Leak stereo 30 plus balance issues - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Derminator · 15th Jul 2020, 12:44 pm

Quote:

Originally Posted by thermionic

What Input to the amp are you using, I assume it’s a line in level?

If you use the ‘Tuner 2’ input for example, there is a switchable attenuator linked to this input on the rear panel.

SimonT.

Hi, I've got the Cd player on that input. I think I didn't use it for the tuner as it was a bit crackly on "Lo Gain" I suppose I could revisit that and clean the switch. That could potentially just leave me with the phono input to deal with.

Derminator · 15th Jul 2020, 1:10 pm

The "aux" cable is connected to the ceramic cartridge input "pickup 2". I think this has switchable hi and lo gain, the tuner is on "tuner 1" input - no gain switch and the record player is on "pickup 1" no switch.

Derminator · 15th Jul 2020, 1:25 pm

Thanks Bikerhifinut and PaulR, the attenuator idea beginning to appeal. PaulSherwin suggested that back in post 4 but I had misunderstood thinking he meant attenuating the amp's speaker outputs. Apols.

Goodizzy · 16th Jul 2020, 4:42 pm

TUNER 1
25mV @ 47k OR 2mV @ 47k

TUNER 2 (switched)
60mV @ 50k OR 250mV @ 50k

PICKUP 2 (switched)
10mV @ 33k OR 30mV @ 100k

Has the amp been serviced?

Derminator · 17th Jul 2020, 9:29 pm

Not professionally in the 5 or so years I've owned it. The previous owner, who bought it new, did have it serviced periodically and I believe the last time was not long before I bought it. I have done some basic stuff like cleaning the contacts on the slot-in boards some switch lube/cleaner here and there. I also replaced a pair of electrolytics when one failed. I haven't disassembled any switches for cleaning though.

Goodizzy · 17th Jul 2020, 11:46 pm

I recently finished bringing back one of these I purchased from a fellow on this site. I did a full clean, recap and changed all the higher wattage resistors, including the (2) headphone resistors. For those I used 1% tolerance resistors. The only thing I didn't do, (yet) is change the signal path resistors to metal film. I have had it as my daily listener now for several months and it has performed wonderfully so far. Great improvement to my ears.

I would recommend taking a look "under the hood" so to speak and seeing how many components were changed. I certainly would strongly consider changing the speaker coupling caps, filter caps, and really any other electrolytic cap in the amp. That thing is close to 60 years old at this point! Cleaning the boards and switches certainly a good idea too. Not sure why you'd need to disassemble the switch to clean?

Derminator · 18th Jul 2020, 1:24 am

Hi Goodizzy, yes it was the speaker coupling caps that I replaced but that was only because one of the originals failed. The amp has always sounded great to my ears and I lean to the 'leave well alone' camp. Regarding disassembling switches I mean those gain selectors on the back panel. Not sure if it is absolutely necessary but squirting switch cleaner into them hasn't worked for the tuner 2 switch. The input works fine set to 'hi' with my CD player connected but 'lo' is a bit crackly. As far as I could tell it looked all original under the cover when I replaced those caps.

PaulR · 18th Jul 2020, 9:50 am

I really like my Delta 30. I also replaced the speaker caps as they were leaky. The main smoothing cap was also leaky but the others were not so I replaced just that one. I find the amp to be almost silent hum-wise.

I bought sufficient caps to replace all the electrolytics but ended up only doing those on the power amp board as it sounded so good after they were done.

I had a problem on another amp with the potentiometers which control the quiescent current. On that and the Leak they are completely open to dust and oxidisation. I therefore changed them for multi turn Bourns ones. In hindsight a mistake there was to get ones that adjust from the front which means they can only easily be adjusted when the board in front is removed. I should have got ones with the adjustment screw on the top. Nevertheless I think they are a lot safer than the original ones.

I am trying to resist the urge to get a 35 w.p.c one now.

Goodizzy · 18th Jul 2020, 11:41 pm

Paul,

Very interesting as I did not replace those but was aware of the problem. I have a Rogers Ravensbourne rebuild that was fairly filthy. The small board trimmers are all gonna get replaced.

Do you have a link for the top adjustment screw ones you were talking about? I'd be interested in purchasing for my own repairs.

