly head, A810's head is low impredance so right behind repro head has a line level amp for enough gain amplifying first before go to repro amp, so Doshi for Steve's A810 directly from head is no problem but I don't know Mike's A820 and your A820 is constructed with the same head or not anyway Nick will fix for you reduce gain is more easier than increase
good lucky
tony ma
good lucky
tony ma
Leif has said it and Tony said it too, so can I say it as well ?
The Studer A820 and A 810 has so much digital control circuitry that both these machines generate an enormous amount of electronic noise. You can demonstrate this to yourself by taking a small battery operated AM radio,tune it slightly off station and bring the area with the ferrite rod close to an A820/A810. All hell will break loose.(On an A80 the only source of RF noise is the digital tape counter found on later models)
To overcome this RF mess,Studer installed a head amp in the headblock,providing a bit of amplification before sending the signal to the actual amplifying stage in the card cage.
Looking at the position of the selector switch in Tango's machine one has to assume that that first stage headamp in the headblock is still in circuit,thus overloading the outboard Doshi. Compare this to the photos of Mike Lavigne's A820 where ( I assume Ki Choi?) has cleverly run the wires straight from the head over the front panel of the A820 ,keeping the delicate signal as far away as possible from the RF hell hole that is the interior of an A820(or A 810)
The Studer A820 and A 810 has so much digital control circuitry that both these machines generate an enormous amount of electronic noise. You can demonstrate this to yourself by taking a small battery operated AM radio,tune it slightly off station and bring the area with the ferrite rod close to an A820/A810. All hell will break loose.(On an A80 the only source of RF noise is the digital tape counter found on later models)
To overcome this RF mess,Studer installed a head amp in the headblock,providing a bit of amplification before sending the signal to the actual amplifying stage in the card cage.
Looking at the position of the selector switch in Tango's machine one has to assume that that first stage headamp in the headblock is still in circuit,thus overloading the outboard Doshi. Compare this to the photos of Mike Lavigne's A820 where ( I assume Ki Choi?) has cleverly run the wires straight from the head over the front panel of the A820 ,keeping the delicate signal as far away as possible from the RF hell hole that is the interior of an A820(or A 810)
Ok. Straight from the head and away from the hell hole.
If MikeL is reading this, can you show me how ugly it is to run the wire over the front panel. Or is it not so ugly.
Kind regards,
Tang
It sounds like you have an extreme level problem & this would certainly explain it... thank you all for your expertise - wonderful to see such connnection!
I spent yesterday with Tatsuki at the atelier of legendary French bow maker Alain Herou in Paris.
I heard first hand why Tatsuki goes to Paris every 3 months to have his bows rehaired there..
Much like our audio tweaking, the bow hair brings out so much colour, warmth & detail to the sound of the violin..
I heard an amazing Carmen Fantasy with Yun-Yang in Alain’s music room, followed by a fantastic dinner with Alain, in a French bistro.
The French are such passionate open people!
This is all preparation for our March recordings.... I believe you will hear an even move amazing violin sound....
Ed
I spent yesterday with Tatsuki at the atelier of legendary French bow maker Alain Herou in Paris.
I heard first hand why Tatsuki goes to Paris every 3 months to have his bows rehaired there..
Much like our audio tweaking, the bow hair brings out so much colour, warmth & detail to the sound of the violin..
I heard an amazing Carmen Fantasy with Yun-Yang in Alain’s music room, followed by a fantastic dinner with Alain, in a French bistro.
The French are such passionate open people!
This is all preparation for our March recordings.... I believe you will hear an even move amazing violin sound....
Ed
Last edited:
very exciting...every little detail affects the harmonic flavour......
I feel I´m close to putting in a new order again....long time now...have mostly bought jazz and rock masters
probably correct that the headblock pre is still in the equation....
better to skip the onboard reproboards all together and solder directly on the back of the head
alternately have a separate headblock for this purpose only
I feel I´m close to putting in a new order again....long time now...have mostly bought jazz and rock masters
probably correct that the headblock pre is still in the equation....
better to skip the onboard reproboards all together and solder directly on the back of the head
alternately have a separate headblock for this purpose only
That is exactly what I am going to do. I purchased a 2nd head block that John French will wire out which will allow me to use my Doshi with my A810.
have you done anything to the stock line and repro boards on the A810?
my A810 is heavily modified in the signal path acc to instructions from Todor Dimitrov of MTSL
pretty close to an all out A80, but not quite there
changed all 5532 to 49720H metal cans...including the one in the headblock pre......did a lot to resolution
my A810 is heavily modified in the signal path acc to instructions from Todor Dimitrov of MTSL
pretty close to an all out A80, but not quite there
changed all 5532 to 49720H metal cans...including the one in the headblock pre......did a lot to resolution
recapping and checking bearings are first priority
you changed ALL electrolytics in the machine?MB, main psu and motor caps, RIFA X2 s etc?
I´ve done MTSL mods on two A810 and a friend on the 3rd.
only missing on mine now is rewiring with kapton/silver wire, which improves on resolution as well
you changed ALL electrolytics in the machine?MB, main psu and motor caps, RIFA X2 s etc?
I´ve done MTSL mods on two A810 and a friend on the 3rd.
only missing on mine now is rewiring with kapton/silver wire, which improves on resolution as well
I have some of the repro board too...thats the most modified, bypassing functions and ripping out components...
detailed inxs and parts are to be bought from MTSL, apart from the opamps
detailed inxs and parts are to be bought from MTSL, apart from the opamps
I am sure that is the reason, although I don't know the detail of A820 but I know A820 has same looking transport of A80 and circuitry same as A810, then I think it may also has a pre amp behind the head too and the guy modify the deck for you is place the switch selector before the repro amp not after the head ( in A810 from head to the pre amp has a metal tube over the wire for protection not easy to cut it off for connection what I know the only way to do is connect from the in put terminal of the pre amp ), there are two way to soft the problem either re wiring the deck inside ( your modify guy job) or by pass Doshi first stage by Nick
tony ma
You will definitely want to find this out. Soon!
Unfortunately, the photo tells us very little. Yet the location of the pictured switch is totally baffling to me. Makes me want to know why it is placed there, on the transport control side and not on the audio side.
Is the switch in the photo controlling a relay bank?
Or something like CMOS switch gates located in the headblock?
Or did someone actually wire the raw repro head two-channel output down to a 4PDT toggle switch located in the transport control frame?
Can you contact the person responsible for this mod and get the schematic for it?
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