APT Holman preamp manual, schematic?

sdstarnes · 20th December 2007, 02:36 PM

Hey all,

Newbie here. Glad to have found this forum as I am puting a "vintage" system together and will be most likely needing some help.

Just purchased an APT Holman preamp, and Adcom 535 amp off of Craig's List. Does anyone have access to schematics and/or owner's manual for the APT Holman pre amp? Can they be bought new? Any "tweaks" for the pre amp?

Thanks!

sealevel · 5th January 2008, 02:00 AM

I have an APT, if you remove the cover the circuit diagram is attached to
the inside of the cover.
hth

sdstarnes · 5th January 2008, 03:41 AM

Thanks

planet10 · 5th January 2008, 03:50 AM

I have the pdf of the manual on-line but i can't at the moment tell you the URL.

dave

sealevel · 6th January 2008, 07:52 PM

Not so much a tweak, but from what I've seen on the net, the mute
circuit is the problematic area of this pre-amp. Thats why I know
where the schemo is, as mine is suffering from this issue. Haven't had
the time to trace thru and fix it yet. Otherwise and outstanding pre-amp.

sealevel

planet10 · 7th January 2008, 12:39 AM

Apt Pre Manual

http://homepage.mac.com/planet10/TLS...nPreManual.pdf

dave

sdstarnes · 7th January 2008, 12:41 AM

Thanks!

Good resource..

unclejed613 · 7th January 2008, 07:40 AM

sealevel, if the mute circuit is causing a channel (or both) to drop out, here's the factory fix (i worked as the customer service tech at APT for a few years):

1)remove the cover from the relay
2) put a piece of brown paper bag between the contacts of the relay
3) hold the contacts closed and use the brown paper to burnish the contacts.

4) reassemble the relay

planet10 · 7th January 2008, 07:45 AM

Quote:

Originally posted by unclejed613
here's the factory fix]

Good trick.. i've had that problem with a couple of the APTs i've had thru here... (i maganged to recover from them by repeatedly toggling the mute switch.

dave

Original Burnedfingers · 7th January 2008, 10:36 AM

I always used a burnishing tool and then ran paper thru the contacts to clean. May be better just to replace the relay in the long run.

20th December 2007, 02:36 PM	#1
sdstarnes diyAudio Member Join Date: Dec 2007	APT Holman preamp manual, schematic? Hey all, Newbie here. Glad to have found this forum as I am puting a "vintage" system together and will be most likely needing some help. Just purchased an APT Holman preamp, and Adcom 535 amp off of Craig's List. Does anyone have access to schematics and/or owner's manual for the APT Holman pre amp? Can they be bought new? Any "tweaks" for the pre amp? Thanks!

5th January 2008, 03:50 AM	#4
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	I have the pdf of the manual on-line but i can't at the moment tell you the URL. dave __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

7th January 2008, 12:39 AM	#6
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	Apt Pre Manual http://homepage.mac.com/planet10/TLS...nPreManual.pdf dave __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

7th January 2008, 07:40 AM	#8
unclejed613 diyAudio Member Join Date: Dec 2006	sealevel, if the mute circuit is causing a channel (or both) to drop out, here's the factory fix (i worked as the customer service tech at APT for a few years): 1)remove the cover from the relay 2) put a piece of brown paper bag between the contacts of the relay 3) hold the contacts closed and use the brown paper to burnish the contacts. 4) reassemble the relay __________________ Vintage Audio and Pro-Audio repair ampz(removethis)@sohonet.net spammer trap: http://www1284177414881.v-dc.net/

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5th January 2008, 02:00 AM	#2
sealevel diyAudio Member Join Date: Jan 2008	I have an APT, if you remove the cover the circuit diagram is attached to the inside of the cover. hth

5th January 2008, 03:41 AM	#3
sdstarnes diyAudio Member Join Date: Dec 2007	Thanks

6th January 2008, 07:52 PM	#5
sealevel diyAudio Member Join Date: Jan 2008	Not so much a tweak, but from what I've seen on the net, the mute circuit is the problematic area of this pre-amp. Thats why I know where the schemo is, as mine is suffering from this issue. Haven't had the time to trace thru and fix it yet. Otherwise and outstanding pre-amp. sealevel

7th January 2008, 12:41 AM	#7
sdstarnes diyAudio Member Join Date: Dec 2007	Thanks! Good resource..

7th January 2008, 10:36 AM	#10
Original Burnedfingers diyAudio Member Join Date: Nov 2002	I always used a burnishing tool and then ran paper thru the contacts to clean. May be better just to replace the relay in the long run.

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