PaulR · 19th Jul 2020, 9:44 am

This was the type I bought
https://cpc.farnell.com/bourns/3296w...00r/dp/RE06701
but it is a little awkward to get to the adjustment screw. You have to remove the board in front to do so.

It isn't really a problem, but I later thought that the pattern of this one https://cpc.farnell.com/bourns/3296x...200r%20trimmer

would have made adjustment easier.

I didn't necessarily want 25 turn ones but the pattern of these seemed to fit the bill and the large number of turns does make it easier to adjust

Goodizzy · 19th Jul 2020, 1:56 pm

Paul,

Thank you that was very useful!

chris

PaulR · 19th Jul 2020, 2:10 pm

You are welcome, Chris. If you do get some make sure the pins are in line and not in a sort of triangle. I nearly got caught out with that.

Goodizzy · 20th Jul 2020, 2:30 pm

Paul, thanks! I saw that- The Leak appears to use the straight pattern while the Rogers has the triangle pattern so I’ll be getting both..

To OP: I had forgot to include last- what is the AUX on PICKUP2? Refer to The table I posted. The only somewhat line level input to the amp is TUNER2. You will overload the preamp stages trying to drive either PICKUP input with a hot line level signal. If you’ve done this for any substantial length of time you could have damaged some of the transistors...or maybe crapped out some of those old caps!

I never drive my speakers far beyond noon with the Stereo 30, but I also only use higher sensitive older speakers. For what it’s worth..

Derminator · 21st Jul 2020, 12:17 am

I don't use it very much to be honest. If I do it's usually my iPod but I am always careful with the levels. I don't think it has done it any harm but if you think it risky I'll disconnect it. My amp is connected to a pair of Acoustic Research AR18S speakers. Sounds great!

Goodizzy · 21st Jul 2020, 12:40 pm

If it were me, I would alternate the ipod and cd player on TUNER2 as I used them.

Your amp, your property, do as you please!

PaulR · 21st Jul 2020, 1:10 pm

Quote:

Originally Posted by PaulR

This was the type I bought
https://cpc.farnell.com/bourns/3296w...00r/dp/RE06701
but it is a little awkward to get to the adjustment screw. You have to remove the board in front to do so.

It isn't really a problem, but I later thought that the pattern of this one https://cpc.farnell.com/bourns/3296x...200r%20trimmer

would have made adjustment easier.

I didn't necessarily want 25 turn ones but the pattern of these seemed to fit the bill and the large number of turns does make it easier to adjust

I have just been looking at these again and the second one wouldn't help, I suspect, as the adjustment screw would probably be on the side against the other components. Maybe the one I got was the best of the Bourns ones.

Derminator · 22nd Jul 2020, 12:17 am

Quote:

Originally Posted by Goodizzy

If it were me, I would alternate the ipod and cd player on TUNER2 as I used them.

Your amp, your property, do as you please!

Thanks, I think I'll follow your advice.

Goodizzy · 22nd Jul 2020, 4:02 pm

I was looking over the paper again as I had a sneaking suspicion I may have mixed up amps and led you astray.

The Leak Stereo 30 PLUS has a TUNER2 250mV 50Kohm input as well as the TAPE REPLAY input of 400mV 47Kohm which should be acceptable for a line level input. Tape Monitor switch should be on with the TAPE REPLAY input AND it bypasses the preamp and controls except for the volume. (Essentially just the power amp it seems)

Edit: Had to update this!! I went downstairs and tried both inputs again and think the TAPE REPLAY actually develops much more low end and better overall sound. But I really have to push the amp on my highly sensitive 4ohm DLS-1 speakers. This is why I hadn't heard it before! And is a good exercise to always keep experimenting! Just don't drive anything too hard too long- it's not a beast of an amp no matter which inputs you use. Best to keep all switches in LO position to be safe while fooling about with the volume and in general if you want to not worry about driving/clipping the amp.

Also- final note and very important- DON"T use the TAPE RECORD input as its meant for very low signal levels of a tape record head.

15th Jul 2020, 1:10 pm	#22
Derminator Pentode Join Date: Feb 2009 Location: Crystal Palace, London, UK. Posts: 118	Re: Leak stereo 30 plus balance issues The "aux" cable is connected to the ceramic cartridge input "pickup 2". I think this has switchable hi and lo gain, the tuner is on "tuner 1" input - no gain switch and the record player is on "pickup 1" no switch.

