Studer A810 Pre Amp mods

[337alant]

I was looking at the wiring diag for the Studer A810 and there is a small preamp just behind the head block which amplifies the very low signal from the heads
Like a phono pre amp its susceptible to noise and there is plenty of that in a reel to reel unit so I checked over the components that are directly in the signal path and decided to change them out for known good quality components as what is in there is at least 30 years old.

There was 2 electrolytics in there that needed to be changed out so I used some 470uf Panasonic aluminium polymer oscon type as space is tight.
There is 2 x 100 ohm resisters in the signal path so I put 2 Vishay naked foil types in there. and also changed out a couple of old ceramics for COG type.
I also changed the NE5532 op amp for a LM4562
The 2 orange caps are not tants they are solid aluminium BC128 type which are very reliable so I left them as is
All in all it sounds cleaner and most noticeable is voice sounds more natural :) happy days


https://farm1.staticflickr.com/785/40898993002_9222ebce75_c.jpg (https://flic.kr/p/25j72HL)20180208_160504 (https://flic.kr/p/25j72HL) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr

before

https://farm2.staticflickr.com/1588/25898659420_73c04ef311_c.jpg (https://flic.kr/p/Fszp9G)20160325_123227 (https://flic.kr/p/Fszp9G) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr

https://farm1.staticflickr.com/803/40232230054_3e60c97ddf_c.jpg (https://flic.kr/p/24ibGjS)20180208_171541 (https://flic.kr/p/24ibGjS) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr


Alan

[Audio Al]

You do like a tinker Alan

Excelent job

[Firebottle]

Cracking job Alan :thumbsup:

[Jimbo]

Hope to get to hear one of you R2R again one day Alan.:) I would be tempted to buy one myself but not sure what to buy. I presume the biggest issue with them is if parts are worn and getting spares. I presume electronics are fixable?
If you see any up for sale you could recommend give me the nod.:cool:

[337alant]

Just trying to squeeze the last ounce out of it Al, bloody fabulous tape machine though :eyebrows:
My mother used to say every toy she bought me I would go and get a screw driver and take it to bits, old habits I guess :D
Alan

[337alant]

Hope to get to hear one of you R2R again one day Alan.:) I would be tempted to buy one myself but not sure what to buy. I presume the biggest issue with them is if parts are worn and getting spares. I presume electronics are fixable?
If you see any up for sale you could recommend give me the nod.:cool:

maybe there will be another Nebo one day Jim be great to meet up again ?
I love tape machines more so than turntables.
The Tascam BR 20 still gets my vote as a superb machine and very reliable, and not so old that the caps need to be replaced either
The Technichs RS1500 are also a very nice machine but suffer from a cheap cap brand that eventually leak and can damage the circuit boards so its now recommended to recap, once done they are excellent and very nice looking machines, I have one and I have bought all the caps necessary to completely overall it just need to find the time
Another very well made machine is the Otari MX55N also has good quality caps that seem very reliable havent had to change any in mine
The Revox Pr99 are also very good machines but again need to be recapped to be on the safe side as the frako caps are very old now and the little blue phllips and tantalum caps go well out of spec and the rifa X2 caps go up in smoke once fettled you have a very nice machine.
The Teac X1000 are nice machines but stay clear of the X2000 as they are not very well made and not so reliable even though the fetch very high prices.
I dont see any bargains out there on ebay now the prices have just gone crazy
Latest project is a new pair of power amplifier boards to fit in my voyager's, watch this space, ill post when I get them finished

Alan

[Jimbo]

Thanks for the recommendations and info regarding R2R machines. I will keep a look out on some of the vintage sites and eBay. I maybe able to get a machine recapped if necessary.

I remember hearing your voyager mono blocks - they were excellent so will be interested to hear how the new boards go.