Dared VP-845

[skularatna]

Hey fellow AK members,

I have a Dared VP-845 amp that has recently stopped working. Tubes are lighting up but no sound. Not getting any reading on ammeter when hooked up to a variac and also appears the plate voltage and bias for driver tube and preamp is missing.

I was wondering if anyone knew where I could get the schematics for this amp or if you have could you share it pls ?

 

[EL504]

With the tubes still lighting up the amplifier must draw current so there has to be something wrong with the way you are measuring the current draw.

While searching for a schematic, I got the impression that there are at least two versions of the Dared VP-845, one with 6L6G's (triode connected) as drivers and one with 6SN7's as drivers. Which version do you have?

 

[zackthedog]

Hey fellow AK members,

I have a Dared VP-845 amp that has recently stopped working. Tubes are lighting up but no sound. Not getting any reading on ammeter when hooked up to a variac and also appears the plate voltage and bias for driver tube and preamp is missing.

I was wondering if anyone knew where I could get the schematics for this amp or if you have could you share it pls ?

If I had to guess, I would speculate that there's a relay circuit to delay the high voltage that has failed and is not turning on the HV.

 

[skularatna]

The 6SN7 version

With the tubes still lighting up the amplifier must draw current so there has to be something wrong with the way you are measuring the current draw.

While searching for a schematic, I got the impression that there are at least two versions of the Dared VP-845, one with 6L6G's (triode connected) as drivers and one with 6SN7's as drivers. Which version do you have?

 

[EL504]

I have this schematic (of the amplifier part only) in my collection of schematics but I can't be sure if it is the right one. The style of the schematic resembles the style of the schematic of the version with the 6L6 as driver that I also have and of which I'm pretty sure it is from Dared. You could check if this schematic represents your amplifier.



If this is the right schematic, the second triode section of the 6SN7 is being fed + 200 V and - 200 V, while the output stage is being fed 960 V. It is very likely that these voltages are being produced by two seperate windings on the power transformer. Maybe the 410 V for the first two stages is being produced by yet an other seperate winding on the power transformer but it is possible that this 410 V is taken from the winding that produces the 960 V.

From your description it looks like the + 200 V and - 200 V are not there anymore. Could you measure/confirm if that is the case? And could you measure/confirm if the 960 V and the 410 V are still present? If your measuring equipment can't handle 960 V you can measure the voltage over the 1K5 cathode resistor of the 845 instead.

 

[skularatna]

Thanks yes the schematic matches. I’ll have to confirm reading again. The issue is that it seems the power supply is heavily under powering the output tubes. Maybe why the amp is only 18WPC

 

[cademan]

Sounds like you lost plate (B+) voltages. Carefully check to see if you have the 960 volts to the 845.

A power supply bridge rectifier or tube rectifier would be a good place to check first.

 

[tubeactive]

Be very careful inside these amps ! There is no "easy" way to support these beastly, 80 pound amps. They have no support sides or the ability to simply flip it on its' rear, or side, while it's on.

I had to use cushions on the bench top, plus pillows under the binding posts, for crushproof resting. Putting these on their side requires strong leaning/holding posts available...Do not even think about leaning the chassis on your body, while testing voltages, please...

Now that the inconvenience warning is over, HIGH VOLTAGE requires serious troubleshooting awareness. I highly recommend wearing tight fitting, deerskin or soft leather, suede-out gloves, on both hands, even if you only probe with one hand/test lead. No part of your body should touch any part of the chassis.

With close to 1KV DC underneath, confidence and competence are needed. If unsure, do not proceed until you read up and feel sure. High Voltages can easily arc and your first shock can be your last...Please proceed with caution...

Aother concern with the dared 845 amps are the tube sockets, not having the tightest or cleanest connections. The other tube sockets also have limitations with their undersized holes for the tube's pins.

Fortunately, the output transformers are very high fi. In spite of certain quality issues, these amps sound lovely when working well. Best of luck bringing it back to life...

 

[skularatna]

Thank you yes will proceed with caution

Be very careful inside these amps ! There is no "easy" way to support these beastly, 80 pound amps. They have no support sides or the ability to simply flip it on its' rear, or side, while it's on.

I had to use cushions on the bench top, plus pillows under the binding posts, for crushproof resting. Putting these on their side requires strong leaning/holding posts available...Do not even think about leaning the chassis on your body, while testing voltages, please...

Now that the inconvenience warning is over, HIGH VOLTAGE requires serious troubleshooting awareness. I highly recommend wearing tight fitting, deerskin or soft leather, suede-out gloves, on both hands, even if you only probe with one hand/test lead. No part of your body should touch any part of the chassis.

With close to 1KV DC underneath, confidence and competence are needed. If unsure, do not proceed until you read up and feel sure. High Voltages can easily arc and your first shock can be your last...Please proceed with caution...

