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#1 2010-09-26 09:56:57

Casey4s
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Registered: 2010-09-26
Posts: 28

V4 midrange inductor

Hi I am a newbie, here I just found this site with Google.

I am working on a V4 preamp variation.

I am trying to find the midrange inductor (Ampeg # 8910001) but I am having no luck. Can anyone help me with this?

Thanks in advance...

Casey4s

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#2 2010-09-26 12:53:26

hangman
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Re: V4 midrange inductor

Mercury magnetics has a reproduction.

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#3 2010-09-26 14:08:48

Casey4s
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Re: V4 midrange inductor

Thanx


EDIT:

I coulden't find it on their page so I emailed them.

Last edited by Casey4s (2010-09-26 14:47:35)

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#4 2010-09-26 17:26:47

Liquids
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From: CT
Registered: 2010-08-01
Posts: 491

Re: V4 midrange inductor

If you click on the ampeg list on the main page, you will find it at the bottom.  It's listed as a choke:
    C     AV4-MC     V4 -- mid control toroid choke     90.00

Likewise, you may be off cheaper (and less space on the board) with discreet inductors - give it some consideration. 

If you want a toroidal and don't want to pay that much, Heyboer may be willing to make you one for cheaper?  Maybe they've gotten this request before, even.  Worth a shot.


Matthew

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#5 2010-09-26 17:31:19

Casey4s
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Registered: 2010-09-26
Posts: 28

Re: V4 midrange inductor

Thanks for the info,  WoW!  $90   I wasn't expecting that at all.

I may need a plan B.

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#6 2010-09-26 19:28:26

hangman
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Re: V4 midrange inductor

yeah the Mercury has gone up in price a lot. 

The values for discrete inductors are:800,300, and 100mh

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#7 2010-09-27 05:26:22

Liquids
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Posts: 491

Re: V4 midrange inductor

I'm not familiar with the layout, but I just found out about the V9, which seems to do the similar thing with discreet inductors(?) so it's not altogether strange - seems simplified too (only one tube involved).  I'll have to check it out via spice and compare.

http://www.drtube.com/schematics/ampeg/v9pre-jp.gif


Matthew

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#8 2010-09-27 05:54:32

Casey4s
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Registered: 2010-09-26
Posts: 28

Re: V4 midrange inductor

hangman wrote:

yeah the Mercury has gone up in price a lot. 

The values for discrete inductors are:800,300, and 100mh

Hmmm Another guy told me it took 400+300+100 to make the 800mhz.

I did see in a newer version of the schematic (Magnovox) that it had the three seperate inductors wired in series. So perhaps I can find an easier way $$ to do this.

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#9 2010-09-27 06:06:15

Liquids
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Re: V4 midrange inductor

It's the same...the large transformer/inductor is total 800, with taps at 100 and 300. You can see how they did this on a V4 schematic.  If you check the V9, you see they used 3 separate discrete inductors - one 800, one 300, one 100. But you could arrange a configuration with a 400, 300, and 100 discrete inductors in series, too.  Same result.


Matthew

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#10 2010-09-27 07:04:26

Casey4s
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Registered: 2010-09-26
Posts: 28

Re: V4 midrange inductor

Thanks...

I am looking for a way to do this but I am having no luck locating part numbers at Allied or Mouser.

If anyone knows where I can get the 800 - 300 - 100 individual inductors I would be fine going that route.

Can somebody point me in the right direction?


Everybody has been really helpful and I do appreciate it.

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#11 2010-09-27 07:12:30

Liquids
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From: CT
Registered: 2010-08-01
Posts: 491

Re: V4 midrange inductor

To be honest, I'm clueless about inductor specs (does more than the inductance matter here?)

But...

http://www.mouser.com/Passive-Components/_/N-5g73/   --->
http://www.mouser.com/Passive-Component … /_/N-5gb4/

After that, I'd assume common mode or RF inductors...but I'm lost after that, if not before!


Matthew

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#12 2010-09-27 07:43:35

Casey4s
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Registered: 2010-09-26
Posts: 28

Re: V4 midrange inductor

I did find a 100mH and a 150mH RF inductor but I honestly don't know if the "RF" type is correct or not.

But 150+150=100 = 400
    150 + 150   = 300
and 100 stand alone

So if the RF type is acceptable I can go this route.

http://www.mouser.com/ProductDetail/Xic … umVQ%3d%3d

http://www.mouser.com/ProductDetail/Xic … RwRA%3d%3d

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#13 2010-09-27 08:49:15

hangman
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Re: V4 midrange inductor

Mesa used discrete inductors in the graphic eq section of the mark series... the values aren't exact,  but you could get pretty close. 

http://www.tubeampdoctor.com/index.php? … 545dffc742

note: if you call up mesa direct, you could probably get the parts cheaper than buying them from TAD.

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#14 2010-09-27 09:02:12

Casey4s
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Registered: 2010-09-26
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Re: V4 midrange inductor

hangman wrote:

Mesa used discrete inductors in the graphic eq section of the mark series... the values aren't exact,  but you could get pretty close. 

http://www.tubeampdoctor.com/index.php? … 545dffc742

note: if you call up mesa direct, you could probably get the parts cheaper than buying them from TAD.

Thanks for the link. 

If I can't find anything else I might go this route.

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#15 2010-09-27 15:47:45

Casey4s
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Registered: 2010-09-26
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Re: V4 midrange inductor

I just heard that Ampeg is reiisueing the V9 to original specs and drawings, I wonder if they can sell me one as a replacement part?

