| ronenash |
Hi,
After many year of service, I am upgrading my Beard P100 power amp. I will be installing ClarityCap SA series 0.1uF bypass capacitors on the power suply of both channels and will be replacing the DC coupling caps between the tube amplification stages to ClarityCap SA series caps. One issue I have is that the capacitors between the first and second amplification stage is 0.022uF. I could not find a ClarityCap SA of the same value. Can I replace the 0.022uF caps with 0.1uF caps instead. What would be the effect of such a change?
Are there any other changes you would recomend?
thanks
Ronen |
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| poynton |
Hi.
Do you have a circuit for the P100 ?
I bought mine some years ago, second-hand from a local Hifi shop.
A bargain !! I replaced 1 KT88 to get it going .
Like yours, it is probably in need of some TLC.
Andy |
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| poynton |
| quote: | Originally posted by ronenash
Hi,
After many year of service, I am upgrading my Beard P100 power amp. I will be installing ClarityCap SA series 0.1uF bypass capacitors on the power suply of both channels and will be replacing the DC coupling caps between the tube amplification stages to ClarityCap SA series caps. One issue I have is that the capacitors between the first and second amplification stage is 0.022uF. I could not find a ClarityCap SA of the same value. Can I replace the 0.022uF caps with 0.1uF caps instead. What would be the effect of such a change?
Are there any other changes you would recomend?
thanks
Ronen |
With regard to bypass capacitors, there is a current thread on the forum with opinion divided as to whether this is a good thing. My advice would be 'Try it and see if it changes things for the better!'
Changing the values of the caps from 0.022 to 0.1uF will alter the LF rolloff point but will do no harm.
Ideally, you should check and replace all components that are outside the original spec. or are showing signs of aging.
Andy |
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| craigius |
Hello I have recently purchsed a Beard P100 power amplifier, does anyone know the correct valve order. Looking from the front (beard P100 logo infront of you) to back of the amplifier I have e82cc on the left and right sides. Then I have e81cc on the left and e83cc on the right in the second row, and on the third row I have e83cc on the left and e81cc on the right? then the Kt88 after. Does anyone know which is the correct order. Below is the order of my valves at the moment
KT88 KT88
KT88 KT88
e83cc e81cc
e81cc e83cc
e82cc e82cc
If anyone has a manual or ideally schematic could they send it to me please.
Also does anyone know what the two variable resistors are for on the inside of the amplifier by 33uF capacitor and the preamp valves on the PCB are for, and what upgrades would you recommend. |
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| traf |
Craig
Did you ever receive the schematic I emailed you? If not get back in touch.
The two VRs balance the current flowing on each side of the push/pull circuit. Simply adjust such that there is 0V across it.
From a now ex- Beard P100, P101, P505 and CA506 owner :(
Simon |
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| poynton |
| quote: | Originally posted by traf
Craig
Did you ever receive the schematic I emailed you? If not get back in touch.
The two VRs balance the current flowing on each side of the push/pull circuit. Simply adjust such that there is 0V across it.
From a now ex- Beard P100, P101, P505 and CA506 owner :(
Simon |
Simon,
Please could you mail me a copy of the schematic.
I did request a copy from RONENASH but never received it.
Andy |
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| traf |
Can't email being a lowly newbie :(
But I can hopefully attach the files ;)
Part 1: |
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| traf |
Part 2:
Note there is an error in the V3 stage. If noone spots it I can elaborate but it should be fairly obvious. |
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| ethermion |
| Valve V3B is on holiday. |
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| cocosal |
Hello, I´m owner Beard P505 MKII preamplifier. I need replace the tubes. Are you the schematic of this preamp? Types of nine valves?
sorry but my english is poor
Thanks
Ruben |
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| traf |
| quote: | Originally posted by cocosal
Hello, I´m owner Beard P505 MKII preamplifier. I need replace the tubes. Are you the schematic of this preamp? Types of nine valves?
sorry but my english is poor
Thanks
Ruben |
Ruben
I don't have a schematic for my old P505mk2 but do remember the valve layout being
Left Centre Right
Back ECC82 ECC83 ECC83
Middle CV4085 ECC83* ECC83*
Front CV4085 ECC83 ECC83
* The middle ECC83s can be replaced by ECC81 for slightly lower gain.
The 2 CV4085s can of course be replaced by EF86s |
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| cocosal |
Traf,
Thanks for this important information for me.
You recomend the replace for midle ecc83 to ecc81?
I'm a "valve beginner"....
The original GEC/Mullard/Brimar (I'm not sure) is very, very rare and expensive....what your opinion brand of replacement?
Electro-Harmonix?
Very, very thanks for your help....
Best regards,
Ruben from Uruguay (a nice little country-Latin América) |
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| traf |
Ruben
Personally, I'm a big fan of JAN GE 5751s as a substitute for ECC83s and these can be picked up pretty cheaply on ebay. They have slightly lower gain than the ECC83, but this should only be a problem if you have a particularly low output MC cartridge. Otherwise, out of current production the EH is fine.
Substituting the middle ECC83 for ECC81 only reduces the overall gain slightly - I never noticed a particular change in tone. Mullard CV4024s (milspec ECC81s) are still reasonably cheap so this makes better sense than spending $$$ on another pair of Mullard ECC83s or CV4004s!
If you need any GEC CV4085s and Mullard CV4024s (or indeed have trouble finding some 5751s) I have a few NOS which I never got around to using in the P505. pm me if you need any ;)
cheers
simon |
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| vdub8 |
traf you said you had a beard p505 im needing some help please new valves problems switching on left channel power supply suspect would love to upgrade valves in machine are
rca usa 5751 5 off
mullard ecc81 12at7 2 off
gec cv4085 kb/2^7124 2 off
any help or info would be great thanks for your time or anybody |
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| traf |
hi vdub
I had a Mk2 which is a bit different to the Mk1 (the Mk1 had a iflter switch on the far right - the Mk2 had a mon switch, and I suspect the internal circuitry is slightly different.
I'm slightly puzzled by the valves you have fitted - in particular the 5x5751s. I was expecting to see and ECC82 or CV4003 in there somewhere (back left corner looking from the front?), assuming the Mk1 has an output buffer stage after the CV4085s like the Mk2.
If you do suspect any of the valves may be duff, its worth swopping left/right pairs around to see when the problem switches channel. This should identify the culprit pretty quickly.
I would also drop Chris Found an email via www.beardaudio.com
He used to work for Bill Beard and should be able to tell you the exact valve configuration for the Mk1.
(if you need some new mullard CV4004 and CV4003 you know who to ask...:) )
simon |
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| vdub8 |
also having a problem when switching on the pre amp it trips out the power amplifers (meridian 605 monos) so i have to switch the pre on first the the power amplifers any ideas again would help ??? on fixing is it something that can be fixed cheers for your help and time
jim |
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