Hi MarkVariac said:
I did not get scared with Andrewá comments.... I am always willing to learn more... It makes sence that replacing psu caps can not alter freq response....😉
Now I do not want to break any rules here so could you explain what you mean by posting only three lines ?
Regards
Ricardo
I think he means your signature lines underneath your posts.
ps: I'm still working on that board layout, adding shunt reg.
Cheers, Lee.
ps: I'm still working on that board layout, adding shunt reg.
Cheers, Lee.
Thank you Lee
I will amend that right away.😉
Can you help me with the volume knob on the 101 ?
I see a small screw like hole in each knob (volume/balance) but can not find any wrench to suit... maybe it is not a screw ?
Ricardo
I will amend that right away.😉
Can you help me with the volume knob on the 101 ?
I see a small screw like hole in each knob (volume/balance) but can not find any wrench to suit... maybe it is not a screw ?
Ricardo
it could be a slotted grub screw, or a cross head grub screw, or a hex headed (allen key) grub screw.RCruz said:
AndrewT said:
I imagine that is possible but the size is so small (less than 1.5 mm), that I can not find any suitable wrench.
both 1.5mm and 1.6mm hex keys are available.
I have seen and used smaller but at these small sizes the keys must be good quality else you risk rounding the key and damaging the grub screw.
UNBRAKO are good.
I have seen and used smaller but at these small sizes the keys must be good quality else you risk rounding the key and damaging the grub screw.
UNBRAKO are good.
AndrewT said:
I believe these must be 1.4mm
Thank you so much for the tip.
My system is sound awefull now.
Hi Ricardo.
It is a tiny Allen key grub screw.
Are you positive you need to remove it? I don't remember doing so before. I won't get chance to have a proper look til tomorrow night though.
Lee.
It is a tiny Allen key grub screw.
Are you positive you need to remove it? I don't remember doing so before. I won't get chance to have a proper look til tomorrow night though.
Lee.
Hi GordyGordy said:
Following the general ideas from this thread I decided to upgrade the Meridian instead of replacing the power amp.
I already recaped the 103 psu, made a dedicated direct Mains cord and started to mod the 101b pre.
In this case I replaced the regulators and rectifier by a 317/337 / hexfred setup and recaped the psu.
In the output module, I have replaced the stock opamp by a LM4562.
Now I would like to replace this opamp by a buffer stage. (Pedja...)
As I am a bit confused about the idea (a buffer should be used to couple between different impedances)
My big question is:
Do I need a gain of x 6.5 on this buffer ?
Regards
Ricardo
Attachments
you should be able to decipher the resistors on the input & output pins to determine the gain currently set up through the opamp.
Then arrange for either a 0dB buffer or +xdB discrete gain stage to fit the opamp pins.
Then arrange for either a 0dB buffer or +xdB discrete gain stage to fit the opamp pins.
AndrewT said:
Hi Andrew
So you mean I can replace the LM4562 by a pedja buffer (o gain) once I figure the pin layout ?
Well I know this opamp is arranged to have x6.5 gain.AndrewT said:
I could replace it by a better opamp (like the new metal can available) but I know that a discrete design is much better, particularly if it is built with jfets and no feedback.
So I decided to build a pedja but I am afraid this kind of buffer is a pure voltage follower (0 gain).
Can the pedja be modified to have some gain ?
Regards
Ricardo
Hi Ricardo. Are you sure you need any gain in the pre?
I built a Pedja buffer and I still have more than enough for loud volumes.
Cheers, Lee.
I built a Pedja buffer and I still have more than enough for loud volumes.
Cheers, Lee.
Hi Lee
With my present RIAA, I need this gain, otherwise the sound would be too low.
With the CDP, I really have too much gain so maybe I could do with the buffer.
How does the output from Salas RIAA compare to the CDP on your setup ?
Ricardo
With my present RIAA, I need this gain, otherwise the sound would be too low.
With the CDP, I really have too much gain so maybe I could do with the buffer.
How does the output from Salas RIAA compare to the CDP on your setup ?
Ricardo
The Salas RIAA has around the same output as my cdp. I haven't measured it, but it's plenty loud enough.
Lee.
Lee.
Hi Gordy
It may seem strange to get back here, but I understand you have acces to Meridian info.
I replaced the 101 pre by a buffer (DCB1) with great results.
Now I would like to know how to determine the Meridian 103 power amp gain based on it´s specs:
Output: 35W/ch in 8ohm
input: odBm (775mV) over 10k for 35W (Does it mean the input impedance is 10k?)
Now I want to replace the Meridian 103 PSU but I do not know what are the specifications of the toroid... anyone ?
After a long search for suitable transformers I found the FEAS 26V 250VA.
Due to sme T$me constraints I could only buy two and as these have single 26v secondaries, I could not implement a true double mono setup, so I used them in series to feed dual rectifiers as in the schematic.
Due to sme T$me constraints I could only buy two and as these have single 26v secondaries, I could not implement a true double mono setup, so I used them in series to feed dual rectifiers as in the schematic.
Attachments
So far so good.... sound is much more open and detailed with the new setup.... but I am having trouble at power on. My house has an old electrical instalation that can not withstand too much inrush current.
Every time I power the new psu and have other appliances running, the mainsboard fuses trigger.
How can I limit inrush current during power on ?
Every time I power the new psu and have other appliances running, the mainsboard fuses trigger.
How can I limit inrush current during power on ?
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