Replica Pre QUAD 22 - Questions on mids

Scabiko · 27th January 2006, 12:48 PM

Hi,

I just replicated a simplified circuit of preamp 22 of Quad, added a PSU and used on the audio signal path caps of 4.4uf (instead of only 2.2 uf) and of 0.47 uf. The pre seems to lack of mids. Modifiying the value of 0.47 uf to a lesser value would increase mid presentation? the 2.2uf cap, has any effect on mids? are there any other mods or changes to improve mid´s definition?
Thank you for your time and consideration. Sebastian

nafunga · 27th January 2006, 01:03 PM

Hi,
Are you sure you'r talking about the Quad 22? Coupling caps are around 0.1uf or less on this model, not 2.2uf or 4.7uf.. Is this a transistor amp? I've done quite a bit of work on 22's over the years so am reasonably familiar with the circuitry.

Kind regards,

David..

Scabiko · 27th January 2006, 01:28 PM

Thanks for your reply. I am trying to transmit to you what the tecnitian who made it for me told me. Unfortunately, he does not speak English. I will reconfirm with him and get back. I can tell you that on signal path I have 0.47 evox rifa caps (metallized polypropilene) and the cap of 4.4uf was put instead to the electrolityc cap of 25 uf included in the original plan. I really don´t know the importance of the 25 uf cap on the signal.

Please note that we did not put tone controls and from the 0.47 uf signal cap goes straight to the output (passing through certain resistors). We omitted a cap of 0.5 uf that goes before the tone controls on the original plan.

Best ragdrs, Sebastian

27th January 2006, 12:48 PM	#1
Scabiko diyAudio Member Join Date: Jul 2005 Location: City of Buenos Aires	Replica Pre QUAD 22 - Questions on mids Hi, I just replicated a simplified circuit of preamp 22 of Quad, added a PSU and used on the audio signal path caps of 4.4uf (instead of only 2.2 uf) and of 0.47 uf. The pre seems to lack of mids. Modifiying the value of 0.47 uf to a lesser value would increase mid presentation? the 2.2uf cap, has any effect on mids? are there any other mods or changes to improve mid´s definition? Thank you for your time and consideration. Sebastian

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27th January 2006, 01:03 PM	#2
nafunga diyAudio Member Join Date: Jul 2005 Location: Whitstable , Kent. UK	Hi, Are you sure you'r talking about the Quad 22? Coupling caps are around 0.1uf or less on this model, not 2.2uf or 4.7uf.. Is this a transistor amp? I've done quite a bit of work on 22's over the years so am reasonably familiar with the circuitry. Kind regards, David..

27th January 2006, 01:28 PM	#3
Scabiko diyAudio Member Join Date: Jul 2005 Location: City of Buenos Aires	Thanks for your reply. I am trying to transmit to you what the tecnitian who made it for me told me. Unfortunately, he does not speak English. I will reconfirm with him and get back. I can tell you that on signal path I have 0.47 evox rifa caps (metallized polypropilene) and the cap of 4.4uf was put instead to the electrolityc cap of 25 uf included in the original plan. I really don´t know the importance of the 25 uf cap on the signal. Please note that we did not put tone controls and from the 0.47 uf signal cap goes straight to the output (passing through certain resistors). We omitted a cap of 0.5 uf that goes before the tone controls on the original plan. Best ragdrs, Sebastian