DIY: Pass F5 turbo v2 initiated

[sachu888]

sachin/om

Let me know when the GB parts will be shipped.

Thanks

Hi Pandu,
We are waiting for remaining Diodes and Power supply caps.There is also one resister .47ohm 3 watt resister in back order.I didn't notice until Anilva has pointed this.The supplier has sent me all the parts except this when I checked it 2 days back this part was on back order.it may take few days to receive.
I will send you PCBs and all other parts by tomorrow's courier.

Regards,
Sachin

 

[captrajesh]

We are waiting for remaining Diodes and Power supply caps.There is also one resister .47ohm 3 watt resister in back order.I didn't notice until Anilva has pointed this.The supplier has sent me all the parts except this when I checked it 2 days back this part was on back order.it may take few days to receive.

I will send you PCBs and all other parts by tomorrow's courier.

Sachin, why don't you wait for all components to come and send them in one shot rather than sending them piece meal which would jack up the courier cost unnecessarily?

 

[sachu888]

Sachin, why don't you wait for all components to come and send them in one shot rather than sending them piece meal which would jack up the courier cost unnecessarily?

Hi Capt,
I am waiting for all components but it is taking longer than I expected.one part is still on back order and we are yet to receive remaining Vishay Diodes from US.I am sending components and boards to only Pandu since he has almost finished his cab and boards will help him for measurement purpose.I have a wedding at my home this month end,and I won't be able to ship in this month if I don't get remaining parts in 2-3 days.

Regards,
Sachin

 

[pdhanwada]

Got the parts today

Contains almost all parts except Caps.

Parts look great. Parts are well labelled. PCBs too are well marked on the board saying what part goes where.

As the days go by I might get to understand them better. There are so many parts to be soldered, It is intimidating. I will move slow.

One thing I observed was on the rectifier board, where teh caps need to be fitted, the soldering leads on the board look very close. We need to solder very carefully to make sure we dont short them out.

To solder such closely spaced joints Do you feel the need of pointed tip solder instead of a screw driver tip solder.

Suggestions welcome.

Edit:
Spoke to Om last night.

It seems c1&c2 terminals are close but not a problem. They are connected inside the rectifier pcb.

Thanks
Pandu

 

[kroyin]

Guess what.. i saw some FQA Mosfets in the local market (shop called Nahar Electrosales in Kolkata which came highly recommended by SHAAN- The SSA thread)

Well, didnt ask the price but they look identical to what i got from BUZZ (diyaudio).

So if any of your mosfets blow, then i think you can get it locally, match & put it in circuit.

 

[vktarun]

Is this Nahar Electronics in the Building named something starting with "Bimla" ?

Regards,

Vipin.

 

[kroyin]

Yes it is in a building , 2 shops on 1st & 2nd floor

29/1 B, Bimla Chowk Building, Near Haji Hotel, Chandni Chawk Street (Near Ganesh Avenue), Princep Street, Kolkata - 700072 |

 

[pdhanwada]

Sachin,

ANy news on caps yet. Not much progress in past two weeks. Got the box ready. will start loading the pcbs in the comming week.

Need a grounding schematic from any of you guys for dual mono


Thanks
Pandu

 

[sachu888]

Sachin,

ANy news on caps yet. Not much progress in past two weeks. Got the box ready. will start loading the pcbs in the comming week.

Need a grounding schematic from any of you guys for dual mono


Thanks
Pandu

Hi Pandu,
I will receive them in few days.I have a wedding at home so may not be able to ship kits in this month.I will start shipping kits on Dec 3rd.

Regards,
Sachin

 

[omishra]

Sachin,

ANy news on caps yet. Not much progress in past two weeks. Got the box ready. will start loading the pcbs in the comming week.

Need a grounding schematic from any of you guys for dual mono


Thanks
Pandu

Pandu, I am busy with carpenter for GR Research LS Encore speakers and getting my box ready for this amp too. That grounding came to my mind today while I was buying new NTC for toroidal transformer because earlier were busted on first on. So I will send this new NTC to everybody.

On box front, I am getting box skeleton of 14"(W) X 12"(D) X 6"(H) welded together from MS angle with internal partition of 10" width in middle making 3"+3". I will post some pics after completion. All angle will have holes to mount plates and heatsink on opposite sides. Partition will hold toroidal at downside and PS boards on upside.

 

[anilva]

For those who are following my build would know that I have been having problems with one channel, predominantly in the P3 and the input transistor area. Tried checking various things but could not find problems. I have had problems with properly biased, but low gain and in another situation lower bias but proper gain and somewhere there is play of P3 trimmer.

Finally blew the 2Sk170 jFet and possible the 'P' Channel MOSFETs of the channel that is giving me problems. Cannot point my finger at anything specific but could be a bad P3 trimmer component or something else.

Sachin has been kind enough to send me a spare F5T kit to fix the problem. I am going to wire a new board and see where I end up with. I have been having problems with a F5 build for the first time after 4 builds earlier. The other channel is working brilliantly.

Cheers.

 

[omishra]

For those who are following my build would know that I have been having problems with one channel, predominantly in the P3 and the input transistor area. Tried checking various things but could not find problems. I have had problems with properly biased, but low gain and in another situation lower bias but proper gain and somewhere there is play of P3 trimmer.

