Power transformer for DBX586 preamplifier

Dear all,
a frend of mine gave me a broken DBX586 preamplifier, to get
repaired. It has the power transformer out of order, with secondaries
broken.

The problem is that I can't find the specifications of the transformer
(output voltage, current), because I can't measure them.

So, I see two solutions:
1) Is there anyone who has the schematics of the DBX586 preamplifier,
with transformer output voltages reported ?
2) Or, do you know which are the specifications of the power
transformer, which is a 'Toroid' TI-65781

Many thanks in advance

Matteo

"matteo" <matteo_bonino@virgilio . it > wrote in message
news:1b4ad655-3a6e-43b1-8a72-c29dc0ee7446@c58g2000hsc.googlegroups . com ...
> Dear all,
> a frend of mine gave me a broken DBX586 preamplifier, to get
> repaired. It has the power transformer out of order, with secondaries
> broken.
>
> The problem is that I can't find the specifications of the transformer
> (output voltage, current), because I can't measure them.
>
> So, I see two solutions:
> 1) Is there anyone who has the schematics of the DBX586 preamplifier,
> with transformer output voltages reported ?
> 2) Or, do you know which are the specifications of the power
> transformer, which is a 'Toroid' TI-65781
>
> Many thanks in advance
>
> Matteo

ftp://ftp.dbxpro . com /pub/PDFs/discontinued/Schematics/586H%20Schematic.pdf

On Wed, 7 May 2008 02:13:07 -0500, "Elvis Kabong"
<ampscience@tuneland . com > wrote:

>
>"matteo" <matteo_bonino@virgilio . it > wrote in message
>news:1b4ad655-3a6e-43b1-8a72-c29dc0ee7446@c58g2000hsc.googlegroups . com ...
>> Dear all,
>> a frend of mine gave me a broken DBX586 preamplifier, to get
>> repaired. It has the power transformer out of order, with secondaries
>> broken.
>>
>> The problem is that I can't find the specifications of the transformer
>> (output voltage, current), because I can't measure them.
>>
>> So, I see two solutions:
>> 1) Is there anyone who has the schematics of the DBX586 preamplifier,
>> with transformer output voltages reported ?
>> 2) Or, do you know which are the specifications of the power
>> transformer, which is a 'Toroid' TI-65781
>>
>> Many thanks in advance
>>
>> Matteo
>
>ftp://ftp.dbxpro . com /pub/PDFs/discontinued/Schematics/586H%20Schematic.pdf
>
How about a free schematic for this old Barcus Berry 1715 amp? It has
a part in it I cannot identify..may be a thermistor..not sure...about
as thick as a dime. Two wires comong off of it but I am not sure where
as one was off, disk about half diameter of dime. Was thermal glued to
chassis with fiber holder screwed to chassis..

"J.P." <jpasano@hotmail . com > wrote in message
news:tnq224plgoo3vtto6qpouc1069mhpia876@4ax . com ...
> On Wed, 7 May 2008 02:13:07 -0500, "Elvis Kabong"
> <ampscience@tuneland . com > wrote:
>
>>
>>"matteo" <matteo_bonino@virgilio . it > wrote in message
>>news:1b4ad655-3a6e-43b1-8a72-c29dc0ee7446@c58g2000hsc.googlegroups . com ...
>>> Dear all,
>>> a frend of mine gave me a broken DBX586 preamplifier, to get
>>> repaired. It has the power transformer out of order, with secondaries
>>> broken.
>>>
>>> The problem is that I can't find the specifications of the transformer
>>> (output voltage, current), because I can't measure them.
>>>
>>> So, I see two solutions:
>>> 1) Is there anyone who has the schematics of the DBX586 preamplifier,
>>> with transformer output voltages reported ?
>>> 2) Or, do you know which are the specifications of the power
>>> transformer, which is a 'Toroid' TI-65781
>>>
>>> Many thanks in advance
>>>
>>> Matteo
>>
>>ftp://ftp.dbxpro . com /pub/PDFs/discontinued/Schematics/586H%20Schematic.pdf
>>
> How about a free schematic for this old Barcus Berry 1715 amp? It has
> a part in it I cannot identify..may be a thermistor..not sure...about
> as thick as a dime. Two wires comong off of it but I am not sure where
> as one was off, disk about half diameter of dime. Was thermal glued to
> chassis with fiber holder screwed to chassis..

All I did was google the other unit and googled this for you:
* w w w .musicparts . com /products.asp?Company=Barcus-Berry

It's not my fault DBX doesn't charge for schematics
and this company does.

