They're neither 'small' nor 'glass'!
They're ceramic, industrial, high voltage (600V) High Breaking Capacity (10,000A) fuses.
Search found 46 matches
- Tue Mar 26, 2024 3:18 am
- Forum: Amplifiers
- Topic: MV-55 output issues
- Replies: 14
- Views: 3586
- Mon Mar 25, 2024 3:06 pm
- Forum: Amplifiers
- Topic: MV-55 output issues
- Replies: 14
- Views: 3586
Re: MV-55 output issues
The MV-55 was specified with Bussmann BBS-3/4 (i.e. 750mA fast blow).
An alternative is the Littelfuse BLS.750 - same rating and behaviour.
They're both 0.406" dia. by 1.375" long.
An alternative is the Littelfuse BLS.750 - same rating and behaviour.
They're both 0.406" dia. by 1.375" long.
- Mon Mar 18, 2024 8:33 am
- Forum: Amplifiers
- Topic: Cap Upgrade: DIY
- Replies: 14
- Views: 2784
Re: Cap Upgrade: DIY
Looking at the Prem 12 schematic, my immediate choices for caps to upgrade would be: 1. The 0µ15 600V in each grid of the 6550s 2. The 1µ 400V with 0µ15 400V bypass in the 6FQ7 grids to ground These are arguably the 'most' audible. I would suggest Solen FEP (Tin/PTFE). In my MV-55 I did the No.1 cap...
- Tue Mar 12, 2024 3:27 pm
- Forum: Preamps
- Topic: Tubes for PV10al
- Replies: 5
- Views: 118
Re: Tubes for PV10al
Agree fully re matching, and note that this means both sections as well as both tubes. Remember you have no balance control... I've had my PV-10AL for 20 years and it remains a fine-sounding preamp. The only 'bad' tubes have been brand new chinese tubes - I've had several failures, poor performers, ...
- Wed Feb 14, 2024 7:41 am
- Forum: Preamps
- Topic: PV-12 help needed
- Replies: 17
- Views: 1878
Re: PV-12 help needed
Subjectively: those resistors are life-expired. Replace. Objectively: you've done well measuring the temps. Assuming correct, the burnt pair (which you've confirmed are approximately the same value to the lesser damaged ones) are some 7˚C hotter, which assuming an ambient of about 20˚C is about 20% ...
- Sat Feb 10, 2024 11:15 am
- Forum: CJO Feedback, Suggestions and Report Site Problems
- Topic: Cannot find member details
- Replies: 4
- Views: 243
Re: Cannot find member details
Very odd. I am now able to, after temporarily pausing, then re-enabling, my VPN connection.
I wonder if the original VPN connection was possibly showing up as a 'blacklisted' one?
Anyway, sorry for the excursion, clearly an issue at my end.
I wonder if the original VPN connection was possibly showing up as a 'blacklisted' one?
Anyway, sorry for the excursion, clearly an issue at my end.
- Fri Feb 09, 2024 2:30 pm
- Forum: CJO Feedback, Suggestions and Report Site Problems
- Topic: Cannot find member details
- Replies: 4
- Views: 243
Cannot find member details
If I click on a member name, I get routed to an error page.
"Not Acceptable
An appropriate representation of the requested resource /memberlist.php could not be found on this server."
"Not Acceptable
An appropriate representation of the requested resource /memberlist.php could not be found on this server."
- Fri Feb 09, 2024 2:22 pm
- Forum: Amplifiers
- Topic: MV-55 - most significant improvement yet
- Replies: 2
- Views: 127
MV-55 - most significant improvement yet
My MV-55 sprang a hum, which was traced to a failed heater rectifier, or possibly a dry joint on one due to the heat. I took the opportunity to do some replacements and upgrades: 1. Replaced heater rectifiers with Vishay SBYV28-100-E3/54 which are faster and softer recovery, plus lower dissipation -...
- Fri Feb 09, 2024 7:29 am
- Forum: General Discussion - CJ related topics
- Topic: MV-55 anyone with experience of this?
- Replies: 5
- Views: 4147
Re: MV-55 anyone with experience of this?
Let me post a separate thread on that.
- Fri Feb 09, 2024 4:05 am
- Forum: General Discussion - CJ related topics
- Topic: MV-55 anyone with experience of this?
- Replies: 5
- Views: 4147
Re: MV-55 anyone with experience of this?
(Sorry - bit late to this conversation but only just spotted it). Having owned a MV-55 for nearly 30 years I can attest to it being a very sweet performer, and so much so that this month I chose to perform a few minor upgrades to assure its future. in terms of what I have observed, accepting I am bu...
