Garrard 401 Owners & Discussion Thread

[Full Range]

  On 19/09/2017 at 9:29 AM, Telecine said:

There are probably load resistors internally that would need to be changed.

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I am not going inside the case to change a perfectly good phono stage designed by John Curl 

[Telecine]

  On 19/09/2017 at 9:32 AM, Full Range said:

 

I am not going inside the case to change a perfectly good phono stage designed by John Curl 

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What is the phono stage? It may be that it was designed to be changed that way.

[Full Range]

 

  On 19/09/2017 at 9:34 AM, Telecine said:

What is the phono stage? It may be that it was designed to be changed that way.

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It's part of the Control amp 

And that is a Nakamichi CA5 II

 

I am looking for a pre loved.   iFi iphono2 

[Telecine]

  On 19/09/2017 at 9:37 AM, Full Range said:

 

 

It's part of the Control amp 

And that is a Nakamichi CA5 II

 

I am looking for a pre loved.   iFi iphono2 

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From an online source:

 

"The MC-cartridge termination, normally 100 ohms, can be changed to another value (from 3 to 50 ohms) by dealer installation of additional resistors supplied with the preamplifier."

 

Any decent tech could change it for you and I think you know one  

[Full Range]

  On 19/09/2017 at 9:41 AM, Telecine said:

From an online source:

 

"The MC-cartridge termination, normally 100 ohms, can be changed to another value (from 3 to 50 ohms) by dealer installation of additional resistors supplied with the preamplifier."

 

Any decent tech could change it for you and I think you know one  

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But I still need to know the equivalent 22k value converted to db to make a judgement call 

[Telecine]

No, you need to know the appropriate resistor value. Gain is a different matter.

[Full Range]

 

  On 19/09/2017 at 10:04 AM, Telecine said:

No, you need to know the appropriate resistor value. Gain is a different matter.

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Probably best to pull of the cover and have a look at what resistor/s are installed now -and then see what can be done ✅ 

 

 

[Telecine]

Yes, I am guessing that they are soldered in, hence the suggestion that they are dealer upgradeable.

 

The DB options on the back are gain settings. The resistors that are internal are for loading.

[Full Range]

 

@12ax7 @Telecine 

I have found the schematic of the phono stage and a photo with the top off 

And the parts list 

Based on the info uploaded 

R103 R203 should be changed from 10k to 22k 

Or other changes to the other resistors in that section ?

Advice needed ?

 

 

Edited September 19, 2017 by Full Range

[PKay]

  On 19/09/2017 at 11:47 AM, Full Range said:

 

@12ax7 @Telecine 

I have found the schematic of the phono stage and a photo with the top off 

And the parts list 

Based on the info uploaded 

R103 R203 should be changed from 10k to 22k 

Or other changes to the other resistors in that section ?

Advice needed ?

 

 

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No wonder they say leave it to the dealer. 

[Full Range]

  On 19/09/2017 at 12:22 PM, Nap250 said:

No wonder they say leave it to the dealer. 

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And that is only the phono stage

That is one quarter of the whole thing 

 

 

[Telecine]

I believe that you will need to add resistors of the appropriate value to the areas labelled imp adj (impedance adjustment). The manual should tell you the values to use.

[Full Range]

  On 19/09/2017 at 12:43 PM, Telecine said:

I believe that you will need to add resistors of the appropriate value to the areas labelled imp adj (impedance adjustment). The manual should tell you the values to use.

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I have that info as well 

Just need guidance as to what needs changing to get the result needed 

Or leave it alone if it's within the sweet spot range 

 

Edited September 19, 2017 by Full Range

[Telecine]

There must be something else about the resistor values in the manual. That doesn't tell us what we need to know.

[12ax7]

@Full Range

Dont panic.

 

Your Decca should be going into the MM input, NOT the MC input.

 

Most moving magnet phono stages have an input impedance of 47k.  Changing the input impedance will not significantly affect the gain. However with the Decca reducing the load from 47k to approx 22k will tame the top end.

 

The easiest solution for you would be to solder additional loading resistors from +ve to -ve across the input.

 

If you solder  two 47k resistors at the cartridge end, 1 from right channel +ve to -ve, 1 from left +ve to -ve, then you will now have 2 47k loading resistors in parallel for each channel.

This arrangement would give you an input impedance of 23.5k.

 

If you solder 39k resistors  instead of 47k at the cartridge end , 1 from right channel +ve to -ve, 1 from left +ve to -ve, then you will now have 1 47k and 1 39k in parallel each channel which will result in a load of 21k.

 

By soldering the additional resistors at the cartridge end for the Decca you can change to other MM's again without having to make any changes to the phono as it will still be 47k if you remove the Decca ( with loading resistors ).

 

Have that all makes sense.

[Full Range]

  On 19/09/2017 at 12:55 PM, 12ax7 said:

@Full Range

Dont panic.

 

Your Decca should be going into the MM input, NOT the MC input.

 

Most moving magnet phono stages have an input impedance of 47k.  Changing the input impedance will not significantly affect the gain. However with the Decca reducing the load from 47k to approx 22k will tame the top end.

 

The easiest solution for you would be to solder additional loading resistors from +ve to -ve across the input.

 

If you solder  two 47k resistors at the cartridge end, 1 from right channel +ve to -ve, 1 from left +ve to -ve, then you will now have 2 47k loading resistors in parallel for each channel.

This arrangement would give you an input impedance of 23.5k.

 

If you solder 39k resistors  instead of 47k at the cartridge end , 1 from right channel +ve to -ve, 1 from left +ve to -ve, then you will now have 1 47k and 1 39k in parallel each channel which will result in a load of 21k.