On Wed, 7 May 2008 04:10:56 -0500, "Elvis Kabong"
<ampscience@tuneland . com > wrote:

>
>"J.P." <jpasano@hotmail . com > wrote in message
>news:tnq224plgoo3vtto6qpouc1069mhpia876@4ax . com ...
>> On Wed, 7 May 2008 02:13:07 -0500, "Elvis Kabong"
>> <ampscience@tuneland . com > wrote:
>>
>>>
>>>"matteo" <matteo_bonino@virgilio . it > wrote in message
>>>news:1b4ad655-3a6e-43b1-8a72-c29dc0ee7446@c58g2000hsc.googlegroups . com ...
>>>> Dear all,
>>>> a frend of mine gave me a broken DBX586 preamplifier, to get
>>>> repaired. It has the power transformer out of order, with secondaries
>>>> broken.
>>>>
>>>> The problem is that I can't find the specifications of the transformer
>>>> (output voltage, current), because I can't measure them.
>>>>
>>>> So, I see two solutions:
>>>> 1) Is there anyone who has the schematics of the DBX586 preamplifier,
>>>> with transformer output voltages reported ?
>>>> 2) Or, do you know which are the specifications of the power
>>>> transformer, which is a 'Toroid' TI-65781
>>>>
>>>> Many thanks in advance
>>>>
>>>> Matteo
>>>
>>>ftp://ftp.dbxpro . com /pub/PDFs/discontinued/Schematics/586H%20Schematic.pdf
>>>
>> How about a free schematic for this old Barcus Berry 1715 amp? It has
>> a part in it I cannot identify..may be a thermistor..not sure...about
>> as thick as a dime. Two wires comong off of it but I am not sure where
>> as one was off, disk about half diameter of dime. Was thermal glued to
>> chassis with fiber holder screwed to chassis..
>
>All I did was google the other unit and googled this for you:
> * w w w .musicparts . com /products.asp?Company=Barcus-Berry
>
>It's not my fault DBX doesn't charge for schematics
>and this company does.
>
It's okay..I forgive you..just slap m.v. wackyweiner for me and we'll
call it even...

"matteo"
> a frend of mine gave me a broken DBX586 preamplifier, to get
> repaired. It has the power transformer out of order, with secondaries
> broken.
>
> The problem is that I can't find the specifications of the transformer
> (output voltage, current), because I can't measure them.


** Common problem, when supply transformers are damaged.


> So, I see two solutions:
> 1) Is there anyone who has the schematics of the DBX586 preamplifier,
> with transformer output voltages reported ?
> 2) Or, do you know which are the specifications of the power
> transformer, which is a 'Toroid' TI-65781


** A link to the schem has been posted by Elvis.

But this is not much help as the original transformer ( although not shown)
is a clearly specially made part with a very unusual combination of
secondary windings.

If the dbx folk have no spares to sell - you are outa luck.



...... Phil

"Phil Allison" <philallison@tpg . com .au> wrote in message
news:68d4i0F2sfnclU1@mid.individual . net ...
>
> "matteo"
>> a frend of mine gave me a broken DBX586 preamplifier, to get
>> repaired. It has the power transformer out of order, with secondaries
>> broken.
>>
>> The problem is that I can't find the specifications of the transformer
>> (output voltage, current), because I can't measure them.
>
>
> ** Common problem, when supply transformers are damaged.
>
>
>> So, I see two solutions:
>> 1) Is there anyone who has the schematics of the DBX586 preamplifier,
>> with transformer output voltages reported ?
>> 2) Or, do you know which are the specifications of the power
>> transformer, which is a 'Toroid' TI-65781
>
>
> ** A link to the schem has been posted by Elvis.
>
> But this is not much help as the original transformer ( although not
> shown) is a clearly specially made part with a very unusual combination of
> secondary windings.
>
> If the dbx folk have no spares to sell - you are outa luck.
>
>
>
> ...... Phil

Hi Phil -

So he can't get it rebuilt?

"Elvis Kabong"
> "Phil Allison"
>>
>> "matteo"
>>> a frend of mine gave me a broken DBX586 preamplifier, to get
>>> repaired. It has the power transformer out of order, with secondaries
>>> broken.
>>>
>>> The problem is that I can't find the specifications of the transformer
>>> (output voltage, current), because I can't measure them.
>>
>>
>> ** Common problem, when supply transformers are damaged.
>>
>>
>>> So, I see two solutions:
>>> 1) Is there anyone who has the schematics of the DBX586 preamplifier,
>>> with transformer output voltages reported ?
>>> 2) Or, do you know which are the specifications of the power
>>> transformer, which is a 'Toroid' TI-65781
>>
>>
>> ** A link to the schem has been posted by Elvis.
>>
>> But this is not much help as the original transformer ( although not
>> shown) is a clearly specially made part with a very unusual combination
>> of secondary windings.
>>
>> If the dbx folk have no spares to sell - you are outa luck.
>>
>>
>>
>> ...... Phil
>
> Hi Phil -
>
> So he can't get it rebuilt?