Finally blew the 2Sk170 jFet and possible the 'P' Channel MOSFETs of the channel that is giving me problems. Cannot point my finger at anything specific but could be a bad P3 trimmer component or something else.

Sachin has been kind enough to send me a spare F5T kit to fix the problem. I am going to wire a new board and see where I end up with. I have been having problems with a F5 build for the first time after 4 builds earlier. The other channel is working brilliantly.

Cheers.

Anil thanks for the update. I was consistently suspicious about P3 because that part if can not be kept in middle can give improper gain. That why I was pressing to soldering that by measuring it exactly centred around middle pin resistance value. Avoid tweaking it unless one has distortion analyser. Best way is to avoid it populating on board.

 

[anilva]

Anil thanks for the update. I was consistently suspicious about P3 because that part if can not be kept in middle can give improper gain. That why I was pressing to soldering that by measuring it exactly centred around middle pin resistance value. Avoid tweaking it unless one has distortion analyser. Best way is to avoid it populating on board.

Thanks. I made it to middle of the value before I soldered. But must have got disturbed somehow. I agree, it's too dangerous a component to twiddle with.

Cheers.

 

[anilva]

Today night I completed the build of F5 Turbo V2. Both the channels are working perfectly and stable. Detailed listening tests to be done. First impressions are that it has the characteristic Pass amp sound. Very clean and detailed.

One of the channels was giving me a problem earlier and I had to wire up a new PCB and kit to overcome the problem related to few faults in that channel. Now both the channels are working well.

Will post detailed pictures soon.

Cheers.

 

[1MOR]

Congrats anilva! How would compare to the sound of your F5 amp build?

 

[pdhanwada]

Anilva,

Good. We are waiting for the good news. I know it has been rough few weeks for you. But in the end, good news comes everything is forgotten.


Please put back a list of things which we (newcomers) need to make sure or which we need to do during the course of the build.

Thanks
Pandu

 

[anilva]

Today night I completed the build of F5 Turbo V2. Both the channels are working perfectly and stable. Detailed listening tests to be done. First impressions are that it has the characteristic Pass amp sound. Very clean and detailed.

One of the channels was giving me a problem earlier and I had to wire up a new PCB and kit to overcome the problem related to few faults in that channel. Now both the channels are working well.

Will post detailed pictures soon.

Cheers.

The amp sounds more dynamic and stronger in bass than a standard F5, which is a terrific amp as it is. The sound signature is clearly a F5. The turbo amp is definitely a keep.

Thanks to Om and Sachin for making this GB possible. It is an awesome effort. Couple of observations: The 10000 uF caps are not sufficient if you want to drive V2 to full spec. It got to be alteast 15000 uF or 22000 uF better. The heatsink better be big and capable of sinking this huge heat. I have seen few people who have not built a F5 or seen one, comment about exaggerated claims on heatsink requirement. They are in a denial mode! This is my 5th Pass amp build and this is not an exaggeration at all.

Don't worry too much on grounding. It needs to be kept straightforward and simple. No loops. All points should terminate near the power supply '0V'.

Here are the pictures:

 

[sachu888]

15000 UF caps arived

I have received 15000 Uf CDE caps today.I request members to transfer their share to my bank account.I already paid interest on credit card.

I will start shipping kits in two days.

 

[captrajesh]

What kroyin suggested is temperature protection. But it does not guarantee the speaker protection because of DC. I just checked out diyaudio for speaker protection boards. It is going to turn out to be another F5 project to create the protection boards.

there are 2 ways an output device like mosfet can fail (this will pass deadly DC to blow up your spks)

--Sudden current surge which mitigated by diodes & thermistors
---Heat which can be mitigated by the thermostatic switch

If you want complete peace then you can have spk protection circuit in between the amps output and the spks input but IMHO its an overkill

I will be using this speaker protection for my Le Monstre build:

Speaker Protection Module

Thanks for your advices guys, they are very helpful. Will the readymade module suggested by Bininmb work out here? Will it affect the SQ in any adverse way? Sorry for the noob questions.

Connected everything and tested with light bulb. Every thing OK.

Which are the things that are tested with the light bulb?

Removed the light bulb and powered on. NTC Thermistor burst into pieces due to heavy current (required at the time of charging those massive caps initially). Changed to a heavy duty thermistor and powered on.

Om and Sachin, do we have the NTCs in the supplied kits? If yes, are they heavy duty?

I request members to transfer their share to my bank account.I already paid interest on credit card.

You better PM them, call them, SMS them and mail them as well.

 

[omishra]

Which are the things that are tested with the light bulb?

Using 100W filament bulb in series of main live wire of toroidal transformer you can test
1) standalone power supply
and
2) zero current biased amp connected to PS
Bulb should flash for a moment and go off. It should not be glowing constantly. If it glows continuously then it indicates some short circuit in PS and more current through PS without any configuration.

Om and Sachin, do we have the NTCs in the supplied kits? If yes, are they heavy duty?

Yes they are replaced already. I am sending 1 heavy duty NTC and 2 normal NTC to everybody including anilva.