Fidelity Record Player. Model ID? - UK Vintage Radio Repair and Restoration Discussion Forum

Station X · 16th Jul 2018, 9:52 pm

Does anyone know the model ID of this Fidelity Record Player. I'm aware that it's featured in the forums before. I'm guessing HF...something.

The transistorized amplifier (no audio IC) appears to have had some work done on it. The non-heat sinked transistor has something similar to

M06B
851
IBC

written on it.

Any ideas welcomed. A circuit is probably too much to hope for and I'll have to reverse engineer it.

Thanks.

Station X · 16th Jul 2018, 9:53 pm

More pictures.

AndiiT · 16th Jul 2018, 10:02 pm

Hi, I would say that it's the transistorised version of the HF35.
As you have already indicated there isn't a great deal of information available around for the Fidelity "Solid State" models of this type which use discrete transistor circuitry.
Reverse engineering the circuit may be the only way to go although it should be a relatively simple circuit

Regards
Andrew

AndiiT · 16th Jul 2018, 10:05 pm

Hi again, I've also just noticed a seperate mains transformer. It's possible that this may have been "retrofitted" as most of these players used a 24 volt winding on the autochanger motor to provide the AC feed for the bridge rectifier.

Andrew

ms660 · 16th Jul 2018, 10:15 pm

Amplifier circuit....similar?:

https://www.vintage-radio.net/forum/...9&d=1326228731

EDIT: Another link added...?:

https://www.vintage-radio.net/forum/...d.php?t=108358

Lawrence.

Station X · 16th Jul 2018, 10:24 pm

Thanks Lawrence. I'll check the HT voltage.

Note the smoothing cap voltage. It may not be original though.

ben · 16th Jul 2018, 10:57 pm

Judging by the PCB and some of the components I would say this is quite an early transistorized effort - circa 1968-70 ? Transistor looks like a BD140 or something.

AJSmith625 · 16th Jul 2018, 11:38 pm

This amplifier, I think was Fidelity's first effort of a transistor record player amp after the usual UL84/UY85 valve arrangement. The first model I ever saw it in when I started in the trade in 1971 was the HF38, but it probably also covered a few other models. The most common problem was the MJE340 output transistor which ran quite hot as far as I can remember, and would cause crackling and popping sounds almost like instability after the set had been on for a few minutes. Application of freezer would prove the point.

Alan.

Edward Huggins · 17th Jul 2018, 11:04 am

At first glance you would think this was the prolific Fidelity HF35 UL84/UY85 valved version. This very early transistorised type (their first) used the same/very similar metal chassis.

Station X · 17th Jul 2018, 11:45 am

At first glance it does look like an HF35, but the lid details are different. The HF35 has a deep lid which doesn't reach of the front of the case, whereas this player has a shallow lid which does reach the front of the case.

HF35's certainly came in valve and IC versions, but did they ever use this "first attempt" transistor amplifier?

AJSmith625 · 17th Jul 2018, 2:23 pm

When I first saw this type of high voltage transistor amp by Fidelity when other record player makers were starting to use the more conventional low voltage type fed from a mains transformer or a low voltage overwind on the gram motor, I wondered why? Could it be that Fidelity had a glut of BSR turntables with the 90volt heater tap and this amp could run off this dispensing with the 110volt mains transformer, even though this still meant a live chassis like the valve model. I never saw such a set but it was just a thought that some could have been made this way. Also, could they have had a glut of 3 ohm speakers they needed to use up. All other transistorised amps were using 8 and 16 ohm speakers by then. Any ideas?

Alan.

julie_m · 17th Jul 2018, 2:55 pm

The amplifier could be this one..... No, I couldn't quite believe it at first sight, either!

Station X · 17th Jul 2018, 4:03 pm

Possibly Fidelity's earliest attempt at a transistor amplifier before they discovered the PCB?

If the player depicted there is an HF38 or HF39 it doesn't match the case of my own player.

The HF39 linked to by Lawrence in post #5 appears to be a better match case wise to my own player.

Station X · 17th Jul 2018, 8:31 pm

Reverse engineering the amplifier shows that the circuit is that linked to in post #5, with an HT of around 100 VDC. Minor differences are that my player has a tape socket and the smoothing caps in the can are 60uF and 150uF.

A quick functional test showed that the player works, but, not unexpectedly, the auto-change mechanism is seized. Needs to be stripped down and relubricated.

There are minor faults which are of no consequence to me, but would no doubt cause great distress to a record player newbie expecting HiFi performance:-

Mains hum audible between tracks.
Speed is a bit slow on 33 1/3 RPM. Other speeds not tried.
Turntable rumble.
Tone control not very effective.

Station X · 19th Jul 2018, 7:49 pm

It's good to have a circuit which is a close match to the actual player, but I'd still like to know whether it's an HF38, HF39 or some other model. Does anyone have either of these players with a model name plate or label attached.

I wonder if the HF38 and HF39 were Fidelity's first attempt at a transistor amplifier after which they revisited the HF35 fitting it first with a transistor amplifier and then with an IC amplifier?