** Finding anyone able to rewind a small, special toroidal would be near
impossible. The HT winding is probably made with hair fine wire =
nightmare job.

Likely " dbx" DO have spares - the OP has not asked them for one,
AFAIK.


..... Phil

On Wed, 7 May 2008 00:04:38 -0700 (PDT), matteo
<matteo_bonino@virgilio . it > wrote:

>Dear all,
> a frend of mine gave me a broken DBX586 preamplifier, to get
>repaired. It has the power transformer out of order, with secondaries
>broken.
>
>The problem is that I can't find the specifications of the transformer
>(output voltage, current), because I can't measure them.
>
>So, I see two solutions:
>1) Is there anyone who has the schematics of the DBX586 preamplifier,
>with transformer output voltages reported ?
>2) Or, do you know which are the specifications of the power
>transformer, which is a 'Toroid' TI-65781
>
>Many thanks in advance
>
>Matteo

I don't know how much space you have in the case for this thing, but
your best bet may be to buy several transformers to give you all the
different voltages you need here. I think you should be able to do it
with two. If you can't get hold of the clearly bespoke original item,
this may be the best alternative.

For the unregulated voltages, near enough will be good enough - within
a volt or so. For the regulated ones, as long as you have enough volts
to let the regulator work, they will be good; but don't have so many
excess volts that the regulators start running hot. You may need to
experiment a bit.

d
--
Pearce Consulting
* w w w .pearce.uk . com

On 7 Mag, 09:56, nos...@nospam . com (Don Pearce) wrote:
> On Wed, 7 May 2008 00:04:38 -0700 (PDT), matteo
>
>
>
>
>
> <matteo_bon...@virgilio . it > wrote:
> >Dear all,
> >  a frend of mine gave me a broken DBX586 preamplifier, to get
> >repaired. It has the power transformer out of order, with secondaries
> >broken.
>
> >The problem is that I can't find the specifications of the transformer
> >(output voltage, current), because I can't measure them.
>
> >So, I see two solutions:
> >1) Is there anyone who has the schematics of the DBX586 preamplifier,
> >with transformer output voltages reported ?
> >2) Or, do you know which are the specifications of the power
> >transformer, which is a 'Toroid' TI-65781
>
> >Many thanks in advance
>
> >Matteo
>
> I don't know how much space you have in the case for this thing, but
> your best bet may be to buy several transformers to give you all the
> different voltages you need here. I think you should be able to do it
> with two. If you can't get hold of the clearly bespoke original item,
> this may be the best alternative.
>
> For the unregulated voltages, near enough will be good enough - within
> a volt or so. For the regulated ones, as long as you have enough volts
> to let the regulator work, they will be good; but don't have so many
> excess volts that the regulators start running hot. You may need to
> experiment a bit.
>
> d
> --
> Pearce Consulting * w w w .pearce.uk . com - Nascondi testo tra virgolette -=

>
> - Mostra testo tra virgolette -

Many thanks to everyone for your help; I've downloaded the schematics
(thanks !), but it doesn't report the transformer output voltages.
I'll try to guess those data, based on the schematics.

If it was not for a frend, I'd have suggested to him to buy another
preamplifier ! But I don't want to leave the challenge now !

Matteo

"matteo" <matteo_bonino@virgilio . it > wrote in message
news:944249c3-6e17-43e0-b0f5-a8de09ac4516@d77g2000hsb.googlegroups . com ...
On 7 Mag, 09:56, nos...@nospam . com (Don Pearce) wrote:
> On Wed, 7 May 2008 00:04:38 -0700 (PDT), matteo
>
>
>
>
>
> <matteo_bon...@virgilio . it > wrote:
> >Dear all,
> > a frend of mine gave me a broken DBX586 preamplifier, to get
> >repaired. It has the power transformer out of order, with secondaries
> >broken.
>
> >The problem is that I can't find the specifications of the transformer
> >(output voltage, current), because I can't measure them.
>
> >So, I see two solutions:
> >1) Is there anyone who has the schematics of the DBX586 preamplifier,
> >with transformer output voltages reported ?
> >2) Or, do you know which are the specifications of the power
> >transformer, which is a 'Toroid' TI-65781
>
> >Many thanks in advance
>
> >Matteo
>
> I don't know how much space you have in the case for this thing, but
> your best bet may be to buy several transformers to give you all the
> different voltages you need here. I think you should be able to do it
> with two. If you can't get hold of the clearly bespoke original item,
> this may be the best alternative.
>
> For the unregulated voltages, near enough will be good enough - within
> a volt or so. For the regulated ones, as long as you have enough volts
> to let the regulator work, they will be good; but don't have so many
> excess volts that the regulators start running hot. You may need to
> experiment a bit.
>
> d
> --
> Pearce Consulting * w w w .pearce.uk . com - Nascondi testo tra virgolette -
>
> - Mostra testo tra virgolette -

Many thanks to everyone for your help; I've downloaded the schematics
(thanks !), but it doesn't report the transformer output voltages.
I'll try to guess those data, based on the schematics.