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#16 2010-09-27 17:32:12

hangman
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Re: V4 midrange inductor

hadn't heard that they were doing that.   they still use an 800mh inductor in the SVTs  but there are four taps, and thus different frequencies.  if that doesnt bother you, you could order that one
part number is:94-602-32

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#17 2010-09-27 17:37:53

Casey4s
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Registered: 2010-09-26
Posts: 28

Re: V4 midrange inductor

hangman wrote:

hadn't heard that they were doing that.   they still use an 800mh inductor in the SVTs  but there are four taps, and thus different frequencies.  if that doesnt bother you, you could order that one
part number is:94-602-32

Thanks for the part number, I'll have to eMail Ampeg and see if I can get that one.

This is a scratch amp build so I am pretty flexible, I just got the pre amp drawing set up last week and the power supply today.

I have plenty of time so I am going to check every lead I can get, I am still sourcing parts at the moment.

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#18 2010-09-29 12:28:27

Casey4s
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Registered: 2010-09-26
Posts: 28

Re: V4 midrange inductor

I called Ampeg yesterday and talked to the service Dept.  They have no replacement parts for the 70's era amps what so ever.  The new SVTs etc have the boards stuffed overseas they don't even have repair parts.

Mercury Magnetics is $90 and I just can't make myself do that.

So I have found some 100mH coiled inductors.  If I run 8 in series it will give me the 800mH I need and I can tap it at 400,300,100mH ,but is this method going to cause me problems?

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi … K:MEWAX:IT


What do you guys think?

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#19 2010-09-29 12:53:28

Liquids
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Posts: 491

Re: V4 midrange inductor

I think that $6 x 8 + Shipping = $50+, and who knows what their specs are...or how they'll sound.

I just did a quick search of Jameco, and they have an assortment of small toroidal inductors (for example) for much cheaper than that. I'd rather take chances on three to eight of those at $1 a pop than $6 each for eight!  Also, don't sweat the inductor spec/listing is exact. The transformer is 20% tolerance at best anyhow, inductors are notoriously variable.  If you're losing sleep over accuracy, buy two of each of the closest to 100/300/400 you can find, measure the actual inductance, and pick the closest ones, if you like...

Even if, in the end, you end of going for the all out mercury or heyboer route, buying some of the above kind (they're like $1 each) or a couple varieties of cheap ones might help you experiment...and help you get to know more of what you're looking for if anything, beyond just inductance value.

In the end, if you want the easiest and most similar way, I'd get the MM and pay the money. Or heck, find a DOA V series amp, yank the toroidal out, then sell the rest for parts around here (heresy, I know...)!   The all-metal knobs sell on fliptops for $25+ each(!?)  And it's hard to find those rocker switches.

And, if you just want the mid control, well an op amp could do this pretty well too....

Last edited by Liquids (2010-09-29 12:58:09)


Matthew

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#20 2010-09-29 13:02:11

Casey4s
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Registered: 2010-09-26
Posts: 28

Re: V4 midrange inductor

Actually that is $5.99 for 10 pieces + S&H.  So my intent was to just line them up in series and tap as needed.  I am worried about noise introduction into that part of the circuit.  I know I still need to alternate the orientation of the coils.

I want to finalize my schematics and start building this amp, but util I resolve the inductor issue I am stuck.  At the moment I have (drawing) the wiper of the mid control going to ground without the inductor and it's parts.

I would love to find a V4-vt22 to grave rob but there just aren't any.

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#21 2010-09-29 14:00:37

hangman
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Re: V4 midrange inductor

Casey,  we are a service center for ampeg, and I gave them a call and ordered an inductor for you if you want it.  I'm waiting to hear back on shipping charges from them,  but not including shipping the unit is only $15. 

email me if you want it.

-steve

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#22 2010-09-29 14:50:14

Casey4s
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Registered: 2010-09-26
Posts: 28

Re: V4 midrange inductor

hangman wrote:

Casey,  we are a service center for ampeg, and I gave them a call and ordered an inductor for you if you want it.  I'm waiting to hear back on shipping charges from them,  but not including shipping the unit is only $15. 

email me if you want it.

-steve

Thank you, thank you, thank you.

Just tell me when & where to send the money.

I've spent most of 3 dys looking for that or an alternative. This has been driving me nutz.

David

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#23 2010-10-06 21:45:52

hangman
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Re: V4 midrange inductor

Got the unit in,  $20+shipping to you (its small so it shouldn't cost much) let me know

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#24 2010-10-07 05:57:02

Casey4s
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Registered: 2010-09-26
Posts: 28

Re: V4 midrange inductor

Steve,

I just returned your email.

Thanks a ton for helping me find this rare part.

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#25 2010-10-21 20:50:08

Casey4s
Member
Registered: 2010-09-26
Posts: 28

Re: V4 midrange inductor

Here's what I am doing with this inductor. The design is not 100% finished but pretty close. I need to tweak a few values in the preamp yet.

I've been working on the schematics for 4 days, as soon as I get that inductor I can start the layout. I have no clue what it looks like or how big it is.

V3 wil be a 12AU7 or 12AY7

http://i238.photobucket.com/albums/ff243/Casey4s/AA%20Amp/AAAPreVIII.jpg

http://i238.photobucket.com/albums/ff243/Casey4s/AA%20Amp/AAAPowerIII.jpg

Last edited by Casey4s (2010-10-21 20:54:05)

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