 

By soldering the additional resistors at the cartridge end for the Decca you can change to other MM's again without having to make any changes to the phono as it will still be 47k if you remove the Decca ( with loading resistors ).

 

Hope that all makes sense.

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Much appreciated 

It makes sense and the specs clearly say 47k on the MM side 

I will try and absorb the info and if it is beyond me I will seek assistance ?

 

[Full Range]

The air pump silencer box is complete 

Materials used 

CSR - Hebel

Motor room noise insulation 

Foam 

The pump itself has also been pulled apart and the housing treated with foam 

 

Test results are positive 

Noise reduction from free air is in the range of 95% 

Although I have been successful in this area when close up at 300mm I can hear a hint of exit purrr noise to the equaliser tank from the air feed hose 

Thankfully I hear nothing from the listening seat 

 

For a test I will fashion a bottle silencer on that section just to get that noise suppression percentage higher 

It will act like a car muffler and it will be placed between the pump and the red equaliser tank 

 

So another update is in order when I make a bottle silencer ✅

 

[andyr]

  On 19/09/2017 at 9:17 AM, Full Range said:

 

When the Decca was fitted on the last occasion I had it on MC - 36db 

The settings available on the phono are 24db 30db 36db 

 

How does one convert 22k to db

 

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You normally don't! 

 

The Decca should be used into the 'MM' input - which will give it a loading (unless your phono stage is very strange!) of 47K.  If you want to lower that to 33K (as per the review I read on "Enjoy The Music") or 22k then you need to:

1. buy some RCA 'T' connectors (which allow 2 RCA inputs with 1 RCA output).
2. put the single output into your phono RCA sockets.
3. for each T connector, plug: a. your phono cable and b. a load plug into the RCA inputs.  The load plug acts in parallel with the 47K of your MM input.
4. Values are: for 33K overall, use a 120K resistor in the load plug; for 22K (actually 23K5), use a 47K resistor.

 

Regards,

Andy

[Full Range]

@andyr  I know that in the past you made a few of these cartridge loading plugs 

 

How do I get my hands on some of these loading plugs in the correct resistance to suit my phono 

And match it to the Decca Gold with Garrott Bros treatment 

Thanks for the helping hand ? 

 

See the phono specifications on the photo 

 

[andyr]

  On 20/09/2017 at 3:42 AM, Full Range said:

@andyr  I know that in the past you made a few of these cartridge loading plugs 

 

How do I get my hands on some of these loading plugs in the correct resistance to suit my phono 

And match it to the Decca Gold with Garrott Bros treatment 

Thanks for the helping hand ? 

 

See the phono specifications on the photo 

 

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Aah, those specs give us the answer:

• 34dB corresponds to a 50ohms load
• 30dB to a 100ohm load, and
• 23dB to a 200ohm load.

Every other phono stage mfr that I've seen would've written the load numbers on the case - not the dB level!  So by using the MC input and selecting 34dB, it would seem you've been loading the Decca at only 50ohms! 

 

Sure, I can make some load plugs for you ... if you don't have a soldering iron, yourself.  Send me a PM.

 

 

Regards,

Andy

[Willco]

  On 19/09/2017 at 9:32 AM, Full Range said:

 

I am not going inside the case to change a perfectly good phono stage designed by John Curl 

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Hi, looks like super system you've put together there--Kudos!

 

If I may correct a point you made above--re the Phono stage in the Control Amp Nakamichi CA5II

 

John Curl did not design the Stage--your info may have mislead--I'm sure it is a fine unit nevertheless

 

Willco

Edited September 20, 2017 by Willco

[Full Range]

  On 20/09/2017 at 7:20 AM, Willco said:

Hi, looks like super system you've put together there--Kudos!

 

If I may correct a point you made above--re the Phono stage in the Control Amp Nakamichi CA5II

 

John Curl did not design the Stage--your info may have mislead--I'm sure it is a fine unit nevertheless

 

Willco

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On my understanding and web research it was a joint effort - 

Nelson Pass designed the power section 

John Curl designed the Phono section 

 

 

 

 

 

[Willco]

  On 20/09/2017 at 8:32 AM, Full Range said:

 

On my understanding and web research it was a joint effort - 

Nelson Pass designed the power section 

John Curl designed the Phono section 

 

 

 

 

 

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Yes I'm sure you did the due diligence--but the source is incorrect

 

I asked John today and his reply was

 

"I know nothing about it"

 

 Willco

 

Just to add --if you care to link me via PM your web research that states JC's involvement --I will pass on to him--ha!--he is getting old and may have had memory lapse!

Edited September 20, 2017 by Willco

[Full Range]

 

  On 20/09/2017 at 8:42 AM, Willco said:

 

Yes I'm sure you did the due diligence--but the source is incorrect

 

I asked John today and his reply was

 

"I know nothing about it"

 

 Willco

 

Just to add --if you care to link me via PM your web research that states JC's involvement --I will pass on to him--ha!--he is getting old and may have had memory lapse!

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John may have worked on a design for Nakamichi but not sure what model it was being installed in or used for ?

 

Most of the info I got a few years ago and not easy to find again 

On a search performed now - Most of the same info is on CA5 preamps for sale 

E.G. — https://www.audiogon.com/listings/phono-rarely-seen-nakamichi-ca-5-preamp-with-john-curl-designed-phono-stage-shares-heritage-w-2013-08-18-preamplifiers-60091-wilmette-il

 

 

 

 

[Willco]

Ah thank you !--- Strange John knows nowt about that--Its 2.30AM in  Calif at present--Ive sent him the link and I'll follow up with a call to him  tomorrow.

 

I'd like to know this conundrum as well

 

Will report outcome---thanks again and enjoy the system

 

Willco