16th Jul 2018, 9:52 pm	#1
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,286	Fidelity Record Player. Model ID? Does anyone know the model ID of this Fidelity Record Player. I'm aware that it's featured in the forums before. I'm guessing HF...something. The transistorized amplifier (no audio IC) appears to have had some work done on it. The non-heat sinked transistor has something similar to M06B 851 IBC written on it. Any ideas welcomed. A circuit is probably too much to hope for and I'll have to reverse engineer it. Thanks. Attached Thumbnails __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

16th Jul 2018, 9:53 pm	#2
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,286	Re: Fidelity Record Player. Model ID. More pictures. Attached Thumbnails __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

16th Jul 2018, 10:02 pm	#3
AndiiT Octode Join Date: Aug 2005 Location: Saltburn-East, Cleveland, UK. Posts: 1,786	Re: Fidelity Record Player. Model ID. Hi, I would say that it's the transistorised version of the HF35. As you have already indicated there isn't a great deal of information available around for the Fidelity "Solid State" models of this type which use discrete transistor circuitry. Reverse engineering the circuit may be the only way to go although it should be a relatively simple circuit Regards Andrew

16th Jul 2018, 10:05 pm	#4
AndiiT Octode Join Date: Aug 2005 Location: Saltburn-East, Cleveland, UK. Posts: 1,786	Re: Fidelity Record Player. Model ID. Hi again, I've also just noticed a seperate mains transformer. It's possible that this may have been "retrofitted" as most of these players used a 24 volt winding on the autochanger motor to provide the AC feed for the bridge rectifier. Andrew

16th Jul 2018, 10:24 pm	#6
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,286	Re: Fidelity Record Player. Model ID. Thanks Lawrence. I'll check the HT voltage. Note the smoothing cap voltage. It may not be original though. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

16th Jul 2018, 10:15 pm	#5
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Fidelity Record Player. Model ID. Amplifier circuit....similar?: https://www.vintage-radio.net/forum/...9&d=1326228731 EDIT: Another link added...?: https://www.vintage-radio.net/forum/...d.php?t=108358 Lawrence. Last edited by ms660; 16th Jul 2018 at 10:25 pm.

16th Jul 2018, 10:57 pm	#7
ben Dekatron Join Date: Aug 2006 Location: Madrid, Spain / Wirral, UK Posts: 7,498	Re: Fidelity Record Player. Model ID. Judging by the PCB and some of the components I would say this is quite an early transistorized effort - circa 1968-70 ? Transistor looks like a BD140 or something. __________________ Regards, Ben.

16th Jul 2018, 11:38 pm	#8
AJSmith625 Pentode Join Date: Nov 2017 Location: Birmingham, West Midlands, UK. Posts: 171	Re: Fidelity Record Player. Model ID. This amplifier, I think was Fidelity's first effort of a transistor record player amp after the usual UL84/UY85 valve arrangement. The first model I ever saw it in when I started in the trade in 1971 was the HF38, but it probably also covered a few other models. The most common problem was the MJE340 output transistor which ran quite hot as far as I can remember, and would cause crackling and popping sounds almost like instability after the set had been on for a few minutes. Application of freezer would prove the point. Alan.

17th Jul 2018, 11:04 am	#9
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,326	Re: Fidelity Record Player. Model ID. At first glance you would think this was the prolific Fidelity HF35 UL84/UY85 valved version. This very early transistorised type (their first) used the same/very similar metal chassis. __________________ Edward.

17th Jul 2018, 11:45 am	#10
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,286	Re: Fidelity Record Player. Model ID? At first glance it does look like an HF35, but the lid details are different. The HF35 has a deep lid which doesn't reach of the front of the case, whereas this player has a shallow lid which does reach the front of the case. HF35's certainly came in valve and IC versions, but did they ever use this "first attempt" transistor amplifier? __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

17th Jul 2018, 2:23 pm	#11
AJSmith625 Pentode Join Date: Nov 2017 Location: Birmingham, West Midlands, UK. Posts: 171	Re: Fidelity Record Player. Model ID? When I first saw this type of high voltage transistor amp by Fidelity when other record player makers were starting to use the more conventional low voltage type fed from a mains transformer or a low voltage overwind on the gram motor, I wondered why? Could it be that Fidelity had a glut of BSR turntables with the 90volt heater tap and this amp could run off this dispensing with the 110volt mains transformer, even though this still meant a live chassis like the valve model. I never saw such a set but it was just a thought that some could have been made this way. Also, could they have had a glut of 3 ohm speakers they needed to use up. All other transistorised amps were using 8 and 16 ohm speakers by then. Any ideas? Alan.

17th Jul 2018, 2:55 pm	#12
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Fidelity Record Player. Model ID? The amplifier could be this one..... No, I couldn't quite believe it at first sight, either! __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

17th Jul 2018, 4:03 pm	#13
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,286	Re: Fidelity Record Player. Model ID? Possibly Fidelity's earliest attempt at a transistor amplifier before they discovered the PCB? If the player depicted there is an HF38 or HF39 it doesn't match the case of my own player. The HF39 linked to by Lawrence in post #5 appears to be a better match case wise to my own player. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

17th Jul 2018, 8:31 pm	#14
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,286	Re: Fidelity Record Player. Model ID? Reverse engineering the amplifier shows that the circuit is that linked to in post #5, with an HT of around 100 VDC. Minor differences are that my player has a tape socket and the smoothing caps in the can are 60uF and 150uF. A quick functional test showed that the player works, but, not unexpectedly, the auto-change mechanism is seized. Needs to be stripped down and relubricated. There are minor faults which are of no consequence to me, but would no doubt cause great distress to a record player newbie expecting HiFi performance:- Mains hum audible between tracks. Speed is a bit slow on 33 1/3 RPM. Other speeds not tried. Turntable rumble. Tone control not very effective. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

19th Jul 2018, 7:49 pm	#15
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,286	Re: Fidelity Record Player. Model ID? It's good to have a circuit which is a close match to the actual player, but I'd still like to know whether it's an HF38, HF39 or some other model. Does anyone have either of these players with a model name plate or label attached. I wonder if the HF38 and HF39 were Fidelity's first attempt at a transistor amplifier after which they revisited the HF35 fitting it first with a transistor amplifier and then with an IC amplifier? __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.