15th Jul 2020, 1:25 pm	#23
Derminator Pentode Join Date: Feb 2009 Location: Crystal Palace, London, UK. Posts: 118	Re: Leak stereo 30 plus balance issues Thanks Bikerhifinut and PaulR, the attenuator idea beginning to appeal. PaulSherwin suggested that back in post 4 but I had misunderstood thinking he meant attenuating the amp's speaker outputs. Apols.

16th Jul 2020, 4:42 pm	#24
Goodizzy Pentode Join Date: Jan 2016 Location: Lynchburg, Central Virginia, USA. Posts: 137	Re: Leak stereo 30 plus balance issues TUNER 1 25mV @ 47k OR 2mV @ 47k TUNER 2 (switched) 60mV @ 50k OR 250mV @ 50k PICKUP 2 (switched) 10mV @ 33k OR 30mV @ 100k Has the amp been serviced?

17th Jul 2020, 9:29 pm	#25
Derminator Pentode Join Date: Feb 2009 Location: Crystal Palace, London, UK. Posts: 118	Re: Leak stereo 30 plus balance issues Not professionally in the 5 or so years I've owned it. The previous owner, who bought it new, did have it serviced periodically and I believe the last time was not long before I bought it. I have done some basic stuff like cleaning the contacts on the slot-in boards some switch lube/cleaner here and there. I also replaced a pair of electrolytics when one failed. I haven't disassembled any switches for cleaning though.

17th Jul 2020, 11:46 pm	#26
Goodizzy Pentode Join Date: Jan 2016 Location: Lynchburg, Central Virginia, USA. Posts: 137	Re: Leak stereo 30 plus balance issues I recently finished bringing back one of these I purchased from a fellow on this site. I did a full clean, recap and changed all the higher wattage resistors, including the (2) headphone resistors. For those I used 1% tolerance resistors. The only thing I didn't do, (yet) is change the signal path resistors to metal film. I have had it as my daily listener now for several months and it has performed wonderfully so far. Great improvement to my ears. I would recommend taking a look "under the hood" so to speak and seeing how many components were changed. I certainly would strongly consider changing the speaker coupling caps, filter caps, and really any other electrolytic cap in the amp. That thing is close to 60 years old at this point! Cleaning the boards and switches certainly a good idea too. Not sure why you'd need to disassemble the switch to clean?

18th Jul 2020, 1:24 am	#27
Derminator Pentode Join Date: Feb 2009 Location: Crystal Palace, London, UK. Posts: 118	Re: Leak stereo 30 plus balance issues Hi Goodizzy, yes it was the speaker coupling caps that I replaced but that was only because one of the originals failed. The amp has always sounded great to my ears and I lean to the 'leave well alone' camp. Regarding disassembling switches I mean those gain selectors on the back panel. Not sure if it is absolutely necessary but squirting switch cleaner into them hasn't worked for the tuner 2 switch. The input works fine set to 'hi' with my CD player connected but 'lo' is a bit crackly. As far as I could tell it looked all original under the cover when I replaced those caps.

18th Jul 2020, 9:50 am	#28
PaulR Dekatron Join Date: Oct 2003 Location: Southport Lancashire, UK. Posts: 3,233	Re: Leak stereo 30 plus balance issues I really like my Delta 30. I also replaced the speaker caps as they were leaky. The main smoothing cap was also leaky but the others were not so I replaced just that one. I find the amp to be almost silent hum-wise. I bought sufficient caps to replace all the electrolytics but ended up only doing those on the power amp board as it sounded so good after they were done. I had a problem on another amp with the potentiometers which control the quiescent current. On that and the Leak they are completely open to dust and oxidisation. I therefore changed them for multi turn Bourns ones. In hindsight a mistake there was to get ones that adjust from the front which means they can only easily be adjusted when the board in front is removed. I should have got ones with the adjustment screw on the top. Nevertheless I think they are a lot safer than the original ones. I am trying to resist the urge to get a 35 w.p.c one now. __________________ Paul

18th Jul 2020, 11:41 pm	#29
Goodizzy Pentode Join Date: Jan 2016 Location: Lynchburg, Central Virginia, USA. Posts: 137	Re: Leak stereo 30 plus balance issues Paul, Very interesting as I did not replace those but was aware of the problem. I have a Rogers Ravensbourne rebuild that was fairly filthy. The small board trimmers are all gonna get replaced. Do you have a link for the top adjustment screw ones you were talking about? I'd be interested in purchasing for my own repairs.

