I have a collection of tube and solid state gear that I would like to restore. The first of which will be a tube mono integrated hi-fi amp.
The caps for this particular amp are:
40mfd 400v
30mfd 350v
10mfd 300v
20mfd 25v
10mfd 250v
100mfd 15v
doing a quick search at Mouser, Newark, Allied and Antique Electronic supply, it seems like I will need to use more than one supplier to get everything I need.
I will be doing many more amps so I am looking for advice to streamline the ordering process, any suggestions will be appreciated.
The caps for this particular amp are:
40mfd 400v
30mfd 350v
10mfd 300v
20mfd 25v
10mfd 250v
100mfd 15v
doing a quick search at Mouser, Newark, Allied and Antique Electronic supply, it seems like I will need to use more than one supplier to get everything I need.
I will be doing many more amps so I am looking for advice to streamline the ordering process, any suggestions will be appreciated.
I order the majority of my supplies from DigiKey.
You can sub some of the parts for higher voltage or capacitance ratings and buy less parts at times- or go to the next value up if the one you want isn't available at your vendor.
Need 40uF? order a 47uF. 20? order a 22. Etc. I'm also of the habit of using the same high voltage rating throughout the circuit for parctically anything other than the low volt stuff like cathode bypass, etc. As amplifiers warm up and aren't loaded yet voltages can be higher than specified, so using all 400 volt caps if the max unloaded b+ is 375 would be a good idea.
You can sub some of the parts for higher voltage or capacitance ratings and buy less parts at times- or go to the next value up if the one you want isn't available at your vendor.
Need 40uF? order a 47uF. 20? order a 22. Etc. I'm also of the habit of using the same high voltage rating throughout the circuit for parctically anything other than the low volt stuff like cathode bypass, etc. As amplifiers warm up and aren't loaded yet voltages can be higher than specified, so using all 400 volt caps if the max unloaded b+ is 375 would be a good idea.
+1 for rounding off to standard values. E3, i.e., 10, 22 ,47, 100 are common values. You may get lucky and find 33 uF as well. If not, and you absolutely need 33 uF, you can make one using a 10 uF and a 22 uF in parallel. Ok, so that's 32 uF, but electrolytic caps tend to have large tolerances. The caps of yesteryear were often +20/-50% tolerance.
Also, there's no harm in using a cap rated for higher voltage. 400-450 V caps are common as those are often used in switching power supplies.
22 uF and 100 uF 25-35 V should be trivial to find.
Tom
Also, there's no harm in using a cap rated for higher voltage. 400-450 V caps are common as those are often used in switching power supplies.
22 uF and 100 uF 25-35 V should be trivial to find.
Tom
thank you for all of the suggestions.
I have two of these mono integrated amps. The previous owner had one restored but left the other as-is. I would like to restore the second one to match.
Here's the schematic and some photos:
View attachment grommes 55pg schematic.pdf
Unrestored Amp:
Restored Amp:
I have two of these mono integrated amps. The previous owner had one restored but left the other as-is. I would like to restore the second one to match.
Here's the schematic and some photos:
View attachment grommes 55pg schematic.pdf
Unrestored Amp:
Restored Amp:
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In the restored amp, the can cap was bypassed with individual caps. I'm guessing they are electrolytics. Are the yellow caps film? None of the caps have any markings indicating the manufacturers.
If you want to keep the original look Hayseed Hamfest has restuffed original looking cans with modern 105* caps. Looks like you might be waiting a while though. Hayseed Hamfest | Life's Too Short for Restuffing Can Capacitors. – Hayseed Hamfest LLC
Also Authenticaps have the same construction in most cases
Also Authenticaps have the same construction in most cases
Digi-Key actually has a free shipping option that's always available. This can save quite a bit, especially on small orders where the cost of shipping is often higher than the cost of the parts. Details here:
Free Shipping On Parts Orders | Audiokarma Home Audio Stereo Discussion Forums
Consider LCSC too. You'll have to pay for shipping, but the prices make up for it and the quality is good if you spec out the right parts.
For instance, here's a 47V 400V 12000H 105C Rubycon for 90 cents. Rubycon|Rubycon 400BXC47MEFC16X25|Aluminum Electrolytic Capacitors - Leaded|LCSC
Digi-key wants 3.26$ for the same capacitor.
For instance, here's a 47V 400V 12000H 105C Rubycon for 90 cents. Rubycon|Rubycon 400BXC47MEFC16X25|Aluminum Electrolytic Capacitors - Leaded|LCSC
Digi-key wants 3.26$ for the same capacitor.
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Digikey says that there is no weight limit on the free shipping option.
Their choice of method, within USA only. You still pay any state sales tax due.
Thanks for the link. Their Magnovox can cap is an exact match for my Grommes...
Magnavox 40-30-10-20 uF Can Capacitor – Hayseed Hamfest LLC
I don't have much confidence that any part distributed by a Chinese company is not counterfeit. It's such a widespread problem that I'm not willing to take the chance.
The huge price difference ($.73 vs $2.36 usd for the cap linked) makes me even more suspicious since all large distributors presumably purchase parts directly from the various manufacturers and buy such large quantities that differences in shipping costs should not result is such a wide disparity in price.
They only order from manufacturers and authorised suppliers and are certified as such. Also they look and test the same. Digi-key has higher profit margins and includes shipping. Of course LCSC is cheaper!
All the factories are in China - Why wouldn't it be cheaper for a Chinese supplier to get them? Shipping from the manufacturer is almost free.
In any case, that's just my experience. You can google to find plenty of other people who say they are legit. If you don't feel comfortable with they, pay more from a US supplier
All the factories are in China - Why wouldn't it be cheaper for a Chinese supplier to get them? Shipping from the manufacturer is almost free.
In any case, that's just my experience. You can google to find plenty of other people who say they are legit. If you don't feel comfortable with they, pay more from a US supplier
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Hayseed makes an excellent product, they stuff them with high quality individual caps. If you don't have room to put individual caps underneath, Hayseed is the way to go.
OTOH, those same caps, using modern values (47uf, 33uf, 10uf, 22uf) can be found at DigiKey for $5.43 with free shipping.
Some say it's worth paying ~8x more (including shipping) for the convenience of simply replacing the can. In most cases, I find it's actually more convenient to mount them underneath because the original cans are typically soldered to the chassis in a few spots and it takes a serious iron to get them out.
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