- Thu Feb 08, 2024 7:22 am
- Forum: Preamps
- Topic: PV-10B - the 'zener board' - was this ever reverse engineered?
- Replies: 0
- Views: 166
PV-10B - the 'zener board' - was this ever reverse engineered?
Anyone?
I'd be really interested to learn of the circuitry, purpose and any other details.
I'd be really interested to learn of the circuitry, purpose and any other details.
- Sun Feb 04, 2024 5:22 pm
- Forum: DIY, mods, tweaks
- Topic: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
- Replies: 14
- Views: 1297
Re: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
I buy only best quality caps for all HV and instrumentation work and they are randomly labelled - they tumble down the production line and the print ends up where it ends up. These days, with semiconductor circuits a bit less susceptible to pickup due to lower impedance maybe, a general lack of AC r...
- Sun Feb 04, 2024 4:01 pm
- Forum: DIY, mods, tweaks
- Topic: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
- Replies: 14
- Views: 1297
Re: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
Yes, you may well be right.
It does emphasise that as modders we need to get this right when we install them, else large sums of money may well end up making the equipment far worse.
It does emphasise that as modders we need to get this right when we install them, else large sums of money may well end up making the equipment far worse.
- Sun Feb 04, 2024 3:38 pm
- Forum: DIY, mods, tweaks
- Topic: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
- Replies: 14
- Views: 1297
Re: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
The lesser Solen PPE FC polypropylene range do not purport to be marked for polarity, and my experience is that they are truly random. The vastly expensive FEP Tin/Teflon ones were stated on my supplier's website as: "S3Q series have the outer foil on the right of the marking. The Outer foil en...
- Sun Feb 04, 2024 12:16 pm
- Forum: DIY, mods, tweaks
- Topic: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
- Replies: 14
- Views: 1297
Re: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
No contact required: (a) as I get close to the cap you see noise increase, and (b) it's insulated!
It's a metal can which acts as an aerial. Although harder to see you may be able to spot that the residual noise level is higher with the 'backwards' cap.
It's a metal can which acts as an aerial. Although harder to see you may be able to spot that the residual noise level is higher with the 'backwards' cap.
- Sun Feb 04, 2024 9:46 am
- Forum: DIY, mods, tweaks
- Topic: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
- Replies: 14
- Views: 1297
Re: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
I thought this practical test might be informative, and hopefully persuasive for anyone who considers orientation unimportant. I have knocked together a simple 12AU7 two-stage cathode-follower amplifier with about 20dB of gain, running at 200V plate. First video shows the input capacitor (which coup...
- Sat Feb 03, 2024 2:08 pm
- Forum: DIY, mods, tweaks
- Topic: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
- Replies: 14
- Views: 1297
Re: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
An alternative is with your 'scope.
See with red end to the 'scope sense connection (red croc clip) we have outer foil 'exposed' and it picks up the 50Hz in my case.
With red end to black croc clip ('scope gnd) we are now 'shielding' the red input and it picks up almost nothing.
See with red end to the 'scope sense connection (red croc clip) we have outer foil 'exposed' and it picks up the 50Hz in my case.
With red end to black croc clip ('scope gnd) we are now 'shielding' the red input and it picks up almost nothing.
- Sat Feb 03, 2024 2:04 pm
- Forum: DIY, mods, tweaks
- Topic: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
- Replies: 14
- Views: 1297
Re: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
I use a bespoke foil side tester - proprietary design to Mr. Carlson's Lab on Patreon. This unit is a very sensitive amplifier with a front end that electronically switches the two capacitor connections between input and gnd in the sensing amplifier. LED bar graph indicates the received 'noise' whic...
- Sat Feb 03, 2024 10:20 am
- Forum: DIY, mods, tweaks
- Topic: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
- Replies: 14
- Views: 1297
Re: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
It is not about the 'polarity' of the capacitor - it is about its behaviour as an aerial. Nearly all film (or foil) caps are essentially a rolled up number of alternate sheets of dielectric and metal foil, or a metallised dielectric. The foil or metallised layers are the 'plates' of the cap. The lea...
- Sat Feb 03, 2024 9:05 am
- Forum: DIY, mods, tweaks
- Topic: WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
- Replies: 14
- Views: 1297
WARNING: incorrectly labelled, but EXPENSIVE, V-Cap and Solen PTFE capacitors
I have just replaced the output tube grid signal caps, and the ground return caps in each channel in my MV-55, with Solen FPE (Tin/PTFE) and V-Cap ODAM respectively. I do a lot of valve equipment restoration and test every film cap before installation as I am used to minimising noise in high-impedan...