If it was not for a frend, I'd have suggested to him to buy another
preamplifier ! But I don't want to leave the challenge now !

Matteo
----------------------------------------------------------
Damn! You mean there are no notations of the secondary voltages?
Sheeks! What a cheeseball reference! It's almost useless.

All I did was google the model name and number, found
the page, took a look before it completely downloaded and
saw that a transformer was on the page so I posted the link.
If I had noticed there were no secondary voltage specs,
I problably would not have posted the link.
What a disappointment.

On Wed, 7 May 2008 04:16:23 -0500, "Elvis Kabong"
<ampscience@tuneland . com > wrote:

>Damn! You mean there are no notations of the secondary voltages?
>Sheeks! What a cheeseball reference! It's almost useless.
>
>All I did was google the model name and number, found
>the page, took a look before it completely downloaded and
>saw that a transformer was on the page so I posted the link.
>If I had noticed there were no secondary voltage specs,
>I problably would not have posted the link.
>What a disappointment.
>

The rectified DC voltages are there, so it is no great hardship to
work back to the AC. Actually, the B+ volts for the tube stage isn't,
but there is plenty of helpful stuff out there for deciding on
something appropriate.

d
--
Pearce Consulting
* w w w .pearce.uk . com

On May 7, 4:23 am, nos...@nospam . com (Don Pearce) wrote:
> On Wed, 7 May 2008 04:16:23 -0500, "Elvis Kabong"
>
> <ampscie...@tuneland . com > wrote:
> >Damn! You mean there are no notations of the secondary voltages?
> >Sheeks! What a cheeseball reference! It's almost useless.
>
> >All I did was google the model name and number, found
> >the page, took a look before it completely downloaded and
> >saw that a transformer was on the page so I posted the link.
> >If I had noticed there were no secondary voltage specs,
> >I problably would not have posted the link.
> >What a disappointment.

If it's a Toroid Corp. part they will probably make you one if it is
not a current part. If it is they will refer you to the OEM.

"Elvis Kabong" <ampscience@tuneland . com > wrote in message
news:greUj.31015$3v1.24987@bignews3.bellsouth . net

> Many thanks to everyone for your help; I've downloaded
> the schematics (thanks !), but it doesn't report the
> transformer output voltages. I'll try to guess those
> data, based on the schematics.
> If it was not for a frend, I'd have suggested to him to
> buy another preamplifier ! But I don't want to leave the
> challenge now !

In this case, you work backwards from the DC voltages in the piece of
equipment.

Looking at page 13 in the schematic, I see +15, +12 and -15 which should be
slam dunks, and then there is that B+ voltage, and +48 which are not exactly
slam dunks.

"Scott Dorsey" <kludge@panix . com > wrote in message
news:fvsbo0$7ig$1@panix2.panix . com
> matteo <matteo_bonino@virgilio . it > wrote:
>> Dear all,
>> a frend of mine gave me a broken DBX586 preamplifier,
>> to get repaired. It has the power transformer out of
>> order, with secondaries broken.
>
> What makes you think so? Transformers don't normally
> fail... if ALL of the secondaries are open, this is a
> sign that it has received severe mechanical abuse.
>
>> The problem is that I can't find the specifications of
>> the transformer (output voltage, current), because I
>> can't measure them.
>>
>> So, I see two solutions:
>> 1) Is there anyone who has the schematics of the DBX586
>> preamplifier, with transformer output voltages reported ?
>
> dbx will send you one if you call the dbx rep in your
> country. My guess is that it uses +/- 15V supplies like
> everything else with that technology, and anything
> providing something in the right ballpark to the 15V
> regulators will be fine.

The schematic says that the internal voltages that are more-or-less direct
from the power supply and have their own power transformer windings are -15,
+12, +15, +43, and something up in the 300 volt range for the toobs.

I'm wondering if all the windings are gone, or if only one or two secondary
windings have opened up, allowing for an effective fix based on an added
standard transformer with just one or two standard secondaries.