Hi MarkVariac said:
Now Ricardo we DID ask you to cut your siglines down to three line maximum, as that is the policy here.
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
it could be a slotted grub screw, or a cross head grub screw, or a hex headed (allen key) grub screw.RCruz said: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 ?
AndrewT said:it could be a slotted grub screw, or a cross head grub screw, or a hex headed (allen key) grub screw.
I imagine that is possible but the size is so small (less than 1.5 mm), that I can not find any suitable wrench.
AndrewT said: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 believe these must be 1.4mm
Thank you so much for the tip.
My system is sound awefull now.
Hi GordyGordy said:Your pre-amp...
1) raises 120mV to 775mV and hence has a gain of x 6.5 . (Note that 775mV is a standard reference level in the professional audio industry, and hence this is why the Meridian is specified reference this level).
2) has a maximum output of +20dBm which is (if I recall accurately) 7.75 V across 600 Ohms.
The Rotel RB 06 and Audiolab 8000P require about 1 V for full output, so you should have no problem with driving them from your pre-amp.
Both of these amps seem to work well at their price points.
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
AndrewT said: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.
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:
Then arrange for either a 0dB buffer or +xdB discrete gain stage to fit the opamp pins.
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
Your pre-amp...
1) raises 120mV to 775mV and hence has a gain of x 6.5 . (Note that 775mV is a standard reference level in the professional audio industry, and hence this is why the Meridian is specified reference this level).
2) has a maximum output of +20dBm which is (if I recall accurately) 7.75 V across 600 Ohms.
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?)
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 ?
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
- Home
- Amplifiers
- Solid State
- Meridian 101 pre amp needs new power amp