19th Jul 2020, 9:44 am	#30
PaulR Dekatron Join Date: Oct 2003 Location: Southport Lancashire, UK. Posts: 3,233	Re: Leak stereo 30 plus balance issues This was the type I bought https://cpc.farnell.com/bourns/3296w...00r/dp/RE06701 but it is a little awkward to get to the adjustment screw. You have to remove the board in front to do so. It isn't really a problem, but I later thought that the pattern of this one https://cpc.farnell.com/bourns/3296x...200r%20trimmer would have made adjustment easier. I didn't necessarily want 25 turn ones but the pattern of these seemed to fit the bill and the large number of turns does make it easier to adjust __________________ Paul

19th Jul 2020, 1:56 pm	#31
Goodizzy Pentode Join Date: Jan 2016 Location: Lynchburg, Central Virginia, USA. Posts: 137	Re: Leak stereo 30 plus balance issues Paul, Thank you that was very useful! chris

19th Jul 2020, 2:10 pm	#32
PaulR Dekatron Join Date: Oct 2003 Location: Southport Lancashire, UK. Posts: 3,233	Re: Leak stereo 30 plus balance issues You are welcome, Chris. If you do get some make sure the pins are in line and not in a sort of triangle. I nearly got caught out with that. __________________ Paul

20th Jul 2020, 2:30 pm	#33
Goodizzy Pentode Join Date: Jan 2016 Location: Lynchburg, Central Virginia, USA. Posts: 137	Re: Leak stereo 30 plus balance issues Paul, thanks! I saw that- The Leak appears to use the straight pattern while the Rogers has the triangle pattern so I’ll be getting both.. To OP: I had forgot to include last- what is the AUX on PICKUP2? Refer to The table I posted. The only somewhat line level input to the amp is TUNER2. You will overload the preamp stages trying to drive either PICKUP input with a hot line level signal. If you’ve done this for any substantial length of time you could have damaged some of the transistors...or maybe crapped out some of those old caps! I never drive my speakers far beyond noon with the Stereo 30, but I also only use higher sensitive older speakers. For what it’s worth..

21st Jul 2020, 12:17 am	#34
Derminator Pentode Join Date: Feb 2009 Location: Crystal Palace, London, UK. Posts: 118	Re: Leak stereo 30 plus balance issues I don't use it very much to be honest. If I do it's usually my iPod but I am always careful with the levels. I don't think it has done it any harm but if you think it risky I'll disconnect it. My amp is connected to a pair of Acoustic Research AR18S speakers. Sounds great!

21st Jul 2020, 12:40 pm	#35
Goodizzy Pentode Join Date: Jan 2016 Location: Lynchburg, Central Virginia, USA. Posts: 137	Re: Leak stereo 30 plus balance issues If it were me, I would alternate the ipod and cd player on TUNER2 as I used them. Your amp, your property, do as you please!

22nd Jul 2020, 4:02 pm	#38
Goodizzy Pentode Join Date: Jan 2016 Location: Lynchburg, Central Virginia, USA. Posts: 137	Re: Leak stereo 30 plus balance issues I was looking over the paper again as I had a sneaking suspicion I may have mixed up amps and led you astray. The Leak Stereo 30 PLUS has a TUNER2 250mV 50Kohm input as well as the TAPE REPLAY input of 400mV 47Kohm which should be acceptable for a line level input. Tape Monitor switch should be on with the TAPE REPLAY input AND it bypasses the preamp and controls except for the volume. (Essentially just the power amp it seems) Edit: Had to update this!! I went downstairs and tried both inputs again and think the TAPE REPLAY actually develops much more low end and better overall sound. But I really have to push the amp on my highly sensitive 4ohm DLS-1 speakers. This is why I hadn't heard it before! And is a good exercise to always keep experimenting! Just don't drive anything too hard too long- it's not a beast of an amp no matter which inputs you use. Best to keep all switches in LO position to be safe while fooling about with the volume and in general if you want to not worry about driving/clipping the amp. Also- final note and very important- DON"T use the TAPE RECORD input as its meant for very low signal levels of a tape record head. Last edited by Goodizzy; 22nd Jul 2020 at 4:29 pm.