modification Studer A80VU into play back only deck

Friend's A80VU left channel blasted with smoke, he asked me not to fix it but modify it with tube like I did in A80RC, and also he like to use as play back only. the audio electronic between this two models are not the same only in same transport, VU separate the out put into other card from repro card and add SYNC card too, also select switch for NAB and CCIR, both build in, some ICs use to replace SS you can see in later model A810 in similar design with more ICs to use in replacing, IMO still RC sound better than VU. anyway I will do in the same way of what I did in RC, keep the both sections ( EQ & control ) in stock, just convert the out put into tube and transformer, because no recording use, so I took out most things from the case, only keep the repro pre amp and power supply ,command card in there, looking for enough space for tube and transformer and 6 new bigger size coupling cap, also I can't keep the meter and play back no meter needs just for style only, without meter connect is better for out put sound quality, there are two version of repro pre amp card, 1080.604 is for 10mH low out put head it with a 1 to 10 step up in put transformer, the other one is 1081.652 without in put transformer but for 200mH head, this one is the first one, my friend like to have a silver wound for it but Studer will not tell the the impedance of it, friendly Jack Elliano made me a sample in copper with multi taps first, let me see which is the best sounding tap and then to silver for saving money. or in future option replace a butterfly head (200mH) into recording head and switch by pass the step up, that can ABX of two different heads, pictures show changed parts and the looking before and after
tony ma

more pictures

mastertapesoundlab said:

Interesting. What is the big thing over/behind the heads?

Best,
Todor
www.mastertapesoundlab.com

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This guy like add woods in his gear and everywhere to make sound change
tony ma

Roger
47uf cap in good quality is not too many choice, either Solen or mundrof, I took this one because they are smaller size of 250V, Solen is cheaper but bigger in 450V only, I don't have too much space for them, so that is the only choice
tony ma

Frank and Tod
Create more than one sound path will effect to image's focus , different construction or different material of cap will give you different sound because cap blocking transfer timing in different by different frequencies that is what I believe, and in the sound path coupling , non polarity always better than with polarity, reduce value maybe OK but it will depend on site combine with other components or room effect, up to the user in final result, like SAKUMA in Japan, he build amp not by math is by changing each part's value and listen for final, but not all audiophile can do the job if he is not a diyer, in this modification , the in put step up transformer with multi taps to check which is the best for match the head in site by listening is the best way, but I can't afford to change those 6 coupling caps' value so keep it in original value.
PS Tod my friend bought two taps from you before and we are doing similar thing as you do but we are not pro just for hobby, our recording equipments is tube and silver, for reference our website is ultraanaloguerecordings.com
tony ma

Nothing can be 100% advantage, just get the balance of give and take, I have more contact points by moving out of caps and make longer sound path but in other way take off a lot of switches in original design, end up still improved, maybe you can say because of with tube out put, in my PR99 mods, just changed those coupling caps into Solen, made sound more direct and clean compared with another one without mods
tony ma