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cuttercollector
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Post: # 4404Unread post cuttercollector
Sun Feb 08, 2009 5:46 pm

I have used a last generartion Shure V15 VxMR as a cd4 cartridge with good results. The Panasonic cd4 strain gauge/piezo sounds quite OK with stereo discs too. I have a used Micro-Acoustics which I have never tried, but might soon. I remember a friend having one back when they were new and it sounded really good!

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motorino
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Re: RIAA Ecoder Jamaica Style

Post: # 4938Unread post motorino
Sun May 10, 2009 5:00 pm

Doug 6N wrote:Hi:

Can anyone tell me the value of the capacitor above the 100k resistor which is above the cutter switch? Between A-3 And A-4.

I cannot make out the printing on the diagram.

Thanks in advance

Doug
hello

i use 318 nanofarad, 0,318 microfarad, MKP the big one at the right in the pic

Image

This preamp works good! its the original, no adds, exactly the Flo schematics

I believe the 318 nanos cap its a part of the filter first step, i need change a little for plus or minus hi frecuency response, but now sounds good

i waiting the current sensor, the last add

Image

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ProbZer
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Post: # 5377Unread post ProbZer
Wed Jun 10, 2009 2:28 am

Great computer I think the owner of that computer is a great care taker of that thing.,



________________
irs problems

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mossboss
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Location: Australia.

Post: # 5383Unread post mossboss
Wed Jun 10, 2009 5:36 am

ProbZer wrote:Great computer I think the owner of that computer is a great care taker of that thing.,



________________
irs problems
Yeah Carlos is in Aragon He may not have IRS issues Is this what you mean?
Cheers

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motorino
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Post: # 5396Unread post motorino
Thu Jun 11, 2009 2:32 am

Probzer thanks for the flowers :D Do you know where is the computer in the pic?

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bancho
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Post: # 6685Unread post bancho
Sat Nov 07, 2009 3:44 am

I'm just wondering.... Is there any decent tube substitution for the NE5534 opamp?
Maybe I'd like to build flo's preamp - tube style...
Probably there is also the circuit modification needed...

Any help would be greatly appreciated!

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markrob
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Post: # 6686Unread post markrob
Sat Nov 07, 2009 7:58 am

Hi,

The op-amp based circuit would not translate well to a tube version. It relies on a high open loop gain. I think the easy way to do a tube based IRIAA would be to use Flo's passive circuit with tube makeup gain, input buffering and output summing for the feedback. IIRC, that circuit had a 20db loss at midband. Some 12AX7's should work well for that.

The best bet would be to pick up an old tube preamp on ebay (e.g. Dyna, Heathkit, Eico, Fisher, etc) and modify it to do the IRIAA. It would give you a big leg up as opposed to contruction from scratch.

Mark

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d
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Post: # 11127Unread post d
Mon Oct 25, 2010 6:11 pm

Hi everyone

does anybody tried to build Flo's simple iRIAA?
I just did on testing board and without any luck. it is very distorted... Looked for my error but haven't found one.

Tried passive one, and it worked good but not enough for my Audax ;)

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Nickou
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Post: # 11132Unread post Nickou
Tue Oct 26, 2010 6:16 am

Yes , I did both
the very simple passive and the active one


they work fine+

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d
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Post: # 11134Unread post d
Tue Oct 26, 2010 10:33 am

Nickou wrote:Yes , I did both
the very simple passive and the active one


they work fine+
Thanks.

I really mest up something. It is unbelivable - so simple and I have problems :D

What kind of op-amp have you used?

D

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opcode66
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Post: # 11136Unread post opcode66
Tue Oct 26, 2010 11:54 am

If your sound is distorted then I can think of a couple things immediately. One, you might have wired your op-amp incorrectly (i.e. you did not wire up the correct pins for voltage, input, output, feedback). Two, you might have wired the resistor on the op-amp such that it is not damping the feedback current and the op-amp is running at full amplification.

Check your pinout diagram for your op-amps and make sure you wired all of your correctly.

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d
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Post: # 11137Unread post d
Tue Oct 26, 2010 12:10 pm

opcode66 wrote:If your sound is distorted then I can think of a couple things immediately. One, you might have wired your op-amp incorrectly (i.e. you did not wire up the correct pins for voltage, input, output, feedback). Two, you might have wired the resistor on the op-amp such that it is not damping the feedback current and the op-amp is running at full amplification.

Check your pinout diagram for your op-amps and make sure you wired all of your correctly.
Thats the thing.... I checked the wiring a couple times. Checked datasheet of op-amp for pins... no philosophy here, straight as is on the schematics by Flo.
Thanks for help... will go to sleep and check again tomorrow. :D
D

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markrob
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Post: # 11138Unread post markrob
Tue Oct 26, 2010 2:14 pm

Hi,

Some things to check. Measure the DC voltage on the output pins of each opamp with no signal applied. They all should be near 0Vdc. Anything over .1 Volt would indicate a hookup problem. If you have a scope, check for oscillation. Note that bypass caps are not shown on the schematic, but their use is implied and necessary. At a bare minimum, you should have .1uf caps located close to the power supply pins for each opamp. Also you should be sure your power and grounding methods are nice low impedance runs.

Mark

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subkontrabob
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Post: # 11139Unread post subkontrabob
Tue Oct 26, 2010 3:43 pm

d wrote:I just did on testing board and without any luck.
By saying testing board, do you mean breadboard?

http://en.wikipedia.org/wiki/Breadboard

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d
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Post: # 11159Unread post d
Wed Oct 27, 2010 4:26 pm

subkontrabob wrote:
d wrote:I just did on testing board and without any luck.
By saying testing board, do you mean breadboard?

http://en.wikipedia.org/wiki/Breadboard
Yep. You are right - breadboard.

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JayDC
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Post: # 14774Unread post JayDC
Fri May 06, 2011 10:02 am

all of flo's info is gone.. wish i would have saved them, coz i could use it now..lol


I found this, it as all the components listed..


http://www.hagtech.com/pdf/iriaa.pdf

you can get the board for $50, or you can make it ur self..


I am interested as to wat people have to say, before i spend time building it
generally its for reproduction.. but i like to play wif it sometimes.. :P

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markrob
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Post: # 14780Unread post markrob
Fri May 06, 2011 11:32 am

Hi Jay,

$50 is pretty steep for a simple blank PCB, but he's probably not getting rich making these.

One issue I see with his design is that it is low impedance (you should drive from a 50 ohm source). I didn't run a SPICE simulation to see how much source impedance affects the response, but most modern SS electronics should be ok with it.

Flo's is version is very similar, but much higher impedance.

Mark

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d
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Post: # 14784Unread post d
Fri May 06, 2011 12:23 pm

hey if you need those I have. so if you haven't got it PM me with email and will send you jpgs

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JayDC
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Post: # 14785Unread post JayDC
Fri May 06, 2011 12:28 pm

well, i was just going to get the parts, and make it on a breadboard, if it works, then move it to a perf board.

mmm.. it's interesting that you think the impedance is low, since it talks about hooking up a CD player as the input..

I wanted to build flo's, it's gone.. do you have the image, and parts list?
generally its for reproduction.. but i like to play wif it sometimes.. :P

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markrob
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Post: # 14786Unread post markrob
Fri May 06, 2011 12:38 pm

Hi Jay,

Check you email. I have sent the images I have from Flo. Let me know if you don't get them.

It is low impedance. Note the indication for 50 ohm input on the schematic. However, most SS devices have very low output impedances, CD players included, so it should be no problem. It might be an issue if you try to drive it from an older tube based device.

Mark

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