Aother concern with the dared 845 amps are the tube sockets, not having the tightest or cleanest connections. The other tube sockets also have limitations with their undersized holes for the tube's pins.

Fortunately, the output transformers are very high fi. In spite of certain quality issues, these amps sound lovely when working well. Best of luck bringing it back to life...

 

[skularatna]

getting much less than 960V getting around 700

Sounds like you lost plate (B+) voltages. Carefully check to see if you have the 960 volts to the 845.

A power supply bridge rectifier or tube rectifier would be a good place to check first.

 

[cademan]

You're still getting B+ and plenty to produce sound so something else is not doing its job like an open resistor or some such.

Without looking at a schematic or knowing what the amp is, I always go to the power supply first then try to find a schematic and go through it entirely. Everybody troubleshoots in their own way, this is just me and how I do it.

 

[EL504]

I don't understand why the focus shifted to only the power stage.

In the first post it says that the plate voltage and bias for the driver and preamp is missing and that there is no sound. It is highly likely that atleast the driver stage has its own B+ (+200V and -200V) coming from a seperate winding on the power transformer (b.t.w.: the version of this amplifier with a 6L6 as the driver has B+ for the power stage and B+ for the rest of the amplifier coming from two seperate windings on the power transformer).

Is B+ of the driver stage (so the +200 V and -200 V) there or not? And is B+ of the first two stages (410 V) there or not?

 

[skularatna]

So actually in posting on behalf of my technician older guy very savvy with tube amps but not so much on forums. He’s trying to get the power schematic as the readings he was getting was not what he’s normally used to seeing for an 845


This schematic for the 6L6 version I found my technician said seems to be highly underpowered for an 845 more suited to an EL34 KT88 power amp.

 

[EL504]

To stoN_Cold: You posted the version with 6L6 as driver while the amplifier of TS is the version with 6SN7 as pre-stage/driver. If you would have read the posts in this thread you would have known.

To skularatna: Since the problem with your amplifier seems to change over time and since you don't answer my questions, I wish you and your savvy technician good luck with the repair.

I'm out of this thread.

 

[skularatna]

I was waiting for my technician so basically there is b+ at driver stage is there and also in the 1st two stages

I don't understand why the focus shifted to only the power stage.

In the first post it says that the plate voltage and bias for the driver and preamp is missing and that there is no sound. It is highly likely that atleast the driver stage has its own B+ (+200V and -200V) coming from a seperate winding on the power transformer (b.t.w.: the version of this amplifier with a 6L6 as the driver has B+ for the power stage and B+ for the rest of the amplifier coming from two seperate windings on the power transformer).

Is B+ of the driver stage (so the +200 V and -200 V) there or not? And is B+ of the first two stages (410 V) there or not?

 

[skularatna]

not getting anywhere near 960V

Sounds like you lost plate (B+) voltages. Carefully check to see if you have the 960 volts to the 845.

A power supply bridge rectifier or tube rectifier would be a good place to check first.

 

[skularatna]

prob from start of thread still applies no sound, plate voltage and bias for preamp and driver stage missing. Technician said he was getting unusual readings from the power transformer and hence wanted to see schematic to check if those readings are expected as in by design or if it might be indicative of a problem

To stoN_Cold: You posted the version with 6L6 as driver while the amplifier of TS is the version with 6SN7 as pre-stage/driver. If you would have read the posts in this thread you would have known.

To skularatna: Since the problem with your amplifier seems to change over time and since you don't answer my questions, I wish you and your savvy technician good luck with the repair.

I'm out of this thread.

 

[RickB]

I have a set of Dared monos that use a pair of 300bs in them, I have tried for years to get a schematic from them for these things to no avail...

I wouldn't have anything from Dared, no matter how good it sounds, based on the construction of these things and the absolute lack of support...

I do realize that they were once the darlings of inexpensive, highly styled, audiophile gear, in fact the fellow who gave me these amps has one of the 845 w/6SN7s amp, but there is no schematic that I know of for it...it is a decent sounding amplifier and does run the OP tubes very conservatively (but them SOBs still get incredibly hot!)

Good luck

 

[skularatna]

yeah never buying their stuff again

I have a set of Dared monos that use a pair of 300bs in them, I have tried for years to get a schematic from them for these things to no avail...

I wouldn't have anything from Dared, no matter how good it sounds, based on the construction of these things and the absolute lack of support...

I do realize that they were once the darlings of inexpensive, highly styled, audiophile gear, in fact the fellow who gave me these amps has one of the 845 w/6SN7s amp, but there is no schematic that I know of for it...it is a decent sounding amplifier and does run the OP tubes very conservatively (but them SOBs still get incredibly hot!)

Good luck