8mm Forum: GS-1200 Re-recording Question

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Posted by Alan Rik (Member # 73) on April 18, 2006, 12:06 PM:

I have a question for you gents. I went to Re-Record the Madagascar Penguin short and it came out fairly well. I had to ride the speed switch and speed up/slow down here and there but all went well. The stripe on the print is not the best however.
I noticed that on the GS I put the record levels all the way up till it was peaking PAST the 0 mark so in theory it should have been distorted. However when it was played back the meters were registering very low. The sound through the headphones was not very good but the sound out of the speakers was nice.
I then went and used an older film, prestriped Bambi cut down and recorded the same track just to hear the difference. Well the prestriped old film recorded perfectly with the VU meters matching the actual recorded levels.
So.. is this happening because the new stripe sucks? The old prestripe had much better fidelity. I have the new capacitor in the machine and this was the same as the older GS I had.
Any ideas?

Posted by Kevin Faulkner (Member # 6) on April 18, 2006, 04:41 PM:

Alan you are spot on. I have not been able to get the same levels on playback from Deranns latest stripe. The quality is quite good but the playback level is a lot lower. It seems that the record current needs to be higher for these latest jollops of stripe. I did a rerecord of Phil Sheards "Nick Nack" and that was fine. This is also the same thing as trying different tapes in your cassette recorder.....some makes will play back at level, some higher and some lower.
There is a resisitor in each circuit of the GS which you can alter to change the currect through to the heads but then you are in danger of over recording on some stripes.

Kev.

Posted by Tony Milman (Member # 7) on April 18, 2006, 05:10 PM:

Alan.

We recently had the opportunity to visit Dave Locke (sorry if there is not an e at the end!) who was kind enough to show us some of the modifications he has made over the years to a GS1200, Very impressive!

One of these was the ability to alter the components that Kev is talking about which he advised was always necessary to get the best out of any stripe. I am sure that he would be delighted to explain in more detail and maybe he can be persuaded to email you? I know he has a vast knowledge of GS1200's and wish there was a way of persuading him to share it with us. Perhaps he could write a book!

Posted by Andrew Wilson (Member # 538) on April 19, 2006, 10:55 AM:

tony what a good idea.how about it kev?.andy

Posted by Kevin Faulkner (Member # 6) on April 19, 2006, 11:27 AM:

This is certainly info that I can part with here on the forum, as well, but the reason I am very wary of doing this is that a person not knowing what they are doing could down their GS permanently.

These mods need to have the front cover removed and then the amplifier unplugged from the GS's main control board. There is a very delicate output IC sitting next to the plug connection on the main board which if disturbed in an incorrect manner can result in a dead IC so you can see that I would rather tell people on an individual basis providing I know they are capable of doing the job. Good soldering knowhow is also esential as Elmo's circuit tracks can lift away from the board very easily.

We have to remember that there are no spares or very few spares for these machines and we dont want to send them to an early grave because of a silly, irriversible mistake.

There.....I have said my bit. Private me if you want further info on where these resistors reside and what to do to change the record current etc. You have been warned.

Kev

Posted by Bill Parsons (Member # 244) on April 19, 2006, 01:12 PM:

Hello All,
The remedy for this is pretty straight forward, what Dave did on his GS was to remove the amplifier cover and drill two small holes below the record level meters to allow access to the two presets that are mounted on the front of the board to adjust the bias (one for each track) these can then be adjusted with an insulated tool, (making a note of the original settings) As the stripe does vary a lot I actually removed the presets from the pcb and fitted two pots to the rear of my GS, this made life a lot easier, and I usually managed to obtain a good recording, but this of course does require some soldering skills.

Bill.

Posted by Alan Rik (Member # 73) on April 19, 2006, 01:34 PM:

Drilling...?
Now that is scary...!!

Posted by Bill Parsons (Member # 244) on April 19, 2006, 02:13 PM:

Be brave Alan, as long as the drill does not slip you will be ok!

Posted by Tony Milman (Member # 7) on April 19, 2006, 03:15 PM:

Hi Bill,

Thks for posting.

Alan, use a small drill [Wink]

Posted by Kevin Faulkner (Member # 6) on April 20, 2006, 11:25 AM:

Bill that's not the mod I was thinking about. Providing the quality is good then the Bias controls wont make a huge differnce to the rcording level. Alan was remarking about low level on playback from some of his recordings. I have found that this can be remedied by changing a resistor from the output of the recording amp (output IC) so that you get 0db playback for 0bd record level.
The bias pots do have an effect on record level but not as much as the level from the output IC's. The bias mainly effects the bass/treble content. Record current is just as important an adjustment as bias but Elmo saw fit not to make the current adjustable but fixed [Frown]

I think this was one of the mods I talked to you about via email a few months ago? I used good quality Kodak, Agfa and Fuji striped film to check the record Current and have now changed the value of this resistor in each channel to give 0db record/palyback with a 1Khz tone as is done on normal tape recorders. It is now possible for me to over record on some stripes but then I just reduce the record level but at least by having it adjusted like this I dont have to push the record meters well into the red to get a decent playback level which can lead to distortion.

I have to say that I wouldnt want to drill holes in my Xenon [Frown]

Kev.

Posted by Adrian Winchester (Member # 248) on April 20, 2006, 01:02 PM:

"I have to say that I wouldnt want to drill holes in my Xenon [Frown]

"

Kev,
Mightn't a bit of extra interior ventilation be beneficial. [Big Grin]

Posted by Bill Parsons (Member # 244) on April 20, 2006, 01:32 PM:

I understand what you are saying Kevin, my idea was for a simple remedy that does not require any technical skills, and in spite of what you say makes a big difference to the Derann stripe recordings, the holes by the way are very small and hardly show. Anyway I will not bother with anymore forum postings I will leave it all up to you Kevin.

Bill.

Posted by Tony Milman (Member # 7) on April 20, 2006, 02:45 PM:

Bill,

Please don't! Your input is really really appreciated and I think it would be a great shame if you didn't post. I know you don't very often and I appreciate that Kevin and you can differ on certain aspects but we non-technical idiots out here that own and love our Elmos need all of the opinions and advice that we can get.

There is certainly room for both of you on this forum and I am sure that I am not alone in saying this. Personally I like the idea of the drilled holes and I agree that they are hardly noticeable as was evident by Dave Locke's machine.

So Bill, on behalf of all the forum members can I please ask that you don't take offence at Kevin's post and remain a contributor (however rare!!!!!!)

Posted by Alan Rik (Member # 73) on April 20, 2006, 02:51 PM:

Hi Bill,
Yes..I agree! Please continue to post. I did find the information that you have given useful. As well as getting my GS Xenon sorted a few years back! There are never enough GS technicians in the world. [Smile]

Posted by Kevin Faulkner (Member # 6) on April 20, 2006, 04:53 PM:

Bill, That was not a personal knock at your technical expertise and I certainly didnt want you to take offence. We both have our own ideas on certain aspects of these machines and they are ideas and info that can be pooled together for use by the members on the forum here if they wish to take those ideas on board.
I for one certainly dont wish to see you leave the forum and I certainly have a lot of time and respect for you and your knowledge.
My reply on the forum was written during a few free moments at work this afternoon and maybe I didnt explain myself too well which may have made my reply sound a bit off. If so then please accept my appologies.

Bill, Please dont leave us. I and the other members need your valued input.

Kevin.

PS. I'm sending you an email direct.

Posted by John Clancy (Member # 49) on April 21, 2006, 02:24 AM:

Bill and Kevin, I'd like all these modifications made to my Elmo's. So anytime you can both get over together to implement them will be fine with me!

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