Foreplay III troubleshooting

[q]

Hi
I'm a bit of a newbie and was wondering if this is the right place to bring up troubleshooting the Foreplay III?
Just finished quite a few similar projects with no problems at all and really want to get the ForeplayIII right
The Quickie should not be kicking it's butt.
I'll do one more Voltage check just to make sure
thx a bunch for your time and patience with noobs like me
q

 

[Doc B]

Yup, this is the place. What kind of problem are you having?

 

[q]

Thx for the fast reply mate
I wanted to do one more voltage check so that we have a good place to start
Continuity check was fine.
Sound wise, It's very thin with very little gain, lots of distortion in the bass
I'm convinced that i did something wrong with this
Stay tuned please. I'll have some better info soon
thx again
q

 

[q]

One thing was obvious was i left a long uncut lead in the PS
The cap nearest the rectifier circuit. The lead "was"(cuz i snipped it) about a 16th" away from the diodes
also, I am suspicious about where all of the grounds are attached at #28. I don't think I did that right because I ran out of room real quick
again, thx so much for the help
I'll have some better data Sunday, been working 70hrs 6days...thank goodness!..=more kits to build he he
q

 

[q]

Well how to begin to describe the embarrassment you feel when you find the problem
Hard to type when listening to my system now...Thank you all
Unbelievable!...and, I built it all with me own wee hands!
can't thank you guys enough
q

 

[Paul Joppa]

Well how to begin to describe the embarrassment you feel when you find the problem...

Oh, yeah - trust me, we've all been there!

Glad you got it running.

 

[q]

Thanks Paul,
I've heard some great systems (used to be in the High End business in the UK)
I am humbled by what I hear now. I used to think that you could get to a to a certain level in DIY. You could always accept the compromise with saying to yourself "Hey I built it all myself"
Well that's out the window now.
thx again guys
q

 

[Len]

Thanks Paul,
I've heard some great systems (used to be in the High End business in the UK)
I am humbled by what I hear now. I used to think that you could get to a to a certain level in DIY. You could always accept the compromise with saying to yourself "Hey I built it all myself"
Well that's out the window now.
thx again guys
q

Yeah, this is the real thing.

 

[q]

You are not kidding Bro!!
Can't wait to build a Quickie LowPass
But right now, it's time for a nice single malt ,a fine cigar, and stunning tunes
q

 

[RKH]

My FP-III has been up and running for a couple of weeks.  A couple of issue-ettes (I hope).  I did search the forum for 'hiss/rush' issues.  It seems the gain issue got me.  On my SS amp the hiss (with the FP-III) is too much for low-level listening.  I've ordered attenuators.  Connected to my tube amp, I can't hear the hiss at all and it sounds fab.

Now to my real question.  Things play beautifully.  But I have a low not-periodic 'crackle' in one channel.  It's not the tubes, I've swapped those back and forth.  It's not a hum, simply a low level, aperiodic crackle.  I can hear it clearly without music.  With music, it is mostly unnoticeable at all but the lowest levels.  All my voltages check.  Again, it plays well, so I presume that I've built it correctly.  Any ideas on what could be causing the 'crackling'.  I can't yet tell if it's temperature dependent, i.e. if it goes away after things get warm. 

Any advice would be appreciated!

Cheers,
Ryan

 

[Grainger49]

  My FP-III has been up and running for a couple of weeks.  A couple of issue-ettes (I hope).  I did search the forum for 'hiss/rush' issues.  It seems the gain issue got me.  On my SS amp the hiss (with the FP-III) is too much for low-level listening.  I've ordered attenuators.  Connected to my tube amp, I can't hear the hiss at all and it sounds fab.

Ryan, I assume you searched the old forum?  That should have brought up the resistors supplied in the kit for padding inputs.  If not, that is where to look.  (It sounds like you got the answer.)  You can always put a voltage divider on the input of the SS amp and end up where you can use the whole volume control.

.  .  .  Now to my real question.  Things play beautifully.  But I have a low not-periodic 'crackle' in one channel.  It's not the tubes, I've swapped those back and forth.  It's not a hum, simply a low level, aperiodic crackle.  I can hear it clearly without music.  With music, it is mostly unnoticeable at all but the lowest levels.  All my voltages check.  Again, it plays well, so I presume that I've built it correctly.  Any ideas on what could be causing the 'crackling'.  I can't yet tell if it's temperature. dependent, i.e. if it goes away after things get warm. 

Any advice would be appreciated!

Cheers,
Ryan

If it doesn't follow the tubes and it isn't in both channels that gives good information. It isn't in the power supply, unless you have the dual mono power supplies of the "Extended" version. 

The crackle can be anything in the audio path, probably not outside the audio path.  If you know how try to rewet the solder joints through the audio path of the affected channel.

Post back.

 

[RKH]

Yes, but re-wetting means I have to stop listening?!   Seriously, I'll have a go at it.  It is very possible that I didn't get a joint to flow entirely.  Thanks for the advice.

As to the padding, yes, I can swap out the resistors, that's simple enough.  Before I do that, I'll try a different source to be certain it's a level issue.  The hiss/rush is uniform across channels.  I do have fairly sensitive speakers which make it all the more noticeable.  It is non-existent on my low-power tube amp (with speakers of even higher sensitivity) ... so part of my hesitation is that I haven't completely decided on the final destination (which complement of equipment) for the FP-III .

Again, thanks very much for the advice.  I will report back.

Cheers,
Ryan

 

[Grainger49]

The old site has much about attenuators for highly sensitive SS amps.  A search there will yield more than you want to know.

Sorry about having to stop listening.  It is only necessary if you want to solve the problem.  I understand not wanting to botch up something that works very well.  Don't worry.

 

[RKH]

The old site has much about attenuators for highly sensitive SS amps.  A search there will yield more than you want to know.

Sorry to bother, but I had a poke around and could not find the 'old site'.  Can you point me in the right direction?

Cheers
Ryan

 

[Grainger49]

No problem:

http://www.audioasylum.com/forums/bottlehead/bbs.html

I think it should be at the top of every page for the first year.  Not everybody here is from the old site.  I would guess less than half.

 

[Doc B]

The #1 sticky on the general board has a link to the old forum. Been up there since this new forum went live.

 

[Len]

The #1 sticky on the general board has a link to the old forum. Been up there since this new forum went live.

That's fine for those of us who know it's there. But there is no way to know it's there from the forum homepage. The General Forum subheading describes it as a place to discuss anything we want. That really isn't a clue, IMHO.

 

[RKH]

So I purchased the Harrison Labs inline attenuators (12 dB) (from Parts Express, no affiliation on my part) and inserted them between my FP III and my solid state amp (AKSA 55 N+). That took care of the tube hiss/rush almost entirely.  I'm using some ~93 dB/watt open baffle speakers that I built and can only hear the hiss when I put my ear right next to the driver.  All I can say is, wow.  Make that WOW!  I now get to listen to the FP-III with all that is has to offer.  I've only just begun to listen to my library and I really enjoy this combination.  Now I need to finish my Seduction and get my vinyl out... so many projects, so little time.

Cheers for the support and great preamp!
Ryan